[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.

Clinical characteristics of dural arteriovenous shunts in 446 patients of three different ethnicities.

SUMMARY: Dural arteriovenous shunts (DAVSs) developing in either the ventral, dorsal or lateral epidural spaces (VE, DE and LE-shunts) predictably drain in either cranio/spino-fugal or -petal directions. Associated conditions like venous outflow restrictions (VOR) may be responsible for changes in this drainage pattern. The goal of this study was to compare demographic, angiographic and clinical characteristics of different types of DAVS in Europe, South America, and Asia to find out whether the same clinical profile is present in different ethnicities. Charts and angiographic films of 446 patients with DAVS from three hospitals in Europe, Asia and South America were retrospectively evaluated. Clinical symptoms were separated into benign and aggressive and the presence or absence of cortical venous reflux (CVR) and VOR was noted. LE-shunts were present in elderly men and were always associated with CVR resulting in aggressive symptoms. VE-shunts were present in females and almost always had benign symptoms. There were no differences among the three populations for these shunts. DE-shunts in the Asian population were more aggressive secondary to a higher rate of VOR with associated CVR. VE-shunts rarely lead to CVR even in the presence of VOR, whereas LE-shunts invariably lead to CVR, irrespective of the population investigated. CVR in DE-shunts is not related to the primary disease (i.e. the shunt itself) but to associated factors that led to VOR. Since the occurrence of these varied between different ethnicities, DE-shunts were aggressive in the Asian population and benign in the European and South American populations.

Diffusion tensor imaging characteristics of the corpus callosum in mild, moderate, and severe traumatic brain injury.

BACKGROUND AND PURPOSE: The corpus callosum is an important predilection site for traumatic axonal injury but may be unevenly affected in head trauma. We hypothesized that there were local differences in axonal injury within the corpus callosum as investigated with diffusion tensor imaging (DTI), varying among patients with differing severity of traumatic brain injury (TBI). MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Ten control subjects (7 men, 3 women; mean age, 37 +/- 9 years) and 39 patients with TBI (27 men, 12 women; 34 +/- 12 years) were investigated, of whom 24 had mild; 9, moderate; and 6, severe TBI. Regions of interest were selected in the callosal genu, body, and splenium to calculate fractional anisotropy (FA), apparent diffusion coefficient (ADC), and the number of fibers passing through. Statistical comparison was made through analysis of variance with the Scheffé post hoc analysis. RESULTS: Compared with controls, patients with mild TBI investigated <3 months posttrauma (n = 12) had reduced FA (P < .01) and increased ADC (P < .05) in the genu, whereas patients with mild TBI investigated > or =3 months posttrauma (n = 12) showed no significant differences. Patients with moderate and severe TBI, all investigated <3 months posttrauma, had reduced FA (P < .001) and increased ADC (P < .01) in the genu compared with controls and reduced FA in the splenium (P < .001) without significant ADC change. CONCLUSION: Mild TBI is associated with DTI abnormalities in the genu <3 months posttrauma. In more severe TBI, both the genu and splenium are affected. DTI suggests a larger contribution of vasogenic edema in the genu than in the splenium in TBI.

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.

Patterns of the Cranial Venous System from the Comparative Anatomy inVertebrates. Part III. The Ventricular System and Comparative Anatomy of the Venous Outlet of Spinal Cord and Its Homology with the Five Brain Vesicles.

SUMMARY: Ontogenetically, the ventricular venous systemmay develop in order to drain the gray matter(cells of the mantle layer of the neural tube) which migrates dorsally. On primitive brain vesicles of submammals especially fish, amphibianand reptile, the ventricular venous system is the major venous collector located on the middorsal surface, in between the meningeal layers comparable to the subarachnoid space in mammals. The ventricular venous system functions as a major drainage system for the brain vesicles in these submammals but its role decreases when the other two venous systems develop. Concerning the route of venous exit from the brain vesicles, we found that it resembles the spinal cord but could not be found all the way along the brain vesicles.

The aneurysmal wall. The key to a subclassification of intracranial arterial aneurysm vasculopathies?

SUMMARY: The pathogenesis of intracranial arterial aneurysms (AA) has been debated for many years and still remains unclear, although these entities might pose life-threatening risks to the patient and understanding the disease is of utmost importance for choosing treatment concepts. Apart from the "classical" berry-type aneurysm, there are different other types of intracranial AA such as infectious, dissecting or giant, partially thrombosed aneurysms. From the clinician's perspective, the hypothesis that some of these intracranial aneurysms might be due to abluminal factors has been put forward for many years. Alterations of the vessel wall, either due to luminal or abluminal factors may be employed for an etiological classification of aneurysmal vasculopathies as will be discussed in this article. Moreover, regarding certain aneurysmal vasculopathies as an abluminal disease might alter current therapeutic strategies since therapy should not only aim at the intraluminal repair of the artery but may also target the vessel wall.

Patterns of the Cranial Venous System from the Comparative Anatomy in Vertebrates. Part II.The Lateral-Ventral Venous System.

SUMMARY: Comparing the adult submammalian brain with the human embryonic brain, some patterns of venous drainage are quite similar. The veins lying on the lateral surface of the brain in submammals resemble those of the human embryo. In addition, the new longitudinal venous anastomosis ventral to the brain vesicles occurring late in human embryonic development seems to be similar to the late appearance of the basal vein and the ventral brain stem venous plexus found in adult mammals including man. The evolution of the new structures of the brain vesicles throughout the vertebrate series may have an induction role on the appearance of the cranial venous system. This part of the article series focuses on the evolution of the lateral-ventral venous system of the five brain vesicles. Nevertheless, the limitation of this article is due in part to the paucity of circumstantial papers and different names used for the veins.

