[Chiari type 1 malformation and magnetic resonance imaging]. / La malformation de Chiari de type 1 à l'ère de l'imagerie par résonance magnétique.

The Chiari type 1 malformation is common. Unlike the Chiari type 2 and 3 malformations, it may remain latent for a long time, becoming symptomatic only in adulthood. The introduction of MRI has resulted in an increased number of diagnoses of this malformation in pediatric patients. It appears to be related to underdevelopment of the posterior cranial fossa. It must be differentiated from acquired tonsillar herniation, particularly when herniation results from intracranial hypotension; these cases are sometimes reported as acquired Chiari I malformation with spontaneous resolution. Tonsillar ectopia may cause symptoms by its direct effect on any or all of the medulla and the cerebellar and upper spinal cord. The most suggestive of the oculomotor disturbances is oscillopsia with downbeat nystagmus. Dysphonia and dysphagia are common. Potentially serious autonomic disturbances are also frequent: sleep apnea, respiratory failure, syncope and even sudden death. Another risk is syrinx formation, resulting from obstruction of CSF circulation in the cisterna magna. Syringomyelia is detected in 32 to 74% of patients with Chiari I malformation. Treatment is surgical. Posterior fossa decompression is achieved by suboccipital craniectomy combined with laminectomy of the upper cervical segments. Surgical intervention is indicated when the malformation is symptomatic and there is no doubt that it is the cause of the symptoms. When a Chiari I malformation is identified fortuitously on MRI, long-term monitoring is essential. The risk of developing symptoms increases over time. Patients should be advised not to participate in contact sports.

[Disruption of the thoracic spinal cord with unilateral ligament damage and no spine fracture]. / Section traumatique de la moelle épinière thoracique sans lésion osseuse avec atteinte ligamentaire unilatérale.

We report a case of total spinal cord disruption confirmed surgically. The spinal cord injury resulted from a traumatic event involving the thoracic spine which did not provoke any bone lesion. The patient presented joint injury and unilateral ligament damage. No spinal fracture was observed. In patients with neurological signs, the imaging work-up should associate CT-scan and magnetic resonance imaging to obtain a complete study of the bone and joint structures as well as the ligaments and the spinal cord.

[Functional anatomy of the central nervous system]. / Anatomie fonctionnelle du système nerveux central.

The central nervous system (CNS) has a particular regional functional anatomy. The morphological support of cognitive functions can now be depicted using functional imaging. Lesions of the central nervous system may be responsible of specific symptoms based on their location. Current neuroimaging techniques are able to show and locate precisely macroscopic lesions. Therefore, the knowledge of functional anatomy of the central nervous system is useful to link clinical disorders to symptomatic lesions. Using radio-clinical cases, we present the functional neuro-anatomy related to common cognitive impairments.

[Primary acute disseminated encephalomyelitis in the adult. Study of 6 year follow-up of 2 patients]. / Encéphalomyélite aiguë disséminée primitive de l'adulte. Etude de deux patients suivis pendant 6 ans.

INTRODUCTION: The relationship between acute disseminated encephalomyelitis (ADEM), a monophasic disease, and multiple sclerosis (MS), a potentially progressive disease with periods of recurrence or remission, remains debatable. In a large number of patients, the diagnosis initially retained is that of ADEM, whilst the progression is subsequently towards a defined MS. This has incited some authors to consider that there is a continuum between these two diseases and to underline the frailty of the criteria retained for the diagnosis of ADEM. Further interest has presently been paid to this subject and the question of whether a basic treatment of MS should be started after the first episode has been raised, although such a treatment is obviously not justified if the diagnosis retained is an ADEM. OBJECTIVES: Two cases observed in adults, followed-up for 6 years, contribute to the validation of a number of clinical, biological and radiological arguments which are all in favor of the diagnosis of ADEM versus that of an initial episode of MS. CLINICAL ARGUMENTS: These are the absence of any neurological past history, the existence of a multi-focal neurological symptomatology right from the start and, particularly in children, the presence of a meningeal syndrome. BIOLOGICAL ARGUMENTS: Presence in the cephalo-spinal liquid, of an increase in cells and cervicospinal proteins to levels not usually found in MS. RADIOLOGICAL ARGUMENTS: MRI reveals multi-focal, extensive and bilateral lesions, beneath the cortex rather than peri-ventricular, which may extensively involve the thalamus and the bone marrow; these lesions are of the same age and often regress.

