Glomus jugulare (jugulotympanic paraganglioma) surgery requires tumor dissection in the region of the jugular bulb, upper internal jugular vein, and sigmoid sinus. Despite ligation or external compression of the sigmoid sinus proximally and ligation of the internal jugular vein distally, troublesome venous bleeding can arise from the inferior petrosal sinus or condylar veins at the medial wall of the jugular bulb. Excessive packing in this area can place the integrity of the lower cranial nerves at risk. We report a technique in which Tisseel(®) fibrin sealant is injected into the ligated sigmoid sinus and internal jugular vein. This forms an internal cast around the tumor in the sigmoid-jugular complex and helps seal the inferior petrosal sinus and condylar veins. This allows for safer dissection with reduced venous bleeding. Our experience in five cases has shown this technique to be effective.

Recent reports have emerged suggesting that multiple sclerosis (MS) may be due to abnormal venous outflow from the central nervous system, termed chronic cerebrospinal venous insufficiency (CCSVI). These reports have generated strong interest and controversy over the prospect of a treatable cause of this chronic debilitating disease. This review aims to describe the proposed association between CCSVI and MS, summarize the current data, and discuss the role of endovascular therapy and the need for rigorous randomized clinical trials to evaluate this association and treatment.

INTRODUCTION: Dural arteriovenous fistulas involving marginal sinus are relatively rare. Transvenous embolization is a curative treatment of choice for them. Regional anatomy surrounding the marginal sinus comprises complex craniocervical bony structures and abundant venous interconnections. Therefore, dural arteriovenous fistulas involving marginal sinus may have various routes for a transvenous approach. The purpose of this article was to analyze endovascular treatment of marginal sinus dural arteriovenous fistulas with emphasis on the routes of transvenous embolization. METHODS: Five patients with dural arteriovenous fistulas (DAVFs) involving the marginal sinus who were treated with transvenous embolization were retrospectively analyzed in terms of endovascular treatment: angiographic architecture, routes of venous approach, and treatment results case by case. RESULTS: There were no significant complications except for headache, ocular pain, and facial flushing after transvenous embolization. Immediate angiographic outcomes were complete in four patients and partial in one patient. Clinical outcomes during follow-up were complete recovery in four patients and intermittent tinnitus in one patient. Three different transvenous approaches were used for transvenous coil embolization: ipsilateral internal jugular vein in three patients, contralateral internal jugular vein in one patient, and vertebral venous plexus in one patient. CONCLUSION: Transvenous coil embolization in treating marginal sinus DAVF is a safe and effective method. In case of failure of an internal jugular venous approach, alternative routes of embolization should be considered. Understanding the regional venous anatomy of the craniocervical junction is important for targeting fistulous sites and selecting routes for transvenous embolization.

OBJECTIVE We aimed to assess whether migraine is associated with changes in the distribution of the venous drainage through primary and secondary pathways by using phase-contrast magnetic resonance imaging (MRI). METHODS We examined 26 patients (37.3 ± 13.9 years) with recurring migraine headaches and 26 age- and gender-matched controls with no neurologic disease (37.3 ± 13.7 years) on a 3 Tesla MR scanner. A 2D time-of-flight MR-venography of the upper neck region was performed to visualize the venous vasculature. Cine-phase contrast scans with high-velocity encoding were employed to quantify arterial inflow and flow in the primary venous channels (right and left jugular veins), whereas scans with low-velocity encoding were employed to quantify flow in the secondary venous channels (epidural, vertebral, and deep cervical veins). RESULTS Patients with migraine showed (i) a higher prevalence of dense secondary extracranial venous networks (15 vs. 2, P = 0.00002) and (ii) a significantly larger percentage of venous outflow through secondary channels (10.5% vs. 5.5%; of total cerebral blood flow, P = 0.02). This mainly included drainage through epidural, vertebral, and deep cervical veins. CONCLUSION Migraine patients showed a significantly larger percentage of venous outflow through secondary channels. The mechanism of this alteration remains to be elucidated. Potential mechanisms include repeated release of vasoactive substances or growth factors.

