[Morphological anatomy of the cranial nerves in their cisternal segment (III-XII)]. / Anatomie morphologique des nerfs crâniens dans leur portion cisternale (du III au XII).

One hundred brains (first injected in cerebral arteries and veins with latex neoprene or India ink and studied under optic magnification) illustrate this anatomic chapter concerning the microsurgical anatomy of the cisternal segment, the neurovascular relationships, and the blood supply of the IIIrd to the XIIth cranial nerves.

Estimates of maternal risks of pregnancy for women with hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome): suggested approach for obstetric services.

OBJECTIVES: Hereditary haemorrhagic telangiectasia (HHT) affects 1 in 5-8000 individuals. Pregnancy outcomes are rarely reported. The major reason is that most women do not have their HHT diagnosed prior to pregnancy. Using a large well-characterised series, we studied all pregnancies known to have occurred in HHT-affected women, whether or not their diagnosis was known at the time of pregnancy. Our aim was to estimate rates and types of major complications of HHT in pregnancy, to guide management decisions. DESIGN: Cohort study, with prospective, retrospective and familial components. SETTING/POPULATION: Tertiary referral centre population. METHODS: All 262 pregnancies in the 111 women with HHT and pulmonary arteriovenous malformations (PAVMs) reviewed between 1999 and 2005 were studied. Eighty-two women (74%) did not have a diagnosis of HHT/PAVM at the time of pregnancy. 222 pregnancies in their 86 HHT-affected relatives were also studied. MAIN OUTCOME MEASURES: PAVM bleed, stroke and maternal death. RESULTS: Thirteen women experienced life-threatening events during pregnancy: 1.0% (95% CI 0.1-1.9) of pregnancies resulted in a major PAVM bleed; 1.2% (0.3-2.2%) in stroke (not all were HHT related); and 1.0% (0.13-1.9%) in maternal death. All deaths occurred in women previously considered well. In women experiencing a life-threatening event, prior awareness of HHT or PAVM diagnosis was associated with improved survival (P = 0.041, Fisher's exact test). CONCLUSIONS: Most HHT pregnancies proceed normally. Rare major complications, and improved survival outcome following prior recognition, means that pregnancy in a woman with HHT should be considered high risk. Recommendations for pregnancy management are provided.

[Arterial ischemic stroke in the healthy child. Practical approach (neonate and foetus excluded)]. / Accident artériel ischémique cérébral d'apparence primitive chez l'enfant. Démarche pratique (nouveau-né et foetus exclus).

Primary stroke can be due to embolism or an obstructive process of the vascular wall. Embolism may come from a parietal lesion of a large artery in the neck (traumatic dissections), from a cryptic cardiopathy, from a venous thrombosis associated with a right-left shunt. Among pathologies of endocranial arteries, the most frequent is the acute, postviral arteriopathy of the sus-clinoïd carotid, which evolves toward stabilisation or regression. Insidious obstructive arteriopathies of the Willis circle, including development of a transparenchymal suppletive circulation (Moya-Moya disease), cumulate chronic circulatory insufficiency and repetitive strokes. Inflammatory multifocal cerebral arteriopathies mainly involve mean and small arteries. Most of them are secondary to a multisystemic disease, but some are primary. The basic investigation is anatomical and begins with MRI. Emergency conventional cerebral angiography is discussed when heparinotherapy is difficult to decide (evolutive thrombosis), or when an endovascular intervention appears possible (anoeuvrism). Secondarily, conventional angiography is indicated in any chronic situation where a precise anatomical follow-up is necessary. Investigations of the cardiovascular system, of the thrombophilic risk, of a dysimmune process are discussed according to the clinico-anatomical diagnosis.

