Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2000-2004  (259)
  • 1995-1999  (8,465)
  • Biochemistry and Biotechnology  (5,292)
  • Analytical Chemistry and Spectroscopy  (2,388)
  • Magnetic resonance imaging  (1,043)
  • Nuclear reactions
Material
Years
Year
Keywords
  • 101
    ISSN: 1432-1920
    Keywords: Key words Hemimegalencephaly ; Positron emission tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report hemimegalencephaly in a 44-year-old woman with mental retardation, epilepsy and a mild hemiparesis. In addition to typical findings on MRI, 2-deoxy-2[18F]fluorodeoxyglucose positron-emission tomography (PET) demonstrated glucose hypometabolism of the affected hemisphere. The results of PET have been coregistered with morphological information from the MRI studies by image fusion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 102
    ISSN: 1432-1920
    Keywords: Key words Cerebral palsy ; Birth asphyxia ; Magnetic resonance imaging ; Single-photon emission computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We describe the findings on single-photon emission computed tomography (SPECT) in patients with perinatal asphyxia at term, with perirolandic cortico-subcortical changes on MRI, and to correlate them with clinical features. SPECT of 7 patients was obtained after injection of 185–370 MBq of Tc-99m-ECD (ethyl cysteinate dimer). The patients had spastic quadriplegia (7/7) with perinatal asphyxia (6/7) at term (7/7). The results were correlated with the MRI findings. Hypoperfusion of the perirolandic cortex was clearly seen on SPECT in all patients, even in two with subtle changes on MRI. SPECT demonstrated a more extensive area of involvement than MRI, notably in the cerebellum (in 4), the thalamus (in 7) and basal ganglia (in 5), where MRI failed to show any abnormalities.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 103
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 917-922 
    ISSN: 1432-1920
    Keywords: Key words Mouth, cysts ; Neck, cysts ; Glands, salivary ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We reviewed the MRI of 20 patients with a ranula (8 simple and 12 plunging) and ten with other cystic masses in the floor of the mouth and/ or suprahyoid portion of the neck (three haemangiomas, two neuromas, one monomorphic adenoma, one lipoma, two lateral cervical cysts and one dermoid cyst). Histological diagnoses were obtained in all cases with the exception of one presumed haemangioma. Ranulas were all well-defined, homogeneous masses giving low signal on T1-and markedly high signal on T2-weighted images. While simple ranulas were all confined to the sublingual space, plunging ranulas were centered on the submandibular space and tended to spill into one or more adjacent spaces. They extended into the sublingual space anteriorly (producung a so-called tail sign) in eight of 12 cases and into the parapharyngeal space superiorly in five. Although they sometimes filled a considerable part of the parapharyngeal space, displacement of surrounding muscles or vessels was usually slight, which was thought to reflect the nature of extravasation pseudocysts. All other cystic masses in our study had one or more MRI finding different from those of ranulas and could be easily differentiated from them.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 104
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 112-114 
    ISSN: 1432-1920
    Keywords: Key words Hypophosphataemia ; Brain ; Myelinolysis, extrapontine ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a 38-year-old woman with extreme hypophosphataemia in whom CT and MRI disclosed bilateral lesions within the basal ganglia, thalamus and occipital lobes. After adequate substitution of phosphate the lesions grossly resolved and the patient recovered. This case is the first to demonstrate that profound changes of serum phosphate may be associated with reversible brain lesions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 105
    ISSN: 1432-1920
    Keywords: Key words Carcinoma nasopharyngeal ; Radionecrosis ; Magnetic resonance imaging ; Pulse sequences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined nine patients with histologically proven nasopharyngeal carcinoma (NPC), treated with radiotherapy, using dynamic susceptibility contrast MRI (DSC-MRI). In eight there was clinical evidence of radionecrosis of the temporal lobe, and one was examined for local recurrence in the nasopharynx. All patients had either high-signal finger-like or cystic lesions in the temporal lobes on T2-weighted images. Heterogeneous contrast enhancement occurred in all patients. Relative regional cerebral blood volume (rrCBV) mapping revealed marked hypoperfusion in all patients. One underwent bilateral temporal lobectomy and radionecrosis was confirmed histologically.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 106
    ISSN: 1432-1920
    Keywords: Key words Dysplasia, focal cortical ; Hamartomas ; Epilepsy ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Focal cortical dysplasia (FCD) is a pathological entity first described in 1971. Other more subtle cortical malformations found in patients with epilepsy include microdysgenesis (MD), and glioneuronal hamartias. Although these glial and neuronoglial malformations have distinct histological features, there is terminological confusion in the radiological literature. Few cases have been reported in adults with both imaging and histology. We address these issues, giving a radiological-pathological correlation of histologically proven cortical malformations in adults. We describe clinical, radiological and histological features of 12 cases (five FCD, five MD with glioneuronal hamartias, and two hamartomas), unassociated with other conditions, and discuss them in the light of the literature. FCD is usually seen on MRI as cortical thickening, with or without signal change, which may extend into the adjacent white matter. On histology, abnormal neurons and/or glial cells, blurring of the grey-white matter interface, myelin pallor, demyelination, and gliosis may be found. Glioneuronal hamartias and hamartomas usually appear as complex masses on MRI. FCD and hamartias may be associated, and a combination of imaging findings may be seen on MRI. Atrophy of the ipsilateral hippocampus may be present on MRI in patients with hamartias, and minor cell loss on histology, but not definitive hippocampal sclerosis. Although the imaging findings of cortical malformations are protean, some characteristic MRI features, with histological correlates, may be found. The relevance of most of these observations remains unclear.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 107
    ISSN: 1432-1920
    Keywords: Key words Acquired immunodeficiency syndrome ; Magnetic resonance imaging ; Contrast-enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our purpose was to determine whether triple-dose delayed contrast-enhanced images would improve lesion detection in patients with symptomatic human immunodeficiency virus (HIV) infection. We reviewed 33 MRI studies on 29 patients. Single-dose immediate T 1-weighted spin-echo (1x-T 1) images were compared with delayed triple-dose images (D3x-T 1). Two neuroradiologists decided which technique showed more lesions, increased lesion conspicuity and/or altered the radiologic diagnosis. The D3x-T 1 technique improved lesion detection in 14 of 29 patients (48 %). In two patients (7 %), the improvement changed the radiologic diagnosis by showing new meningeal lesions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 108
    ISSN: 1432-1920
    Keywords: Key words Cerebral autosomal dominant arteriopathy ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clinical data and MRI findings are presented on 18 subjects from two families with neuropathologically confirmed CADASIL. DNA analysis revealed mutations in exon 4 of Notch 3 gene in both families. All family members with mutations in Notch 3 gene had extensive abnormalities on MRI, principally lesions in the white matter of the frontal lobes and in the external capsules. Of several family members in whom a diagnosis of CADASIL was suspected on the basis of minor symptoms, one had MRI changes consistent with CADASIL; none of these cases carried a mutation in the Notch 3 gene. MRI and clinical features that may alert the radiologist to the diagnosis of CADASIL are reviewed. However, a wide differential diagnosis exists for the MRI appearances of CADASIL, including multiple sclerosis and small-vessel disease secondary to hypertension. The definitive diagnosis cannot be made on MRI alone and requires additional evidence, where available, from a positive family history and by screening DNA for mutations of Notch 3 gene.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 109
    ISSN: 1432-1920
    Keywords: Key words Rhombencephalosynapsis ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rhombencephalosynapsis is an unusual disorder characterised by maldevelopment of the rhombencephalon, sometimes with supratentorial midline anomalies. We report MRI findings in a 39-year-old woman, the oldest in the literature. MRI demonstrated hypoplasia of the cerebellar vermis, with fusion of the cerebellar hemispheres and abnormally oriented folia. Supratentorial anomalies were also seen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 110
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 360-362 
    ISSN: 1432-1920
    Keywords: Key words Cyst, cavum septi pellucidi ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 20-year-old woman with secondary amenorrhoea and an empty sella turcica was found to have a cyst of the cavum septi pellucidi (CSP) on MRI. The cyst had regressed spontaneously on follow-up MRI.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 111
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 406-412 
    ISSN: 1432-1920
    Keywords: Key words Lymphoma, primary central nervous system ; Chemotherapy ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract On MRI, primary brain tumors are commonly seen as contrast-enhancing masses surrounded by areas of abnormal signal on T2-weighted images. Following successful treatment tumors may no longer show contrast enhancement. The residual abnormalities are assumed to be represent “edema” and infiltrating tumor cells. We report nine patients with primary lymphoma of the central nervous system who had complete responses to intravenous methotrexate, but did not receive intrathecal chemotherapy or cranial irradiation. After complete resolution of contrast-enhancing lesions, persistent abnormalities on T2-weighted images in the region of prior tumor were initially assumed to reflect residual viable tumor. As they remained unchanged for years, however, this may not hold true in the cases in which primary central nervous system lymphoma responds to chemotherapy alone.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 112
    ISSN: 1432-1920
    Keywords: Key words Corpus callosum ; White matter lesions ; Cerebral ischaemia ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, midanterior and midposterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and midanterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 113
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 551-563 
    ISSN: 1432-1920
    Keywords: Key words Acquired immune deficiency syndrome ; Spine ; infections ; Spine ; neoplasms ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our purpose was to describe the range of MRI findings in infectious and neoplastic involvement of the spine and spinal cord in symptomatic patients with the acquired immunodeficiency syndrome (AIDS). MRI studies in 55 patients with AIDS and neurological signs and symptoms thought to be related to the spine or spinal cord were reviewed. We categorized the findings according to the spinal compartment involved. There were 29 patients with extradural, 11 with intradural-extramedullary and 9 with intramedullary disease. In 6 patients more than one compartment was involved simultaneously, and patients presented with multiple lesions in the same compartment. The most common causes of extradural disease were bone lesions (28); an epidural mass was seen in 14 and spondylodiscitis in 4 patients. Cytomegalovirus polyradiculitis was the most common cause of intradural-extramedullary disease (in 10 cases); herpes radiculitis was seen in two, and tuberculous infection in another two. In three cases leptomeningeal contrast enhancement was due to lymphoma. Human immunodeficiency virus (HIV) myelitis was seen in two patients, presumed vacuolar myelopathy in two, toxoplasma myelitis in four, intramedullary lymphoma in one, and herpes myelitis in one. Familiarity with the various potential pathological entities that can affect the spine and spinal cord in the AIDS population and their imaging characteristics is crucial for initiation of further diagnostic tests and appropriate medical or surgical treatment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 114
    ISSN: 1432-1920
    Keywords: Key words Progressive supranuclear palsy ; Magnetic resonance imaging ; Diffusion-weighted imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We measured the apparent diffusion coefficient (ADC), using diffusion-weighted imaging (DWI) and signal intensity on T2-weighted MRI in the cerebral white matter of patients with progressive supranuclear palsy (PSP) and age-matched normal subjects. In PSP, ADC in the prefrontal and precentral white matter was significantly higher than in controls. There was no significant difference in signal intensity on T2-weighted images. The ADC did correlate with signal intensity. The distribution of the elevation of ADC may be the consequence of underlying pathological changes, such as neurofibrillary tangles or glial fibrillary tangles in the cortex. Our findings suggest that ADC measurement might be useful for demonstrating subtle neuropathological changes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 115
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 676-678 
    ISSN: 1432-1920
    Keywords: Key words. Syringomyelia, spontaneous drainage ; Cerebrospinal fluid, hydrodynamics ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We present five cases of syringomyelia associated with Chiari I or other causes of partial obstructions at the cervicomedullary junction, with spontaneous disruption of the wall of a cervical syrinx and formation of a communication between the cavity and the subarachnoid space, shown on axial MRI. MRI can be used to investigate the hydrodynamics, showing the liquid inside the disrupted syrinx wall and the pathway of drainage. The finding of spontaneous drainage may be important for understanding the pathogenesis of syringomyelia and may be helpful for choosing a surgical approach.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 116
    ISSN: 1432-198X
    Keywords: Key words Henoch-Schönlein purpura ; Methylprednisolone ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Neurological complications are rare during the course of Henoch-Schönlein purpura (HSP). We report a 7-year-old girl with HSP who presented with seizures, loss of vision and disturbance of consciousness. Magnetic resonance imaging (MRI) showed high signal intensity in the gray and white matter over the left parietal and both occipital lobes, compatible with MRI findings of cerebral vasculitis. The eye fundi revealed multiple branches of retinal artery occlusion. Intravenous pulse methylprednisolone (MTP) followed by oral steroid therapy was initially administered for HSP nephritis. Cerebral vasculitis developed 10 days post-MTP treatment, with progressive worsening of consciousness. Oral steroid was discontinued and plasmapheresis was performed alone. Her level of consciousness dramatically improved after plasmapheresis. The brain MRI and eye fundi findings were consistent with her clinical improvement. To the best of our knowledge, this is the first description of MRI abnormalities and multiple retinal artery branch occlusion of cerebral vasculitis in a patient with HSP that was successfully treated by plasmapheresis alone. In conclusion, we propose that plasmapheresis may be used as a first-line therapy or rescue therapy for cerebral vasculitis in HSP.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 117
    ISSN: 1432-198X
    Keywords: Key words Hemolytic uremic syndrome ; Cerebral hypoxia ; Magnetic resonance imaging ; Central nervous system lesions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report a 20-month-old girl with post- diarrheal (Shiga toxin) hemolytic uremic syndrome and severe encephalopathy. Magnetic resonance (MR) images were obtained in the acute phase of the disease and after 10 months. The first MR images showed widespread high signal intensity on T2-weighted and low signal intensity on T1-weighted images, in deep and subcortical white matter; the splenium of the corpus callosum was also involved, as well as cerebellar hemispheres. Neurological symptoms and signs gradually disappeared within 35 days. Follow-up MR imaging showed almost complete resolution of the previous findings, and the patient recovered without central nervous system impairment. The neurological lesions were probably due to hypoxia, although several other mechanisms could be involved, such as metabolic derangements and the action of Shiga toxin. In spite of the dramatic clinical manifestations, we observed a good outcome, indicating that patients with similar lesions do not necessarily have a poor prognosis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 118
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 904-915 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Leber ; Sonographie ; Computertomographie ; Magnetresonanztomographie ; Szintigraphie ; Positronenemissionstomographie ; Keywords Liver ; Ultrasonography ; Computed tomography ; Magnetic resonance imaging ; Radionuclide imaging ; Positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Highly specific methods are required for the diagnostic workup of focal hepatic lesions, since benign circumscribed liver changes are very common. Although cross-sectional imaging techniques have a high diagnostic accuracy, radionuclide imaging techniques such as colloid, red blood cell, or hepatobiliary scan are commonly performed when a benign lesion is assumed since these permit a definite diagnosis with high specificity. The diagnosis of a primary or secondary malignant liver tumor, however, usually relies on radiological imaging techniques alone, supported by needle biopsy. Whether positron emission tomography as a primary or supplementary diagnostic tool will have a role in the routine staging of malignant tumors remains to be determined.