BACKGROUND Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system, believed to be triggered by an autoimmune reaction to myelin. Recently, a fundamentally different pathomechanism termed 'chronic cerebrospinal venous insufficiency'(CCSVI) was proposed, provoking significant attention in the media and scientific community. METHODS Twenty MS patients (mean age 42.2 ± 13.3 years; median Extended Disability Status Scale 3.0, range 0-6.5) were compared with 20 healthy controls. Extra- and intracranial venous flow direction was assessed by colour-coded duplex sonography, and extracranial venous cross-sectional area (VCSA) of the internal jugular and vertebral veins (IJV/VV) was measured in B-mode to assess the five previously proposed CCSVI criteria. IJV-VCSA ≤ 0.3 cm(2) indicated 'stenosis,' and IJV-VCSA decrease from supine to upright position 'reverted postural control.' The sonographer, data analyser and statistician were blinded to the patient/control status of the participants. RESULTS No participant showed retrograde flow of cervical or intracranial veins. IJV-VCSA ≤ 0.3 cm(2) was found in 13 MS patients versus 16 controls (p=0.48). A decrease in IJV-VCSA from supine to upright position was observed in all participants, but this denotes a physiological finding. No MS patient and one control had undetectable IJV flow despite deep inspiration (p=0.49). Only one healthy control and no MS patients fulfilled at least two criteria for CCSVI. CONCLUSIONS This triple-blinded extra- and transcranial duplex sonographic assessment of cervical and cerebral veins does not provide supportive evidence for the presence of CCSVI in MS patients. The findings cast serious doubt on the concept of CCSVI in MS.

We report a patient with a rare dural arteriovenous fistula of the anterior condylar vein, who presented with unusual clinical symptoms due to the anomalous venous drainage. The patient had progressive ocular signs, a dilated venous pouch at the skull base and, on angiography, retrograde venous drainage into the superior ophthalmic vein. Transvenous embolization of the venous pouch produced complete amelioration of the ocular symptoms. Such treatment may be curative for dural arteriovenous fistulas of the anterior condylar vein.

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The aim of this study was to examine the clinical characteristics and angiographic findings of spontaneous idiopathic subarachnoid hemorrhage (ISAH) and to compare these with those of aneurysmal SAH (ASAH). We retrospectively reviewed the clinical characteristics and venograms of 118 consecutive patients with ISAH during the past 10years for possible abnormalities in venous structures. Also, 57 patients with ASAH during the past 4years were examined. Patients with ISAH showed low frequency of hypertension and no patient suffered from an episode of re-bleeding, or delayed ischemic deficits. Physical actions, including varieties of the Valsalva maneuver, were the causes of ISAH in 17 (29.8%) patients. Compared with patients with ASAH, patients with ISAH showed a significant difference in the drainage patterns of the basal vein of Rosenthal (BVR)(p=0.001). In addition, whereas a linearly decreasing trend toward the primitive type was evident in ASAH, each drainage pattern was distributed evenly in ISAH (linear by linear association, p=0.000). In this study, the primitive drainage pattern of BVR has a relationship with ISAH compared to ASAH. The way in which this venous configuration might influence bleeding remains unknown.

The aim of this study was to evaluate the anatomy of and normal variations in the craniocervical junction veins. We retrospectively reviewed 50 patients who underwent contrast-enhanced CT with a multidetector scanner. Axial and reconstructed images were evaluated by two neuroradiologists with special attention being paid to the existence and size of veins and their relationships with other venous branches around the craniocervical junction. The venous structures contributing to craniocervical junction venous drainage, including the inferior petrosal sinus (IPS), transverse-sigmoid sinus, jugular vein, condylar vein, marginal sinus and suboccipital cavernous sinus were well depicted in all cases. The occipital sinus (OS) was identified in 18 cases, including 4 cases of prominent-type OS. The IPS showed variations in drainage to the jugular vein through the jugular foramen or intraosseous course of occipital bone via the petroclival fissure. In all cases, the anterior condylar veins connected the anterior condylar confluence to the marginal sinus; however, a number of cases with asymmetry and agenesis in the posterior and lateral condylar veins were seen. The posterior condylar vein connected the suboccipital cavernous sinus to the sigmoid sinus or anterior condylar confluence. The posterior condylar canal in the occipital bone showed some differences, which were accompanied by variations in the posterior condylar veins. In conclusion, there are some anatomical variations in the venous structures of the craniocervical junction; knowledge of these differences is important for the diagnosis and treatment of skull base diseases. Contrast-enhanced CT using a multidetector scanner is useful for evaluating venous structures in the craniocervical junction.