MR diffusion tensor imaging and fiber tracking in spinal cord arteriovenous malformations: a preliminary study.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) of the spinal cord in patients harboring spinal arteriovenous malformations (AVMs) was carried out to evaluate the feasibility of this new technique to determine the displacement of the spinal cord tracts and to correlate morphologic and functional DTI data (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]) with the clinical symptoms. MATERIALS AND METHODS: Nine patients with spinal cord AVMs were investigated at 1.5T using a sagittal spin-echo single-shot echo-planar generalized autocalibrating partially parallel acquisition diffusion-weighted imaging sequence. ADC and FA maps were computed in different regions of interest (both above and below the nidus), and tractography was used to visualize the course of the tracts. The data were correlated with the clinical symptoms and compared with 12 healthy control subjects. RESULTS: At the level of the nidus, tracts were normal, shifted, separated, or interrupted but not intermingled with the nidus. Interruption of the tracts was coherent with the clinical symptoms. In patients with severe neurologic deficits, FA values caudal to the nidus showed a reduced anisotropy consistent with loss of white matter tracts. CONCLUSIONS: We demonstrate that AVMs may interrupt, displace, or separate the fiber tracts and that clinical symptoms may be reflected by the quantitative FA results and the morphologic loss of fibers distant to the lesion. DTI with fiber tracking offers a novel approach to image spinal cord AVMs and may open a window to understand the complex pathophysiology of these lesions.

Management of spontaneous haemorrhagic intracranial vertebrobasilar dissection: review of 21 consecutive cases.

INTRODUCTION: Haemorrhagic intracranial vertebrobasilar dissection is an uncommon cause of nontraumatic subarachnoid haemorrhage (SAH) and accounts for only 1-10% of non-traumatic SAH. Treatment in the acute phase is considered to be essential because of the high risk of rebleeding and the consequent unfavourable outcome. However, the location, the potential for involvement of eloquent vessels and the histopathological characteristics of the vessel wall make treatment demanding from both a technical and anatomical point of view. We report our experience in the management of this disease. PATIENTS AND TREATMENTS: From 1989 to June 2006, we managed 21 patients with spontaneous haemorrhagic dissection located in the intracranial vertebrobasilar system, 13 patients were treated using an endovascular approach, 1 by surgical clipping, and 7 were managed conservatively. RESULTS: Among the 13 patients treated endovascularly, 7 underwent proximal occlusion, 4 underwent parent artery embolization at the site of dissection, and 2 underwent endovascular trapping. Severe, treatment-related complications due to dislodgement of the thrombus during the procedure occurred in 1 patient, who then died from brainstem ischaemia. One patient died from severe pneumonia and one patient was left disabled from vasospastic ischaemia resulting from severe initial SAH. The remaining 10 patients had satisfactory outcomes: none rebled after treatment and when discharged they had Karnovsky scores of 80-100. Of the 7 conservatively treated patients, three died of rebleeding and four were discharged with Karnovsky scores of 50-100. One patient, who was treated surgically, was discharged with a Karnovsky of 90. CONCLUSION: The high rate of rebleeding and consequent mortality among the patients treated conservatively argues for treatment in the acute phase. Treatment should be guided by each patient's angiomorphology, clinical condition and the experience of the neurosurgical/neuroradiological team. Options include endovascular or surgical trapping of the dissection and proximal occlusion and embolisation of the parent artery at the site of the dissection.

Segmental unfused basilar artery with kissing aneurysms: report of three cases and literature review.

Basilar artery "fenestration" is the result of a failed fusion of the bilateral longitudinal neural arteries and can be associated with a saccular aneurysm, which typically arises at the proximal juncture of the unfused segment. "Kissing" aneurysms at this site, i.e. two aneurysms arising from the proximal junction of the unfused segment of the basilar artery pointing anteriorly and posteriorly are reported to be exceedingly rare. We present three patients with this rare condition, all of them being treated by endovascular techniques.

[Pediatric neurovascular malformations: vein of Galen arteriovenous malformations (VGAM), pial arteriovenous malformations (pial AVM), dural sinus malformations (DSM)]. / Pathologie neurovasculaire malformative de l'enfant: malformations anévrismales de la veine de Galien (MAVG), malformations artérioveineuses piales (MAVP), malformations des sinus duraux (MSD).

The purpose of this article is to give an overview of the cerebral and spinal cord pediatric malformations; we particularly describe three of them: Vein of Galen arteriovenous Malformation, Pial Arteriovenous Malformation, and Dural Sinus Malformation. We report the experience of Bicêtre since 1981 to 2003, with 317 VGAM, 302 Pial AVM and 30 DSM. We describe natural history, clinical and imaging features, endovascular management and the clinical and morphologic results. The clinical consequences of the VGAM and Pial AVM are systemic or cerebral. When they are cerebral they are mainly from hydrovenous type, as melting brain, or chronic hydrocephalus with calcifications and seizures. Depending of their angioarchitecture and amount of arteriovenous shunt, their gravity and the time of revealing are variable. Pial AVM, they carry the risk of hemorrhage, unlike VGAM. The presence of a fistula type should lead to suspect hereditary hemorrhagic telangiectasia. The main risk of DSM is hemorrhage due to thrombosis of the malformation, more than hydrovenous disorders. In VGAM, we obtain the complete cure of the shunt in 55% of case, and reduction of more than half of the shunt in 93.8%. Seventy-four percent of treated cases had a normal neurologic examination. DSM have a worse prognostic, and mortality is 38% despite treatment.

