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  • 1
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Magnetresonanzspektroskopie ; Protonenspektroskopie ; Knochenmark ; Lendenwirbelsäule ; Relaxometrie ; Keywords Magnetic resonance (MR) spectroscopy ; Magnetic resonance (MR) proton studies ; Bone marrow ; Lumbar vertebrae ; Relaxometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Background. Magnetic resonance imaging has shown to be a sensitive method for diagnostics of the red bone marrow, the composition of which changes physiologically and during pathological processes. However, the interpretation of MRI in patients with disorders of the red bone marrow is very difficult. The aim of this study was the characterization of the proton spectrum of healthy bone marrow and its age- and sex-dependent changes to obtain a data basis for measurements in patients. Methods. 154 healthy volunteers have been examined. After imaging, a spectroscopic measurement was performed to determine the relative intensities of fat and water, and their respective T2 times. Results. While T2 (water: 46.9 ms and fat: 75.4 ms) does not depend on age or sex, the relative signal intensity of fat increases by about 6% per decade. In the age groups between 31 and 50 years it diverses significantly between men (43.5%) and woman (32.5%) (p≤0.01, Mann-Whitney-Test. Conclusions. Proton spectroscopy can increase the reliability of diagnosis by offering information on composition of the marrow. The analysis of spectroscopic measurements requires exact knowledge about normal physiological values.
    Notes: Zusammenfassung Hintergrund. Die Magnetresonanztomographie ist ein sensitives bildgebendes Verfahren zur Beurteilung des roten Knochenmarkraums. Die Zusammensetzung des Knochenmarks ändert sich mit zunehmenden Alter, aber auch bei krankhaften Prozessen. Als Basis für die Interpretation von Patientenuntersuchungen bei Erkrankungen des hämatopoetischen Systems wurden im Rahmen der vorliegenden Studie an Probanden die alters- und geschlechtsabhängigen Veränderungen des Protonenspektrums aus dem Knochenmarkraum analysiert. Methode. Bei 154 gesunden Probanden wurde nach einer MR-Bildgebung eine spektroskopische Messung des Lendenwirbelkörpermarks zur Bestimmung der relativen Fett- und Wasseranteile sowie der T2-Relaxationszeiten durchgeführt. Ergebnis. Die T2-Zeiten (46,9 ms für Wasser, 75,4 ms für Fett) zeigen keine Alters- oder Geschlechtsabhängigkeit. Der relative Fettanteil steigt pro Dekade um ungefähr 6% an und ist bei Frauen im Alter von 31–50 Jahren signifikant geringer als bei Männern gleichen Alters (p≤0,01, Mann-Whitney-Test). Schlussfolgerungen. Es ist zu hoffen, dass durch die ergänzende Protonenmagnetresonanzspektroskopie die Deutung der MR-Bildgebung bei Patienten mit pathologischem Markraumsignal erleichtert werden kann. Die erarbeitete Methode ist in einem zeitlich und technisch vertretbaren Rahmen am Patienten einsetzbar, die Interpretation solcher Messungen setzt allerdings genaue Kenntnisse der physiologischen Verhältnisse voraus.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European radiology 10 (2000), S. 832-840 
    ISSN: 1432-1084
    Keywords: Key words: Osteochondroma ; Complications ; Chondrosarcoma ; Bone tumors ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Osteochondromas can be complicated by mechanical irritation, compression or injury of adjacent structures, fracture, malignant transformation, and postoperative recurrence. Magnetic resonance imaging represents the most valuable imaging modality in symptomatic cases, because it can demonstrate typical features of associated soft tissue pathology, which can be differentiated from malignant transformation. Reactive bursae formation presents as an overlying fluid collection with peripheral contrast enhancement. Dislocation, deformation, and signal alterations of adjacent soft tissue structures can be observed in different impingement syndromes caused by osteochondromas. Magnetic resonance imaging provides excellent demonstration of arterial and venous compromise and represents the method of choice in cases with compression of spinal cord, nerve roots, or peripheral nerves, depicting changes in size, position, and signal intensity of the affected neural structures. Malignant transformation as the most worrisome complication occurs in approximately 1 % of solitary and 5–25 % of multiple osteochondromas. Magnetic resonance imaging is the most accurate method in measuring cartilage cap thickness, which represents an important criterion for differentiation of osteochondromas and exostotic (low-grade) chondrosarcomas. Cartilage cap thickness exceeding 2 cm in adults and 3 cm in children should raise the suspicion for malignant transformation. Finally, MR imaging can detect postoperative recurrence by depiction of a recurrent mass presenting typical morphological features of a cartilage-forming lesion.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1084
