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Biomedical subjects

C Derosier

Publications and source records attributed to C Derosier.

35 records · Page 2Linked to original sources
PubMed1991

MRI and stereotaxis. Choice of an approach route on an independent console.

The authors report their experience of cerebral stereotaxis for biopsy purposes. Since January 1990, they have been using MRI which provides vascular images and makes it possible to simulate surgical procedures beforehand. The authors have developed a specific program on an independent console. MRI sections are acquired with a 1.5 Tesla Sigma (G.E.) apparatus in 3DFT volume and T1-weighted SPRG sequence, after gadolinium injection. The sections are memorized and reconstructed by a SUN computer. After automatic recognition of the referential of a Leksell G plane, the target and the puncture vector are chosen by a radiologist and a neurosurgeon. The X, Y, Z co-ordinates of the point of puncture and the angles of penetration into the cerebral volume are delivered automatically. Provided the entire measurement chain is constantly tested and corrected if necessary, the precision of the system is of the order of one millimetre.

Brain Mapping↗
PubMed1986

[Blue tympanic membrane. Apropos of 3 cases].

A CT scan allowed simple diagnosis of the affection in three patients with the blue tympanic membrane syndrome. Lesions included prolapse of the internal jugular vein sinus into the tympanic cavity, an aberrant trajectory of the internal carotid artery in the middle ear and a tympano-jugular glomus tumor. Angiographic investigation of the latter lesion was performed more as a pre-treatment procedure rather than for diagnostic purposes, since it served as a guide to surgery, consisting usually of embolization.

Adult↗
PubMed1986

[Delayed, triangular, hyperdense, computed x-ray tomography images of the renal parenchyma following iodide injection. Interpretation of transient renal ischemia?].

Three cases of renal ischemia diagnosed by Computed Tomography (CT) are presented. The pathophysiology of renal ischemia which accounts for the CT findings observer in these cases are reviewed. In the appropriate climate setting a diagnosis of renal ischemia may be made by CT, when a zone or zones of low attenuation after injection and enhancement of these same zones 6 to 72 hours later are observed in the kidney.

Adult↗
PubMedDate not supplied

[Primary brain lymphoma in AIDS. 17 cases studied by MRI before stereotaxic biopsies].

AIM: Determining which semiological criteria might help to suggest lymphoma when an intracerebral mass in observed in a patient with AIDS. The use of these criteria might shorten the duration of the anti-toxoplasmic test treatment and to perform puncture earlier. The fast growth of the lymphomas may account for the rapid death of these patients if untreated, but as a corollary, its increase in size can be objectively measured over a short period, about ten days. MEANS: Retrospective study of 17 lymphomas diagnosed with stereotaxic puncture. RESULTS: The most discriminating criteria are ventricular encasement or an original site in the white matter, as well as the moderate character of the edema and of the mass effect relative to the volume of the tumor. Other arguments also help: simple lesion, large size, sinuous contour, no signs of hemorrhage. CONCLUSION: The diagnosis of lymphoma can often be proposed at once. A control must then be performed very soon, with stereotaxic puncture if the volume of the lesion has increased in the meantime.

Adult↗
PubMedDate not supplied

[MRI, geometric distortion of the image and stereotaxy].

The MRI technology may be the starting-point of geometric distorsion. The mathematical preciseness of a spatial location may be disturbed and alter the guidance of an MRI interventionnal act, especially in stereotactic brain biopsy. A review of the literature shows errors of 1 to 1.5 mm. Our results show an error of 0.16 +/- 0.66 mm. The control of quality: homogeneity and calibration of magnetic-field gradients, permit an improve of the balistic preciseness and give permission to realize the guidance of a stereotactic brain biopsy with the alone MRI.

Brain Mapping↗
PubMedDate not supplied

[Emergency stereotaxic cerebral punctures].

Based on a series of about a hundred CT-guided stereotactic biopsies, the basic principles of stereotaxic approach of the brain are reviewed. The authors also report their preliminary experience of stereotaxic aspiration in the management of brain abscesses and hypertensive intracerebral hematomas. CT-guided stereotaxic aspiration is useful in the management of brain abscesses and is a viable treatment modality of hypertensive hematomas.

Adult↗
PubMedDate not supplied

[Hemorrhagic pseudocyst of pancreas. A case of X-ray computed tomography diagnosis].

Arteriography failed to detect a pancreatic pseudocyst complicated by hemorrhage, a positive diagnosis being established only after CT scanning. Identification of this rare lesion by angioscan imaging illustrates. The value of this technique, which provides data on vascular dynamics, rapidly, in the selected plane of the section. Results in this case demonstrate the very close correlation between Ct scan images and pathological findings.

Hemorrhage↗
PubMedDate not supplied

[MRI of the internal auditory meatus. Is injection of gadolinium indispensable?].

OBJECT: To compare prospectively high resolution fast spin echo T2 weighted (FSE-T2W) images and gadolinium-enhanced spin echo T1 weighted images for diagnosis of pathology of the internal auditory meatus (IAM). PATIENTS AND METHODS: 114 patients underwent MR imaging at 1.5 T with the following protocol: axial images; whole brain FSE-T2W sequence (256 matrix); 2 sequences focused on IAM with high resolution FSE-T2W acquisitions (512 matrix, 3 mm sections with 1.5 mm overlapping); pre and postcontrast T1 weighted sequences focused on IAM. Examinations were viewed by senior neuroradiologists. RESULTS: 31 lesions were detected in the IAM by high resolution FSE-T2W images; 25 lesions were found in the IAM by postcontrast T1 weighted images, i.e. 6 false-positive results and none false-negative. On the basis of 228 studied IAMs the sensitivity, specificity and negative predictive value of this high resolution FSE-T2W sequence were 100%, 97% and 100% respectively. CONCLUSION: Gadolinium enhanced sequence is not indispensable if high resolution FSE-T2W images are normal. Gadolinium-enhanced sequence remains essential in others equivocal cases (difficult diagnosis or abnormal IAM).

Adult↗