    Notes: Zusammenfassung Die Abklärung umschriebener Leberveränderungen erfordert den Einsatz von Methoden hoher Spezifität, da die Prävalenz benigner, fokaler Läsionen sehr hoch ist. Hierfür sind radiologische Schnittbildtechniken grundsätzlich gut geeignet. Wenn aufgrund der sonographischen, computertomographischen oder magnetresonanztomographischen Befunde eine gutartige Läsion anzunehmen ist, werden jedoch häufig ergänzend die Kolloiderythrozyten- oder hepatobiliäre Szintigraphie – ggf. in Kombination – eingesetzt, da hiermit rasch eine abschließende Diagnose mit hoher Spezifität gestellt werden kann. Bei malignen primären oder sekundären Lebertumoren hingegen werden nuklearmedizinische Zusatzuntersuchungen seltener angefordert, da der radiologische Befund, ggf. gestützt durch eine Ultraschall- oder CT-gezielte Biopsie, eine Diagnose in den meisten Fällen erlaubt. Inwieweit sich der primäre oder ergänzende Einsatz der Positronenemissionstomographie im Vergleich zu radiologischen Schnittbildtechniken beim Staging bösartiger Tumoren bewährt, ist noch nicht abschließend geklärt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 119
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 1064-1076 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Sarkoidose ; Neurosarkoidose ; Granulom ; MRT ; Keywords Sarcoidosis ; Sarcoidosis complications ; Neurosarcoidosis ; Granuloma ; Brain diseases complications ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract The central nervous system is frequently affected during the course of sarcoidosis. Many of these lesions remain without clinical correlates. Unenhanced and contrast enhanced CT and MRI play an important role during the diagnostic work-up of patients with sarcoidosis and suspected or proved CNS involvement. This article summarizes the most frequent manifestations of neurosarcoidosis and provides illustrative examples of MRI findings.
    Notes: Zusammenfassung Das Nervensystem ist bei der Sarkoidose häufiger mitbeteiligt als nach klinischen Gesichtspunkten zu vermuten wäre. Den bildgebenden Untersuchungsverfahren kommt eine große Bedeutung beim Nachweis der pathologischen Veränderungen zu. Insbesondere die Kernspintomographie sichert die Diagnosestellung und dient der Verlaufsbeurteilung. In dieser Übersichtsarbeit werden die typischen klinischen und bildgebenden Befunde bei der Neurosarkoidose vorgestellt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 120
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 870-877 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Lunge ; Perfusion ; Ventilation ; Computertomographie (CT) ; Magnetresonanztomographie (MRT) ; Keywords Lung ; Perfusion ; Ventilation ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Radiological cross-sectional imaging modalities, particularly computed tomography (CT) have become the mainstays for diagnosing lung disease in recent years. These enable morphological visualization of pathological processes with the greatest possible spatial resolution. Modern technical developments and complementary strategies have led to new applications and new functional assessments which need to be reviewed together with state-of-the-art techniques in nuclear imaging. The diagnosis of pulmonary embolism using spiral CT angiography and magnetic resonance (MR) angiography certainly belongs in this category. CT has become the an alternative modality of first choice, and it is also challenging pulmonary angiography as the gold standard. Direct visualization of patent pulmonary arteries and thromboembolic material is complemented by that of effects on the pulmonary parenchyma and right heart function; it also provides perfusion studies and MR-based flow measurement to assess hemodynamic compromise. Ventilation studies have long been a domain of nuclear imaging, and new techniques for the direct visualization of ventilation are emerging from recent developments in the field of MR imaging, for example, using hyperpolarized inert gases. New functional parameters of ventilation can be derived from these studies. For the diagnosis of metabolically active disease, such as tumor and pneumonia, CT offers very high sensitivity, for example, in screening for intrapulmonary nodules using low-dose CT and in the early detection of pulmonary infiltrates in high-risk patients. Especially for characterizing pulmonary nodules there is a need to combine nuclear medicine techniques, such as in positron-emission tomography.
    Notes: Zusammenfassung Die radiologischen Schnittbildverfahren, insbesondere die CT, haben sich innerhalb kurzer Zeit einen herausragenden Stellenwert in der Diagnostik von Lungenerkrankungen erworben. Dies umfasst in erster Linie die morphologische Darstellung pathologischer Prozesse mit hoher räumlicher Auflösung. Moderne technische Entwicklungen und kombinierte Untersuchungsstrategien eröffnen neue Einsatzgebiete und auch funktionelle Aussagen, die nach einer aktuellen Standortbestimmung gemeinsam mit den nuklearmedizinischen Verfahren verlangen. Dazu gehört die Diagnostik der Lungenembolie mittels Spiral-CT-Angiographie und MR-Angiographie der Pulmonalarterien. Hier hat sich mittlerweile die CT als alternatives Verfahren der Wahl etabliert und die Rolle der Pulmonalisangiographie als Goldstandard infrage gestellt. Die reine direkte Darstellung der durchströmten Pulmonalarterien und des thromboembolischen Materials wird durch Diagnostik intrapulmonaler und kardialer Veränderungen, Perfusionsuntersuchungen sowie MR-basierte Flussmessungen zur hämodynamischen Beurteilung erweitert. Nachdem Untersuchungen der Ventilation lange Zeit eine Domäne der Nuklearmedizin waren, eröffnen aktuelle Entwicklungen in der MRT neue Verfahren zur direkten Visualisierung der Lungenbelüftung, z. B. mittels polarisierter Edelgase. Aus diesen Verfahren lassen sich auch neue funktionelle Parameter der Ventilation ableiten. In der Diagnostik von Tumoren und Entzündungen überzeugt die CT insbesondere durch ihre hohe Sensitivität, z. B. beim Screening auf intrapulmonale Rundherde mittels Niedrigdosis-CT oder bei der Früherkennung pneumonischer Infiltrate bei Risikopatienten. Insbesondere bei der Charakterisierung intrapulmonaler Rundherde ist eine Kombination mit nuklearmedizinischen Verfahren (PET) grundsätzlich anzustreben.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 121
    ISSN: 1432-2102
    Keywords: Schlüsselwörter ; Koronare Herzkrankheit ; Magnetresonanztomographie ; Myokardperfusion ; SPECT ; Key words ; Coronary artery disease ; Magnetic resonance imaging ; Myocardial perfusion ; SPECT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Aim: Performance of combined rest/stress MR perfusion studies and the analysis of qualitative signal intensity parameters in comparison with 99mTc-SestaMIBI SPECT in patients with known coronary artery disease (CAD). Methods: Sixteen patients with CAD underwent MR myocardial perfusion assessment at rest and after dipyridamole-induced hyperemia. Qualitative parameters (SI increase, SI upslope) of the SI time-curves were evaluated and characteristics of normal, reversible and persistent hypoperfused myocardium as assessed by 99mTc-SestaMIBI SPECT were compared. Results: Compared with the rest values, normal myocardium showed a significant increase of the SI upslope during hyperemia (P〈0.001), whereas persistent (P=0.07) and reversible (P=0.15) hypoperfusions showed only minor changes. SI increase over baseline also showed a significant increase only in normal myocardium (P〈0.001). At rest, reversible ischemic areas showed no significant differences from normal myocardium, whereas during hyperemia SI increase was significantly lower (P=0.02). Conclusions: Qualitative SI parameters of a combined rest/stress MR myocardial perfusion study allow to differentiate normal from reversibly or persistently hypoperfused myocardium.
    Notes: Zusammenfassung Fragestellung: Die kombinierte Ruhe- und Belastungsuntersuchung der myokardialen Durchblutung in der MRT sowie die Analyse qualitativer SI-Parameter der MR-Myokardperfusion bei Patienten mit koronarer Herzkrankheit wurden mit der 99mTc-SestaMIBI SPECT verglichen. Methode: Bei 16 Patienten mit koronarer Herzkrankheit (KHK) wurde in der MRT mit einer Mehrschichtgradientenechotechnik die Myokardperfusion unter Ruhe- und Belastungsbedingungen untersucht. Qualitative Signalintensitätsparameter der Kontrastmittelanflutung wurden berechnet und die Parameter in normalen, reversibel und persistierend minderperfundierten Myokardarealen miteinander verglichen. Ergebnisse: Normales Myokard zeigte im Gegensatz zu reversiblen (P=0,15) und persistierenden (P=0,07) Ischämien eine signifikante Zunahme der SI-Anstiegssteilheit unter Belastung (P〈0,001). Die SI-Zunahme zeigte ebenfalls nur in normal perfundierten Arealen eine signifikante Zunahme (P〈0,001) nach Belastung. Unter Belastung zeigte sich bei reversiblen Ischämien eine signifikant niedrigere SI-Zunahme als in normalem Myokard (P=0,02), während sich in Ruhe kein Unterschied zeigte. Schlussfolgerung: Qualitative SI-Parameter der kombinierten MR-Perfusionsuntersuchung des Myokards in Ruhe und unter Belastung erlauben die Differenzierung zwischen normalem sowie reversibel oder persistierend minderperfundiertem Myokard.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 122
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 465-468 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Fäkale Inkontinenz ; Magnetresonanztomographie ; Endoanalspule ; Key words Faecal incontinence ; Magnetic resonance imaging ; Endoanal coil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Purpose. Within the recent years several studies have been performed to determine the value of endoanal magnetic resonance imaging (MRI) in faecal incontinence. Methods. MRI is performed using a 0.5 – 1.5T unit. A surface coil with a maximum diameter of 19 mm is placed in the anal canal. T2* 3D gradient-echo-sequences and T2-weighted turbo-spin-echo-sequences in coronal, axial und sagittal orientation are acquired. Results. Compared to endoanal ultrasound (EUS), which is the gold standard for diagnosis in faecal incontinence, endoanal MRI is better in visualization of the external sphincter. The accurate delineation of the external sphincter has led to the possibility to evaluate sphincter atrophy. Preliminary results have shown, that endoanal MRI has an accuracy of 90–95% in the demonstration of lesions in the external sphincter. In detection of lesions of the internal sphincter EUS is still superior to endoanal MRI. Conclusion. EUS and endoanal MRI are currently the optimal imaging techniques for faecal incontinenc, with the advantage of detecting external sphincter atrophy with endoanal MRI.
    Notes: Zusammenfassung Zielsetzung. In den letzten Jahren wurden mehrere Studien durchgeführt, deren Ziel es war, den Stellenwert von Endoanalspulen in der Magnetresonanztomographie (MRT) zur Abklärung von Sphinkterdefekten bei fäkaler Inkontinenz (FI) zu bestimmen. Methode. Die endoanale MRT wird an 0,5–1,5-Tesla-Geräten durchgeführt. Zur Darstellung der Sphinkteren werden Oberflächenspulen mit einem maximalen Querdurchmesser von 19 mm endoanal appliziert. T2*-gewichtet 3D-Gradientenechosequenzen und T2-gewichtete Turbospinechosequenzen in koronaler, axialer und sagittaler Schnittführung werden zur Darstellung des Analkanals angefertigt. Ergebnisse. Im Vergleich zum endoanalen Ultraschall (EUS), der den Goldstandard bei der Abklärung einer FI darstellt, kann mit der endoanalen MRT v. a. der M. sphincter externus besser abgegrenzt werden. Die exakte Differenzierung des M. sphincter externus vom ischiorektalem Fettgewebe ermöglicht die Diagnose einer Atrophie des äußeren Schließmuskels. Erste Studienergebnisse haben gezeigt, daß die endoanale MRT eine Treffsicherheit von 90–95% bei der Detektion von Defekten im M. sphincter externus erreicht. Die Abklärung einer Kontinuitätsunterbrechung im M. sphincter internus ist nach wie vor eine Domäne des EUS. Schlussfolgerung. Die endoanale MRT stellt eine ergänzende Methode zum EUS dar und ist diesem in der Beurteilung der Morphologie des M. sphincter externus überlegen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 123
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 40 (2000), S. 625-631 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Computertomographie ; Magnetresonanztomographie ; Pharynx ; Tumoren ; Key words Computed tomography ; Magnetic resonance imaging ; Pharynx ; Tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Background. Malignant tumors of the head and neck region are amongst the six most often occurring tumors of the body. They can be associated with the different anatomical compartments as well as different histologic types. The way of tumor spread of these malignancies depends on their histologic type and on the region. These compartments can be separated into the nasopharynx, the oropharynx, and the hypopharynx. Most of the malignant tumors belong to the squamous cell carcinomas, other histologic types are depicted less frequently. The histologic types of the other groups which are seen more often comprise of lymphomas and adenoidcystic carcinomas. The undifferentiated carcinoma of the nasopharynx is supposed to be a special type of tumor. The malignant tumors of the pharynx can also involve all three compartments. Beside these tumors, malignancies of mesenchymal origin can also be delineated. Imaging modalities. The imaging modalities most frequently used to detect these tumors and to clarify their extension are contrast enhanced computed tomography, magnetic resonance imaging, nuclearmedicine imaging modalities such as positron emission tomography. Other scintigraphic imaging methods play a less important role. Conclusion. The different imaging modalities of malignant pharyngeal tumors and of potentially infiltrated lymphnodes with the weightness on computed tomography and magnetic resonance imaging and their appearance in these imaging techniques shall be enhanced in this paper.
