Facial nerve: from anatomy to pathology.

The facial nerve (CN VII) emerges from the facial nerve nucleus in the pons. It is accompanied by CN VIII along its cisternal pathway, as well as at the internal auditory meatus. Its petrous pathway includes a labyrinthine segment, a horizontal tympanic segment and a vertical mastoid segment until the stylomastoid foramen. It then continues to the parotid gland. Pontine impairment is usually associated with other neurological symptoms. Lesions of the cerebellopontine angle (most often meningioma and schwannoma) initially result in impairment of CN VIII. The impairment of CN VII takes second place. Peripheral impairment (outside of a traumatic context) is most often due to Bell's palsy.

[Vascular emergencies of the head and neck]. / Urgences vasculaires cervicofaciales.

The clinical manifestations of vascular lesions of the head and neck may be variable (hemorrhagic, ischemic, compressive). Diagnosis often is made at the time of acute presentation, but delayed manifestations, sometimes long after the initial presentation, should not be overlooked. Hemorrhagic manifestations are characterized by epistaxis, corresponding mainly to lesions of the nasal cavities but involvement of the internal carotid artery should be excluded (life threatening). In addition, some vascular malformations may lead to severe hemorrhage. Ischemic manifestations typically result from arterial dissection. A venous origin is also possible. Carotid-cavernous fistulas rarely lead to hemorrhagic or ischemic manifestations and tend to result in ocular manifestations, typically delayed and sometimes misleading.

[Natural history and management of mycotic intracranial aneurysm]. / Anévrysme mycotique cérébral: histoire naturelle et prise en charge thérapeutique.

INTRODUCTION: mycotic intracranial aneurysms are a rare complication of infectious endocarditis. We report four cases of patients with endocarditis, complicated by an acute stroke, revealing a mycotic intracranial aneurysm. PATIENTS AND METHODS: four men (aged range 24 to 63 year old) were admitted for endocarditis, complicated by ischemic stroke in two cases and hemorrhagic stroke in the two other cases, including one with subarachnoid hemorrhage. Neuroimaging disclosed a mycotic cerebral aneurysm in all four cases. DISCUSSION: we will discuss the natural history and the management of mycotic intracranial aneurysm based on a review of the literature and our experience. Three therapeutic options are possible: medical treatment, surgery and endovascular embolisation. CONCLUSION: management of mycotic intracranial aneurysms is still controversial, frequently requiring a multidisciplinary strategy with priority given to endovascular interventions.

Ehlers-Danlos syndrome type IV and recurrent carotid-cavernous fistula: review of the literature, endovascular approach, technique and difficulties.

We report the follow-up of a previously published case (Forlodou et al. Neuroradiology 38:595-597, 1996) of carotido-cavernous fistulas (CCFs) in a patient presenting with type IV Ehlers-Danlos syndrome (EDS 4) that were successfully treated twice by an endovascular approach. Initial treatment with a detachable balloon was in 1994 for a right CCF, and, 8 years later, a left CCF was treated by selective transarterial occlusion of the cavernous sinus with coils. Unfortunately, the patient suffered from a spontaneous post-operative intracranial haemorrhage in the left hemisphere and died. Review of the literature, technical considerations for bilateral CCF and complication are discussed.

[Hypertrophic olivary degeneration. MR imaging findings and temporal evolution]. / Degenerescence olivaire hypertrophique. Aspect IRM et évolution temporelle.

PURPOSE: to describe the magnetic resonance imaging features of hypertrophic olivary degeneration (HOD) subsequent to lesion in the "Guillain-Mollaret triangle". MATERIALS AND METHODS: 15 cases of HOD were diagnosed at MR imaging in 12 patients (4 women and 8 men) with posterior fossa lesion. The time interval from the beginning of the disease to the MR examination was 3 weeks to 8 (1/2) years. Evaluation of the changes in signal intensity over time of the lesions was available in 6 patients. RESULTS: Nine cases of HOD were unilateral and three were bilateral. HOD was associated to a lesion of the contralateral dentate nucleus in 8 cases, to a lesion of the ipsilateral central tegmental tract in 5 cases and to a lesion of the contralateral superior cerebellar peduncle in 2 cases. Hyperintensity and hypertrophy of the olive on proton density and T2-weighted images appeared as early as 3 weeks after the ictus. A curved central hyperintensity (CCH) could be observed 7 months after the initial presentation. Decrease in the signal intensity was observed after 3 (1/2) years and abnormal signal intensity could persist for up to 13 years. Palatal myoclonus at 5 months was associated with HOD in one case. CONCLUSION: HOD is considered a trans-synaptic degeneration subsequent to lesions in the Guillain-Mollaret triangle. Hyperintensity and hypertrophy of the olive are observed, sometimes with palatal myoclonus.

Multiple de novo vascular malformations in relation to diffuse venous occlusive disease: a case report.

Brain vascular malformations are dynamic disorders. Although mostly considered to be of congenital origin, the improvement of clinical imaging and vasculogenesis knowledge has shown that they might also result from a biological dysfunction of the remodeling process after birth. Venous occlusive disease and ishemia may represent powerful revealing triggers and support the capillary venous origin of some vascular malformations. We report a unique case of the development of multiple de novo vascular malformations (transverse sinus dural fistula and posterior fossa cavernomas) following acoustic neuroma surgery.

[Emergency imaging of cerebrovascular accidents]. / Imagerie des accidents vasculaires cerebraux en urgence.

