Biomedical subjects
Publications and source records attributed to T Duprez.
Local changes in the white matter underlying a focus of cortical thickening were monitored using MRI in an epileptic 2-month-old boy. We hypothesise that these changes reflected seizure-induced premature myelination.
We describe a neurologically symptom-free adolescent with aggressive vertebral body haemangiomas at two sites.
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The European High-Performance Information Infrastructure in Medicine, n(o)B3014 (HIM3) project of the Trans-European Network--Integrated Broadband Communications (TEN-IBC) program, started on March 1996 and finished on February 1997, aimed to test the medical usability of the European asynchronous transfer mode (ATM) network in medical image transmission. The Department of Radiology, University of Pisa, Pisa, Italy, and St-Luc University Hospital, Brussels, Belgium, involved in the project as healthcare partners in the radiological domain, established several connection sessions finalized to test the usability of Digital Imaging and Communication (DICOM) image transmission and interactive telediagnosis tools in the daily radiological practice. The Pisa site was connected to the Italian ATM pilot (Sirius Network) through the Tuscany metropolitan area network (MAN), while St-Luc University Hospital was connected to Belgium ATM network through the Brussels MAN. By means of international connections provided by the European JAMES project, a link between the two sites was established, connecting both national ATM networks. Due to the large variety of hardware present in the medical centers, multiplatform software tools were used and tested: central test node (CTN) release 2.8 [3], VAT [6], NV-3.3 [7], and IDI (UCL homemade multiplatform teleradiology tool for interactive visualization and processing of DICOM images). During the telediagnosis session, lead by radiologists in both hospitals, each site submitted neuroradiological clinical cases to the other for remote consultation. The connection, available for a period of two weeks, at 2-Mbit/s bandwidth, allowed the transmission of MR images (256 x 256 x 12 bit) and simultaneous multimedia interactive discussion of the cases. Both off-line transmission and review of the images, using the CTN DICOM transfer routines, and on-line interactive image discussion, using the IDI telediagnosis software, were tested successfully from the technical and medical point of view.
PURPOSE: Our goal was to determine the accuracy of MR angiography at 0.5 T for the diagnosis of intracranial aneurysms. METHODS: We retrospectively studied 140 patients, 70 with acute subarachnoid hemorrhage, who were either at high or low risk for intracranial aneurysm. Three-dimensional time-of-flight MR angiography was typically performed to cover the circle of Willis, with a volume thickness of 30 mm. Conventional spin-echo MR images and MR angiograms were reviewed together, and the results were compared with those obtained at intraarterial cerebral angiography to determine the sensitivity and specificity of MR angiography. RESULTS: Eighty-nine aneurysms (size range, 2 to 27 mm; 25 aneurysms < 5 mm) were identified at intraarterial cerebral angiography. Six aneurysms were missed by MR angiography and two were doubtful (sensitivity, 91% to 93%; specificity, 100%). Missed aneurysms were located outside the MR angiographic acquisition volume (n = 3) or on the carotid siphon (n = 3; size = 2, 3, and 5 mm). CONCLUSION: Even if MR angiography presents some restrictions in acquisition volume and spatial resolution, the detection rate of intracranial aneurysms is excellent at 0.5 T in both asymptomatic patients and in those with subarachnoid hemorrhage. A midfield system is not a restriction to the detection of intracranial aneurysms by MR examination.
We describe the case of a 76-year old woman complaining of headaches and progressive sight loss. Cerebral CT scan and MRI disclosed a large sellar tumour. Endocrine evaluation showed no evidence of pituitary hypersecretion, but a slight hyperprolactinemia related to stalk compression. A non-functioning pituitary adenoma was suspected. The pathological diagnosis was however a meningioma. In the literature, about 5% of sellar tumours are not pituitary adenomas and this is an alternate diagnosis to consider in the presence of non-secreting macroadenomas.
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OBJECTIVE: To define specific brain magnetic resonance features in methanol intoxicated patients and to evaluate the clinical relevance of monitoring these features. BACKGROUND: During the past decade magnetic resonance imaging has proven to be an exquisitely sensitive modality in depicting subtle water changes in diseased areas of the brain, allowing the definition of high-risk structures in numerous pathological conditions. METHOD: Four patients admitted to our institution for acute methanol intoxication were repeatedly evaluated by brain magnetic resonance imaging or a combination of computed tomography and magnetic resonance imaging. Common features of initial brain status were shown in all four cases and compared to those of patients presenting with other intoxications or critical deprivation states. RESULTS: Preferential localization of methanol-induced lesions within the putamina was observed in all four cases. This finding is specific compared to intoxication by other substances like carbon monoxide, or in the critical phase of metabolic disorders. The striking regression of the putaminal lesions on follow-up magnetic resonance examinations correlated with complete neurological recovery and the absence of extrapyramidal disturbance. Two patients exhibited discrete symmetric additional lesions in the medial areas of the parieto-occipital lobes. In a third one, the occipital lesions were severe. All three suffered from permanent visual impairment. The fourth patient, in whom magnetic resonance examinations failed to reveal any occipital lesion, never complained of visual disturbance though signs of optic neuropathy were detected in the visual evoked potentials. CONCLUSION: Magnetic resonance imaging appeared as a well suited neuroimaging modality in methanol intoxicated patients both in revealing a specific pattern of brain lesions and in demonstrating valuable correlation between evolution of brain changes on magnetic resonance images and clinical outcome.
Calcifications of a subependymal giant cell astrocytoma were not recognized by MR. Therefore a CT scan is recommended before stereotaxic needle biopsy in order to avoid intracerebral hemorrhage.
The authors describe a case of iatrogenic Cushing's syndrome in which an emergency orbital decompression was performed. This procedure was necessary because major ocular hypertension and severe bilateral exophthalmos had caused a decrease in visual function and recurrent painful episodes of eyeball luxation.
The authors review the general requirements for contrast enhancement after gadolinium administration, peculiar status and function of the brain-blood barrier (BBB), effect of corticoids on the broken BBB, parallelism between the effects of iodinated contrast agents on CT and gadolinium-chelates on MRI. The mechanisms producing enhancement differ completely, which explains the potential qualitative and quantitative differences between the techniques in vascular compartment or cerebral tissue. The effects of contrast medium doses and strength of the main magnetic field, contrast enhancement and time, enhancement and pulse sequence data are discussed. Rules for interpretation are the conclusion.
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We describe a case of osteosarcoma of the mandible presenting as a soft tissue mass associated with an enlargement of the mandibular canal at imaging work-up. Radiographic, isotopic, CT and MR features are reported.
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We describe the clinical presentation and surgical findings of a 42-year-old man who was found to have a unilateral sensorineural deafness due to a hamartoma of the internal auditory canal.