Safety and efficacy of balloon angioplasty in symptomatic intracranial stenosis: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: Endovascular treatment is offered for symptomatic intracranial stenosis (ICS) when medical therapy fails. The purpose of this meta-analysis is to evaluate the risks and effectiveness of balloon angioplasty (BA) alone. MATERIALS AND METHODS: Systematic review and meta-analysis of all available articles on BA for symptomatic ICS was conducted. Data was analyzed separately for > 70% (Group 1) and > 50% (Group 2) stenosis. The results of the Group 1 were compared with those of SAMMPRIS study to the extent possible. RESULTS: A total of 25 studies comprising 674 patients were included. The cumulative incidence of periprocedural (within 30 days) stroke and death were 16.3% (Group 1), 7.6% (Group 2) and 11.5% (all studies). Incidence rates of ischemic stroke in the qualifying artery territory during follow-up (per 100 patient-years) were 2.0, 2.4 and 2.3, any stroke and death during follow-up were 4.4, 7.4 and 6.9, restenosis rates were 4.9, 11.5 and 8.9 respectively. While comparison of cumulative incidences of periprocedural ischemic stroke between Group 1 (13.0%) and the medical arm from SAMMPRIS study(4.4%) showed a significant difference (P = 0.008), there was no significant difference between the Group 1 and the stenting arm from SAMMPRIS study(10.7%) in the same variable. CONCLUSION: Balloon angioplasty for stenosis of more than 70% is likely to have similar outcome comparable to the stenting arm in the SAMMPRIS study, however it presents lower rates of late ischemic events and restenosis. These data may help deciding on the endovascular method of choice in case of medical therapy failure.

Cranial dural arteriovenous shunts: selection of the ideal lesion for surgical occlusion according to the classification system.

BACKGROUND: The types of cranial dural arteriovenous fistulae (cDAVFs) that constitute good surgical candidates are unclear despite the use of classifications. We aimed to compare the DES classification with other classification schemes in identifying "ideal lesions for surgery." The DES scheme is based on two features: the level of the shunt (BVS, bridging vein shunt; DSS, dural sinus shunt; ISS, isolated sinus shunt; EVS, emissary vein shunt) and the type of leptomeningeal venous reflux (LVR) (direct, exclusive, strained). METHODS: In this observational cohort study, the angiographies of 20 consecutive patients treated over 1 year were analyzed retrospectively. We defined cDAVFs as ideal for surgery, if cure may be achieved by disconnecting the arterialized draining vein through a single craniotomy. To evaluate the performance of each classification scheme in identifying the "ideal lesion for surgery," we carried out a sensitivity analysis of the Borden, Cognard, and DES schemes. RESULTS: Eight lesions were Borden type 3 and 1 type 2, and 11 type 1. According to Cognard, 2 lesions were type IV, 2 type III, 1 type IIa+b, 11 type I, and 4 lesions could not be clearly classified. According to the DES scheme, 8 lesions were DSS, 4 BVS, 3 ISS, and 5 EVS. All 4 lesions classified as BVS in the DES were ideal lesions for surgery (sensitivity, specificity, PPV, NPV 100%). Not all high-grade lesions according to Borden were good surgical candidates. CONCLUSION: The DES scheme, as opposed to other classifications, facilitates the therapeutic decision-making especially for selecting candidates for surgery.

Glioblastoma in the Canton of Zurich, Switzerland revisited: 2005 to 2009.

BACKGROUND: A population-based analysis of patients with glioma diagnosed between 1980 and 1994 in the Canton of Zurich in Switzerland confirmed the overall poor prognosis of glioblastoma. To explore changes in outcome, registry data were reevaluated for patients diagnosed between 2005 and 2009. METHODS: Patients with glioblastoma who were diagnosed between 2005 and 2009 were identified by the Zurich and Zug Cancer Registry. The prognostic significance of epidemiological and clinical data, isocitrate dehydrogenase 1 (IDH1)(R132H) mutation status, and O6 methylguanine DNA methyltransferase (MGMT) promoter methylation status was analyzed using the Kaplan-Meier method and the Cox proportional hazards model. RESULTS: A total of 264 patients with glioblastoma were identified, for an annual incidence of 3.9 compared with the previous incidence of 3.7. The mean age of the patients at the time of diagnosis was 59.5 years in the current cohort compared with 61.3 years previously. The overall survival (OS) rate was 46.4% at 1 year, 22.5% at 2 years, and 14.4% at 3 years in the current study compared with 17.7% at 1 year, 3.3% at 2 years, and 1.2% at 3 years as reported previously. The median OS for all patients with glioblastoma was 11.5 months compared with 4.9 months in the former patient population. The median OS was 1.9 months for best supportive care, 6.2 months for radiotherapy alone, 6.7 months for temozolomide alone, and 17.0 months for radiotherapy plus temozolomide. Multivariate analysis revealed age, Karnofsky performance score, extent of tumor resection, first-line treatment, year of diagnosis, and MGMT promoter methylation status were associated with survival in patients with IDH1(R132H) -nonmutant glioblastoma. CONCLUSIONS: The OS of patients newly diagnosed with glioblastoma in the Canton of Zurich in Switzerland markedly improved from 1980 through 1994 to 2005 through 2009. Cancer 2016;122:2206-15. © 2016 American Cancer Society.