The brain vascular system develops in such a way that it continuously adapts the supply of oxygen and other nutrients to the needs of the parenchyma. To accompany the developing brain vesicles, it evolves in several steps: superficial meningeal network first; intraventricular choroid plexuses which determine the arterial pattern; penetrating capillaries from the surface to the ventricular germinal matrix forming simple transcerebral arteriovenous loops; cortical capillaries last, mainly in the last trimester. The venous return becomes connected to both the surface and to the choroidal veins, so forming distinct meningeal and subependymal venous drainage systems, while the arteries are on the surface only. While the arterial system was determined early (week 8), the venous system is continuously remodeled by the morphological changes of the base of the skull and the expansion of the brain vesicles. Until late in gestation, the vascular system is made of simple endothelial channels in which the arterial or venous fate is determined primarily by the direction of flow.

This article provides a comprehensive description of the morphology of the human petrosquamosal sinus (PSS) derived from original observations made on 13 corrosion casts of the cranial venous system combined with routine clinical imaging studies in two patients. The PSS is not a rare finding in the adult human. In particular, continuous developments in imaging techniques have made radiologists become increasingly aware of this anatomical entity in recent years. The role of the PSS as a major encephalic drainage pathway and its potential implication in pathological conditions such as intracranial venous hypertension are discussed.

INTRODUCTION: To report a retrospective series of 84 cerebral developmental venous anomalies (DVAs), focusing on associated parenchymal abnormalities within the drainage territory of the DVA. METHODS: DVAs were identified during routine diagnostic radiological work-up based on magnetic resonance imaging (MRI)(60 cases), computed tomography (CT)(62 cases) or both (36 cases). Regional parenchymal modifications within the drainage territory of the DVA, such as cortical or subcortical atrophy, white matter density or signal alterations, dystrophic calcifications, presence of haemorrhage or a cavernous-like vascular malformation (CVM), were noted. A stenosis of the collecting vein of the DVA was also sought for. RESULTS: Brain abnormalities within the drainage territory of a DVA were encountered in 65.4% of the cases. Locoregional brain atrophy occurred in 29.7% of the cases, followed by white matter lesions in 28.3% of MRI investigations and 19.3% of CT investigations, CVMs in 13.3% of MRI investigations and dystrophic calcification in 9.6% of CT investigations. An intracranial haemorrhage possibly related to a DVA occurred in 2.4% cases, and a stenosis on the collecting vein was documented in 13.1% of cases. Parenchymal abnormalities were identified for all DVA sizes. CONCLUSION: Brain parenchymal abnormalities were associated with DVAs in close to two thirds of the cases evaluated. These abnormalities are thought to occur secondarily, likely during post-natal life, as a result of chronic venous hypertension. Outflow obstruction, progressive thickening of the walls of the DVA and their morphological organization into a venous convergence zone are thought to contribute to the development of venous hypertension in DVA.

BACKGROUND AND PURPOSE: The termination of the superficial middle cerebral vein is classically assimilated to the sphenoid portion of the sphenoparietal sinus. This notion has, however, been challenged in a sometimes confusing literature. The purpose of the present study was to evaluate the actual anatomic relationship existing between the sphenoparietal sinus and the superficial middle cerebral vein. METHODS: The cranial venous system of 15 nonfixed human specimens was evaluated by the corrosion cast technique (12 cases) and by classic anatomic dissection (three cases). Angiographic correlation was provided by use of the digital subtraction technique. RESULTS: The parietal portion of the sphenoparietal sinus was found to correspond to the parietal portion of the anterior branch of the middle meningeal veins. The sphenoid portion of the sphenoparietal sinus was found to be an independent venous sinus coursing under the lesser sphenoid wing, the sinus of the lesser sphenoid wing, which was connected medially to the cavernous sinus and laterally to the anterior middle meningeal veins. The superficial middle cerebral vein drained into a paracavernous sinus, a laterocavernous sinus, or a cavernous sinus but was never connected to the sphenoparietal sinus. All these venous structures were demonstrated angiographically. CONCLUSION: The sphenoparietal sinus corresponds to the artificial combination of two venous structures, the parietal portion of the anterior branch of the middle meningeal veins and a dural channel located under the lesser sphenoid wing, the sinus of the lesser sphenoid wing. The classic notion that the superficial middle cerebral vein drains into or is partially equivalent to the sphenoparietal sinus is erroneous. Our study showed these structures to be independent of each other; we found no instance in which the superficial middle cerebral vein was connected to the anterior branch of the middle meningeal veins or the sinus of the lesser sphenoid wing. The clinical implications of these anatomic findings are discussed in relation to dural arteriovenous fistulas in the region of the lesser sphenoid wing.