    Notes: Zusammenfassung Hintergrund. Der Kopf-Hals-Bereich zählt weltweit zu den 6 am häufigsten von malignen Tumoren befallenen Körperregionen. Maligne Tumoren des Pharynx können dabei entsprechend der anatomischen Unterteilung – d. h. Nasopharynx, Oropharynx und Hypopharynx – diesen Regionen zugeordnet werden. Neben der grundsätzlich heterogenen Wachstumstendenz weisen diese Tumoren je nach histologischer Herkunft ein recht unterschiedliches Ausbreitungsmuster auf. Bei der überwiegenden Mehrzahl handelt es sich um Plattenepithelkarzinome, die anderen histologischen Typen – wie adenoidzystische Karzinome oder Lymphome – sind weitaus seltener vertreten. Daneben kommen sehr selten auch noch maligne Tumoren mesenchymalen Ursprungs wie z. B. die Rhabdomyosarkome vor. Bildgebung. Die bildgebende Abklärung erfolgt mit der kontrastmittelverstärkten CT, der MRT und in jüngster Zeit mit nuklearmedizinischen Methoden, z. B. PET. Andere szintigraphische Untersuchungsmethoden spielen eine untergeordnete Rolle. Resümee. Verschiedene bildgebende Methoden (schwerpunktmäßig CT und MRT) und die entsprechenden Erscheinungsbilder sowie Lokalisations- bzw. Ausbreitungsdiagnostik der malignen Tumoren und evtl. befallener Lymphknoten dieser Regionen werden vorgestellt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 124
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Zerebrovaskuläre Erkrankung ; Arteriosklerose ; Magnetresonanztomographie ; Magnetresonanzangiographie ; Digitale Subtraktionsangiographie ; A. carotis ; Keywords Cerebrovascular disease ; Arteriosclerosis ; Magnetic resonance imaging ; Magnetic resonance angiography ; Digital subtraction angiography ; Carotid artery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Purpose. To compare high resolution contrast-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in the assessment of supraaortic vessel stenosis. Methods. 14 patients with suspicion of cerebrovascular disease or upper limb ischemia underwent selective DSA and high resolution contrast enhanced MRA employing a new Panoramic-Array coil. Stenosis assessment in comparison to DSA followed NASCET criteria. Additionally signal-/noise ratios (SNR) were evaluated to assess contrast enhancement. Results. Diagnostic image quality was achieved in all patients. Sensitivity and specificity for assessing high-grade stenosis of the supraaortic vessels were 100% and 96% respectively. In the assessment of high-grade common or internal carotid artery stenosis sensitivity and specificity was 100%. Conclusion. High resolution contrast enhanced supraaortic MRA combined with new coil sytems allow for a reliable assessment of stenoses along the whole vessel course including the aortic arch. Previous stent procedures limit its use in post-interventional follow-up.
    Notes: Zusammenfassung Fragestellung. Ziel der Studie war ein Vergleich zwischen hochauflösender kontrastverstärkter MR-Angiographie (MRA) und digitaler Subtraktionsangiographie (DSA) in der Diagnostik von Stenosen der supraaortalen Gefäße. Methoden. 14 Patienten mit Verdacht auf eine zerebrovaskuläre Erkrankung oder Durchblutungsstörung der oberen Extremität wurden mit DSA und hochaufgelöster, kontrastverstärkter MR-Angiographie mit Verwendung einer Panoramic-Array-Spule untersucht. Neben der Beurteilung der Kontrastierung erfolgte die Bestimmung der Stenosegrade im Vergleich zur selektiven DSA nach den NASCET-Kriterien. Ergebnisse. Bei allen Patienten konnte mit der MRA eine diagnostisch ausreichende Bildqualität erzielt werden. In der Diagnostik hochgradiger Stenosen der supraaortalen Gefäße ergab sich eine Sensitivität von 100% und eine Spezifität von 96%. In der Erkennung hochgradiger Stenosen der A. carotis communis oder interna lagen Sensitivität und Spezifität bei 100%. Schlussfolgerung. Die ultraschnelle MRA der supraaortalen Gefäße in Kombination mit einer geeigneten Spulenkombination ermöglicht die zuverlässige Erkennung stenotischer Veränderungen im gesamten Gefäßverlauf einschließlich des Aortenbogens. Stentimplanationen limitieren derzeit den Einsatz in der postinterventionellen Kontrolle.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 125
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 247 (2000), S. 943-948 
    ISSN: 1432-1459
    Keywords: Key words Transverse myelitis ; Motor evoked potentials ; Somatosensory evoked potentials ; Electromyography ; Prognosis ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A systematic evaluation of anterior horn cell, motor and sensory pathways is possible by electromyography (EMG), motor (MEPs) and somatosensory (SEPs) evoked potentials, respectively, which may provide valuable information on acute transverse myelitis (ATM). In a prospective hospital-based study, EMG, MEP and SEP studies were carried out on admission and after 3 months in 39 patients with ATM. All the patients also underwent detailed clinical evaluation, and spinal magnetic resonance imaging (MRI) was performed in 28. Outcome was defined at the end of 3 months as poor, partial or complete recovery on the basis of functional status. Spinal MRI revealed hyperintense signal changes in T2 extending for two segments to the entire spinal cord. Central motor conduction time to tibialis anterior (CMCT-TA) was more frequently abnormal (90%), followed by tibial SEP (77%). CMCT to abductor digiti minimi (ADM) was abnormal in 30% and median SEP in 15% of patients. Evidence of denervation on EMG was present in 51% of patients. The CMCT-TA improved in 48% patients and tibial SEP in 32%. Median SEP improved in all patients, and CMCT-ADM remained prolonged in two. At 3 months 2 patients had died, and 18 had poor, 10 partial and 9 complete recovery. CMCT was correlated with miscle power, tone, reflec and MRI changes. Patients' outcome of was correlated with CMCT, SEP and EMG. These results are consistent with pronounced involvement of dorsal region of spinal cord in ATM. MEP is more frequently abnormal than SEP.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 126
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 247 (2000), S. 252-258 
    ISSN: 1432-1459
    Keywords: Key words Cerebral venous ¶thrombosis ; Dural sinuses ; Magnetic resonance imaging ; Heparin ; Thrombolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In contrast to arterial stroke, cerebral venous thrombosis (CVT) is an infrequent condition which presents with a wide spectrum of signs and with a highly variable mode of onset. The clinician must therefore consider it systematically in all brain syndromes and perform the appropriate neuroimaging investigations: computed tomography (CT) with computed tomography angiography and/or magnetic resonance imaging with magnetic resonance angiography and, if necessary intra-arterial angiography. Once the diagnosis is established, a wide investigation for should be carried out in search of the cause, and treatment started as soon as possible. Treatment is based on the combination of intravenous heparin (followed by oral anticoagulants for 3–6 months), symptomatic treatment (anticonvulsants, analgesics, treatment of increased intracranial pressure) and treatment of the cause. Local thrombolysis is indicated if there is deterioration due to thrombosis extension despite adequate anticoagulation. Diagnosis and treatment of CVT should be considered as an emergency because of the considerable potential for full recovery in this condition.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 127
    ISSN: 1432-1459
    Keywords: Key words Multiple sclerosis ; Neuropsychological ; Cognitive ; Magnetic resonance imaging ; Lesion load
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neuropsychological deficits and the relationship to brain pathology were examined in 13 primary progressive (PP) and 12 secondary progressive (SP) multiple sclerosis patients with a similar duration of the progressive phase and comparable physical disability. A battery of neuropsychological tests to assess attention, short-term and working memory was administered to the patients, and their performance was compared to that of 20 healthy controls matched for age and premorbid IQ. Total cerebral lesion load on T2-weighted magnetic resonance imaging was measured in the patients. Both PP and SP patients performed significantly worse than controls in most of the neuropsychological tests. There were only subtle differences between SP and PP on the working memory task although magnetic resonance imaging lesion load was significantly higher in SP than in PP patients. In this exploratory study only subtle differences in cognitive impairment were detected between SP and PP patients matched for physical disability and relevant illness features. The results also suggest that the severity of cognitive impairment cannot be fully explained by the extent of abnormalities detected on conventional T2-weighted magnetic resonance images, and that other pathological abnormalities such as in normal-appearing white matter are likely to be involved.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 128
    ISSN: 1432-1459
    Keywords: Key words Leukoaraiosis ; Aged ; Atherosclerosis ; Magnetic resonance imaging ; Carotid artery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cerebral white matter lesions are frequently observed on magnetic resonance imaging of elderly, nondemented persons. There is evidence that white matter lesions are involved in the pathophysiology of cognitive decline and dementia. White matter lesions can be divided into those in the periventricular and those in the subcortical region. Pathological and epidemiological studies suggest that atherosclerosis is involved in the pathogenesis of these lesions. Our study reports on the association between atherosclerosis in the carotid arteries and white matter lesions in a population-based study among 1077 elderly subjects. We randomly sampled 1077 subjects aged between 60–90 years from two prospective population-based studies. All subjects underwent ultrasonography of the carotid artery. In addition, 1.5 T magnetic resonance imaging was performed; white matter lesions in the subcortical and periventricular regions were rated separately. With increasing number of plaques in the carotid artery the severity of periventricular white matter lesions increased (P trend = 0.03), but not the severity of subcortical white matter lesions (P trend = 0.19). In addition, an increase in intima media thickness was borderline significantly associated with an increased severity of periventricular white matter lesions (P trend = 0.09), but not of subcortical white matter lesions (P trend = 0.68). These findings suggest that partly dissimilar pathogenetic mechanisms are involved in the etiology of periventricular and subcortical white matter lesions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 129
    ISSN: 1432-1459
    Keywords: Key words Multiple sclerosis ; Fatigue ; Magnetic resonance imaging ; Motor evoked potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fatique is a common symptom of multiple sclerosis (MS) even in the early phases of the disease, when neurological disability is usually still not present. To investigate the pathophysiology of fatigue we compared neurophysiological (motor evoked potentials of the four limbs, MEPs) and brain magnetic resonance imaging (MRI) findings in two groups of nondisabled MS patients, those with (n=15) and those without (n=15) fatigue. Fatigue was assessed by an interview and scored by the Fatigue Severity Scale. The two groups were matched for sex, age, disease duration, Expanded Disability Status Scale score, pyramidal Functional System (FS) score, and depression score. MEPs were abnormal in five patients with fatigue and in one patient without fatigue. A significant association was found between the patient scores on the Fatigue Severity Scale, and the burden of MRI lesions (r=0.5; P〈0.005). Significantly higher parietal lobe (P〈0.05), internal capsule (P〈0.05), and periventricular trigone (P〈0.05) lesion loads were found in patients with fatigue than in those without. Our results agree with a central nervous system origin of fatigue in MS patients. This symptom might be a consequence either of a functional deafferentation of the cortex due to cortico-subcortical interconnection damage or of a demyelination in critical sites of the CNS, such as the cortico-spinal tract.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 130
    ISSN: 1432-1459
    Keywords: Key words Small subcortical ¶infarction ; Large-vessel disease ; Magnetic resonance imaging ; Silent white-matter hyperintensity ; Lacunar infarction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Small subcortical infarctions resulting from large-vessel disease are often observed. It is important to distinguish these from pure lacunar infarction resulting from small-vessel disease because the investigations and examinations differ. We investigated the differences on brain magnetic resonance imaging (MRI) between small subcortical ¶“lacunar-like” infarcts resulting from large-vessel disease and pure lacunar infarcts. Thirteen subjects with small lacunar-like infarcts (size 〈 2 cm), resulting from large-vessel disease, ¶and 30 subjects with lacunar infarcts (〈 2 cm), without large-vessel disease were studied. We measured infarction size using a 1.5-T MRI device and evaluated silent subcortical hyperintensity lesions using the modified Scheltens’ score. Large-vessel lesion was confirmed by conventional angiography, duplex carotid scan, and magnetic resonance angiography. There was no difference in the mean age of the two groups. Cerebrovascular risk factors and atherosclerotic complications were also comparable for the two groups. Progressive stroke was more common ¶in the lacunar-like infarction group than in the lacunar infarction group ¶(P = 0.004). Scores for periventricular hyperintensity, white matter hyperintensity, basal ganglia hyperintensity, and total subcortical hyperintensity scores were significantly higher in the lacunar infarction group than in the lacunar-like infarction group. The difference in basal ganglia hyperintensity scores was remarkable (P = 0.001). The enlargement of the perivascular space was also significantly greater in the lacunar infarction group than in the lacunar-like infarction group. These findings seem to reflect differences in the pathogenesis of infarction between the two groups. Silent subcortical hyperintensity lesions and enlargement of perivascular space are useful for between distinguishing small lacunar-like infarct resulting from large-vessel disease and pure lacunar infarction. This may have significant implications for the management of patients with lacunar-sized infarctions. It suggests that the pathogenesis of lacunar-sized infarction is variable.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 131
    ISSN: 1432-1459
