Biomedical subjects
Publications and source records attributed to S Dechambre.
We report the radiological and high resolution CT (HRCT) findings of the pulmonary involvement in a case of subtype B Niemann-Pick disease, diagnosed in an asymptomatic 22-year-old man, which was proved by bone marrow biopsy and sphingomyelinase assessment. In the present case, HRCT showed smooth interlobular septa thickening and a subtle ground-glass pattern.
OBJECTIVE: This study in myeloma patients treated with myeloablative therapy and bone marrow transplantation assessed the prognostic value of MR imaging before and after treatment of the bone marrow and the prognostic value of an index reflecting changes on MR images obtained before and after treatment. SUBJECTS AND METHODS: MR images (T1-weighted images before and after injection of gadolinium and T2(*)-weighted images) of the spine and pelvis were obtained 1 month before and 1 month after marrow transplantation in 25 consecutive patients with stage III myeloma. Pre- and posttreatment MR imaging patterns of marrow involvement (normal, focal, diffuse), number of focal lesions, and a "marrow evolution index" (0-8 on the basis of comparison of the lesions [number, size, contrast enhancement] and of the surrounding marrow background on pre- and posttreatment MR images) were determined. Hematologic and MR imaging parameters were correlated with the quality of response to treatment (complete versus partial remission) and with relapse-free and overall survival. RESULTS: Response quality did not differ among categories of patients determined on the basis of MR images. Individual MR imaging parameters did not correlate with response duration and survival. Patients with a low marrow evolution index had significantly longer relapse-free (p < 10(-3)) and overall survival (p = 0.005) than patients with a high index. CONCLUSION: Individual MR imaging parameters before and after treatment had no prognostic significance in our series of myeloma patients treated with marrow transplantation. Comparison of MR images before and after treatment using a marrow evolution index may help predict response duration and survival.
OBJECTIVE: The purpose of this study was to assess the improvement in the detection of ureteral stones on abdominal radiographs when the stones were viewed on multislice helical CT scans and maximum-intensity-projection (MIP) images. SUBJECTS AND METHODS: The study included 72 patients with renal colic who underwent abdominal radiography and multislice helical CT. For each patient, a frontal MIP image was generated, and the stone, when present, was marked with a cross on the transverse CT scan. The cross appeared automatically on the corresponding MIP image. The CT examination was used as the standard of reference. The presence and location of ureteral stones on the abdominal radiographs were assessed during three interpretation sessions. In the first session, the abdominal radiographs were viewed alone. In the second, they were viewed with the transverse CT scans. In the third, the abdominal radiographs were viewed with the CT scans and the MIP images. RESULTS: Ureteral stones were present in 58 patients. The percentage of stones detected on the abdominal radiographs was 45% when the radiographs were viewed alone, 66% when they were viewed with the CT scans (p = 0.002 vs radiographs alone), and 78% when viewed with the CT scans and MIP images (p = 0.016 vs radiographs with CT scans). CONCLUSION: The sensitivity of stone detection on abdominal radiographs was greatest when the interpreters viewed the radiographs in conjunction with the CT scans and MIP images.
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The sensitivity of diffusion-weighted MR imaging to detect a lesion within 6 hours of stroke onset was approximately 90%. The false negative results were usually small lesions (1 ml), were seen early, and were usually located in the brain stem. The specificity of this technique was nearly 100% when it was used correctly. The volume and the value of the apparent diffusion coefficient of the detected lesions provided prognostic information. After injection of a contrast agent (perfusion imaging), a time series of volumes were obtained using a T2* sensitive gradient echo EPI sequence. Hemodynamic perturbations of the cerebral parenchyma could be detected as well as the type of perturbation in the lesion. A map representing the mean transit time for each voxel was used to define the maximum volume of the perturbation. A hemodynamic penumbra was defined to be when this volume was larger than the volume detected on the diffusion images. The quantitative measure of cerebral blood flow could predict the irreversibility of the lesions when the value was below 18 ml/min/100g, and the extension of the ischemia in the penumbra zone when the value was below a threshold of 30 ml/min/100g.
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Cerebellopontine angle epidermoid tumour generally has a typical appearance with conventional MRI sequences. The lesion is irregular in shape and gives slightly higher signal than cerebrospinal fluid on T1- and T2-weighted images, with a characteristic marbled inner pattern on T1-weighted images. Diffusion-weighted imaging (DWI) can be useful for the diagnosis of an atypical epidermoid tumour. Our case report illustrates the usefulness of DWI for postoperative assessment of residual foci of tumour. The specific appearance of an epidermoid tumour is illustrated, with emphasis on apparent diffusion coefficient (ADC) measurements.
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The X-ray and CT follow-up features of unilateral peripheral pulmonary masses spontaneously varying in size and amount in a patient with limited Wegener disease are reported. Diagnosis was established by nasal biopsy and dosage of the neutrophils anti-cytoplasmic autoantibodies. The current literature over the condition is reviewed.
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