Clinically isolated neurosarcoidosis: a recommended diagnostic path.

The involvement of the central nervous system in sarcoidosis can manifest with a variety of neurological symptoms, most of them nonspecific. We identified 13 patients with neurosarcoidosis diagnosed at our clinic. Six of 13 patients presented with clinically isolated neurosarcoidosis (CINS) without signs or symptoms of systemic disease. CINS patients were not different with respect to age, as well as imaging and spinal fluid findings, or disease course. However, we found spinal cord involvement in neurosarcoidosis patients much more common than previously described (in 8 out of 13 patients). Spinal cord affection was associated with older age at diagnosis and a less favorable response to therapy. Based on our findings, we propose a diagnostic path for neurosarcoidosis, including spinal magnetic resonance imaging (MRI) as a mandatory and early step during diagnostic workup.

The collateral circulation in pediatric moyamoya disease.

PURPOSE: The descriptions of collateral circulation in moyamoya have so far been a mixture of topography-based and vessels' source-based analyses. We aimed to investigate the anatomy and systematize the vascular anastomotic networks in pediatric moyamoya disease. METHODS: From a series of 25 consecutive complete angiographic studies of newly diagnosed children with moyamoya, 14 children had moyamoya disease and 11 were diagnosed with moyamoya syndrome, i.e., moyamoya angiopathy with some additional concomitant systemic disease. We retrospectively analyzed the arterial branches supplying the moyamoya anastomotic networks, their origin, course, location, and connections with the recipient vessels. RESULTS: We describe four types of anastomotic networks in children with moyamoya disease, two superficial-meningeal and two deep-parenchymal. As superficial-meningeal, we defined the leptomeningeal and the durocortical networks. Apart from the previously described leptomeningeal network observed in the convexial watershed zones, we report on the basal temporo-orbitofrontal leptomeningeal network. The second superficial-meningeal network is the durocortical network, which can be basal or calvarian in location. We define as deep-parenchymal networks the nonpreviously described subependymal network and the inner striatal and inner thalamic networks. The subependymal network is fed by the intraventricular branches of the choroidal system and diencephalic perforators, which at the level of the periventricular subependymal zone, anastomose with medullary-cortical arteries as well as with striatal arteries. The inner striatal and thalamic networks are constituted by intrastriatal connections among striatal arteries and intrathalamic connections among thalamic arteries when the disease compromises the origin of one or more sources of their supply. CONCLUSION: The previously inexplicitly described "moyamoya abnormal network" in pediatric moyamoya disease can be described as a composition of four anastomotic networks with distinct angioarchitecture. A better understanding of the collateralization in moyamoya may help in defining a new staging system of the disease with clinical relevance.

Langer-Giedion syndrome associated with congenital dural arterio-venous fistula.

Langer-Giedion syndrome (LGS) is a rare disease caused by deletion of chromosome 8q23.3-q24.11. Clinical manifestations include among others multiple exostoses, short stature, intellectual disability, and typical facial dysmorphism. Dural arterio-venous shunts (DAVS) in the pediatric age are rare lesions, which have been classified into three types: dural sinus malformations (DSM), infantile type DAVS (IDAVS), and adult type DAVS (ADAVS). We report a case of a patient with a known LGS who was diagnosed with complex intracranial dural AV fistula at the age of 20. An association between LGS and intracranial dural AV fistulas has to our knowledge never been reported before.

Cranial dural arteriovenous shunts. Part 3. Classification based on the leptomeningeal venous drainage.