    Keywords: Key words Sarcoidosis ; Spinal cord ; Magnetic resonance imaging ; Corticosteroid therapy ; Prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Spinal cord sarcoidosis is a rare disorder whose natural history and therapeutic outcome are not fully known. We examined four patients with spinal cord sarcoidosis both clinically and radiologically, particularly in relation to corticosteroid treatment. The initial manifestation was cervical myelopathy in three and uveitis in one. All four patients progressed slowly until corticosteroid therapy was initiated. The cervial spine was involved in all patients. Magnetic resonance imaging (MRI) showed spinal cord swelling with T2-weighted high intensity and linear leptomeningeal and patchy or diffuse intramedullary enhancement with gadolinium diethylene triaminepentaacetic acid. With corticosteroid therapy, dramatic improvement was seen on MRI, including disappearance or marked reduction of swelling and enhancement. Plasma levels of angiotensin-converting enzyme (ACE) were also markedly improved. In contrast, the clinical symptoms were little improved in one patient, unchanged in two, and rather worsened in one patient. Recurrence was seen on MRI at the maintenance dose in all four patients, without any dramatic change in clinical manifestation. MRI findings and plasma ACE are well correlated with active leasion of the spinal cord sarcoidosis, providing a useful marker for recurrence, but do not parallel the clinical manifestations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 132
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 29 (2000), S. 726-728 
    ISSN: 1432-2161
    Keywords: Keywords Developmental dysplasia ; Hip ; Membrane ; Interposition ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Intra-articular membranous interposition was detected by MRI in the hip joint with residual subluxation of a girl aged 5 years 10 months. This structure, which had low signal intensity on both T1- and T2-weighted images, separated the femoral head from the acetabulum. Histological examination revealed chondrometaplasia, which suggested that this interposition might be transformed to a surface cartilaginous tissue of the secondary acetabulum often observed in residual subluxation of the hip.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 133
    ISSN: 1432-2161
    Keywords: Key words Rheumatoid arthritis ; Cervical spine ; Magnetic resonance imaging ; Dynamic imaging ; Flexion views
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. To determine whether MR imaging in flexion adds value relative to imaging in the neutral position with respect to displaying involvement of the subarachnoid space, brainstem and spinal cord. Design and patients. T1-weighted MR images of the cervical spine in 42 rheumatoid arthritis patients with cervical spine involvement were obtained and analyzed prospectively. We assessed changes between images obtained in the neutral position and following active flexion, especially horizontal atlantoaxial and subaxial motion, presence or absence of brainstem compression, subarachnoid space involvement at the atlantoaxial and subaxial level and the cervicomedullary angle. Vertical atlantoaxial subluxation and the amount of pannus were correlated with motion and change in subarachnoid space. Results. The flexion images showed horizontal atlantoaxial motion in 21 patients and subaxial motion in one patient. The flexion view displayed brainstem compression in only one patient. Involvement of the subarachnoid space increased at the atlantoaxial level in eight (19%) patients (P=0.004) and at the level below C2 in five (12%) patients (P=0.03). There were no patients with a normal subarachnoid space in neutral position and compression in the flexed position. The cervicomedullary angle changed significantly with flexion. Vertical atlantoaxial subluxation and the amount of pannus did not show a significant correlation with motion or subarachnoid space involvement. Conclusion. MR imaging in the flexed position shows a statistically significant narrowing of the subarachnoid space at the atlantoaxial level and below C2. Cord compression is only observed on flexion views if the subarachnoid space in neutral position is already decreased. MR imaging in the flexed position might be useful, since subarachnoid space involvement may be an indicator for the development of neurologic dysfunction.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 134
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 29 (2000), S. 104-108 
    ISSN: 1432-2161
    Keywords: Key words Adult teratoma ; Dumb-bell type tumor ; Lumbar spine ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report a case of a lumbar teratoma in a 50-year-old woman. The teratoma showed a dumb-bell-type expansion at the level of the left L3/4 foramen with massive erosion of the L3 vertebral body. MRI revealed inhomogeneous signal changes in the tumor, which were histologically compatible with a mixture of bone, muscle, fat, and cyst containing sebaceous material. Complete resection of the tumor and spinal arthrodesis with pedicle screw fixation was necessary to obtain stability of the affected spinal segment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 135
    Electronic Resource
    Electronic Resource
    Springer
    Child's nervous system 16 (2000), S. 138-142 
    ISSN: 1433-0350
    Keywords: Key words Craniopharyngioma ; Posterior fossa tumors ; Microsurgery ; Magnetic resonance imaging ; Computerized tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Between 1991 and 1998, 24 patients underwent surgery for a craniopharyngioma in our department. This group included two patients who had tumors with extensive growth along the midline, and along the posterior fossa in particular. In both cases suprasellar calcifications were typical features on magnetic resonance imaging (MRI) and computed tomography (CT). A 7-year-old boy presented with a 6-month history of headache, nausea, and progressive unilateral hearing loss. With a suboccipital approach it was possible to remove the main part of the tumor. In a 13-year-old boy headache and visual deterioration led to the diagnosis of a craniopharyngioma, which was removed with a pterional approach. For the neuroimaging work-up in such cases of atypically growing craniopharyngiomas MRI is the method of choice. Additional CT scanning is recommended, which provides valuable information about bony changes at the skull base due to space-occupying growth. CT substantiates the differential diagnosis if typical calcifications are seen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 136
    Electronic Resource
    Electronic Resource
    Springer
    Child's nervous system 16 (2000), S. 398-401 
    ISSN: 1433-0350
    Keywords: Keywords Primitive neuroectodermal tumor ; Diffuse leptomeningeal neoplasia ; Magnetic resonance imaging ; Pseudotumor cerebri ; Sinus thrombosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Primitive neuroectodermal tumors are easily detected by neuroradiologic imaging, as a rule. We report on two patients with early diffuse leptomeningeal primitive neuroectodermal tumors which escaped detection by contrast-enhanced magnetic resonance imaging.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    Springer
    Child's nervous system 16 (2000), S. 551-554 
    ISSN: 1433-0350
    Keywords: Keywords Acute myelitis of childhood ; Fibrocartilaginous embolism ; Magnetic resonance imaging ; Spinal cord infarction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Fibrocartilaginous embolus causing acute spinal cord infarction is a rare cause of acute-onset paraplegia or quadriplegia. Few cases of survivors have been reported in the neurosurgical literature, with most reports involving post-mortem or biopsy findings. There is little information on MRI findings in such patients. We present the youngest patient ever reported, and discuss the important differences between fibrocartilaginous embolus and acute myelitis of childhood. A 6-year-old girl with a history of back pain presented with sudden-onset nontraumatic paraplegia, with a clinical anterior spinal artery syndrome. Initial MRI scan revealed intervertebral disc disease at L1–2 and an incidental thoracic syrinx, but no cause for her acute-onset paraplegia was identified. Cerebrospinal fluid and other investigations were all negative. Sequential MRI scans revealed development of spinal cord expansion from T10 to the conus medullaris, with increased cord signal in the anterior aspect of the spinal cord. The intervertebral disc disease was unchanged. The imaging and clinical findings were caused by fibrocartilaginous embolus, which meant there was no need for spinal cord biopsy. The report describes the clinical and imaging criteria for diagnosis of fibrocartilaginous embolus, highlighting the case for avoiding an unnecessary biopsy. The clinical pattern in the paediatric group is discussed, with features differentiating it from acute myelitis of childhood.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 138
    ISSN: 1433-0350
    Keywords: Keywords Cavernous angioma ; Cerebral angiography ; Dynamic scan ; Magnetic resonance imaging ; Sinus pericranii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objects: Sinus pericranii is only a symptom complex, and it can have a variety of etiologies. Therefore, it is important to differentiate these etiologies preoperatively by means of radiological examinations. A 5-year-old boy was admitted with a soft and fluctuant tumor in the right parietal region near the midline. The tumor appeared when the child was in a recumbent position, distending noticeably with the Valsalva maneuver and disappearing completely when the patient was in the sitting position. Methods: Magnetic resonance imaging showed the lesion with honeycomb-like heterogeneous iso- and low-intensity signals on the T1-weighted image and with heterogeneous high- and iso- intensity signal on the T2-weighted image. Dynamic study with an injection of gadolinium diethylene-triaminopentaacetic acid demonstrated and nodular peripheral enhancement at early phase and subsequent progressive enhancement towards the center of tumor. The internal carotid angiogram was normal. The external carotid angiogram, however, showed a tumor stain fed by the superficial temporal arteries. The stain was retained until the late phase and drained into the scalp veins and into the superior sagittal sinus. Following direct injection of contrast medium into the tumor there was prolonged retention of the medium in the tumor and leakage into scalp veins and the superior sagittal sinus. The mass under the periosteum was totally removed and proved to be a cavernous angioma. Conclusions: Scalp cavernous angioma is one of the etiologies of sinus pericranii and may be diagnosed preoperatively by cerebral angiography or magnetic resonance imaging. Serial dynamic magnetic resonance imaging will be particularly helpful for this diagnosis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 139
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Diffusionsgewichtete Kernspintomographie ; Wirbelkörpermetastasen ; Diffusionskoeffizient ; Keywords Diffusion weighted imaging (DWI) ; Magnetic resonance imaging ; Vertebral metastases ; Diffusion coefficient ; ADC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Aim of the study. The aim of the study was the evaluation of the diffusion coefficient (ADC) of vertebral metastasis and regular vertebral bodies with diffusion weighted MRI (DWI). DWI evaluates the tissue-specific molecular diffusion of protons. In tissues with high cell densities (neoplasm) a decreased ADC can be expected due to restricted diffusion according to an exaggerated amount of intra- and intercellular membranes (i. e. diffusion barriers). Methods. In 5 breast cancer patients the ADC of both known vertebral metastases and of adjacent regular vertebral bodies were measured with DWI (1.0 T; Phased-Array-Body-Coil; b: 880 and 440 s/mm2). Results. The ADC of regular vertebral bodies (1.3±0.23×10–,3s/mm2) was significantly (p≤0.0002) higher than in vertebral metastases (0.39±0.11×10–3s/mm2). Conclusions. These data demonstrate that the ADC can be reliably measured in vertebral bodies. The quantitative evaluation of the ADC in vertebral bodies seems to be an objective and comparable parameter for differentiating malign from benign vertebral tissue.
    Notes: Zusammenfassung Ziel. Ziel der Arbeit war die Messung des Diffusionskoeffizienten (ADC) mittels diffusionsgewichteter (DW) MRT in Wirbelkörpermetastasen und in MR-morphologisch unauffälligen Wirbelkörpern. Die DW-MRT misst den für ein Gewebe spezifischen ADC, welcher der Eigendiffusion von Wasserstoffmolekülen entspricht. In zellreichem Tumorgewebe mit zahlreichen intra- und interzellulären Membranen (d. h. Diffusionsbarrieren) ist ein niedriger, in zellarmen oder nekrotischem Gewebe, ein hoher ADC zu erwarten. Methode. Bei 5 Patientinnen mit Mammakarzinom wurde der ADC von Lendenwirbelkörpermetastasen sowie von angrenzenden, MR-morphologisch unauffälligen Wirbelkörpern ermittelt (1,0 T; Phased-Array-Body-Coil; b: 880 und 440 s/mm2). Ergebnisse. Der ADC in MR-morphologisch unauffälligen Wirbelkörpern (1,3±0,23×10–3s/mm2) war signifikant (p≤0,0002) höher als in Wirbelkörpermetastasen (0,39±0,11×10–3s/mm2). Schlussfolgerung. Anhand dieser Daten konnte gezeigt werden, dass der ADC von Wirbelkörpern verlässlich gemessen werden kann, und dass durch die quantitative Bestimmung des ADC ein objektiv vergleichbarer Parameter zur Verfügung steht, der zur Differenzierung von malignem und benignem Gewebe gut geeignet erscheint.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 140
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Diffusion ; Magnetresonanztomographie ; Encephalitis disseminata ; Keywords Diffusion ; Magnetic resonance imaging ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Magnetic resonance (MR) imaging is one of the best methods in diagnosis of multiple sclerosis, particularly in disclosure of active demyelinating lesions. Aim of this study was to compare diffusion weighted imaging and contrast enhancement in the detection of active lesions. A MR study with a contrast enhanced T1-weighted pulse sequence with magnetization transfer presaturation and a diffusion weighted echoplanar pulse sequence (b=1000 s/mm2) was performed in 17 patients (11 women, 6 men) with multiple sclerosis. 29 of 239 lesions showed an increased signal intensity in diffusion weighted imaging, 24 lesions a contrast enhancement, but only 16 lesions were visible in both pulse sequences. In patients with short clinical symptomatology significant more lesions could be detected with diffusion-weighted pulse sequence in comparison to patients with long standing symptomatology showing more lesions with contrast enhancement. Hence it is likely, that both pulse sequences detect different histopathologic changes. The early detection of demyelinating lesions in diffusion weighted imaging is attributed to the extracellular edema, however the contrast enhancement is caused by a blood brain barrier abnormality. It can be expected that diffusion weighted imaging will have a high impact on imaging of multiple sclerosis not only in therapeutic trials, but also in clinical routine.