    Keywords: Key words: CT ; Pulmonary coin lesion ; Diagnostic errors ; Observer variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to assess interobserver variability in size determination of pulmonary nodules at spiral CT. Twenty-three patients with known pulmonary nodules (diameter 2–40 mm, mean diameter 7 mm) underwent spiral chest CT (collimation 5 mm, pitch 1). Images were reconstructed at 3- and 5-mm intervals (RI). Hard copies were analyzed by two radiologists who recorded every nodule with regard to location, diagnostic confidence (“definite,”“probable”) and nodule size in increments of 1 mm with specific attention to correct classification into one of three size classes (≤ 5 mm, 6–10 mm, 〉 10 mm). Interobserver variability was determined with Pearson's correlation coefficient and k measure. Of a total of 286 nodules, 103 nodules were found accordingly by both readers at 3 mm RI, and 96 at 5 mm RI. There was a good correlation of measurements (in millimeters) between both readers (Pearson's correlation coefficient: 0.89–0.95). Interobserver variability in categories was good at both reconstruction intervals (k: 0.61 at 3 mm, 0.74 at 5 mm RI) and very good (0.81) at 5 mm RI when uncertain nodules were excluded. Spiral CT allows reproducible size determination of pulmonary nodules as shown by good interobserver agreement in exact size measurement and categorization into three size classes.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1084
    Keywords: Contrast media ; Comparative study ; Intravenous digital subtraction angiography ; Iodixanol ; Iopamidol ; Kidney function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Iodixanol (visipaque, 320 mgI/ml) was compared with iopamidol (Solutrast, 370 mfI/ml) in a double-blind, randomized, parallel group, intravenous DSA phase-III trial for evaluation of safety and efficacy. A total of 117 patients received iodixanol (n = 60) or iopamidol (n = 57). Diagnostic efficacy was evaluated using categoric and visual analogue scales. Discomfort and adverse evenets were recorded. A total of 39 patients collected urine up to 72 h after the examination for analysis. Diagnostic efficacy and radiographic density were similar in both groups. Discomfort was milder with iodixanol. The difference between the frequency of adverse events between both groups (iodixanol = 7, iopamidol = 2) was without statistical significance. Creatinine clearance was slightly more affected by iodixanol, whereas the increase in renal excretion ofN-acetyl-beta-glucosaminidase (NAG) in the first 24 h collection period after the examination was significantly higher (p 〈 0.01) with iopamidol. Iodixanol was of equal diagnostic efficacy compared with iopamidol despite its reduced iodine content. Both contrast media are well suited for IV DSA.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1084
    Keywords: Key words: Liver neoplasms ; Surgery ; Echinococcosis ; Focal nodular hyperplasia ; Hemangioma ; US ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of our work was to provide data on the recurrence of resected benign hepatic lesions and to evaluate the value of follow-up examinations in this group of patients. From August to October 1993, 75 patients who had been admitted for liver surgery for benign tumors between 1975 and 1993 were controlled by physical examinations, serological tests, US, and, in the case of equivocal US findings, by CT. The histological diagnoses of the operative specimen included hydatidosis in 43 patients, focal nodular hyperplasia (FNH) in 12 patients, liver cell adenoma in 8 patients, cavernous hemangioma in 8 patients, and congenital cyst in 4 patients. Hepatic scars were observed in 36 of the 75 patients. Four cases of intrahepatic recurrence and 1 case of intraperitoneal spread were observed in the 42 patients with recent hydatosis. Long-term postoperative controls (specific serological tests, US) are necessary in the management of patients with hydatid disease. Follow-up examinations are not indicated in asymptomatic patients who have been operated on for FNH, hemangioma, or congenital cysts.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1084
    Keywords: Key words: Balloon test occlusion ; Somatosensory evoked potentials ; Cerebral ischemia ; Cerebrovascular reserve capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to evaluate somatosensory evoked potentials (SEP) as a simple neurophysiological monitoring method in supra-aortal balloon test occlusions (BTO). The 13 patients examined had carcinoma of the larynx (n = 6), nasopharyngeal malignancy (n = 3), sphenoid meningioma (n = 2), mycotic aneurysm (n = 1), and a tumor of the carotid body (n = 1). Transfemoral balloon occlusion of the internal carotid artery was maintained for 30 min and monitored both clinically and by SEP. None of the 13 patients showed neurological deficits or pathological changes in the SEP. No thromboembolic complications occurred during BTO. In 11 cases the cervical vessels could be spared or reconstructed during surgery. No neurological symptoms occurred during the clinical follow-up. One patient died the day after BTO due to cardiac arrest. Neurophysiological monitoring of preoperative BTO using SEP is a technically simple method. A similar method has been shown to have a high sensitivity and reliability in carotid surgery.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using localized proton magnetic resonance spectroscopy (1H-MRS), accumulation of branchedchain amino acids (BCAA) and their corresponding 2-oxo acids (BCOA) could be non-invasively demonstrated in the brain of a 9-year-old girl suffering from classical maple syrup urine disease. During acute metabolic decompensation, the compounds caused a signal at a chemical shift of 0.9 ppm which was assigned by in vitro experiments. The brain tissue concentration of the sum of BCAA and BCOA could be estimated as 0.9 mmol/l. Localized1H-MRS of the brain appears to be suitable for examining patients suffering from maple syrup urine disease in different metabolic states.
    Type of Medium: Electronic Resource
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