Biomedical subjects
Publications and source records attributed to A M De Schepper.
MR imaging is the study of choice for the examination of patients with suspected acoustic schwannoma, because of its high sensitivity, especially after the use of contrast material. This essay illustrates the common MR features of acoustic schwannomas as seen in a study of 84 tumors. We pay special attention to the role of MR imaging in the distinction between acoustic schwannoma and meningioma.
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Since well-known grading parameters such as cellularity, mitotic rate, matrix and presence of necrosis all influence MRI signal intensity, the value of MRI in predicting malignancy is potentially high. To assess this value we studied retrospectively the findings in 141 soft tissue tumours (84 benign, 57 malignant) and evaluated a wide variety of MRI features (size, margins, signal homogeneity, shape, signal intensity, neurovascular and bone involvement, degree and pattern of enhancement and evidence of necrosis after injection of Gd-DTPA). Statistical analysis was carried out to determine accuracy of parameters individually and in combination, for predicting malignancy. Highest sensitivity was obtained for "absence of low signal intensity on T2" (100%), "mean diameter greater than 33 mm" (90%), and "inhomogeneous signal on T1" (88%). Highest specificity was obtained for "evidence of necrosis" (98%), "bone or neurovascular involvement or metastases" (94%), and "mean diameter greater than 66 mm" (87%). Association of best sensitivity and specificity was seen for "absence of low signal intensity on T2", "signal inhomogeneity on T1", and "mean diameter of the lesion greater than 33 mm" (81 and 81%).
The value of magnetic resonance imaging (MRI) in histological classification was studied in a series of 164 histologically proven soft tissue tumors (STT) and was rather limited. MRI was only valuable in characterization of lipomatous, vascular and fibrous tumors. There are two main reasons for this limitation i.e. STT belonging to the same histological group may have different composition or different proportions in tumor components resulting in different MRI signals. Secondly tumor components may change individually or proportionally during natural evolution or as a consequence of therapy. Because well known grading parameters such as cellularity, mitotic rate, matrix and presence of necrosis all influence MRI signal intensity, the value of MRI in predicting malignancy is potentially high. To assess this value we retrospectively studied the findings in the first 141 soft tissue tumors (84 benign, 57 malignant) and evaluated a wide variety of MRI features (size, margins, signal homogeneity, shape, signal intensity, neurovascular and bone involvement, degree and pattern of enhancement and evidence of necrosis after injection of Gd-DTPA). Statistical analysis was carried out to determine accuracy of parameters individually and in combination, for predicting malignancy. Highest sensitivity was obtained for "absence of low signal intensity on T2" (100%), "mean diameter > 33 mm" (90%) and "inhomogeneous signal on T1" (88%). Highest specificity was obtained for "evidence of necrosis" (98%), "bone or neurovascular involvement or metastases" (94%) and "mean diameter > 66 mm" (87%). Association of best sensitivity (81%) and specificity (81%) was seen for "absence of low signal intensity on T2", "signal inhomogeneity on T1" and "mean diameter of the lesion > 33 mm". In a prospective study of 23 consecutive patients we reevaluated sensitivity and specificity in predicting malignancy of all parameters. Excellent correlation with the results of the retrospective study was found. Although a quantitative approach to the staging potentials of MRI was not possible, well known staging parameters are evaluated to the best by this method (size, depth, compartmental versus extra-compartmental location, relationship to adjacent structures).
Despite the increasing importance of MR imaging, CT investigation remains a very useful and frequently applied method in the study of ankle pathology. In a short pictorial essay, the contribution of this technique to the diagnosis of soft tissue pathology of the ankle is discussed and illustrated.
The authors describe the MR appearance of extra-abdominal desmoid in three patients, with longitudinal follow-up during a period of up to 29 months in two of them. For the MR examinations various pulse sequences, including spin-echo and gradient-echo sequences, were used. Both non-enhanced and Gd-DTPA contrast enhanced studies were made. We found gradient-echo T2*-weighted sequences best suited for the detection of extra-abdominal desmoids. Best correlation between MR features and histologic findings was obtained on spin-echo T2- and contrast enhanced T1-weighted studies. Although preliminary, our results suggest that MRI might predict evolution of extra-abdominal desmoids by providing data about cellularity and relative amount of mucoid matrix of the lesions.
Three cases of calcific tendinitis occurring at an unusual site (vastus lateralis tendon) are described. Findings on conventional radiography and computed tomography together with the clinical history are characteristic for this disorder and reflect its natural evolution. The actual role of magnetic resonance imaging seems limited to excluding neoplasm and to demonstrating inflammatory changes better in the early stages of disease.
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The authors report an unusual case of jejunal mesenchymal hamartoma which presented as a bleeding pedunculated polyp in a 67-year-old woman. The lesion was detected by enteroclysis and resected after localization by intraoperative endoscopy.
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A case of multiple inverted papillomas of both ureters, in association with a bladder carcinoma, is presented. Inverted papilloma is a rare benign urothelial tumor. Because of its curability by conservative surgery, it should be considered in the differential diagnosis of a ureteral filling defect and ureteral obstruction. Inverted papilloma may be associated with carcinomas of the urinary tract.
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Two cases of eosinophilic fasciitis are described, in which magnetic resonance imaging (MRI) clearly demonstrated thickening of the fascia and increased signal intensity in the superficial muscle fibers correlating with inflammation. MRI is a useful noninvasive imaging technique in the diagnosis of eosinophilic fasciitis and can guide biopsy of selected abnormal areas.
Cocaine drug packets were found in the gastro-intestinal tract of seven persons, charged with and arrested for presumed drug smuggling. Plain abdominal roentgenograms were positive in 4, while computer tomography of the abdomen (CT-scan) was necessary in 3 others to make the diagnosis. There were no signs of acute intoxication or bowel obstruction. All patients were treated with enemas and/or laxatives in order to evacuate the hidden packets; no complications occurred. A clinical description of the seven cases is followed by a short review of the literature, mainly focused on the possible complications of ingested drug packets and possible methods of removal.
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The computed tomographic appearance of the polysplenia syndrome in 2 cases is presented. Both are associated with absence of the hepatic segment of the inferior vena cava. Computed tomography can determine the exact location of the malpositioned organs, the presence of multiple spleens, and the type of the associated venous anomalies, which are the major features of the polysplenia syndrome.