The commonly used Borden and Cognard classification systems for the prediction of clinical behavior of cranial dural arteriovenous shunts focus on the venous drainage, particularly the presence of leptomeningeal venous drainage, and on the direction of flow, particularly the presence of retrograde flow. In addition, the latter includes ectasia and spinal drainage as criteria of two distinct grades. However, none of the above classifications (a) differentiates direct from exclusive leptomeningeal venous drainage, (b) considers cortical venous congestion as a factor potentially associated with an aggressive clinical course, and (c) anticipates ectasia in shunts with a mixed dural-cortical venous drainage (type 2). In this study, we analyzed the angiographic images of 107 consecutive patients having a cranial dural arteriovenous fistula with leptomeningeal venous drainage, based on a newly developed scheme. This scheme, symbolized with the acronym "DES," groups the dural shunts according to three factors: directness and exclusivity of leptomeningeal venous drainage and signs of venous strain. According to the combination of the three factors, eight different groups were distinguished. All analyzed cases could be assigned to one of these groups. Directness of leptomeningeal venous drainage expresses the exact site of the shunt (bridging vein vs sinus wall), whereas exclusivity expresses venous outlet restrictions. All bridging vein shunts had a direct leptomeningeal venous drainage. Almost all bridging vein shunts and all "isolated" sinus shunts had an exclusive leptomeningeal venous drainage. Venous strain, manifested as ectasia and/or congestion, denotes the decompensation of the cerebral venous system due to the shunt reflux. The comparison of the presented concept with the currently used classifications highlighted the advantages of the former and the weaknesses of the latter.

Cranial dural arteriovenous shunts. Part 4. Clinical presentation of the shunts with leptomeningeal venous drainage.

Cranial dural arteriovenous fistulae have been classified into high- and low-risk lesions mainly based on the pattern of venous drainage. Those with leptomeningeal venous drainage carry a higher risk of an aggressive clinical presentation. Recently, it has been proposed that the clinical presentation should be considered as an additional independent factor determining the clinical course of these lesions. However, dural shunts with leptomeningeal venous drainage include a very wide spectrum of inhomogeneous lesions. In the current study, we correlated the clinical presentation of 107 consecutive patients harboring cranial dural arteriovenous shunts with leptomeningeal venous drainage, with their distinct anatomic and angiographic features categorized into eight groups based on the "DES" (Directness and Exclusivity of leptomeningeal venous drainage and features of venous Strain) concept. We found that among these groups, there are significant angioarchitectural differences, which are reflected by considerable differences in clinical presentation. Leptomeningeal venous drainage of dural sinus shunts that is neither direct nor exclusive and without venous strain manifested only benign symptoms (aggressive presentation 0%). On the other end of the spectrum, the bridging vein shunts with direct and exclusive leptomeningeal venous drainage and venous strain are expected to present aggressive symptoms almost always and most likely with bleeding (aggressive presentation 91.5%). Important aspects of the above correlations are discussed. Therefore, the consideration of leptomeningeal venous drainage alone, for prediction of the clinical presentation of these shunts appears insufficient. Angiographic analysis based on the above concept, offers the possibility to distinguish the higher- from the lower-risk types of leptomeningeal venous drainage. In this context, consideration of the clinical presentation as an additional independent factor for the prediction of their clinical course seems superfluous and possibly misleading. Topography is connected to the clinical presentation of the dural shunts inasmuch as the former determines the venous anatomy and the angioarchitectural features of the lesions.

Cranial dural arteriovenous shunts. Part 2. The shunts of the bridging veins and leptomeningeal venous drainage.

Leptomeningeal venous drainage of cranial dural arteriovenous fistulae is the most important determinant of adverse clinical course. Factors that predispose to its occurrence have not been adequately addressed in the literature. In the present study, we investigated the relation of shunt location to the development of leptomeningeal venous drainage, with regard to the bridging veins. Angiographic data of 211 consecutive patients with cranial dural arteriovenous fistulae treated over 19 years were analyzed. Dural shunts with leptomeningeal venous drainage were found in 107 patients; of these, 71 patients had pure leptomeningeal venous drainage (Borden type 3). The angioarchitecture of the shunt, including pattern of arterial feeders, relation with the bridging veins, primary venous drainage, and venous outflow restrictions were recorded. After analysis of the 71 Borden type 3 shunts with exclusive leptomeningeal venous drainage, three patterns emerged. The commonest was the fistula engaging a bridging vein that had lost its connection to the parent sinus into which it previously drained; it was characterized by an arterial network of feeders converging onto the wall of a bridging vein, with leptomeningeal venous reflux. The other patterns were those of "isolated" sinus segment characterized by arterial feeders converging on to the wall of the dural sinus with leptomeningeal venous reflux following the opacification of the sinus and fistulae in the vicinity of the cribriform plate with two subtypes. The main angioarchitectural features of the 36 Borden type 2 shunts with mixed sinusal-cortical venous drainage were the presence of a diffuse arterial network of vessels converging onto a site in the wall of the dural sinus, with leptomeningeal venous reflux following the opacification of the sinus. In this group, four exceptions were noticed with arterial feeders converging onto a bridging vein and having a mixed venous drainage to the cortical venous system and the sinuses. We concluded that the exact location of the shunt with regard to the bridging veins is a key factor in the development of leptomeningeal venous drainage. Cranial dural arteriovenous fistulae (CDAVFs) of either Borden type 2 or 3 do not constitute a homogeneous group. The great majority of these shunts present thrombotic phenomena.

