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Biomedical subjects

G Cosnard

Publications and source records attributed to G Cosnard.

102 records · Page 6Linked to original sources
PubMedDate not supplied

Time dependence of serial diffusion-weighted imaging features in a case of pyogenic brain abscess.

Both signal intensity on trace images and apparent diffusion coefficient measurements on mapped images evolved rapidly on serial diffusion-weighted sequences in a case of pyogenic brain abscess that was monitored primarily by MRI before a biopsy was performed. Considering only the signal intensities on the trace images would have led to an underestimation of the intrinsic tissue changes.

Adolescent↗
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

Lumbar plexus involvement with chronic inflammatory demyelinating polyneuropathy (CIDP): a variant case of the generic disorder.

We report the magnetic resonance (MR) findings in a male patient presenting with a variant chronic idiopathic demyelinating polyneuropathy (CIDP). He developed a slowly progressive weakness of the right leg associated with sensory dysfunction. Electrophysiologic studies were pathognomonic for a lower limb demyelinating polyneuropathy based on the slowed conduction velocities of the nerves. MRI showed the two major features of the disease: marked asymmetric enlargement of the lumbar plexus nerve roots and strong hypersignal of the enlarged roots on STIR images.

Humans↗
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

[MRI of the operated lumbar spine and enhancement of intradural nerve roots. 478 cases].

Authors report a study of 478 MR imaging in failed back surgery syndrome. Enhancing nerve roots were detected in 73.8%, with a significant higher percentage in male patients, and long postoperative delay. There was no significant correlation with age, enhancement of epidural scar (epidural scar was seen in 75.7%) and disk herniation (seen in 25.9%). Alteration of blood-nerve-barrier causes enhancement, but the mecanism is nuclear: mechanical, biological, immunological or Wallerian degeneration. Diagnostic and prognostic value of enhancement are not proven and a study of asymptomatic patients is necessary.

Adult↗
PubMedDate not supplied

[Rhabdomyolysis and truncular sciatica. 2 cases studied by MRI].

We report two cases of acute rhabdomyolysis in pelvic girdle muscles with sciatic palsy secondary to compression of the sciatic nerve trunk, with clinical and MRI correlation. The diagnosis of rhabdomyolysis is based on clinical and biological data, but diagnosis of compression complications secondary to swelling of the muscles, especially the compression of nerve trunk, is done by imaging. T2 weighted images give a definite anatomical evaluation. They show enlarged high signal intensity muscles and anatomic relationship with the sciatic nerve from its emergence out of pelvis, giving a good correlation between rhabdomyolysis and the compressed nervous trunk. It helps for planning a possible surgical fasciotomy. However, MRI provides only morphological informations, but not differentiates edema from necrosis in involved muscles.

Acute Disease↗
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↗
PubMedDate not supplied

[Hypersignal of the intervertebral disks in T1-weighted spin-echo MRI sequences].

In magnetic resonance imaging, when there is calcification of the intervertebral disk, signals usually become weaker in all the sequences. Exceptionally, a spontaneous hypersignal is obtained in T1 weighted spin-echo sequences. We report 4 cases of spontaneous hypersignals from disks in T1 weighted spin-echo sequences. In 3 cases, calcifications were visualized with conventional radiology or computed tomography. In 1 case, there was no calcification of the disk, but its density, compared with adjacent disks, was 20 HU greater, suggesting inframacroscopic calcification.

Adult↗
PubMedDate not supplied

[Secondary malignant tumors of the vestibulocochlear and facial nerves].

INTRODUCTION: Neuromas and meningiomas represent by far the most frequent tumors of the cerebellopontine cistern (respectively over 80% and over 10%). Secondary malignant tumors are exceptional. METHOD: Presentation of four cases of malignant tumors of the cerebellopontine cistern, either revealing or complicating a primary tumor: a bronchial cancer, a cancer of the kidney, a medulloblastoma and a lymphoma. Patients were studied in T2- and T1-weighted high-field MRI sequences before and after gadolinium injection. RESULTS: The four tumors were enhanced by gadolinium and shown to invade the internal auditory canal, including one bilateral involvement. In most cases, the tumors were slightly heterogeneous and had irregular margins. CONCLUSION: These observations suggest that other diagnoses than acoustic neuroma should be taken into account.

Adenocarcinoma↗