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  • 1
    ISSN: 1432-1084
    Keywords: Key words: Perfusion-weighted MRI ; Cerebral perfusion ; Parameter images ; Cerebrovascular disease ; Brain tumours
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of the present study was to analyse specific advantages of calculated parameter images and their limitations using an optimized echo-planar imaging (EPI) technique with high spatial and temporal resolution. Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) was performed in 12 patients with cerebrovascular disease and in 13 patients with brain tumours. For MR imaging of cerebral perfusion an EPI sequence was developed which provides a temporal resolution of 0.68 s for three slices with a 128 × 128 image matrix. To evaluate DSC-MRI, the following parameter images were calculated pixelwise: (1) Maximum signal reduction (MSR); (2) maximum signal difference (ΔSR); (3) time-to-peak (Tp); and (4) integral of signal-intensity-time curve until Tp (SInt). The MSR maps were superior in the detection of acute infarctions and ΔSR maps in the delineation of vasogenic brain oedema. The time-to-peak (Tp) maps seemed to be highly sensitive in the detection of poststenotic malperfused brain areas (sensitivity 90 %). Hyperperfused areas of brain tumours were detectable down to a diameter of 1 cm with high sensitivity ( 〉 90 %). Distinct clinical and neuroradiological conditions revealed different suitabilities for the parameter images. The time-to-peak (Tp) maps may be an important advantage in the detection of poststenotic “areas at risk”, due to an improved temporal resolution using an EPI technique. With regard to spatial resolution, a matrix size of 128 × 128 is sufficient for all clinical conditions. According to our results, a further increase in matrix size would not improve the spatial resolution in DSC-MRI, since the degree of the vascularization of lesions and the susceptibility effect itself seem to be the limiting factors.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0942-0940
    Keywords: Meningioma ; brain oedema ; tumour margin ; tumour-brain interface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Peritumoural brain oedema was examined retrospectively in 175 patients with 179 intracranial meningiomas. The influence of tumour size, location and histology were investigated. Tumour volume and localization, and the presence of peritumoural brain oedema (PTBOe) were determined by computed tomography (CT). The oedema-tumour volume ratio was defined as Oedema Index (Oel). All patients underwent microsurgical removal of the tumour. Surgically resected meningiomas were classified histopathologically based on criteria of the new World Health Organization (WHO) classification. A close relationship was found between the tumour size and the incidence of peritumoural oedema: with increasing size of the tumour the incidence of oedema also rises, the oedema index, however decreases. Frontobasal and temporobasal meningiomas showed a significant increase in the oedema incidence and the mean oedema index. If major parts of the surface of meningiomas were adjacent to subarachnoid cisterns only a slight tendency for the development of oedema was observed. WHO-III-meningiomas showed a significantly higher oedema incidence (61.1% vs. 94.4%; p〈0.004) and mean oedema index (Oel=2.7 vs. 3.7; p〈0.0009) than WHO-I-meningiomas. Brain tissue was affected in 59 cases. 19 meningiomas with infiltration into adjacent brain parenchyma revealed a statistically significant increase in oedema incidence (94.7% vs. 51.7%; p〈0.0003) and mean oedema index (Oel=3.9 vs. Oel=2.2; p〈0.0001) when compared to tumours without any brain tissue involvement in the histopathological specimens. Tumours with large volume, fronto-temporo-basal location and anaplastic histology were not only associated with the highest incidence of oedema formation but also presented with an overproportionate infiltrative growth. Thus, a disruption of the arachnoid or a true brain infiltration may be an essential factor for the development of a PTBOe.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0942-0940