    Notes: Zusammenfassung Die Magnetresonanztomograpie ist eine der wichtigsten Untersuchungsmethoden in der Diagnostik der Encephalitis disseminata, insbesondere im Nachweis aktiver Entmarkungsherde. Ziel der Untersuchung war es, diffusionsgewichtete und kontrastverstärkte Untersuchungen bezüglich der Erkennung aktiver Läsionen zu vergleichen. Bei 17 Patienten (11 Frauen, 6 Männer) mit bekannter Encephalitis disseminata wurden sowohl eine kontrastverstärkte T1-gewichtete Sequenz mit Magnetization-Transfer-Sättigung als auch eine diffusionsgewichtete Echoplanar-Sequenz (b=1000 s/mm2) durchgeführt. 29 der 239 Läsionen zeigten eine Signalsteigerung in der diffusionsgewichteten Sequenz, 24 eine Kontrastmittelaufnahme, jedoch waren nur 16 Läsionen in beiden Techniken nachweisbar. Bei Patienten mit kurzzeitig bestehender Symptomatik zeigten sich signifikant mehr Entmarkungsherde mit Signalsteigerung in der Diffusionswichtung im Vergleich zu Patienten mit länger bestehender neurologischer Symptomatik, die mehr kontrastmittelaffine Läsionen aufwiesen. Dies lässt darauf schließen, dass mit beiden Verfahren unterschiedliche histopathologische Veränderungen beobachtet werden. Das sehr frühe Auftreten der Diffusionsänderung in den Entmarkungsherden wird auf das Ödem zurückgeführt, während die Kontrastmittelaufnahme durch eine Blut-Hirnschranken-Störung verursacht wird. Es ist zu erwarten, dass die diffusionsgewichtete Magnetresonanztomographie einen hohen Stellenwert in der Bildgebung der Encephalitis disseminata nicht nur in Therapiestudien, sondern auch in der klinischen Routinediagnostik erlangen wird.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 141
    ISSN: 1433-7347
    Keywords: Key words Osteonecrosis ; Bone marrow edema ; Knee ; High tibial osteotomy ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Notes: Abstract Symptoms in patients suffering from spontaneous osteonecrosis of the knee (SONK) may be reduced by high tibial osteotomy (HTO). However, the fate of the necrotic lesion is unknown and needs further investigation. We conducted a prospective study to evaluate magnetic resonance imaging (MRI) changes after operative and nonoperative treatment. Ten consecutive patients suffering from SONK of the medial compartment were given two treatment options: either HTO (n = 6) or conservative treatment with partial weight bearing for 3 months (n = 4). We measured the greatest extent of well-defined subchondral low signal intensity abnormality, considered to represent necrosis, and the surrounding area of intermediate signal intensity, considered to represent perifocal bone marrow edema, on T1-weighted coronal MRI images before and after treatment. The MRI follow-up period was 17.5 months (range 12–¶27) in the HTO group and 14.5 months (range 8–25) in the nonoperative group. At follow-up the MRI evaluation revealed a decrease in the low signal intense areas (necrosis) in five of the six patients in the HTO group. Only one of the four nonoperative patients showed a decrease in the low signal intense area. The intermediate intense areas (edema) decreased in all patients in the HTO group and in three of four in the nonoperative group. The mean decrease in the area of perifocal edema was significantly greater in the HTO group than in the nonoperative group (P = 0.019). No statistically significant difference was found for the area of necrosis between the two groups (P = 0.171). A clinical improvement was observed in all patients of the HTO group but in only two of the four patients of the nonoperative group. We conclude that the decrease in perifocal bone marrow edema seems to be associated with improved patient comfort. The MRI appearance of the necrotic lesion does not alter with either treatment mode.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 142
    Electronic Resource
    Electronic Resource
    Springer
    Child's nervous system 16 (2000), S. 829-831 
    ISSN: 1433-0350
    Keywords: Keywords Intraoperative imaging ; Magnetic resonance imaging ; Anatomical and functional neuronavigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The Erlangen-concept of image-guided-surgery is based on the installation of an open magnetic resonance (MR) scanner (Magnetom Open, 0.2 T, Siemens AG) in a twin operating room in combination with two neuronavigation systems (Stealth NeuroStation, Sofamor Danek, MKM Zeiss). Since March 1996 this method has been used for a total of 402 patients, among them 44 children. In 214 patients, mainly with gliomas or pituitary adenomas or who needed surgery for epilepsy, we performed intraoperative MR imaging to monitor the extent of resection, allowing a second look for possible tumor remnants and also compensating for brain shift by an intraoperative update of neuronavigation. Functional neuronavigation, i.e. the combination of anatomical neuronavigation with functional imaging [e.g. magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI)] was used in patients with lesions in brain areas such as the motor and speech areas. For MEG we used a MAGNES II biomagnetometer (Biomagnetic Technologies, San Diego, Calif.) and for fMRI a 1.5 T Siemens Symphony MR scanner. So far we have treated 89 patients with functional neuronavigation. Our preliminary experience indicates that intraoperative MR imaging, especially in combination with functional neuronavigation, allows more radical resections with lower morbidity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 143
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 250 (2000), S. 76-78 
    ISSN: 1433-8491
    Keywords: Key words Septum pellucidum ; Developmental ¶disorder ; Schizophrenia ; Magnetic resonance imaging ; Cavum veli interpositi ; Cavum septi pellucidi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The case of monocygotic twins discordant for a psychotic disorder is presented. An anomaly of the septum pellucidum, a so-called cavum veli interpositi was found in the psychotic twin while his brother showed no such anomaly. Previous studies have shown a higher prevalence of septum pellucidum anomalies in schizophrenic patients. Abnormalities of the septum pellucidum may be associated with disturbed neuronal development in distinct limbic brain areas which cannot yet be visualized yet by brain imaging techniques. The finding of the cavum veli interpositi in the psychotic twin could be incidental; however, it may indicate a dysgenic process in early brain development and, thus, play a significant role in the etiology of psychosis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 144
    Electronic Resource
    Electronic Resource
    Springer
    Herz 25 (2000), S. 384-391 
    ISSN: 1615-6692
    Keywords: Key Words Cardiomyopathy ; Magnetic resonance imaging ; Schlüsselwörter Kardiomyopathie ; Magnetresonanztomographie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die kardiale Magnetresonanztomographie (MRT) bietet als nichtinvasives Verfahren die Möglichkeit, innerhalb einer Untersuchung die für die verschiedenen Formen der Kardiomyopathien charakteristischen funktionellen und morphologischen Veränderungen darzustellen. In dieser Übersicht werden die Einsatzmöglichkeiten der MRT bei den verschiedenen Formen dieser Erkrankung diskutiert. Die geringe Variabilität der MRT-Messungen gestattet ge-naue Verlaufskontrollen im klinischen Alltag, eröffnet aber auch die Möglichkeit, Therapiestudien mit einer geringeren Anzahl von einzuschließenden Patienten zu sicheren Ergebnissen zu führen. Damit erweitert sich das Spektrum der Indikationen über die Präzisierung unklarer Befunde hinaus auf die Verlaufsbeobachtung während einer pharmakologischen Intervention und auf alle wissenschaftlichen Fragestellungen. Der Vorzug der MRT, nichtinvasiv Gewebe charakterisieren zu können, verdeutlicht das Potential dieser Technik bei sekundären Kardiomyopathien sowie bei entzündlichen und infiltrativen Formen myokardialer Erkrankungen.
    Notes: Abstract Cardiac magnetic resonance imaging (MRI) is a noninvasive tool which is able to diagnose and differentiate cardiomyopathies in a single study. The assessment of essential information such as alterations of myocardial and ventricular geometry and function is possible with a high degree of accuracy and reproducibility, based on a small inter- and intraobserver variability. Thus, very small morphological and functional changes in different types of cardiomyopathy are detectable, thereby enabling the cardiologist to increase the safety of therapeutic decisions. Furthermore, MRI bears the potential to characterize tissue transformation in the different types of myocardial affections including ischemic, toxic, infiltrative or inflammatory forms.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 145
    Electronic Resource
    Electronic Resource
    Springer
    Heart and vessels 15 (2000), S. 44-45 
    ISSN: 1615-2573
    Keywords: Key words Pericardial hydatid cyst ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 146
    ISSN: 1615-2573
    Keywords: Key words Three-dimensional echocardiography ; Magnetic resonance imaging ; Left ventricular volume ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The objective of this study was to investigate the degree of bias with coaxial three-dimensional echocardiography in an experimental animal setup and to establish the minimum number of sections needed for estimation of left ventricular (LV) volume. Epicardial coaxial echocardiography and magnetic resonance imaging (MRI) was used to measure LV volume in 14 pigs, with chronic remodeled left ventricles induced by repeated intracoronary microembolizations. In addition, six animals underwent serial MRI at baseline, immediately after intracoronary microembolization, and after 119–165 days (mean 129 days). Coaxial echocardiography was performed by rotational acquisition of long-axis sections starting from an arbitrary angle. Planimetered MRI contours of LV endocardial borders were analyzed to investigate the relationship between the number of coaxial sections, and the precision of volume estimates. The mean ± 2SD of the differences between coaxial epicardial echocardiography with six sections and MRI were −2.5 ± 16.4 ml, 0.8 ± 13. 1 ml, and 2% ± 14% for end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF), respectively. Numerical analysis conducted on MRI contours of LV endocardial borders showed that with six coaxial sections the average coeffi-cient of error was 〈1% for the EDV and ESV. Three-dimensional echocardiography with six coaxial sections provides unbiased LV volume estimation with minimal geometric error.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 147
    ISSN: 1439-6327
    Keywords: Key words Human ; Muscle function ; Physiological cross-sectional area ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of the present study was to investigate the effect of recruitment on the relationship between peak torque and physiological cross-sectional area (PCSA) in human muscle. A group of 11 healthy men participated in this study. Isokinetic knee extension torques at seven (0, 30, 60, 120, 180, 240, and 300° · s−1) velocities were determined. Magnetic resonance imaging (MRI) was performed to calculate PCSA of right quadriceps femoris (QF) muscle. Exercise-induced contrast shifts in spin-spin relaxation time (T2)-weighted MRI were taken at rest and immediately after repetitive knee-extension exercise and T2 of QF were calculated. The MRI pixels with T2 values more than 1 SD greater than the means at rest were considered to represent QF muscle that had contracted. The area of activated PCSA within the total in QF was expressed as percentage activated PCSA and used as an index of muscle recruitment. The PCSA correlated with peak torque at 0° · s−1 (r=0.615, P 〈 0.05); in contrast, activated PCSA correlated with peak torque at 120° · s−1 (r=0.603, P 〈 0.05) and 180° · s−1 (r=0.606, P 〈 0.05). Additionally, there was a significant difference in correlation coefficients between the activated PCSA-peak torque relationship and the PCSA-torque relationship (P 〈 0.05). These results suggested that muscle recruitment affects the PCSA-torque relationship.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 148
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 82 (2000), S. 391-396 
    ISSN: 1439-6327
    Keywords: Key words B-mode ultrasound ; Bioelectrical impedance ; Data acquisition system ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study aimed to investigate the validity of bioelectrical impedance and ultrasonographic methods for predicting the muscle volume of the upper arm. Bioelectrical impedance of the right upper arm and the thickness of elbow flexor and extensor muscles were measured from 26 healthy young adult men using a specially designed bioelectrical impedance data acquisition system and brightness-mode ultrasound apparatus, respectively. As reference data, the muscle volume (MVMRI) of the right upper arm was determined using a magnetic resonance imaging method. The impedance index was calculated as L 2/Z, where L is the upper arm length and Z is the impedance of the shoulder to the elbow. The muscle volume (MVULT) was calculated as π·(d/2)2·L, where d is muscle thickness. L 2/Z and MVULT were significantly correlated with MVMRI with correlation coefficients of 0.971 and 0.962, respectively. In these relationships, the standard errors of estimation were 44.2 cm3 (6.3%) for L 2/Z and 50.7 cm3 (7.2%) for MVULT. There was no significant difference between the absolute errors of muscle volumes estimated by L 2/Z and MVULT: 36.2 (4.8, SEM) cm3 for L 2/Z versus 40.3 (5.8) cm3 for MVULT. The present results suggest that both bioelectrical impedance and ultrasonographic methods may be useful for predicting the muscle volume of the upper arm.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 149
    ISSN: 1615-6692
    Keywords: Key Words Right ventricle ; Arrhythmias ; Left bundle branch block ; Dysplasia ; Fatty infiltration ; Magnetic resonance imaging ; Schlüsselwörter Rechter Ventrikel ; Arrhythmien ; Linksschenkelblock ; Dysplasie ; Fettige Degeneration ; Kernspintomographie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die arrhythogene rechtsventrikuläre Dysplasie (ARVD), eine Herzmuskelerkrankung unlarer Ätiologie, ist pathologisch durch fettige Degeneration des rechtsventrikulären Myokards gekennzeichnet. Die klinischen Symptome umfassen strukturelle und funktionelle Malformationen des rechten Ventrikels, krankhafte elektrokardiographische Befunde und das Auftreten ventrikulärer Tachykardien mit Linksschenkelblock oder plötzlichem Herztod. Die Krankheit tritt familiär gehäft auf und wird autosomal vererbt. Neben der rechtsventrikulären Dilatation stellen rechtsventrikuläre Aneurysmen typische Fehlbildungen bei ARVD dar. Sie sind im so genannten “Dysplasiedreieck”, das heißt rechtem ventrikulärem Ausflusstrakt, Herzspitze und Infundibulum, verteilt. Dort lokalisierte ventrikuläre Aneurysmen können als pathognomonisch für die ARVD angesehen werden. Ein weiteres typisches Merkmal der ARVD ist die fettige Degeneration der freien rechten Ventrikelwand. Diese funktionellen und strukturellen Charakteristika sind bei der klinischen Untersuchung mit bildgebenden Verfahren wie Kontrastangiographie, Echokardiographie, Radionuklidangiographie, ultraschneller Computertomographie und Magnetresonanztomographie (MRT) von Bedeutung. Unter diesen Verfahren erlaubt die MRT die deutlichste Darstellung des Herzens, insbesondere bei Beteiligung des rechten Ventrikels, der sich mit den anderen bildgebenden Methoden in der Regel schwerer untersuchen lässt. Darüber hinaus bietet die MRT den wesentlichen Vorteil der Darstellung der fettigen Degeneration als helles Signal im rechtsventrikulären Myokard. Die MRT liefert die wichtigsten anatomischen, funktionellen und morphologischen Kriterien zur Diagnose einer ARVD in einem einzigen Untersuchungsgang. Daher scheint sie das beste bildgebende Verfahren zur Identifizierung und Nachsorge von Patienten mit klinischem Verdacht auf ARVD zu sein.
    Notes: Abstract Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called “triangle of dysplasia”, i. e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 150
    ISSN: 1573-9686
    Keywords: Heart ; Left ventricle ; LV contractility ; ESPVR ; Pig ; Rat ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The end systolic pressure–volume relation (ESPVR) has been shown to be a relatively load independent measure of left ventricular (LV) contractility. Recently, several single-beat ESPVR computation methods have been developed, enabling the quantification of LV contractility without the need to alter vascular loading conditions on the heart. Using a single-beat ESPVR method, which has been validated previously in humans and assumes that normalized elastance is constant between individuals of a species, we studied the effects of myocardial infarction on LV contractility in two species, the rat and the pig. In our studies, LV pressure was acquired invasively and LV volume determined noninvasively with magnetic resonance imaging, at one week postinfarction in pigs and at 12 weeks postinfarction in rats. Normalized systolic elastance curves in both animal species were not statistically different from that of humans. Also, the slope of the ESPVR $$\left( {E_{es} } \right)$$ decreased significantly following infarction in both species, while the volume-axis intercept $$\left( {V_0 } \right)$$ was unaffected. These results indicate that a single-beat ESPVR method can be used to measure the inotropic response of the heart to myocardial infarction, and that the basis for this method (i.e., constant normalized elastance) is applicable to a variety of mammalian species. © 2000 Biomedical Engineering Society. PAC00: 8719Uv, 8761Lh, 8719Hh, 8719Rr, 8719Ff
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 151
    ISSN: 1439-099X
    Keywords: Schlüsselwörter: Strahlentherapieplanung ; Stereotaxie ; Magnetresonanztomographie ; FLAIR-Bildgebung ; Gliome ; Metastasen ; Key Words: Radiotherapy planning ; Stereotaxie ; Magnetic resonance imaging ; FLAIR imaging ; Glioma ; Metastases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Background: FLAIR MR imaging has shown to be a valuable imaging modality in pathologic lesions of the brain including intraaxial brain tumors. The aim of the study was to assess the value of a FLAIR technique in the planning process of stereotactic radiotherapy in patients with cerebral gliomas and metastases. Patients and Methods: Thirty-five patients with cerebral gliomas and 12 patients with a total of 39 cerebral metastases were examined by T2/PD-weighted fast spin-echo, fast FLAIR prior and after contrast and contrast enhanced T1-weighted spin-echo using identical slice parameters. The images were evaluated by using quantitative and qualitative criteria. Quantitative criteria were tumor-to-background and tumor-to-cerebrospinal fluid contrast and contrast-to-noise. The qualitative evaluation was performed as a multireader analysis concerning lesion detection, lesion delineation and image artifacts. Results: In the qualitative evaluation (Tables 3 and 6), all readers found the fast FLAIR images to be superior to fast spin-echo in the exact delineation of cerebral tumors (p 〈 0.001) and the delineation of enhancing and non enhancing tumor parts. Fast FLAIR was superior in the delineation of cortically located and small lesions but was limited in lesions adjacent to the ventricles. Fast FLAIR provided a significantly better tumor-to-CSF contrast and tumor-to-CSF contrast-to-noise (p 〈 0.001) (Tables 1, 2a, 2b, 4, 5). The tumor-to-background contrast and tumor-to-background contrast-to-noise of the fast FLAIR images were lower than that of T2-weighted spin-echo images but were significantly increased after the application of contrast media. FLAIR images had more image artifacts, but the image interpretation was not influenced. Conclusions: FLAIR MR imaging was found to be a valuable sequence in the planning protocol of stereotactic radiotherapy. The concurrent presentation of enhancing and non enhancing tumor tissue on contrast enhanced fast FLAIR imaging enables to use a single imaging sequence in the treatment protocol. This enables to load a reduced image amount into the radiotherapy planning software, is therefore time saving and reduces potential errors.