We report a case of bilateral collateral tentorial venous sinus drainage of the basal vein (of Rosenthal)(BV). The observation was made on a corrosion cast of the cerebral venous system obtained from a fresh cadaver. Radiographic correlation was obtained by performing standard X-ray imaging of the corrosion cast. Embryologic and clinical considerations are discussed.

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Cerebral developmental venous anomalies are the most frequently encountered cerebral vascular malformation, and as such, are frequently reported as fortuitous findings in computed tomography (CT) and magnetic resonance imaging (MRI) studies. Developmental venous anomalies (DVAs) are generally considered extreme anatomical variations of the cerebral vasculature, and follow a benign clinical course in the vast majority of cases. Here we review current concepts on DVAs with the aim of helping clinicians understand this complex entity. Morphological characteristics that are necessary to conceptualize DVAs are discussed in depth. Images modalities used in diagnosing DVAs are reviewed, including new MRI or CT techniques. Clinical presentation, association with other vascular malformations and cerebral parenchymal abnormalities, and possible physiopathological processes leading to associated imaging or clinical findings are discussed. Atypical forms of DVAs are also reviewed and their clinical significance discussed. Finally, recommendations as to how to manage asymptomatic or symptomatic patients with a DVA are advanced. Ann Neurol 2009;66:271-283.

INTRODUCTION: Multidetector CT (MDCT) is increasingly used for the investigation of neurovascular disorders, but restricted z-axis coverage (3.2cm for 64-MDCT) currently limits perfusion to a small portion of the brain close to the circle of Willis, and precludes dynamic angiographic appreciation of the entire brain circulation. We illustrate the clinical potential of recently developed 320-MDCT extending the z-axis coverage to 16cm in a patient with symptomatic carotid artery stenosis. METHODS: In a 74-year-old patient presenting with critical symptomatic stenosis of the left CCA, pre- and post-carotid artery stenting whole-head subtracted dynamic MDCT angiography and perfusion were obtained in addition to CT angiography of the supra-aortic trunks. Both whole-head subtracted MDCT angiography and perfusion demonstrated delayed left ICA circulation, which normalized after carotid stenting. DISCUSSION: 320-MDCT offers unprecedented z-axis coverage allowing for whole-brain perfusion and subtracted dynamic angiography of the entire intracranial circulation. These innovations can consolidate the role of MDCT as a first intention imaging technique for cerebrovascular disorders, in particular for the acute management of stroke.

OBJECTIVE: While chronic cerebrospinal venous insufficiency (CCSVI) can be characterized using cervical plethysmography, much remains unknown about the haemodynamics associated with this procedure. The aim of the study was therefore to gain a deeper understanding of the observed haemodynamics. METHOD: Forty healthy controls and 44 CCSVI patients underwent cervical plethysmography, which involved placing a strain-gauge collar around their necks and tipping them from the upright (90(o)) to supine position (0(o)) in a chair. Once stabilized, they were returned to the upright position, allowing blood to drain from the neck. A mathematical model was used to calculate the hydraulic resistance of the extracranial venous system for each subject in the study. RESULTS: The mean hydraulic resistance of the extracranial venous system was 10.28 (standard deviation [SD] 5.14) mmHg.s/mL in the healthy controls and 16.81 (SD 9.22) in the CCSVI patients (P < 0.001). CONCLUSIONS: The haemodynamics of the extracranial venous system are greatly altered in CCSVI patients.