MR diffusion tensor imaging and fiber tracking in inflammatory diseases of the spinal cord.

PURPOSE: Our aim was to study the fractional anisotropy (FA) variations and the fiber tracking (FT) patterns observed in patients with myelitis. MATERIAL AND METHODS: Fifteen patients with symptomatic myelitis and 11 healthy subjects were prospectively selected. We performed T2-weighted and diffusion tensor imaging on a 1.5T MR scanner. FA and apparent diffusion coefficient maps were computed in both healthy subjects and patients. In each patient, we performed FT to study pathologic aspects on this imaging method. FA data were analyzed by using z-scores. RESULTS: For the healthy subjects, averaged FA values ranged from 0.745 to 0.751. All abnormal areas seen on T2-weighted imaging had a significantly decreased FA value. In 9 patients (60%), FA maps showed decreased FA areas, whereas T2-weighted imaging findings were normal. These areas matched the neurologic deficit in 33%. Eighty percent of patients had multiple decreased FA areas. Five patients (33%) had increased FA values in normal T2-weighted areas. CONCLUSION: We observed specific FA and FT pattern variations in patients with myelitis.

MR diffusion tensor imaging and fiber tracking in 5 spinal cord astrocytomas.

Spinal cord astrocytomas are rare neoplasms that can result in alteration of the spinal cord structural integrity, which can be assessed by using diffusion tensor imaging methods. Our objective was to visualize the deformation of the posterior spinal cord lemniscal and corticospinal tracts in 5 patients with low-grade astrocytomas compared with 10 healthy volunteers by using 3D fiber-tracking reconstructions.

Perfusion-weighted MR imaging studies in brain hypervascular diseases: comparison of arterial input function extractions for perfusion measurement.

BACKGROUND AND PURPOSE: Brain hypervascular diseases are complex and induce hemodynamic disturbances on brain parenchyma, which are difficult to accurately evaluate by using perfusion-weighted (PWI) MR imaging. Our purpose was to test and to assess the best AIF estimation method among 4 patients with brain hypervascular disease and healthy volunteers. METHODS: Thirty-three patients and 10 healthy volunteers underwent brain perfusion studies by using a 1.5T MR imaging scanner with gadolinium-chelate bolus injection. PWI was performed with the indicator dilution method. AIF estimation methods were performed with local, regional, regional scaled, and global estimated arterial input function (AIF), and PWI measurements (cerebral blood volume [CBV] and cerebral blood flow [CBF]) were performed with regions of interest drawn on the thalami and centrum semiovale in all subjects, remote from the brain hypervascular disease nidus. Abnormal PWI results were assessed by using Z Score, and evaluation of the best AIF estimation method was performed by using a no gold standard evaluation method. RESULTS: From 88% to 97% of patients had overall abnormal perfusion areas of hypo- (decreased CBV and CBF) and/or hyperperfusion (increased CBV and CBF) and/or venous congestion (increased CBV, normal or decreased CBF), depending on the AIF estimation method used for PWI computations. No gold standard evaluation of the 4 AIF estimates found the regional and the regional scaled methods to be the most accurate. CONCLUSION: Brain hypervascular disease induces remote brain perfusion abnormalities that can be better detected by using PWI with regional or regional scaled AIF estimation methods.

[Diffusion tensor imaging and tractography of central pontine myelinolysis]. / Suivi évolutif d'une myelinolyse centro-pontique en irm de tenseur de diffusion et de tracking de fibres.

