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J L Vézina

Publications and source records attributed to J L Vézina.

11 recordsLinked to original sources
PubMed1995

Magnetic resonance imaging of lateral ventricular tumours.

The authors review their experience with magnetic resonance imaging (MRI) of giant lateral ventricular tumours, placing special emphasis on the imaging features that aid in the differential diagnosis. The tumours illustrated include astrocytoma, oligodendroglioma, neurocytoma, subependymoma, metastatic lesions and subependymal giant cell astrocytoma. Because of their large size, most of these lesions cause hydrocephalus. The presence of associated edema indicates direct brain invasion or a higher grade of tumour differentiation. The degree and pattern of contrast enhancement, as well as the signal characteristics before administration of contrast agent, are nonspecific. The location of the tumour within the lateral ventricles and the patient's age are the most helpful diagnostic clues. Giant lateral ventricular tumours are uncommon, and the patients usually come to clinical attention with symptoms related to increased intracranial pressure. MRI assists in surgical planning by defining the exact location of the lesion and its relation to adjacent structures. Although the signal characteristics and patterns of contrast enhancement are nonspecific, preoperative diagnosis is possible in most cases if the imaging findings are correlated with the patient's age and the specific location of the tumour within the lateral ventricles.

Adolescent↗
PubMed1993

Radiologic correlates of reaction time measurements in olivopontocerebellar atrophy.

We measured simple visual and auditory reaction time (RT) and movement time (MT) in 32 patients with olivopontocerebellar atrophy (OPCA) in comparison to 32 control subjects. In addition, we followed 2 approaches to radiologic assessment by computed tomographic scans: subjective (by inspection of films) and objective (by measurement of 4 radiologic ratios at the level of the posterior fossa and 1 ratio at the supratentorial level). All OPCA patients had various degrees of cerebellar atrophy and lengthened RT and MT in comparison to their controls. There were no significant differences in RT and MT performances in patients with mild-moderate versus those with severe cerebellar atrophy as assessed by inspection of their films. OPCA patients with severe versus mild-moderate atrophy evaluated by 3 measures, i.e., brainstem, brachium pontis and fourth ventricle ratios, presented few significantly lengthened RT and MT performances. In contrast, patients with severe atrophy revealed by the midbrain ratio had significantly lengthened RT and MT performances compared to those with mild-moderate atrophy assessed by this ratio on 7 of 8 measures; the 8th measure showed a borderline significant difference. This could be explained by the fact that atrophy at the midbrain level is the only one which involves dopaminergic, noradrenergic and glutamatergic structures and pathways.

Adult↗
PubMed1988

Cerebellar atrophy in epileptic patients.

High-resolution CT scans of the brain and posterior fossa were performed on 106 phenytoin (PHT)-treated epileptics, 28 de novo epileptics and 43 control subjects. A higher incidence of cerebellar and brainstem (CBS) atrophy was observed in chronic PHT- or PHT+ phenobarbital-treated epileptics compared to the two other groups. Some control subjects and de novo epileptics presented mild CBS atrophy, whereas moderate to severe atrophy was noted exclusively in chronically-treated patients. In attempting to delineate the etiology of CBS atrophy, epileptic patients were divided in three groups: 55 subjects with normal CT scans, 30 with both cerebral and CBS atrophy, and 49 with pure CBS atrophy. Their ages, length of illness, number of generalized seizures, number of other seizures, and amount of PHT received during their lifetime were assessed. Statistical analysis revealed that posterior fossa atrophy in epileptics was significantly correlated with both the length of the illness and the amount of PHT ingested during the patient's lifetime. The number of seizures appears to not be related to CBS atrophy.

Adolescent↗
PubMed1985

Defective revisualization: dissociation between cognitive and imagistic thought case report and short review of the literature.

A 38-year-old shifted-sinistral patient displayed a definite deficit in visual imagery accompanied by defective dreaming capacity, loss of hypnagogic imagery, some defects in topographical memory, a mild unilateral right spatial neglect and mild difficulties in right-left orientation on the examiner's body. CT-scan and NMR studies showed evidence of an inborn hypoplasia of the right hemisphere and a stretched corpus callosum in its posterior and superior part. The vicarious compensatory action of the cognitive-verbal function of the defect of visual imagery was obvious. It is concluded that: there are various forms of visual imagery deficits: some are "pure" whereas in the great majority of reported cases the loss of visual imagery is associated to different forms of visual agnosia; the brain mechanisms underlying cognitive thought and imagistic thought could be obviously dissociated.

Adult↗
PubMed1984

Double blind study of the toxicity of intrathecal iopamidol and metrizamide in lumbar myelography.

Water-soluble contrast agents (metrizamide) provide a finer myelographic assessment of the spinal neuroanatomical structures but at the expense of some occasional toxic side effects. Iopamidol, a new non-ionic water-soluble agent, has been submitted to clinical trial by the authors in their respective institutions. The combined results indicate better tolerance to this new agent with fewer side effects and those of lesser severity.

Dizziness↗
PubMed1975

[Microadenomas and hypersecreting pituitary adenomas].

The early radiographic changes of the sella turcica in the cases of hypersecreting pituitary adenomas (Cushing disease, acromegaly, amenorrhea-galactorrhea) are reported and discussed. The finding of the double contour of the sellar floor and the small crescentic bulging of its antero-inferior wall, with the aid of the tomographic cuts of the sella, has permited the diagnosis of the microadenoma'a localization. With this it si possible the achievement of a selective excision of the lesion in the initial stage, when the tumor has not caused yet irreversible damage to the inside normal pituitary tissue. This surgery is performed in the precocious stage with the primary goal to preserve the normal gland, without hurt it to avoid postoperative hipopituitarism. A anatomo-radiologic classification of the alterations sella turcica in 4 grades is made, which is of great utility for the surgical prognostic, since we have observed clinical and biological cure over 90% in the grade 1, 75% in the grade 2, 50% in the grade 3 and up to 10% in the grade 4 in the first surgery.

Acromegaly↗
PubMedDate not supplied

Herpes zoster vasculitis: demonstration by MR angiography.

A patient presented with multiple cerebral infarcts in various vascular territories after having been treated for herpes zoster ophthalmicus. Magnetic resonance angiography demonstrated multiple focal stenoses involving the proximal intracranial vessels which corresponded to endarteritis at autopsy.

Aged↗