BACKGROUND: Magnetic resonance imaging and echo color Doppler (ECD) scan techniques do not accurately assess the cerebral venous return. This generated considerable scientific controversy linked with the diagnosis of a vascular syndrome known as chronic cerebrospinal venous insufficiency (CCSVI) characterized by restricted venous outflow from the brain. The purpose of this study was to assess the cerebral venous return in relation to the change in position by means of a novel cervical plethysmography method. METHODS: This was a single-center, cross-sectional, blinded case-control study conducted at the Vascular Diseases Center, University of Ferrara, Italy. The study involved 40 healthy controls (HCs; 18 women and 22 men) with a mean age of 41.5 ± 14.4 years, and 44 patients with multiple sclerosis (MS; 25 women and 19 men) with a mean age of 41.0 ± 12.1 years. All participants were previously scanned using ECD sonography, and further subset in HC (CCSVI negative at ECD) and CCSVI groups. Subjects blindly underwent cervical plethysmography, tipping them from the upright (90°) to supine position (0°) in a chair. Once the blood volume stabilized, they were returned to the upright position, allowing blood to drain from the neck. We measured venous volume (VV), filling time (FT), filling gradient (FG) required to achieve 90% of VV, residual volume (RV), emptying time (ET), emptying gradient (EG) required to achieve 90% of emptying volume (EV) where EV = VV-RV, also analyzing the considered parameters by receiver operating characteristic (ROC) curves and principal component mathematical analysis. RESULTS: The rate at which venous blood discharged in the vertical position (EG) was significantly faster in the controls (2.73 mL/second ± 1.63) compared with the patients with CCSVI (1.73 mL/second ± 0.94; P =.001). In addition, respectively, in controls and in patients with CCSVI, the following parameters were highly significantly different: FT 5.81 ± 1.99 seconds vs 4.45 ± 2.16 seconds (P =.003); FG 0.92 ± 0.45 mL/second vs 1.50 ± 0.85 mL/second (P <.001); RV 0.54 ± 1.31 mL vs 1.37 ± 1.34 mL (P =.005); ET 1.84 ± 0.54 seconds vs 2.66 ± 0.95 seconds (P <.001). Mathematical analysis demonstrated a higher variability of the dynamic process of cerebral venous return in CCSVI. Finally, ROC analysis demonstrated a good sensitivity of the proposed test with a percent concordant 83.8, discordant 16.0, tied 0.2 (C = 0.839). CONCLUSIONS: Cerebral venous return characteristics of the patients with CCSVI were markedly different from those of the controls. In addition, our results suggest that cervical plethysmography has great potential as an inexpensive screening device and as a postoperative monitoring tool.

This article discusses the biophysical aspects of venous outflow from the brain in healthy individuals and in patients with chronic cerebrospinal venous insufficiency. Blood flows out of the brain differently, depending on body position. In the supine position it flows out mainly through internal jugular veins, while in the upright position it uses the vertebral veins. This phenomenon is probably not due to the active regulation of the flow but instead results from the collapse of jugular veins when the head is elevated. Such a collapse is associated with a significant increase in flow resistance, which leads to redirection of the flow towards the vertebral pathway. Theoretical calculations respecting the rules of fluid mechanics indicate that the pressure gradients necessary for moving blood from the brain toward the heart differ significantly between the supine and upright positions. The occlusion of internal jugular veins, according to fluid mechanics, should result in significant increase in the flow resistance and the restriction of cerebral flow, which is in line with clinical observations. Importantly, the biophysical analysis of cerebral venous outflow implies that the brain cannot easily compensate for increased peripheral venous resistance (namely, an occlusion of the large extracranial veins draining this organ), either by elevating the pressure gradient or by decreasing the vascular resistance through the recruitment of additional drainage pathways. This may mean that chronic cerebrospinal venous insufficiency may cause the destruction of the delicate nervous tissue of the central nervous system.

A new venous disorder, chronic cerebrospinal venous insufficiency (CCSVI), has been proposed in patients with multiple sclerosis (MS). It is a vascular condition characterized by an impaired cerebrospinal venous drainage due to obstructions in the main extracranial cerebrovenous outflow routes (i.e. internal jugular veins [IJV] and/or azygos veins). In this review, the studies which assessed the prevalence of CCSVI in MS by echo colour Doppler (ECD) will be discussed. The technical aspects of determination of the five CCSVI criteria:(1) reflux in the IJV and/or vertebral veins in supine and upright position,(2) reflux in the deep cerebral veins,(3) high-resolution B-mode proximal IJV stenosis,(4) flow not Doppler detectable in IJVs and/or vertebral veins (VVs) and (5) reverted postural control of the main cerebrovenous outflow pathway are described in detail. We conclude that so far there are many studies with contradictory results, and as yet a strong scientific base to support the evidence for a causative relationship of CCSVI and MS is lacking. Recent studies call into question the validity of using ECD as a proper and reliable test for the diagnosis of CCSVI. One explanation for the variety in interpretation of the individual CCSVI criteria, with the wide-ranging percentages CCSVI, could be the different methods by using ECD to determine various criteria.