OBJECTIVES: To illustrate the value of diffusion tensor imaging and tractography in the diagnosis and follow-up of central pontine myelinolysis. CASE REPORT: We report a case of central pontine myelinolysis in a 29 year old woman, also anorexic, studied using MR Diffusion Tensor Imaging (DTI) and Fibre Tracking (FT) focused on the pons, and compared with the studies of 5 normal volunteers. Tractography showed a swollen aspect of the right corticospinal fiber tract correlating with mild left lower extremity deficit at clinical evaluation. The pontine fibers were posteriorly displaced but intact. The sensory tracts were also intact. Apparent Diffusion Coefficient values were increased and Fractional Anisotropy was decreased in the lesions. Follow up imaging showed persistent abnormal ADC and FA values in the pons although the left cortico-spinal tract returned to normal, consistent with the clinical outcome. CONCLUSION: Diffusion Tensor Imaging MR and Fiber tractography are a new method to analyse white matter tracts. It can be used to prospectively evaluate the location of white matter tract lesions at the acute phase of central pontine myelinolysis and follow up.

Bilateral dystrophic ossification of the thyroid cartilage appearing as symmetrical laryngeal masses.

Primary cartilaginous lesions of the larynx are relatively uncommon. We present a case of bilaterally pseudocystic lesion of the thyroid cartilage that demonstrated progressive calcification. Pathologic analysis showed features suggesting a dystrophic lesion with no evidence of malignancy. We hypothesize that repetitive microtrauma related to muscular overuse probably led to inflammatory changes at tendinous insertions on the laryngeal cartilage and resulted in dystrophic ossification of the laryngeal cartilage.

[Varicella, acute postinfectious arteriopathy and cerebral arterial thrombosis in childhood: a unique clinical and etiologic framework to be fully acknowledged]. / Varicelle, artériopathie aiguë post-infectieuse et infarctus cérébral artériel de l'enfant: un cadre clinique et étiologique à ne pas méconnaître.

Acute arteriopathies are the etiological factor of 25% of all the cerebral arterial thrombosis cases in childhood; they give way to ischemic strokes which have specific clinical and radiological features; varicella is the etiologic factor in 60% of the cases; favorable outcome is the rule; physiopathology and treatment remain under discussion.

Urgent and emergent embolization of lesions of the head and neck in children: indications and results.

Indications for and results and complications of embolization of lesions of the head and neck were analyzed retrospectively. The procedures were performed since 1980 on an emergent or urgent basis in 30 infants and children by an experienced interventional neuroradiologist in Bicetre, France. Indications for embolization included hemorrhage, occular occlusion, respiratory obstruction, CNS complications or potential complications, interference with nutrition, and functional impairment related to the effect of the lesion on the developing facial skeleton and teeth. The specific lesions included seven hemangiomas (palpebral, subglottic, and nasal) and 20 vascular malformations (maxillofacial, auricular, dural, cerebral [including three vein of Galen malformations] and spinomedullary). Embolization was efficacious in 28 of 30 patients. Hemangiomas (potentially involutive tumors) responded dramatically with arrest of the proliferative phase and shrinking of the mass. Combined hemovascular lymphatic malformations (hemolymphangiomas) of the tongue demonstrated a variable decrease in size. High-flow evolutive arteriovenous malformations involving the teeth and dura were controlled but required multiple embolizations. One infant with a vein of Galen arteriovenous malformation died. Three local complications occurred in two patients. No cerebral ischemic or femoral artery complications occurred.

Severe cardiac failure in newborns with VGAM. Prognosis significance of hemodynamic parameters in neonates presenting with severe heart failure owing to vein of Galen arteriovenous malformation.

OBJECTIVE: Neonatal vein of Galen malformation complicated by severe cardiac failure is a rare disease. The purpose was to assess the outcome of this life-threatening malformation and identify hemodynamic prognostic factors. DESIGN: Retrospective study. PATIENTS: Twenty-four newborns with cardiac failure requiring mechanical ventilation were consecutively admitted from 1986 to 2000. INTERVENTIONS: Cardiovascular evaluation including echocardiogram was performed in all cases. Eighteen transarterial shunt occlusions with glue were applied by the same team of three physicians. MEASUREMENTS AND RESULTS: Twelve babies survived and underwent one endovascular session at least (median age 20 days) with a mean 63 months follow-up. Embolization was not performed in 6 of the 12 nonsurvivors because of severe brain damage or profound hypotension Cardiogenic shock occurred in all nonsurvivors, but also in one long-term survivor (p<0.0001). Echocardiogram showed signs of right ventricular failure, most often in the dead babies (p=0.005). The pulmonary systemic arterial pressure ratio was significantly higher in the nonsurvivor group (p=0.031), and it decreased significantly after the first embolization only in patients who survived (p=0.01). Patent ductus arteriosus and a diastolic aortic reversed-flow were present in all nonsurvivors in contrast to 30% of the long-term survivors (p=0.003 ). There was no difference in the left ventricular contractility and mean cardiac output between the two groups. CONCLUSIONS: The outcome of vein of Galen malformation complicated by severe cardiac failure requiring mechanical ventilation remains poor. Neonatal embolization seems to be beneficial only in babies without suprasystemic pulmonary hypertension.