    Keywords: Keywords: Meningioma; vascular endothelial growth factor; pial supply; angiogenesis; brain oedema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The correlation between angiographic neovascularization, peritumoural brain oedema (PTBOe) and the expression of vascular endothelial growth factor (VEGF) , was analysed in 30 patients with intracranial meningiomas. Pre-operative angiograms were examined for the existence of either an exclusively dural tumour blush or an additionally pial tumour supply from cerebral arteries. Furthermore the presence of macroscopic tumour-neovascularization and dysplastic changes of tumour-draining cerebral veins was evaluated. VEGF expression was investigated on histological tissue samples, using immunohistochemical techniques. VEGF immunohistochemistry and neuroradiological evaluations were performed in double blind fashion. Tumour volume and the amount of oedema were calculated by computerized tomography (CT) or magnetic resonance imaging (MRI). The oedema-tumour volume ratio was defined as oedema index (OeI). Compared to VEGF-negative meningiomas, tumours with striking VEGF staining revealed a significant higher mean oedema index (OeI=4,2 vs. OeI=1,5; p〈0.018), and a higher oedema incidence (91,7% vs. 44,4%; p〈0.046). Equally, meningiomas with additionally tumour supply from cerebral arteries were associated with a significant higher mean OeI (OeI=4.1 vs. OeI=1.2; p〈0.01) and oedema incidence (94,7% vs. 20,0%; p〈0,0023) than meningiomas with exclusively tumour supply from dural arteries. All meningiomas with striking VEGF-expression were associated with vascular tumour supply from cerebral arteries, but VEGF-negative tumours only in 50% (p〈0.029). These data suggest a link between VEGF-expression, arterial tumour supply and peritumoural brain oedema. The development of tumour supply from cerebral arteries may be important for formation of meningioma-related oedema. Therefore, VEGF may represent a potent mediator in the evolution of this type of vascularization in meningiomas.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 42 (2000), S. 795-802 
    ISSN: 1432-1920
    Keywords: Key words Corpus callosum ; Ischaemia ; Demyelination ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract MRI has facilitated diagnostic assessment of the corpus callosum. Diagnostic classification of solitary or multiple lesions of the corpus callosum has not attracted much attention, although signal abnormalities are not uncommon. Our aim was to identify characteristic imaging features of lesions frequently encountered in practice. We reviewed the case histories of 59 patients with lesions shown on MRI. The nature of the lesions was based on clinical features and/or long term follow-up (ischaemic 20, Virchow-Robin spaces 3, diffuse axonal injury 7, multiple sclerosis 11, hydrocephalus 5, acute disseminated encephalomyelitis 5, Marchiafava-Bignami disease 4, lymphoma 2, glioblastoma hamartoma each 1). The location in the sagittal plane, the relationship to the borders of the corpus callosum and midline and the size were documented. The 20 ischaemic lesions were asymmetrical but adjacent to the midline; the latter was involved in new or large lesions. Diffuse axonal injury commonly resulted in large lesions, which tended to be asymmetrical; the midline and borders of the corpus callosum were always involved. Lesions in MS were small, at the lower border of the corpus callosum next to the septum pellucidum, and crossed the midline asymmetrically. Acute disseminated encephalomyelitis and the other perivenous inflammatory diseases caused relatively large, asymmetrical lesions. Hydrocephalus resulted in lesions of the upper part of the corpus callosum, and mostly in its posterior two thirds; they were found in the midline. Lesions in Marchiafava-Bignami disease were large, often symmetrically in the midline in the splenium and did not reach the edge of the corpus callosum.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Chemotherapie ; ALL ; AML ; Anfälle ; Kernspintomographie ; Infratentoriell ; Key words Chemotherapy ; ALL ; AML ; Seizures ; MRI ; Infratentorial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Two children on chemotherapy for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) had initially focal, then generalized seizures of short duration. Magnetic resonance imaging (MRI) revealed in one case minor parietal, cortical and subcortical increased signal on T2-weighted images. In a second case extended supratentorial lesions and additional signal changes in the cerebellum were found. Although chemotherapy was continued, a few days later signal changes were considerably reduced or had disappeared. We consider these lesions to be seizure induced in a brain previously sensitized by chemotherapy. Discussion: If post-ictal MRI-imaging shows signal changes, differential diagnosis has to consider other reasons like leukemic infiltrations, encephalitis or hypertensive encephalopathy. However, before extensive diagnostic procedures (e.g. repetitive lumbar punctures) are undertaken, a short-term MRI follow-up should be performed: reversibility within a few days can render the differential diagnosis of transient epileptogenic changes very likely. A temporary anti-epileptic treatment seems to be indicated. Chemotherapy has not to be suspended.