BACKGROUND Sauropod dinosaurs were the largest animals ever to walk on land, and, as a result, the evolution of their remarkable adaptations has been of great interest. The braincase is of particular interest because it houses the brain and inner ear. However, only a few studies of these structures in sauropods are available to date. Because of the phylogenetic position of Spinophorosaurus nigerensis as a basal eusauropod, the braincase has the potential to provide key evidence on the evolutionary transition relative to other dinosaurs. METHODOLOGY/PRINCIPAL FINDINGS The only known braincase of Spinophorosaurus ('Argiles de l'Irhazer', Irhazer Group; Agadez region, Niger) differs significantly from those of the Jurassic sauropods examined, except potentially for Atlasaurus imelakei (Tilougguit Formation, Morocco). The basisphenoids of Spinophorosaurus and Atlasaurus bear basipterygoid processes that are comparable in being directed strongly caudally. The Spinophorosaurus specimen was CT scanned, and 3D renderings of the cranial endocast and inner-ear system were generated. The endocast resembles that of most other sauropods in having well-marked pontine and cerebral flexures, a large and oblong pituitary fossa, and in having the brain structure obscured by the former existence of relatively thick meninges and dural venous sinuses. The labyrinth is characterized by long and proportionally slender semicircular canals. This condition recalls, in particular, that of the basal non-sauropod sauropodomorph Massospondylus and the basal titanosauriform Giraffatitan. CONCLUSIONS/SIGNIFICANCE Spinophorosaurus has a moderately derived paleoneuroanatomical pattern. In contrast to what might be expected early within a lineage leading to plant-eating graviportal quadrupeds, Spinophorosaurus and other (but not all) sauropodomorphs show no reduction of the vestibular apparatus of the inner ear. This character-state is possibly a primitive retention in Spinophorosaurus, but due the scarcity of data it remains unclear whether it is also the case in the various later sauropods in which it is present or whether it has developed homoplastically in these taxa. Any interpretations remain tentative pending the more comprehensive quantitative analysis underway, but the size and morphology of the labyrinth of sauropodomorphs may be related to neck length and mobility, among other factors.

Emissary veins connect the extracranial venous system with the intracranial venous sinuses. These include, but are not limited to, the posterior condyloid, mastoid, occipital, and parietal emissary veins. A review of the literature for the anatomy, embryology, pathology, and surgery of the intracranial emissary veins was performed. Detailed descriptions of these venous structures are lacking in the literature, and, to the authors', knowledge, this is the first detailed review to discuss the anatomy, pathology, anomalies, and clinical effects of the cranial emissary veins. Our hope is that such data will be useful to the neurosurgeon during surgery in the vicinity of the emissary veins.

BACKGROUND AND PURPOSE CCSVI has been proposed as a cause for MS. According to this theory, strictures of the IJV are among the described causes for CCSVI. Little is known about their influence on the hemodynamics of the CVBO. We used positional MR imaging to describe the influence of positional changes on the CVBO. MATERIALS AND METHODS Using the Fonar Upright MR imaging system, we performed venous time-of-flight angiography of the cervical region in the supine and sitting positions in 15 healthy volunteers. The image quality was rated; the positional findings and interindividual variances in the CVBO were analyzed. RESULTS A venous time-of-flight angiography of the cervical spine was feasible with good image quality. Strictures of 1 or both IJVs were found in 8 of 15 healthy volunteers in the supine position; however, none were visible in upright position. The IJV was not the main outflow route in the erect position. No relevant venous reflux was observed. CONCLUSIONS IJV strictures are a common finding in healthy volunteers in the supine position. They seem to be of no relevance in the erect position. This finding questions the validity of this criterion for the diagnosis of CCSVI. Reflux into the venous system was not visualized, and it remains to be seen whether it can be identified in patients with MS. Positional MR imaging enables operator-independent evaluation of the CVBO and may help to clarify the validity of the criteria for CCSVI.