Preoperative embolization of intracranial meningiomas.

The goal of preoperative embolization of intracranial meningiomas is to facilitate their surgical removal by reducing tumor vascularity and decreasing blood loss during surgery. This study is based on personal experience with about 100 embolized meningiomas and on the experience of others. Embolization is performed during the same session as diagnostic angiography. The appropriate embolic materials (absorbable or nonabsorbable) are chosen according to the location of the tumor, the size of the feeding arteries, the blood flow, and the presence of any potentially dangerous vessels (dangerous anastomoses between external carotid artery and internal carotid or vertebral arteries, arteries supplying the cranial nerves). Preoperative embolization appeared to be very useful in large tumors with pure or predominant external carotid artery supply (convexity meningiomas), in skull-base meningiomas, and in middle fossa and paracavernous meningiomas. It was also useful in falx and parasagittal meningiomas receiving blood supply from the opposite side and in posterior fossa meningiomas. CT low densities demonstrated after embolization did not always correlate with necrosis on microscopic examination, and large areas of infarction could be found despite normal CT. Embolic material was found on pathologic examination in 10%-30% of cases; fresh or recent ischemic and/or hemorrhagic necrosis consistent with technically successful embolization was demonstrated in 40%-60% of cases. With careful technique complications are rare.

Experimental models in interventional neuroradiology.

Various experimental models have been developed to test interventional neuroradiologic techniques. Most have been used to test various devices and embolic materials, and a small number of models have been designed for teaching or training purposes. Experimental models in endovascular techniques have seldom been used to stimulate disease processes in order to facilitate their understanding.

Functional anatomy of the facial vasculature in pathologic conditions and its therapeutic application.

The authors describe the functional anatomy of the facial vascular system, using the anastomoses between the facial, maxillary, transverse facial, lingual, and ophthalmic systems to selectively identify the blood flow to a specific territory for embolization and posttreatment evaluation of hemangiomas. In three patients the specific vascular patterns are described and the usefulness of understanding the regional functional anatomy is illustrated for successful embolotherapy of these malformations.

Pseudoaneurysms within ruptured intracranial arteriovenous malformations: diagnosis and early endovascular management.

PURPOSE: To draw attention to pseudoaneurysms within ruptured arteriovenous malformations and to consider their diagnostic and therapeutic features, including pitfalls and precautions needed for safe embolization. METHODS: Radiologic and clinical charts of 189 patients who bled from intracranial arteriovenous malformations were retrospectively reviewed. RESULTS: Fifteen of the 189 (8%) were found to have pseudoaneurysms. Nine of the pseudoaneurysms were arterial, six were venous. In the early period following hemorrhage, nine patients were treated conservatively. The other six were treated with surgery (one case) or embolization (five cases) because urgent intervention was required. The clinical outcome for both conservative and interventional groups was generally favorable, but one patient in the conservative group died of a rebleed. In the patients who underwent embolization, the fragile nature of the pseudoaneurysm made it necessary to first embolize the artery feeding it. Embolization with particles was considered hazardous. Instead, free-flow (nonwedged) N-butyl-cyanoacrylate embolization proved safe and effective in treating both the pseudoaneurysms and arteriovenous malformations in these cases. CONCLUSIONS: This study highlights the importance of recognizing pseudoaneurysms in such patients and the importance of using free-flow liquid adhesive material on the artery feeding the pseudoaneurysm if embolization is required.

The rhesus monkey as an animal model for training in interventional neuroradiology.

The angiographic anatomy of the external carotid artery system in the rhesus monkey is described. Similarities and differences between human and monkey anatomy are emphasized, as well as anatomic variations and potential collateral pathways. Superselective angiography and embolization in the external carotid artery system of the rhesus monkey proved to be technically feasible and potentially represents an excellent training model for surgical neuroangiographic techniques.