    Notes: Hintergrund: Eine FLAIR-(fluid attenuated inversion recovery-)Sequenz wurde in der stereotaktischen Strahlentherapieplanung zerebraler Gliome und Metastasen im Vergleich zu konventionellen Spin-Echo-(SE-)Sequenzen eingesetzt. Überprüft wurde die Wertigkeit dieser Methode anhand der Läsionserkennbarkeit, Läsionsabgrenzung und des Tumorkontrastes. Patientengut und Methode: 35 Patienten mit zerebralen Gliomen und zwölf Patienten mit insgesamt 39 zerebralen Metastasen wurden mit einer FLAIR-Sequenz vor und nach Kontrastmittel, einer T2- und PD-gewichteten SE-(FSE-)Sequenz und einer kontrastmittelunterstützten T1-gewichteten SE-Sequenz untersucht. Eine quantitative Auswertung umfaßte Tumor-zu-Hintergrund- und Tumor-zu-Liquor-Kontrast und Kontrast-zu-Rausch-Bestimmungen. In einer qualitativen Auswertung wurden die Erkennbarkeit und Abgrenzung der Tumoren anhand einer Multireader-Analyse beurteilt. Ergebnisse: Der Tumor-zu-Hintergrund-Kontrast bei zerebralen Gliomen war auf den nativen FLAIR-Aufnahmen den konventionellen FSE-Aufnahmen unterlegen. Beide Reader fanden die FLAIR-Technik aufgrund der Liquorunterdrückung in der Läsionsabgrenzung der T2- und Protonen-gewichteten FSE-Technik hingegen überlegen. Nach Kontrastmittelgabe stieg das Signal bei anreichernden Tumoren auf den FLAIR-Bildern im Mittel um 49%, wodurch der Tumor-zu-Hintergrund-Kontrast den der konventionellen Aufnahmen signifikant (p 〈 0,001) übertraf. Durch die Kontrastmittelgabe wurde auch die Abgrenzung der infiltrativen Tumoranteile signifikant (p 〈 0,001) verbessert. Bei Patienten mit zerebralen Metastasen konnten mittels kontrastmittelunterstützter FLAIR-Aufnahmen signifikant mehr Metastasen als mit nativer FLAIR- und T2/PD-gewichteter FSE-Sequenz, jedoch weniger als mittels kontrastmittelverstärkter T1 SE-Sequenz erkannt werden. Der Nachteil lag hierbei in der geringen Detektionsrate bei sehr kleinen, subkortikal gelegenen Metastasen. Vorteil der Methode war jedoch wie bei den zerebralen Gliomen die gleichzeitige Darstellung von anreicherndem Tumor und umgebendem Ödem. Artefakte nahe der Liquorräume sind auf FLAIR-Bildern häufig, sie störten die Bildinterpretation jedoch nicht wesentlich. Signalhyperintensitäten aufgrund physiologischer Gliosezonen an den Ventrikelrändern sind ebenfalls häufig zu beobachten und müssen in die Bildinterpretation einbezogen werden. Schlußfolgerung: Zusammengefaßt bietet sich die FLAIR-Technik als eine wertvolle Bildgebungssequenz in der stereotaktischen Strahlentherapieplanung von zerebralen Tumoren an. Durch die Verwendung kontrastmittelunterstützter FLAIR-Technik kann sowohl die Definition der radiologischen als auch der makroskopischen Tumorränder auf einer einzigen Bildgebungssequenz erreicht werden. Dieses ist insbesondere für das Einladen der Bilddaten in die verwendeten Bestrahlungsplanungssysteme von Vorteil, da die Bilddatenmenge deutlich reduziert, der Arbeitsaufwand für zusätzliche Bildfusionen vermindert und mögliche Fehlerquellen bei der Bildfusion vermieden werden können.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 152
    ISSN: 1439-7609
    Keywords: Key words Extensibility ; Supraspinatus muscle ; Tendon fiber ; Rotator cuff tear ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An estimate of the extensibility of the supraspinatus muscle after a rotator cuff tear is useful in selecting the most appropriate operative procedure and the prognosis after surgery. We studied the relationship between the morphological findings of the supraspinatus muscle on magnetic resonance imaging and its elongation length. Twenty-one shoulders of 20 patients with massive rotator cuff tears were scanned parallel to the long axis of the supraspinatus muscle. The ratio of the largest width of the supraspinatus muscle belly to the distance from the greater tuberosity to the proximal end of the supraspinatus muscle was termed the supraspinatus muscle belly ratio. The appearance of linear bands and the degree of retraction of the tendon of the supraspinatus muscle were analyzed. The extensibility of the supraspinatus muscle decreased when the degree of retracted tendon was high, while no correlation was found with the length of the rotator cuff defect, the supraspinatus muscle belly ratio, or the appearance of linear bands.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 257 (2000), S. 24-26 
    ISSN: 1434-4726
    Keywords: Key words Pharyngeal neoplasms ; Rhabdomyoma ; Magnetic resonance imaging ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Adult rhabdomyomas of the head and neck are uncommon benign skeletal muscle tumors. Only a few cases occurring in the pharyngeal wall have been described in the world literature. We present a case of recurrent bilateral rhabdomyomas in the pharynx and discuss the clinicopathological features of this lesion, comparing it to those of other neoplasms from which it must be differentiated. To our knowledge, bilaterality of this type of lesion has not been described previously. Although adult rhabdomyomas have a distinct histology, they often are mistaken for a variety of other lesions, particularly granular cell tumor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 154
    Electronic Resource
    Electronic Resource
    Springer
    Brain tumor pathology 17 (2000), S. 97-103 
    ISSN: 1861-387X
    Keywords: Intracranial plasma cell granuloma ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Plasma cell granulomas (PCGs) are benign, inflammatory masses of unknown etiology composed of polyclonal mature plasma and lymphoid cells. The lung is their most common location, and occurrence within the cranial cavity is extremely rare. We report the case of an 11-year-old girl who presented with seizures and was diagnosed as having a dural-based right frontal tumor that extended toward the sagittal sinus and the falx. The lesion was totally excised, together with the abnormal dura. A limited cortical excision was also performed using electrocorticographic guidance. Histopathologic diagnosis of intracranial plasma cell granuloma was reached after extensive immunohistochemical tests and electron microscopy. This is the third case of PCG with description of changes in the neighboring cerebral tissue. Although PCGs are well-circumscribed lesions, lymphoplasmocytic inflammation, neuronal loss, and reactive gliosis occur within the adjacent cortex. Disturbed cortical lamination, as we have observed, appears to be a histological finding that has not been described previously.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    Springer
    Neurological sciences 21 (2000), S. S865 
    ISSN: 1590-3478
    Keywords: Key words Optic neuritis ; Multiple sclerosis ; Magnetic resonance imaging ; CSF examination ; Oligoclonal bands ; Evoked potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We evaluated the risk of developing clinically definite multiple sclerosis (CDMS) after acute isolated optic neuritis in 102 patients in a follow-up study (duration 6.5±2.0 years). The probability of CDMS was 13% after 2 years, 30% after 4 years, 38% after 6 years, and 49% after 8 and 10 years. CDMS occurred in 42 (59%) of 71 patients with brain lesions detected with magnetic resonance imaging (MRI). No patient with normal MRI exam developed the disease. Patients with 3 or more MRI-detected lesions presented a shorter first interattack interval and a higher relapse rate compared to subjects with only 1 or 2 lesions. The predictive value of CSF examination and of evoked potentials was poor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 156
    Electronic Resource
    Electronic Resource
    Springer
    Neurological sciences 21 (2000), S. S877 
    ISSN: 1590-3478
    Keywords: Key words Multiple sclerosis ; Magnetic resonance imaging ; Magnetization transfer imaging ; Diffusion-weighted imaging.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Conventional magnetic resonance imaging (MRI) has markedly increased our ability to detect the macroscopic abnormalities of the brain and spinal cord in patients with multiple sclerosis (MS). Magnetization transfer imaging and diffusion-weighted imaging have the potential to provide relevant and complementary information on the structural changes occurring within and outside these lesions and are contributing significantly to our understanding of the mechanisms leading to the accumulation of irreversible neurological disability in MS patients. These present review will summarize the major results achieved with the application of these two MR techniques to the assessment of the evolution of MS.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 157
    Electronic Resource
    Electronic Resource
    Springer
    Neurological sciences 21 (2000), S. 103-108 
    ISSN: 1590-3478
    Keywords: Key wordsL-2-Hydroxyglutaric aciduria ; Magnetic resonance imaging ; Leukodystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract L-2-Hydroxyglutaric aciduria is a rare inborn error of metabolism, marked by a large and persistent increase of L-2-hydroxyglutaric acid in urine, blood and cerebrospinal fluid (CSF). We present clinical, biochemical and neuroradiological findings of seven Italian patients aged 4–19 years presenting at different stages of the disease. The disorder was characterized by a progressive neurological syndrome with cerebellar and pyramidal signs, mental deterioration, epilepsy and subcortical leukoencephalopathy on magnetic resonance imaging (MRI). We observed a good correlation between the severity of the disease and the extent of lesions on MRI. We report the result of the first positive prenatal diagnosis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 158
    Electronic Resource
    Electronic Resource
    Springer
    Annals of biomedical engineering 28 (2000), S. 934-944 
    ISSN: 1573-9686
    Keywords: Magnetic resonance imaging ; Diffusion imaging ; Fiber orientation ; Ventricular geometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract An imaging method for the rapid reconstruction of fiber orientation throughout the cardiac ventricles is described. In this method, gradient-recalled acquisition in the steady-state (GRASS) imaging is used to measure ventricular geometry in formaldehyde-fixed hearts at high spatial resolution. Diffusion-tensor magnetic resonance imaging (DTMRI) is then used to estimate fiber orientation as the principle eigenvector of the diffusion tensor measured at each image voxel in these same hearts. DTMRI-based estimates of fiber orientation in formaldehyde-fixed tissue are shown to agree closely with those measured using histological techniques, and evidence is presented suggesting that diffusion tensor tertiary eigenvectors may specify the orientation of ventricular laminar sheets. Using a semiautomated software tool called HEARTWORKS, a set of smooth contours approximating the epicardial and endocardial boundaries in each GRASS short-axis section are estimated. These contours are then interconnected to form a volumetric model of the cardiac ventricles. DTMRI-based estimates of fiber orientation are interpolated into these volumetric models, yielding reconstructions of cardiac ventricular fiber orientation based on at least an order of magnitude more sampling points than can be obtained using manual reconstruction methods. © 2000 Biomedical Engineering Society. PAC00: 8761-c, 8757Gg
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 159
    ISSN: 0935-6304
    Keywords: Capillary HPLC ; gradient elution ; temperature programming ; phenolic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This paper describes a liquid chromatographic method using a reversed phase capillary column coupled to an UV detector for the quantitation of thirteen pollutant phenols. Chromatographic separation was carried out with gradient elution at 25.0 ± 0.1°C. The two major anisocratic elution modes (gradient elution and temperature programming) were evaluated. The detection limit range was 10-81 pg (100 nL injected). The chromatographic method combined with liquid-liquid extraction was applied to analysis of these compounds in river water. Recoveries of 75-103% were achieved for most of them.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 160
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 389-392 
    ISSN: 0935-6304
    Keywords: Capillary SFC ; zinc dialkyldithiophosphates ; lubricating oils ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 161
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 393-396 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography (SFC) ; micropacked capillary columns ; waxes ; restoring ; objects of art ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 379-385 
    ISSN: 0935-6304
    Keywords: Aroma ; “lulo del Chocó” ; Solanum topiro ; volatiles ; glycosidically bound volatiles ; glycoside TFA derivatives ; enantioselective gas chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The volatile constituents of lulo del Chocó (Solanum topiro) fruit pulp obtained by liquid-liquid extraction were analyzed by capillary GC and capillary GC-MS. In total, 30 components were identified with methyl salicylate, hexadecanoic acid, hexanal, guaiacol, ethyl butanoate, and ethyl acetate being the major components. Chirospecific MDGC analysis revealed the predominance of (R)-ethyl-3-hydroxybutanoate (ee 40%) and the presence of racemic mixtures both of δ-octalactone and of δ-decalactone. For γ-hexalactone, γ-octalactone, and γ-decalactone enantiomeric distributions of 22.4 : 77.6, 22.9 : 77.1, and 20.0 : 80.0, (R) : (S), respectively, were determined. Glycosidically bound aroma compounds were identified by capillary GC and capillary GC-MS after isolation of the glycosidic fraction obtained by Amberlite XAD-2 adsorption and methanol elution followed by hydrolysis with a commercial pectinase enzyme. In total 13 bound aroma compounds (aglycones) were identified. These aglycones mainly consisted of compounds exhibiting aromatic structures. Additionally, with the aid of capillary GC and capillary GC-MS (EI and NCI) of trifluoroacetylated derivatives we identified eight glucosides: the novel 3,6-epoxy-7-megastigmen-5,9-diol β-D-glucopyranoside and the hexyl, benzyl, linalyl oxide (furanic), 2-phenylethyl, vomifolyl (isomer 1), (6S,9R)-vomifolyl, and scopoletin β-D-glucopyranosides.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 409-412 
    ISSN: 0935-6304
    Keywords: Cyclodextrin ; capillary electrophoresis ; system peak ; CHES 1 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a running buffer containing cyclodextrins (CDs) and 2-[N-cyclohexylamino]-ethanesulfonic acid (CHES), positive system peaks were observed in the analysis of a ganglioside mixture by CE-UV. These system peaks were related to CDs in the running buffer because these peaks were also detected when a plug of solution devoid of CDs but having the same CHES concentration and pH as the running buffer was injected. Neutral CDs were separated owing to the formation of inclusion complexes with the anionic CHES ion. One possible explanation for the positive system peaks is that the anionic CD-CHES inclusion complex is displaced by co-ions with higher UV absorptivity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 565-566 
    ISSN: 0935-6304
    Keywords: Liquid chromatography ; zinc dithiocarbamate ; vulcanization accelerator ; rubber gloves ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 165
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 603-608 
    ISSN: 0935-6304
    Keywords: Solvation parameter model ; ystem constants for poly(dimethyldiphenylsiloxane) HP-5 and poly(ethylene glycol) HP-INNOWax stationary phases ; temperature ; molecular interaction ; retention models ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 561-564 
    ISSN: 0935-6304
    Keywords: Retention factors ; Cinnamomi ramulus ; high-performance liquid chromatography ; capillary electrophoresis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 590-594 
    ISSN: 0935-6304
    Keywords: Ion chromatography ; graphitic carbon stationary phases ; anions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Inorganic anions could be separated on porous graphitic carbon stationary phases in ion chromatography. Ion exchange between eluent anions and sample anions on the stationary phase was confirmed by the retention behavior and the possibility of indirect photometric detection. The elution order of anions was different from that observed for commercially available anion exchangers. Chloride, nitrate, and sulfate contained in tap water could be determined in 7 min.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 168
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 485-488 
    ISSN: 0935-6304