[Inflammatory hypertrophic cranial pachymeningitis]. / Les pachyméningites crâniennes hypertrophiques inflammatoires.

DEFINITION: Inflammatory cranial hypertrophic pachymeningitis (ICHP) is a fibrosing inflammatory process that thickens the dura mater. This condition is increasingly reported owing to the use of CT and MRI. CLINICAL ASPECTS: Chronic headache and cranial neuropathies are the main presentations. Generally the erythrocyte sedimentation rate is elevated and cerebrospinal fluid is inflammatory. DIAGNOSIS: Non-invasive imagery visualizes the thickening of the dura mater that may be focal or diffuse. On MRI diffuse intense enhancement due to intra cranial hypotension must not be confused with ICHP. Focal thickening of the dura may be tumoral. Biopsy of the thickened dura mater is useful for confirming the inflammatory nature of the process and for orienting the etiological diagnosis. "SECONDARY" ICHP: ICHP has many causes, infectious and noninfectious. It may be the presenting manifestation of systemic diseases as sarcoïdosis or Wegener's granulomatosis. "IDIOPATHIC" ICHP: A diagnosis of exclusion, ICHP might be an isolated intracranial localization of multifocal fibrosis, an ill-defined autoimmune disease. TREATMENT: A specific treatment is indicated in some cases of secondary ICHP. In most cases treatment relies on corticosteroids an/or immunosuppressive therapy.

Cerebral venous infarction following thrombosis of the draining vein of a venous angioma (developmental abnormality).

We report two cases of cerebral venous angioma presenting as venous infarction, one in the left parietal lobe, the other in the left frontal lobe. Cerebral imaging demonstrated thrombotic occlusion of the draining vein of the venous angioma associated in the latter case with thrombosis of the anterior part of the superior longitudinal sinus. Both patients were free of coagulopathy. They were treated with anticoagulant therapy. One completely recovered, while the other was left with slight residual disability. Thrombosis of the draining vein has been reported in only 6 previous cases, of whom only 2 received anticoagulant therapy. Discovery of a venous angioma in the diagnostic workup of a patient with recent neurological disorders should raise the question of a possible occlusion of the draining vein and lead to an appropriate therapy.

[Cerebral venous thromboses]. / Les thromboses veineuses cérébrales.

UNLABELLED: VARIABLE EXPRESSION: The clinical expression of cerebral venous thrombosis varies widely. The only manifestation may be an intracranial hypertension if the thrombus is limited to the superior longitudinal sinus or a predominant lateral sinus. Thrombosis of cortical veins, alone or in association with a sinus thrombus causes venous infarction. PROGNOSIS: Deep venous thrombosis generally leads to coma with signs of intracranial hypertension. However, partial or complete recovery is possible, even with a severe initial presentation, underlining the importance of early diagnosis and treatment. DIAGNOSTIC METHODS: Magnetic resonance imaging (MRI) coupled with magnetic resonance angiography (MRA) can usually confirm the diagnosis without conventional angiography. ETIOLOGICAL DIAGNOSIS: Cerebral venous thrombosis often follows prethrombotic conditions. Infectious causes only account for 10% of the cases and no cause can be identified in about 1 out of 5 cases. TREATMENT: Anticoagulation is indicated even in case of venous infarction with spontaneous bleeding. Thrombolysis can be proposed, particularly for deep venous thrombosis.

[A case of cerebral giant-cell angiitis associated with cerebral amyloid angiopathy. Favorable evolution with corticosteroid therapy]. / Un cas d'angéite cérébrale à cellules géantes associée à une angiopathie amyloïde cérébrale. Evolution favorable sous traitement corticoïde.

