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.

Subcortical white matter lesions in osmotic demyelination syndrome.

We describe a case of histologically proved osmotic demyelination syndrome. In addition to abnormal T2 signal within the pons and thalami, MR showed linear enhancing lesions at the cortical medullary junction.

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.

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.

[Current technique of myelography]. / La technique actuelle de la myélographie.

Myelography performed with fine needle technique has become virtually innocuous and can be more liberally used in conjunction with CT to produce the CT-myelogram, a product of remarkable diagnostic precision. The authors contention is based on a series of 1,357 consecutive myelograms or CT-myelograms recently performed using exclusively 26-gauge spinal needles.

Outpatient myelography with fine-needle technique: an appraisal.

Postmyelography headaches are produced mostly by CSF leakage at the dural puncture site and are therefore largely dependent on the size of the needle used. Our study of 300 consecutive outpatients who had lumbar myelograms performed with 25- and 26-gauge spinal needles shows that the procedure has become virtually innocuous. We recommend that 26-gauge spinal needles be widely adopted as the standard for fluoroscopically controlled intrathecal injections of contrast material.

Outpatient myelography with fine-needle technique: an appraisal.

Postmyelography headaches are produced mostly by CSF leakage at the dural puncture site and are therefore largely dependent on the size of the needle used. Our study of 300 consecutive outpatients who had lumbar myelograms performed with 25- and 26-gauge spinal needles shows that the procedure has become virtually innocuous. We recommend that 26-gauge spinal needles be widely adopted as the standard for fluoroscopically controlled intrathecal injections of contrast material.

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.

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.

Reversible chronic cerebellar ataxia after phenytoin intoxication: possible role of cerebellum in cognitive thought.

Reversible chronic cerebellar ataxia followed phenytoin treatment in two epileptic women. Cerebellar ataxia in both patients and axonal polyneuropathy in one patient were improved after administration of thiamine alone or with folate. In one patient, some specific behavioral functions improved. However, recovery could have been spontaneous.

[Late post-traumatic syringomyelia. Discussion apropos an atypical case]. / Syringomyélie post-traumatique tardive? Discussion à propos d'un cas atypique.

Late post-traumatic syringomyelia is uncommon, the clinical signs appearing several years after severe trauma to the cervical spinal cord. It is due to progressive cavitation in the spinal cord. In the case reported here progress was atypical because there were no immediate neurological signs and the symptoms of syringomyelia developed only 3 weeks after injury. Several possibilities are open to discussion. Was the trauma responsible for the syringomyelia? Did it cause an aggravation of a pre-existing hydromyelia or were both lesions purely coincidental? A silicon tube draining the cavity in the cord to the subarachnoid space resulted in a real improvement in the neurological condition.

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.

[Value of digital subtraction angiography in cerebrovascular diseases]. / La valeur de l'angiographie digitale dans les maladies vasculaires cérébrales.

Digital Angiography was done on 1 000 patients with cerebral vascular diseases at the cervical or cerebral level. This was done by intravenous injection in 800 cases and by intra-arterial injection in 200 cases. The study of the cervical carotid bifurcation is favorably compared to the one obtained by the conventional arteriography. The intracranial aneurysms of 1 centimeter are well visualized and this method is valid to eliminate a giant aneurysm before transsphenoidal surgery. The digital angiography also allows the study of venous and sinus malformations. The postoperative controls of the aneurysms, carotid endarterectomies and extra-intracranial bypass are perfectly shown and can be repeated. The comparative study between the intravenous digital angiography and the conventional angiography have shown a good correlation between both tests in 80% of the cases. This rate can be risen by intra-arterial injection. It is a non-invasive method, reliable and economical with very little complications. This test can be done on an external basis and repeated if necessary. The disadvantages are the overlapping of the vessels, the necessity of the strict immobilisation of the head and the difficulty of evaluating the vessels whose diameter is inferior to 1 mm.

[Prolactinoma: radiologic appearance of the sella turcica]. / Le prolactinome: aspects radiologiques de la selle turcique.

Radiologic studies of the sella turcica have been performed in 355 patients operated on for prolactinomas. According to our classification, the grading of the sella in 300 females was normal in seventeen, grade I in one hundred and seventy-eight, grade II in eighty-seven, grade III in nine and grade IV in nine. A suprasellar expansion was evidenced in twenty-four of these patients. In 55 men, the sella was of grade I in eight, grade II in thirty-nine and grade IV in eight. Twenty-three had a suprasellar expansion. The early radiological diagnosis of a prolactin-secreting microadenoma became important when the hypophyseal origin of the clinical syndromes associated with hyperprolactinemia was demonstrated. Prolactinomas can usually be diagnosed by polytomography when they have reached 4 mm in size. Subtle bony changes such as cortical thinning, lateralized blistering or bulging of the floor are reliable radiological signs when associated with a biologically confirmed clinical syndrome.

Bonnet-Dechaume-Blanc syndrome.

A 16 year old girl presenting the visual disturbances was found to have a right retinal arteriovenous communication. The provisional diagnosis of Bonnet-Dechaume-Blanc syndrome was confirmed by angiographic demonstration of ipsilateral orbital and intracranital arteriovenous malformations.