    Keywords: Pyrethroids ; solid-phase microextraction ; water analysis ; temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Synthetic pyrethroids are increasingly being used for insect control on field crops because of their advantageous environmental properties such as short field life, broad spectrum of insecticide activity, and relatively low mammalian toxicity. In the present work, experimental conditions were optimized for trace analysis of pyrethroids in water by using solid-phase microextraction followed by capillary gas chromatography. Effects of temperature, SPME-fiber diameter, and matrix were studied. SPME used off-line with a gas chromatograph electron-capture detection (GC-ECD) showed a linear response over a wide concentration range. Our results showed a strong temperature effect on pyrethroid extraction yield. The detection limit after 5 min of SPME-fiber exposure to the samples changed from 1 ppb (at 30°C) to 0.1 ppt (at 90°C), which is a 10000 increase in pyrethroid detection. The standard deviations of the analyte peak area ratios were typically in the range of 1-7% at 30°C and of 3 to 15% at 90°C. Best conditions for pyrethroids analysis were achieved using high temperature solution and a 100 μm polydimethylsiloxane fiber. No matrix (river water) influence was observed on detection of the investigated pyrethroids.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 19-26 
    ISSN: 0935-6304
    Keywords: Microfabrication ; monolith ; electrochromatography ; peptides ; reactive ion etching ; reversed phase ; nanocolumns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolith columns are generally fabricated by polymerization of monomers within a column. This paper reviews an alternative strategy in which the bed is microfabricated in an inorganic material by ablation. Channels of 1.5 μm width and 10 μm depth were sculpted in quartz by deep reaction ion etching. Using this approach chromatographic beds were constructed in which cubic support structures were created and arranged in rows to mimic particles in a conventional column. Beds ranging from hundreds of thousands to millions of “particles” with volumes of 15 nL to 15 μL were produced. Columns that had been derivatized with an octadecyl silane stationary phase were used to separate both low molecular weight analytes and peptides in the CEC mode. Plate height in the CEC mode was 1.2 μm at maximum efficiency.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 39-43 
    ISSN: 0935-6304
    Keywords: Monoliths ; CIM® monolithic column ; dynamic binding capacity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characterization of CIM® DEAE monolithic columns in terms of dynamic binding capacity is presented in this paper. Breakthrough experiments were performed for capacity determination. Bovine serum albumin (BSA) was used as a model protein. It is shown that CIM® monolithic columns have good batch-to-batch reproducibility as well as long-term stability. The experiments performed under different linear velocities demonstrated that the dynamic capacity is unaffected at least up to a linear velocity of 2450 cm/h. Furthermore, the breakthrough curve slope is constant, indicating that the capacity would remain constant at even higher linear velocities. The adsorption isotherm of BSA dissolved in 20 mM Tris-HCl buffer shows a constant capacity of around 30 mg/mL of support down to a concentration of 20 μg/mL. The capacity is substantially influenced by the ionic strength; however, 20% of the maximal capacity is still preserved at 0.3 M NaCl.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 171
    ISSN: 0935-6304
    Keywords: Monolith ; factor VIII ; affinity chromatography ; combinatorial peptide library ; peptide synthesis ; recombinant proteins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: FVIII is a very complex molecule of great therapeutic significance. It is purified by a sequence of chromatographic steps including immunoaffinity chromatography. A peptide affinity chromatography method has been developed using peptides derived from a combinatorial library. Spot technology using cellulose sheets has been applied for this purpose. The dual positional scanning strategy was used for identification of the amino acids in random positions. Approximately 5000 possible candidates found in the first screening round were reduced to a panel of 36. Six candidates have been selected empirically. Five peptides seem to be directed against the light chain of FVIII, one peptide seems to be directed against the heavy chain. The peptides have been immobilized on conventional beaded material and CIM polymethacrylate monoliths. Much better performance with respect to capacity and selectivity has been observed with the monolithic material. Exposure of the ligand and its ensuing accessibility are responsible for these properties.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 172
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 67-72 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; monolithic column ; electroosmotic flow ; retention mechanism ; aromatic compound ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new kind of monolithic capillary electrochromatography column with poly(styrene-co-divinylbenzene-co-methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically. The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed-phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 73-80 
    ISSN: 0935-6304
    Keywords: Continuous-bed ; sol-gel ; octadecylsilica ; mixed-mode stationary phase ; large-pore ; column technology ; capillary electrochromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Sol-gel bonded packing materials in continuous-bed columns have been prepared for capillary electrochromatography (CEC). Three packing materials were investigated: small-pore Spherisorb ODS1 (3 μm, 80 Å) with octadecyl as stationary phase, small-pore mixed-mode Spherisorb ODS/SCX (3 μm, 80 Å) with octadecyl and propyl sulfonic acid as stationary phases, and large-pore Nucleosil ODS (7 μm, 1 400 Å) with octadecyl as stationary phase. The characteristics of these columns were compared in terms of electroosmotic flow, efficiency, inertness, and retention factors. In contrast to columns containing sol-gel bonded ODS, columns containing sol-gel bonded mixed-mode ODS/SCX generated nearly pH independent electroosmotic flow (EOF) over pH 2-9. Columns containing sol-gel bonded large-pore ODS produced nearly three times lower reduced plate height than those containing small-pore ODS. Efficiencies of 220,000 plates per meter and 175,000 plates per meter were obtained from columns containing sol-gel bonded 7 μm, 1 400 Å ODS and columns containing sol-gel bonded 3 μm, 80 Å ODS, respectively, which are among the highest reported efficiencies for continuous-bed columns. In CEC, over one million plates per meter and pH independent EOF are expected from continuous-bed columns containing sol-gel bonded 1.5 μm particles with large pores and mixed-mode stationary phases.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 81-88 
    ISSN: 0935-6304
    Keywords: Monolithic chromatography columns ; capillary electrochromatography (CEC) ; micro high performance liquid chromatography ; sol-gel based columns for chromatography ; fritless capillary chromatography columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Particle-loaded (3 μm, octadecylsilica) monolithic sol-gel columns have been prepared and selected characteristics measured. Several electrical properties may be calculated from simple current measurements in the column as a whole. Resistivity in the packed segment is approximately three times that in open segments, resulting in a 60% increase in field strength in the packed regions compared to the capillary with no packing. The surprisingly high specific permeability of these sol-gel columns is characteristic of 8-μm particles, which allows their operation in the microLC mode at pressures as low as 69 kPa where their efficiency is about 50,000 plates per meter and in the CEC mode where efficiency is about 106,000 plates per meter at 5 kV. There is a relatively rapid loss of efficiency with increasing linear velocity beyond 0.2 mm/s in microLC mode, which may be due to additional diffusion processes in the inter-particulate voids. A rapid loss of efficiency above 0.5 mm/s is also observed in the CEC mode, for the same reasons. Chromatographic retention behavior in either separation mode is characteristic of conventional octadecylsilica particles, indicating that analytes have significant access to the surface within the pores of the immobilized bonded phase.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 89-92 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; packed columns ; fritless columns ; stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Fritless packed silica gel columns were prepared using sol-gel technology. A part of a 75 μm i.d. fused silica capillary was filled with a mixture of tetramethoxysilane and poly(ethylene glycol). After gelling at 40°C and heating at 300°C, the resultant silica gel was derivatized with dimethyloctadecylchlorosilane. A scanning electron micrograph of a cross-section of the capillary column showed that the gel took the form of a spherical particle aggregate and adhered to the column inner wall. The column performance was evaluated for electrochromatography using acetonitrile-50 mM HEPES buffer (pH 6.6) (60/40 or 40/60, v/v) as the mobile phase. An electroosmotic flow of 1.0 mm/s was generated with (60/40, v/v) acetonitrile/HEPES buffer at a field strength of 546 V/cm. Using a sol-gel-derived packed column at an electroosmotic flow of 0.5 mm/s, efficiencies of up to 1.1×105 plates/m were obtained for retained solutes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 176
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 93-99 
    ISSN: 0935-6304
    Keywords: HPLC ; monolithic column ; silica rod column ; fast separations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The application of a new silica-based, monolithic-type HPLC-column for fast separations is presented. The column is prepared according to a new sol-gel process, which is based on the hydrolysis and polycondensation of alkoxysilanes in the presence of water soluble polymers. The method leads to “rods” made of a single piece of porous silica with a defined pore structure, i. e. macro- and mesopores. The main feature of silica rod columns is a higher total porosity, about 15% higher than of conventional particulate HPLC columns. The resulting column pressure drop is therefore much lower, allowing operation at higher flow rates including flow gradients. Consequently, HPLC analysis can be performed much faster, as it is demonstrated by various applications.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 177
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 3-18 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; monolithic columns ; synthetic polymers ; stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monolithic materials have quickly become a well-established stationary phase format in the field of capillary electrochromatography (CEC). Both the simplicity of their in situ preparation method and the large variety of readily available chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. This review summarizes the contributions of numerous groups working in this rapidly growing area, with a focus on monolithic capillary columns prepared from synthetic polymers. Various approaches employed for the preparation of the monoliths are detailed, and where available, the material properties of the resulting monolithic capillary columns are shown. Their chromatographic performance is demonstrated by numerous separations of different analyte mixtures in variety of modes. Although detailed studies of the effect of polymer properties on the analytical performance of monolithic capillaries remain scarce at this early stage of their development, this review also discusses some important relationships such as the effect of pore size on the separation performance in more detail.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 100-105 
    ISSN: 0935-6304
    Keywords: Preparative chromatography ; silica monoliths ; PrepROD™ ; productivity ; SMB-chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The use of monolithic silica sorbents for the isolation of substances by preparative liquid chromatography is demonstrated. Preparative liquid chromatography is recognized as a valuable technique for the isolation and purification of substances in the pharmaceutical and fine chemicals industry. The system technology has meanwhile reached a high standard, and the greatest future improvements are expected to arise from new and improved adsorbents. Monolithic silica sorbents offer some unique features for preparative liquid chromatography. They exhibit high efficiencies even at high flow rates due to their fast convective mass transfer and can therefore be used at very high mobile phase velocities, leading to high productivity and hence to maximum process economy. The benefits of this new type of adsorbent are illustrated for an example in batch-chromatographic mode and an example using the continuous simulated moving bed (SMB) technology.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 179
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 106-110 
    ISSN: 0935-6304
    Keywords: Silica ; monolithic column ; aging ; mesopores ; pore size distribution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Mesopore formation in silica gels having continuous macropores has been investigated. The macroporous wet silica gel prepared by the sol-gel process including phase separation was aged in a basic solvent making use of hydrolysis of urea in a closed condition. The mesopore structure was finally obtained by subsequent evaporation drying of solvent and heat-treatment at 600°C for 2 h. The dissolution-reprecipitation kinetics at the interfaces between wet gel skeletons and an external solvent affected the size and volume of pores formed within the skeletons. Below 120°C, mesopores suitable for various chromatographic applications have been formed typically within 24 h. On the other hand, at 200°C, the pore size attained the macropore dimensions (〉50 nm), and the whole macroporous morphology was significantly modified.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 180
    ISSN: 0935-6304
    Keywords: Monolithic column ; silica monolith ; HPLC ; capillary liquid chromatography ; capillary electrochromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Two types of monolithic silica columns derivatized to form an ODS phase, one prepared in a fused silica capillary (SR-FS) and the other prepared in a mold and clad with an engineering plastic (poly-ether-ether-ketone) (SR-PEEK), were evaluated. The column efficiency and pressure drop were compared with those of a column packed with 5-μm ODS-silica particles and of an ODS-silica monolith prepared in a mold and wrapped with PTFE tubing (SR-PTFE). SR-FS gave a lower pressure drop than a column packed with 5-μm particles by a factor of 20, and a plate height of 20 μm at a linear velocity below 1 mm/s. SR-PEEK showed higher flow-resistance than the other monolithic silica columns, but they still showed a minimum plate height of 8-10 μm and a lower pressure drop than popular commercial columns packed with 5-μm particles. The evaluation of SR-FS columns in a CEC mode showed much higher efficiency than in a pressure-driven mode.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 181
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 119-126 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; retention volume ; real gas carrier ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of the calculation and interpretation of the net retention volume with a real gas as carrier is revisited. The properties of the carrier are described by a first order virial equation of state. The net retention volume of a solute is related to the mean flow rate of the carrier, therefore determination of the mean flow rate of a real gas carrier is reviewed. It is shown that the mean flow rate cannot be calculated from the mean column pressure. With a real gas carrier the local capacity factor depends on the local pressure of the real gas. The basic relationship between the net retention volume and the function describing this pressure dependence is also reviewed. Precise formulae as well as practical approximations are presented for the calculation of the mean flow rate, of the mean column pressure, and of a representative pressure related to the mean capacity factor.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 182
    ISSN: 0935-6304
    Keywords: Chemiluminescence ; diol compound ; oxalate ; post-column reaction ; ruthenium complex ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In this paper we propose a new post-column detection method for polyols containing 1,2-diol, 1,3-diol, and saccharides. The polyols are oxidized in a photochemical reactor to yield oxalate with subsequent chemiluminescence detection using [Ru(III)(bpy)3]3+. A mixing solution of eluate and oxidizing reagent is delivered to a reaction coil, which is then irradiated with ultraviolet light to promote the oxidation reaction. The detection limits for 1,2-ethanediol (ethylene glycol) and 1,3-propanediol were 38 pmol and 23 pmol, respectively.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 183