We report a biopsy proven case of cerebral giant cell angiitis associated with cerebral amyloid angiopathy. Clinical history and radiological lesions were rapidly progressive. The patient recovered with corticosteroid treatment. The pathogenesis relationship between angiitis and amyloid angiopathy are discussed.

[Neurofibromatosis I and multiple sclerosis. Apropos of a case]. / Neurofibromatose I et sclérose en plaques. A propos d'un cas.

We report a case associating NF1 with multiple sclerosis. There are only seven cases of this association, so that it might be interpreted as resulting from chance. However, although the association is weak, it might be non fortuitous, owing to a particularity of the NF1 gene that embedded oligodendrocyte-myelin glycoprotein gene, even if the responsibility of structural genes of myelin have not been implicated in susceptibility to multiple sclerosis.

[Isolated vertigo disclosing infarction in the area of the posterior and inferior cerebellar arteries]. / Vertige isolé révélateur d'un infarctus dans le territoire de l'artère cérébelleuse postérieure et inférieure.

We report three cases of small cerebellar infarcts mimicking labyrinthine dysfunction. A sudden rotatory vertigo might be the only presenting symptom of a cerebellar infarct. In these cases, the clinical features may closely mimick an acute peripheral labyrinthine disorder. However, the absence of nystagmus or a direction changing nystagmus with different eye position and the normality of caloric responses may be suggestive of a cerebellar infarct. This syndrome may be explained by the involvement of the nodulus, part of the flocculo-nodular complex, that has primary vestibular connections. Cerebellar infarcts mimicking labyrinthine dysfunctions involved usually the cerebellar territory of the posterior inferior cerebellar artery (PICA). Infarcts may be limited to the territory of the medial branch of the PICA which supplies the nodulus.

[Spontaneous sphenoidal rhinorrhea]. / Rhinorrhée sphénoïdale spontanée.

We describe the case of a woman, who presents a spontaneous rhinorrhea. The metrizamid computerized tomographic cisternography proves the precise anatomic location of the dural osseous defect, in the left sphenoidal sinus. Transsphenoidal approach terminated the leakage in a single procedure, without shunt.

[Value of X-ray computed tomography of the brain in controlled carotid surgery]. / Intérêt de la scanographie cérébrale dans la chirurgie carotidienne réglée.

The usefulness of computerized tomography (CT) in elective carotid surgery was evaluated in a prospective study of 402 patients who had a surgical operation on one or two atheromatous arteries and were explored by pre and post-operative CT of the brain. Pre-operative CT scans revealed an ischaemic lesion in 22 per cent of asymptomatic patients and in 29 per cent of patients who had experienced a transient ischaemic accident. Abnormal pre-operative CT scans were associated with a statistically significant increase in per-operative electroencephalographic changes, but there was no significant increase in post-operative neurological complications. Post-operative CT scans showed a "silent" infarct in 6 per cent of the cases; 59 per cent of patients with neurological complications had normal or unchanged post-operative CT images. This study suggests that pre-operative CT is not necessary to evaluate the neurological risk and that post-operative CT alone is inadequate to quantify the morbidity of carotid surgery.

[Transformation of cerebral infarction into hemorrhage during x-ray computed tomography in a patient under anticoagulant treatment]. / Transformation d'un infarctus cérébral en hémorragie, au cours d'un examen tomodensitométrique, chez un patient sous traitement anticoagulant.

Repeated CT scans provide the only means of confirming the initial ischemic nature of a cerebrovascular accident and its eventual course towards a hemorrhage. Precise data can be obtained as to the frequency of this complication as a function of factors such as the embolic origin of the infarct or associated anticoagulant therapy. The present case shows that contrast medium, at least in patients receiving anticoagulant treatment, may constitute a risk factor by increasing the possibility of transformation of a pale infarct into a hemorrhagic one. Possible relevant properties of iodized contrast media with respect to this type of complication are considered.