    Notes: Zusammenfassung Bei 2 Kindern kam es während des ersten Zyklus einer Chemotherapie bei akuter myeloischer Leukämie und akuter lymphatischer Leukämie zu kurzdauernden fokalen, sekundär generalisierten Krampfanfällen. Die kernspintomographische Untersuchung am Anfallstag bzw. 2 Tage postiktal zeigte in 1 Fall nur geringere supratentorielle subkortikale Signalanhebungen im T2-gewichteten Bild. Im 2. Fall fanden sich sowohl ausgedehnte supra- als auch infratentorielle Veränderungen. Trotz Fortsetzung der Chemoterapie waren diese nach wenigen Tagen bereits deutlich rückläufig bzw. rückgebildet. Sie werden daher als anfallsbedingte Veränderungen im Zusammenwirken mit der Chemotherapie angesehen. Diskussion: Bei unmittelbar postiktal gefundenen kernspintomographischen Veränderungen sind differentialdiagnostisch andere Ursachen (zerebrale Beteiligung im Rahmen der Grundkrankheit, entzündlich, hypertensiv) zu erwägen. Ähneln jedoch die gefundenen Läsionen morphologisch den hier beschriebenen, so empfiehlt sich eine kurzfristige Verlaufskontrolle bevor weitergehende diagnostische (z.B. wiederholte Lumbalpunktionen) oder therapeutische Maßnahmen ergriffen werden: Anfallsinduzierte Veränderungen sind nach unserer Erfahrung innerhalb weniger Tage rückläufig. Eine vorübergehende antikonvulsive Behandlung scheint sinnvoll. Die Chemotherapie braucht nicht unterbrochen zu werden.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Knee surgery, sports traumatology, arthroscopy 7 (1999), S. 249-256 
    ISSN: 1433-7347
    Keywords: Key words Pigmented villonodular synovitis ; Shoulder ; Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Sports Science
    Notes: Abstract Pigmented villonodular synovitis (PVNS) as reviewed in detail elsewhere most frequently involves the knee and finger synovial structures; shoulder involvement is rare: A search through the English literature yielded 18 publications describing 25 cases of PVNS affecting the shoulder joint. Analyzing these reports we found the clinical and radiological findings generally to be nonspecific, often mimicking a malignancy, as in the case presented here of a 16-year-old boy with painful swelling in the area of the left proximal humerus. Magnetic resonance imaging showed a suspected malignant soft tissue mass involving the shoulder capsule and measuring 7.5 × 6 × 4 cm. Preoperatively the patient could recall no trauma; however, postoperatively he did report a distorsion trauma of the affected shoulder following a bicycle accident. Intraoperatively, two tumors were found infiltrating the axillary vessels and nerve and tendon structures originating in the capsule of the shoulder joint. Rapid sections of the tissue revealed no signs of malignancy; further pathohistological examination revealed localized PVNS. Preoperatively, the shoulder joint was not suspected as the primary site of origin of the tumor because the patient had no complaints or functional deficits of the shoulder. The clinical presentation of such a PVNS lesion over the proximal humerus is unusual and to date has only twice been described in the literature.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-7373
    Keywords: non-Hodgkin's lymphoma ; primary central nervous system lymphoma ; clinical presentation ; CSF analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunocompetent patients with primary central nervous system lymphoma (PCNSL) present with a median age of 55 years, immunosuppressed patients with a median age of 40 years. They show a broad range of signs and symptoms. Symptoms of increased intracranial pressure and personality change are most frequent, followed in frequency by ataxia and hemiparesis. The median time from onset of symptoms to diagnosis is 3–5 months in immunocompetent patients and 2 months in immunodeficient patients. The time to diagnosis can be considerably longer in patients with slowly developing personality change or fluctuating symptoms due to spontaneous or steroid-induced remission of so-called sentinel lesions. Native CT scans show iso- or hyperdense lesions with homogenous contrast enhancement. T1-weighted MRI scans show hypointense and T2-weighted scans hyperintense lesions. The definitive diagnosis of PCNSL requires biopsy. In some cases, however, the definitive diagnosis may exclusively be made by the demonstration of malignant B-lymphocytes in the cerebrospinal fluid.
    Type of Medium: Electronic Resource
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