BACKGROUND Chronic cerebrospinal venous insufficiency (CCSVI) was proposed as the causal trigger for developing multiple sclerosis (MS). However, current data are contradictory and a gold standard for venous flow assessment is missing. OBJECTIVE To compare structural magnetic resonance venography (MRV) and dynamic extracranial color-coded duplex sonography (ECCS) in a cohort of patients with MS. METHODS We enrolled 40 patients (44 ± 10 years). All underwent contrast-enhanced MRV for assessment of internal jugular vein (IJV) and azygos vein (AV) narrowing, graded into 3 groups: 0%-50%, 51%-80%, and >80%. ECCS analysis of blood flow direction, cross-sectional area (CSA), and blood volume flow (BVF) in both IJV and vertebral veins (VV) occurred in the supine and upright body position. RESULTS MRV identified 1 AV narrowing. IJV analysis yielded 12 patients for group 1 (30%), 19 patients for group 2 (48%), and 9 patients for group 3 (22%). By ECCS criteria, 4 patients (10%) presented with venous drainage abnormalities. Jugular BVF was different only between groups 1 and 3 (616 ± 133 vs. 381 ± 213 mL/min, p = 0.02). No other parameters in supine position and none of the parameters in the upright body position, apart from the IJV-BVF decrease in groups 1 and 3 (479 ± 172 vs. 231 ± 144 mL/min, p = 0.01), were different. CONCLUSIONS Our ECCS data contradict the postulated 100% prevalence of CCSVI criteria in MS. MRV seems more sensitive to detect IJV narrowing compared to ECCS. A measurable hemodynamic effect only exists in vessel narrowings >80%. Our combined data argue against a causal relationship of venous narrowing and MS, favoring the rejection of the CCSVI hypothesis.

The internal and external vertebral venous plexuses (VVP) extend the length of the vertebral column. Authoritative sources state that these veins are devoid of valves, permitting bidirectional blood flow and facilitating the hematogenous spread of malignant tumors that have venous connections with these plexuses. The aim of this investigation was to identify morphologic features that might influence blood flow in the VVP. The VVP of 12 adult cadavers (seven female, mean age 79.5 years) were examined by macro- and micro-dissection and representative veins removed for histology and immunohistochemistry (smooth muscle antibody staining). A total of 26, mostly bicuspid, valves were identified in 19 of 56 veins (34%) from the external VVP, all orientated to promote blood flow towards the internal VVP. The internal VVP was characterized by four main longitudinal channels with transverse interconnections; the maximum caliber of the longitudinal anterior internal VVP veins was significantly greater than their posterior counterparts (P < 0.001). The luminal architecture of the internal VVP veins was striking, consisting of numerous bridging trabeculae (cords, thin membranes and thick bridges) predominantly within the longitudinal venous channels. Trabeculae were composed of collagen and smooth muscle and also contained numerous small arteries and nerve fibers. A similar internal venous trabecular meshwork is known to exist within the dural venous sinuses of the skull. It may serve to prevent venous overdistension or collapse, to regulate the direction and velocity of venous blood flow, or is possibly involved in thermoregulation or other homeostatic processes. Clin. Anat. 25:609-618, 2012. © 2011 Wiley Periodicals, Inc.

Internal Jugular Veins (IJVs) are the principle outflow pathway for intracranial blood in clinostatism condition. In the seated position, IJVs collapse, while Vertebral Veins (VVs) increase the venous outflow and partially compensate the venous drainage. Spinal Epidural Veins are an additional drainage pathway in the seated position. Colour- Doppler-Sonography (CDS) examination is able to demonstrate IJVs and VVs outflow in different postural and respiratory conditions. The purpose of this study was to evaluate CDS quantification of the cerebral venous outflow (CVF) in healthy subjects and patients with multiple sclerosis (MS). In a group of 27 healthy adults (13 females and 14 males; mean age 37.8±11.2 years), and 52 patients with MS (32 females and 20 males; mean age 42.6±12.1 years), CVF has been measured in clinostatism and in the seated position as the sum of the flow in IJVs and VVs. The difference between CVF in clinostatism and CVF in the seated position (ΔCVF) has been correlated with patients' status (healthy or MS), and a number of clinical variables in MS patients. Statistical analysis was performed by Fisher's exact test, non-parametric Mann-Whitney U test, ANOVA Kruskal-Wallis test, and correntropy coefficient. The value of ΔCVF was negative in 59.6% of patients with MS and positive in 96.3% of healthy subjects. Negative ΔCVF values were significantly associated with MS (p<0.0001). There was no significant correlation with clinical variables. Negative ΔCVF has a hemodynamic significance, since it reflects an increased venous return in the seated position. This seems to be a pathologic condition. In MS patients, a vascular dysregulation resulting from involvement of the autonomous nervous system may be supposed. ΔCVF value should be included in the quantitative CDS evaluation of the cerebral venous drainage, in order to identify cerebral venous return abnormalities.