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Biomedical subjects

G Cosnard

Publications and source records attributed to G Cosnard.

At least 73 records · Page 4Linked to original sources

[Stereotaxy, MRI and independent computer. 85 punctures].

After 150 stereotactic biopsy with CT, the team of Val-de-Grâce has made these ones with MRI and simulation of the complete procedure with an independent computer. The result of 85 biopsies is reported. This one imply the acquisition of 3DFT millimetrics slices, the transfer by Ethernet network on a computer where a specific software treat the data and allow to establish the better course for the needle biopsy. The constraints of quality are very important and some test must be executed. The diagnosis are established, avoiding an unless trepanation.

Adult↗

[Thrombosis of the cerebral veins. X-ray computed tomography and MRI imaging. 11 cases].

11 cases of cerebral venous thrombosis in adults are reported. Main clinical signs are: intracranial hypertension (headache, nausea, papilledema in 7 cases, loss of consciousness in 6 cases, neurological deficit in 6 cases, seizure in 4 cases. 1 patient is dead, who did not receive heparin treatment. Delay before diagnosis is between 2 and 20 days, and is shortened when arteriography or MRI are available and prescribed. At least one (or several) CT examination was performed in 10 patients. Direct signs of thrombosis are uneasily detected without contrast injection, seen here in 4 cases. Empty delta sign is observed in 7 patients, lately in 4 cases, and once only afterwards. Cerebral infarction is visualized in 7 cases over 10. Its features frequently seem evocative for cerebral venous thrombosis: triangularin 4 cases or nodular shape in 3 cases with hemorragic infarct in 7 cases, with bilateral topography in 6 cases, in frontal or central areas in 7 cases. 6 patients had a MRI examination. All cerebral infarctions appeared haemorragical, even at early stages. During subacute period, venous thrombosis is constantly and easily detected by the mean of methemoglobin high signal intensity on T1 weighted images. The prediagnosis delay is short, without necessity of arteriography. MRI should take the place of CT and arteriography in investigation of a clinically suspected cerebral venous thrombosis.

Adult↗

[Rare tumors of the cerebellopontine angle].

Tumours of the cerebellopontine angle are essentially benign in adults, are generally treated surgically and require a preoperative assessment as precise as possible. MRI simplifies the diagnostic assessment; it is indicated as the first-line investigation and is usually sufficient whenever a tumour of the posterior cranial fossa is suspected. Acoustic neuromas represent 75% of all tumours of the cerebellopontine angle. Other tumours are rare and essentially consist of meningioma, detected in 10 to 14% of cases and cholesteatoma in 1 to 5% of cases. Cholesteatoma, with a pathognomonic appearance, must be distinguished from arachnoid cyst. Other tumours are exceptional. The authors define the diagnostic criteria based on their experience and present a recent review of the literature.

Cerebellar Neoplasms↗

[Disk highlighting after injection in MRI. Macroscopy and histology of 25 postoperative recurrences].

400 cases of failed back syndrome were examined with MRI in a prospective study (SE w Rho and T2, SE wT1 before and after injection of paramagnetic contrast agent in axial and sagittal planes). After second time surgery, 70 cases of herniated disks were found. 25 herniated disks were studied in microscopy and results correlated with enhanced herniated disks. Authors describe 4 types of enhancement: veinous plexus (5/24), inflammatory or granulomatous tissue (12/24), degenerative disc with fibrosis (5/24) and osteophytosis (2/24). The criterions of each pattern are described.

Adult↗

[Relations between neurinoma of the VIII cranial nerve and the porus of the internal auditory meatus. Apropos of 110 cases].

110 cases of neurinomas of the VIIIth with APC extension (104 patients) were studied using MRI or CT. Classically, it is said that the tumoral mass is centered on the IAC. In our study, among 110 cases of neurinomas, only 9 were centered along the axis of IAC on axial slices and only 23 on coronal slices. The anterior development of the tumor is never more than 1 cm, except in 3 cases of large and multicystic neurinoma. We suggest that the anterior development of large tumors is limited by the VIIth nerve.

Adolescent↗

MRI and cranial traumas in the acute phase.

The authors have reviewed 12 cases of severe cranial trauma examined by MRI and determine the position of this method in exploration in the acute phase. Since the 1970's, computerized tomography (CT) has completely modified the emergency diagnosis. Intra- and extracerebral blood effusions are readily recognized, but the patient is often in a dangerous situation and little help is obtained from CT which does not detect shearing lesions located in the white matter, the corpus callosum or the brain stem. Early MRI examination performed with gradient-echo sequences provides a better anatomico-clinical correlation, a better prognostic approach and even a new therapeutic approach.

Acute-Phase Reaction↗

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↗

[Value of investigation tests in thoracic goiters].

Two groups of substernal goiters should be considered fist; the "simples" ones localised in the anterior and superior part of the mediastin. They are most common and less dangerous. By opposition to the "complexes" ones which have relation with the vessels, the airways and the digestive tube. That surgeons would like to approach with security. The study of those retrosternal goiters requires two categories of complementary examinations. One for diagnosis: X Ray standard of the neck and the chest; Echography Biopsy and Radioactive Iodine scintigraphy. Others for localisations to prevent the risks, particularly vascular seeing in the surgery of the substernal goiters: TDM and IRM.

Biopsy, Needle↗

[Cancer of the testis, sarcoidosis and neurinoma].

The association of testicular cancer, sarcoidosis and neuroma is reported. Review of the literature revealed the rarity of the association of testicular cancer and sarcoidosis which is probably a chance association, but which is important in the context of staging, as overstaging may lead to useless or even dangerous treatment.

Adult↗

[MRI: projectiles, bullets and counter-indications].

The authors present an overview of contraindications of MRI studies with bullets and projectiles. All shell splinters are ferromagnetic. There is a very large variety of bullets and their study cannot be exhaustive. In addition, same bullets of different series can be or not ferro-magnetic. Therefore, all projectiles must be considered as ferromagnetic until evidence of the contrary is found.

Ferric Compounds↗

[Spontaneous hematoma of the mediastinum].

We report a case of spontaneous mediastinal haematoma. This unusual clinical entity, though uncommon, must be considered in any patient presenting with the typical triad of symptoms of acute superior mediastinal compression, widening of the superior mediastinum on chest radiographs, bruises on the neck appearing within 48 hours of exertion, sneezing, coughing or vomiting. The signs observed with computed tomography in mediastinal haemorrhage are described. The exact source of the haemorrhage remains unknown despite careful radiological investigation and thoracotomy.

Hematoma↗

[Aneurysmal bone cyst of the ethmoid. Apropos of a case].

Repeated epistaxis in a 12 year old child revealed an aneurysmal bone cyst of ethmoid, an exceptional localization for this lesion. Modern imaging techniques (CT scan, NMR) provided precise data on its extent, primordial for decision as to surgical approach. NMR imaging was more effective than the CT scan for diagnosis, since blood lakes were identified, and for determination of extent, since tumoral elements were distinguished from sinusal retentions.

Bone Cysts↗