Vascular microanatomy of the pontomedullary junction, posterior inferior cerebellar arteries, and the lateral spinal arteries.

SUMMARY: This study of 25 brains at the pontomedullary junction defined the different possible origins of the perforating arteries and lateral spinal arteries in relation to the posterior inferior cerebellar arteries (PICAs). - If the PICA emerges from the common trunk of the AICA-PICA coming from the basilar artery, it never gives perforating arteries or a lateral spinal artery on the lateral surface of the brain stem but supplies blood to a part of the ipsilateral cerebellar hemisphere. - If the PICA arises extradurally at C1, it never gives perforating arteries for the lateral surface of the brain stem, but it gives pial branches for the posterior surface of the medulla oblongata and is always the origin of the lateral spinal artery. - If the PICA emerges in the intradural vertebral artery, it is the source of the perforating arteries for the lateral surface of the brain stem and of the blood supply of the ipsilateral cerebellum.

Imaging Findings of a Patient with Incomplete Phenotypical Expression of the PHACES Syndrome.

SUMMARY: We present imaging findings of a patient with an incomplete form of the PHACES syndrome with dolichosegmental intracranial arteries as the predominant component, and discuss the etiopathological and clinical significance of this finding.

White matter abnormalities in mild traumatic brain injury: a diffusion tensor imaging study.

BACKGROUND AND PURPOSE: Traumatic axonal injury is a primary brain abnormality in head trauma and is characterized by reduction of fractional anisotropy (FA) on diffusion tensor imaging (DTI). Our hypothesis was that patients with mild traumatic brain injury (TBI) have widespread brain white matter regions of reduced FA involving a variety of fiber bundles and show fiber disruption on fiber tracking in a minority of these regions. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Twenty-one patients with mild TBI were investigated (men:women, 12:9; mean age +/- SD, 32 +/- 9 years). In a voxel-based comparison with 11 control subjects (men:women, 8:3; mean age, 37 +/- 9 years) using z score analysis, patient regions with abnormally reduced FA were defined in brain white matter. MR imaging, DTI, and fiber tracking characteristics of these regions were described and analyzed using Pearson correlation, linear regression analysis, or the chi(2) test when appropriate. RESULTS: Patients had on average 9.1 regions with reduced FA, with a mean region volume of 525 mm(3), predominantly found in cerebral lobar white matter, cingulum, and corpus callosum. These regions mainly involved supratentorial projection fiber bundles, callosal fibers, and fronto-temporo-occipital association fiber bundles. Internal capsules and infratentorial white matter were relatively infrequently affected. Of all of the involved fiber bundles, 19.3% showed discontinuity on fiber tracking. CONCLUSION: Patients with mild TBI have multiple regions with reduced FA in various white matter locations and involving various fiber bundles. A minority of these fiber bundles show discontinuity on fiber tracking.

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.

[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.

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.

Association of cervical internal carotid artery aneurysm with ipsilateral vertebrobasilar aneurysm in two children: a segmental entity?

INTRODUCTION: A combination of cervical and intradural aneurysm in children in the absence of systemic disorders has previously not been reported. CASE REPORT: We report two boys with an identical combination of fusiform cervical internal carotid aneurysm and ipsilaterally located vertebrobasilar aneurysm. They had no history of trauma, they did not display any personal or familial signs of systemic disease, and the testing for collagen disease was negative. The location and appearance of the aneurysms and the identical anatomical disposition in the patients indicated a non-randomly distributed segmental vulnerability. CONCLUSION: The cases demonstrate primary morphological signs of a developmental error being expressed in two seemingly separate segments but linked by the hypoglossal artery. It suggests a segmental error related to this embryonic vessel. They also show that few phenotypes are specific for a genotypic disorder and highlight the importance of analysing different etiologies for aneurysm formation and anatomical disposition when taking treatment strategy decisions.

Extracranial vertebral artery involvement in neurofibromatosis type I. Report of four cases and literature review.

SUMMARY: Neurofibromatosis type 1 (NF-1) is one of the most common inherited diseases and as an autosomal dominant genetic disorder results from NF-1 gene mutation with 100% penetration and wide phenotypic variability. The disease can involve a wide variety of tissues derived from all three embryonic layers. NF-1 vasculopathy has been described primarily in peripheral arteries, but arteries supplying the CNS may also be involved. Of those, extracranial vertebral involvement is the commonest and most important. A series of four patients with NF-1 and vascular disease of the vertebral artery is described with a review of the pathophysiology, vascular phenotypes, their management and the pertinent literature.

Patterns of cranial venous system from the comparative anatomy in vertebrates. Part I, introduction and the dorsal venous system.

SUMMARY: Many classifications of the cerebral venous system are found in the literature but they are seldom based on phylogenic study. Among vertebrates, venous drainage of the brain vesicles differs depending on the species. Due to the variability, poorly descriptive articles, and many different names used for the veins, the comparative study of the cranial venous system can hardly be performed in detail. The cranial venous system in vertebrates can be divided into three systems based on the evolution of the meninges and structures of the brain vesicles: the dorsal, lateral-ventral and ventricular systems. This study proposes a new classification of the venous drainage of brain vesicles using knowledge from a comparative study of vertebrates and focusing on the dorsal venous system. We found that the venous drainage of the neopallium and neocerebellum is involved with this system which may be a recent acquisition of cranial venous evolution.