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 131-137 
    ISSN: 0935-6304
    Keywords: On-line coupled LC-GC ; nitrogen selective detection ; NPD ; carbazoles ; PANH ; personal exposure measurement ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A coupled LC-GC method for the analysis of carbazole-type PANH has been developed and evaluated. Group separation and isolation of carbazoles from interfering acridines in a complex sample matrix was accomplished by using a back-flush technique and an in situ end-capped dimethylaminopropyl silica column in the HPLC part of the system. On-line injection of the carbazole fraction into the GC column was performed with a loop-type interface utilizing concurrent solvent evaporation technique. An LOD of 1-3 pg of individual carbazole compounds was achieved by nitrogen selective detection using an NPD. The method is shown to be robust and is demonstrated by application to personal exposure measurement in an aluminum reduction plant.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 138-142 
    ISSN: 0935-6304
    Keywords: Capillary electrochromatography ; nucleosides ; short-end injection ; phenyl-bonded silica ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The influence of several experimental parameters (pH, ionic strength, organic modifier content of hydro-organic buffer) upon EOF, migration time, and retention factor has been studied in CEC with a phenyl-bonded silica column on a model mixture of five nucleosides. This paper illustrates the current interest in CEC as a method of resolving complex mixtures of neutral and ionic solutes and demonstrates the potential of the short-end injection method as a means of reducing analysis time.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 185
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 143-148 
    ISSN: 0935-6304
    Keywords: Analysis of anthraquinones ; capillary electrophoresis ; high-performance liquid chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The separation and determination of twelve anthraquinones, viz. anthraquinone 1, chrysphanol 2, aloe-emodin 3, alizarin 4, anthraquinone-2-carboxylic acid 5, purpurin 6, sennoside B 7, sennoside A 8, emodin 9, quinalizarin 10, rhein 11, and anthraflavic acid 12, were achieved by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). Detection at 260 nm with a buffer solution containing 30 mM sodium borate (adjusted to pH = 10.56 with 0.05N NaOH) and acetonitrile (9 : 1) in CE or with a linear gradient elution containing 20 mM KH2PO4 with 0.05% phosphoric acid (pH = 2.91) and methanol in HPLC was found to be the most suitable approach for this separation. Contents of six components (2, 3, 7, 8, 9, 11) in crude Rhei Rhizoma extract could easily be determined within 39 min by CE or 63 min by HPLC. The effects of buffers on this separation and the validation of the two methods were studied.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 186
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 156-157 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; trichlorophenols ; ammonia ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 149-155 
    ISSN: 0935-6304
    Keywords: Capillary GC ; fast GC ; on-column injection ; narrow-bore column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In this work a fast gas chromatography set-up with on-column injection was optimized and evaluated with a model mixture of C8-C28 n-alkanes. Usual injection volumes when using narrow-bore (e. g., 0.1 mm i.d.) analytical columns are ca. 0.1 μL. The presented configuration allows introduction of 10-30-fold larger sample volumes without any distortion of peak shapes. In the set-up a normal-bore retention gap (1 m×0.32 mm i. d.) was coupled to a narrow-bore (4.8 m×0.1 mm i. d.×0.4 μm film thickness) analytical column using a low dead volume column connector. The effects of the experimental conditions such as inlet pressure, sample volume, initial injection temperature, and oven temperature on a peak focusing are discussed. H-u curves for helium and hydrogen are used to compare their suitability for high speed gas chromatography and to show the dependence of separation efficiency on the carrier gas velocity at high inlet pressures. In the fast gas chromatography system a baseline separation of C10-C28 n-alkanes was achieved in less than 3 minutes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 182-188 
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional gas chromatography ; GC×GC ; thermal modulation ; oil analysis ; petroleum analysis ; analysis of middle-distillate oil fractions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Comprehensive two-dimensional gas chromatography (GC×GC) is an utterly suitable separation technique for the analysis of complex samples, such as oil fractions. Once the two columns and the operating conditions are properly tuned, the technique is able to provide a detailed characterization of such materials. Some considerations applying to the tuning of a GC×GC system for a specific separation are presented and discussed. The authors present a number of different column sets and conditions which allow the separation of a non-aromatic hydrocarbon solvent, a kerosene, the light end of a crude oil, and an olefinic fraction, respectively. The highly structured GC×GC chromatograms, together with chemical knowledge about the samples, provide a much more comprehensive characterization of the samples than hitherto possible.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 189
    ISSN: 0935-6304
    Keywords: Comprehensive two-dimensional gas chromatography ; thermal desorption modulator ; temperature programming ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---In comprehensive two-dimensional gas chromatography, two individual separations are coupled by means of a rotating thermal desorption modulator interface. The injection pulse introduced via the interface onto the second column should be as short as possible. Parameters affecting the modulator operation are studied. In the set-up used in this study, the temperature of the second column can be programmed independently from that of the first column. Optimization of the second-dimension separation to minimize peak broadening and maximize resolution is discussed and an elegant approach to determine second-dimension retention times using a non-constant modulation frequency is demonstrated. The high separation power of the comprehensive system is demonstrated by the analysis of technical and biota samples containing chlorinated biphenyls and toxaphene.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 190
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 197-201 
    ISSN: 0935-6304
    Keywords: Multidimensional gas chromatography ; comprehensive two-dimensional gas chromatography ; GC×GC ; oxygenates ; MTBE ; reformulated gasoline ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Comprehensive two-dimensional gas chromatography (GC×GC) has been applied to the quantitation of oxygenates in reformulated gasoline. Target oxygenates were C1-C4 alcohols, tert-pentanol, methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These were separated from the gasoline matrix using a volatility-based selectivity in the first chromatographic dimension, followed by a mixed-phase polarity/shape selectivity in the second dimension. The high resolving power of this stationary phase combination completely separated all oxygenates except DIPE, ETBE, and TAME, which exhibited coelution with other nonpolar gasoline components. Oxygenates quantitation was achieved with the use of an internal standard, an FID detector, and calibration curves. Quantitation results are in good agreement with ASTM and EPA standard methods. When coupled with our previous method for BTEX and aromatics, a single GC×GC method can now quantitate MTBE, alcohols, BTEX, and aromatics in a one-hour analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 191
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 474-478 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Solid-phase extraction, on-line derivatization, and measurement by ion trap mass spectrometry (ITD-MS) were used to investigate the biological degradation of pharmaceutical residues (clofibric acid, ibuprofen, diclofenac). The results of the single steps of sample pretreatment and analytical determination are reported. MS/MS measurements were performed on an ITD-MS by selecting collision induced dissociation of the molecular ions (M+) as parent ions to defined daughter ions. A pilot sewage plant and biofilm reactors operating under oxic and anoxic conditions were run as model systems with synthetic sewage water containing 10 to 50 mg/L dissolved organic carbon (DOC) and pharmaceuticals in concentrations of 10 μg/L. Clofibric acid displayed its persistent character in all cases. The pilot sewage plant and the oxic biofilm reactor showed comparable results for diclofenac and ibuprofen, which both were partly degraded. These results can explain the occurrence of these substances in sewage effluents and in the aquatic environment. A high degree of degradation was found especially for ibuprofen in the oxic biofilm reactor, which was attributed to adaptation of the biofilm to the residue. Two metabolites of ibuprofen could be identified on the basis of their mass spectra and comparison with literature data, viz. hydroxyibuprofen and carboxyibuprofen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 192
    ISSN: 0935-6304
    Keywords: Silicone oil ; supercritical fluid chromatography (SFC) ; micropacked columns ; MALDI-TOF ; GC/MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 193
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 511-514 
    ISSN: 0935-6304
    Keywords: CZE ; indirect UV detection ; metal ions ; ecological samples ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 194
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 297-303 
    ISSN: 0935-6304
    Keywords: Sample preparation ; gas extraction techniques ; membrane-type techniques ; water analysis ; soil analysis ; gas chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---This review focuses on the role of so-called solventless methods of sample preparation in contemporary environmental analysis. The basic classification of this group of methods as well as the principal features and advantages of the techniques in current use are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 253-258 
    ISSN: 0935-6304
    Keywords: Comprehensive gas chromatography ; cryogenic modulation ; semi-volatile aromatics ; thermal sweeper ; peak widths ; peak asymmetries ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The two current technologies for achieving comprehensive gas chromatography (GC×GC) - the thermal sweeper and the cryogenic modulator - are compared in an interlaboratory study using a multicomponent semi-volatile aromatic compound sample. The same column set (phases, film thickness, dimensions of columns) and conditions of oven temperature program were used. Carrier gas flow settings however were different for the data reported here. The thermal sweeper has a longer overall length due to the extra ca. 30 cm length of narrow bore tubing used for the modulator/accumulator section. Data reveal that the two methods behave in an analogous manner in respect of delivering GC×GC results, with key peak parameters of peak widths and symmetry measures showing good correlation. Retention time dissimilarity on the first dimension columns in the two systems arises from different flow rates used, however the second column retention is similar, and this is due to the resulting different elution temperatures that peaks elute on the first dimension in each system. Overall, the two approaches to GC×GC appear to produce equivalent results within the scope of the application studied. Each system does have its experimental limitations; the thermal sweeper has what may be called a ‘thick film effect’, where at high temperature it can be difficult to sufficiently trap the migrating bands in the accumulator column, and the pulsing of solutes in the cryogenic system may suffer from a ‘thick wall effect’ if a column with too thick a wall dimension is used at low oven temperature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 196
    ISSN: 0935-6304
    Keywords: Proteomics ; protein analysis ; multidimensional HPLC ; ion-exchange chromatography ; reversed phase chromatography ; comprehensive HPLC ; two-dimensional HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The interactive modes of High Performance Liquid Chromatography (HPLC) of proteins provide a platform for the construction of a multidimensional HPLC system coupled to mass spectrometry. We present a system composed of both anion and cation exchanger columns, in the first dimension, and n-octadecyl bonded 1.5 μm nonporous silica columns in the second dimension. Both columns are operated under gradient conditions. A system suitability test with standard proteins showed that the total analysis can be performed within about 20 minutes. The fractions taken from the ion exchanger column are directly analyzed within one minute on the reversed phase column at a high flow rate. Two reversed phase columns are applied and operated alternatively: while the first column performs the separation within one minute, the analytes leaving the first dimension are enriched in an on-column focusing mode on top of the second column. The sample clean-up and enrichment is performed on a novel type of restricted access cation exchanger column with internal sulfonic acid groups and external diol groups. The columns exhibit a molecular weight exclusion limit for globular proteins of about 15 kDa. Our next studies will be directed towards the analysis of proteins and peptides from extracts of fibroblasts.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 197
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 343-347 
    ISSN: 0935-6304
    Keywords: SPME ; desorption ; fiber conditioning ; field sampling ; sample preparation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 198
    ISSN: 0935-6304
    Keywords: Silver ion high-performance liquid chromatography (Ag-HPLC) ; conjugated linoleic acid (CLA) ; p-methoxyphenacyl derivatives ; single-column Ag-HPLC ; fatty acid analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---No abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 199
    ISSN: 0935-6304
    Keywords: Artemisia palustris ; Asterothamnus centrali-asiaticus ; capillary gas liquid chromatography ; Compositae (Asteraceae) ; Heteropappus hispidus ; seed oil ; silver ion thin layer chromatography ; trans-fatty acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Seed oils from the Compositae plant family are known to contain a variety of unusual fatty acids. Subsequent to the recent discovery of γ-linolenic acid in Saussurea and Youngia, further Mongolian Compositae species were investigated for their seed oil fatty acid composition. A number of δ3trans-fatty acids (16 : 1δ3t, 18 : 1δ3t and 18 : 3δ3t, 9c, 12c) were found in the seed oils of Heteropappus hispidus and Asterothamnus centrali-asiaticus. The latter fatty acid, but not the trans-monoenes, was also found in one species of Artemisia. These unusual fatty acid isomers were characterized by capillary gas-liquid chromatographic (GLC) separations in combination with other chromatographic techniques (analytical thin layer chromatography, TLC and preparative argentation TLC), and infrared spectrocsopy (IR). Their identity was further confirmed by co-chromatography with other seed oils known to contain these trans-fatty acids. The fact that within the Compositae plant family there are apparently two or three distinct groups of genera containing δ3trans-fatty acids is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 200
    ISSN: 0935-6304
    Keywords: 2H/1H ratio analysis ; HRGC-P-IRMS ; stable isotopes ; benzaldehyde ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Isotope ratio monitoring gas chromatography-mass spectrometry of the 2H/1H ratio by pyrolysis isotope ratio mass spectrometry (P-IRMS) was used to analyze benzaldehyde originating from various sources. Based on the δ2HSMOW value of an authentic reference sample determined with an elemental analyzer (EA), the range of reproducibility and linearity was checked. Correct (EA related) and reproducible data were obtained for sample amounts 〉0.6 μg benzaldehyde (on column). In another series of experiments, the influence of sample preparation, i. e. simultaneous distillation-extraction (SDE) was found to be negligible. The following ranges of δ2HSMOW values were determined for benzaldehyde using five types of samples, i. e. (i) synthetic (δ2HSMOW -78 to -85‰, ex benzal chloride; +420 to +668‰, ex toluene) and ‘natural’ (including ‘ex-cassia’) references (δ2HSMOW -83 to -144‰); (ii) bitter almond oils (δ2HSMOW -113 to -148‰); (iii) fruits (δ2HSMOW -111 to -146‰); (iv) kernels (δ2HSMOW -115 to -188‰); and (v) leaves (δ2HSMOW -165 to -189‰).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...