Over the last 25 years, advances in neuroimaging have significantly changed the evaluation and management of acute stroke syndromes. In the seventies, computed tomography (CT) could differentiate between ischemic and hemorrhagic stroke. Magnetic resonance imaging (MRI) is nowadays the imaging modality of choice in the initial assessment of acute stroke. MRI images can better discriminate acute, subacute and chronic infarcts, differentiate venous from arterial infarcts, detect arterial dissection, stenosis or occlusion. Diffusion-weighted images are highly sensitive and specific to acute infarction and the combination with perfusion technique is suitable to define potentially reversible ischemia (area of cerebral "mismatch" which is thought to represent the so-called ischemic penumbra). This penumbra is a potential therapeutic target of valuable interest for the treating physician.

[Endovascular carotid occlusion: a retrospective study of complications in 33 cases]. / L'occlusion carotidienne par voie endovasculaire: etude retrospective des complications á partir de 33 cas.

MATERIAL-METHODS: Thirty three patients (16 men, 17 women), mean age 45 years underwent an intravascular carotid balloon occlusion for intracavernous aneurysms, carotid-cavernous fistulas or cervical carotid injuries by Fogarty balloons (5 patients before 1982) or detachable balloons (28 patients). Transient balloon test occlusion consisted in a clinical examination, an angiographic study for 32 patients with an electroencephalogram for 16 patients. RESULTS: Early complications occurred for four patients by veineous rupture (1 patient) or ischemic injury (3 patients). Late complications occurred for two patients by ischemic injuries, one asymptomatic. DISCUSSION: These results are similar to the literature's results and the transient test occlusion consisting in clinical examination, angiographic study and EEG seems to be reliable compared to cerebral blood flow determination. CONCLUSION: Even if its indications have decreased because of technic improvements permitting carotid flow preservation, carotid endovascular balloon occlusion stays a reliable, cheap technic in carotid injuries' treatment.

[Capillary telangiectasis, angiographically occult vascular malformations. MRI symptomatology apropos of 7 cases]. / Les télangiectasies capillaires, malformations vasculaires angiographiquement occultes. Sémiologie IRM à propos de 7 observations.

OBJECTIVE: Describe the MRI findings in capillary telangiectasias. MATERIALS AND METHODS: Between 1996 and 1999, we observed 9 cases of capillary telangiectasia in 7 patients explored 5 times for posterior fossa symptoms. In two cases capillary telangiectasia was a fortuitous discovery. All patients were explored by MRI with T1 sequences with and without gadolinium injections, turbo spin echo T2 coupled in 5 cases with a double echo gradient echo T2 sequence (TR: 970 ms, TE: 15 and 35 ms). Two patients also underwent vertebral angiography. RESULTS: The telangiectasia gave a low intensity signal on T1 sequences in 2 of the 9 cases and a discretely high intensity signal on T2 sequences in all cases. After gadolinium injection, 9 telangiectasias showed homogeneous or speckled enhancement. The echo-gradient T2 images showed a very low intensity signal in 7 out of 7 cases on the second echo. At the first echo, 4 capillary telangiectasias were undetectable. The two vertebral angiographies were normal and the follow-up MRI in 5 patients showed lesion stability. CONCLUSION: Pontile lesions with no mass effect showing enhancement after gadolinium injection and with or without a discrete T2 high intensity signal but with a frank echo-gradient T2 signal strongly suggest capillary telangiectasia.

[Current imaging of an "aberrant course" of the internal carotid artery]. / Imagerie actuelle d'un "trajet aberrant" de l'artère carotide interne.

Blood flow via an aberrant internal carotid artery within the tympanic cavity is a rare pathogenic embryonic variation causing pulsatile tintinus and a vascularized tympanum. CT-scan provides the diagnosis. MRI and 3D time-of-flight MRA appear ideal for exploring aberrant flow both for diagnostic purposes and to establish the vascular morphology.

[The evaluation of 3DFT time-of-flight MR-angiography versus angiography in the study of carotid atheromatous lesions with a review of the literature]. / Evaluation de l'angio-MR 3DFT temps-de-vol versus angiographie dans l'exploration de lésions athéromateuses carotidiennes avec revue de la littérature

In 37 patients suspected of having a stroke 71 carotid bifurcations were explored by MR-angiography and by digital angiography the reference technique. A 3D sequence was acquired with the time-of-flight technique, using a transmitter-receiver cranial coil, followed by a strictly receiver Helmoltz coil on a 1 Tesla magnet. Two examiners evaluated the carotid bifurcations and measured the degree of stenosis in terms of diameters, according to the north american symptomatic carotid endarterectomy trial (NASCET). Five classes were established: class 1: normal; class 2: 1 to 29%; class 3: 30 to 69%; class 4: 70 to 99% and class 5: thrombosis. The results obtained in the determination of classes were identical with both coils: the coefficient of correlation with straight angiography were 0.973 with the cranial coil and 0.966 with the Helmoltz coil. Five stenoses were overestimated and classified as Class 3 instead of Class 2. The five stenoses greater than 70% (Class 4) showed a signal-void area at their level, due to severe dephasing induced by turbulences. Finally, there was a false-negative image of occlusion: the high-intensity signal of the thrombus was mistaken for one of flow. The data of our study were in accordance with the excellent results obtained by several authors in the literature, which makes it possible for us to propose this type of examination as a novel mean of investigating bifurcations of carotid arteries. Provided a strict technique is applied, and in addition to carotid bifurcation the Willis' circle and the cerebral parenchyma are explored, MR-angiography can complete the results of Doppler-echo. Standard arteriography could then be reserved to surgical patients and to those with discordant results of MR-arteriography and Doppler echo systems.