Cranial dural arteriovenous shunts. Part 1. Anatomy and embryology of the bridging and emissary veins.

We reviewed the anatomy and embryology of the bridging and emissary veins aiming to elucidate aspects related to the cranial dural arteriovenous fistulae. Data from relevant articles on the anatomy and embryology of the bridging and emissary veins were identified using one electronic database, supplemented by data from selected reference texts. Persisting fetal pial-arachnoidal veins correspond to the adult bridging veins. Relevant embryologic descriptions are based on the classic scheme of five divisions of the brain (telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon). Variation in their exact position and the number of bridging veins is the rule and certain locations, particularly that of the anterior cranial fossa and lower posterior cranial fossa are often neglected in prior descriptions. The distal segment of a bridging vein is part of the dural system and can be primarily involved in cranial dural arteriovenous lesions by constituting the actual site of the shunt. The veins in the lamina cribriformis exhibit a bridging-emissary vein pattern similar to the spinal configuration. The emissary veins connect the dural venous system with the extracranial venous system and are often involved in dural arteriovenous lesions. Cranial dural shunts may develop in three distinct areas of the cranial venous system: the dural sinuses and their interfaces with bridging veins and emissary veins. The exact site of the lesion may dictate the arterial feeders and original venous drainage pattern.

Intra-arterial administration of papaverine during mechanical thrombectomy for acute ischemic stroke.

BACKGROUND: The use of stent retrievers for mechanical thrombectomy in acute ischemic stroke may induce significant vasospasm, which at the early phases of reperfusion may be crucial for rethrombosis of the recanalized vessel. We aimed to study whether the use of intra-arterial papaverine in selected cases of vasospasm was associated with improved cerebral perfusion, arterial reocclusion, or increased hemorrhagic complications. METHODS: We retrospectively studied 9 consecutive patients with large artery acute occlusion, treated with stent retriever and intra-arterial papaverine. Onset to administration of intravenous recombinant tissue-plasminogen activator time, baseline National Institute of Health Stroke Scale, time to reperfusion, number of passes of the stent retriever, modified Rankin Scale score at discharge, postprocedural hemorrhage, onset to reperfusion time, papaverine dose, and thrombolysis in cerebral infarction grade were recorded in all patients. RESULTS: After papaverine administration, the caliber of the infused arteries and their flow was increased in all cases. In none of the treated cases a reocclusion occurred after papaverine infusion. In one of the studied patients (11%), a parenchymal bleeding occurred 36 hours postoperatively. CONCLUSIONS: This small study suggests that intra-arterial infusion of papaverine for the treatment of cerebral vasospasm after mechanical thrombectomy in acute ischemic stroke is effective and safe.

Endovascular treatment of 170 consecutive cranial dural arteriovenous fistulae: results and complications.

This study aims to evaluate a single-center experience with endovascular treatment of cranial dural arterievenous fistulae (CDAVF). The clinical and radiological records of 170 consecutive patients harboring a CDAVF and treated endovascularly in a 16-year period were reviewed. A variety of data related to demographics, features of the lesion, treatment, outcome, and follow-up were analyzed with emphasis to the results and complications. Half of the lesions had cortical venous drainage (CVD) in the initial angiographic investigation, whereas 26 % had exclusively CVD. Sixty-seven percent of our patients presented with benign symptoms and 33 % with aggressive symptoms. In 60.5 % of the patients with benign lesion (without CVD), an anatomic cure in the immediate postinterventional angiogram without complication or permanent morbidity was achieved, whereas 69 % of the patients with aggressive lesions (with CVD) had an anatomic cure in the postinterventional final angiogram with all permanent-morbidity cases belonging to this group. The average of endovascular operation sessions per patient was 1.2. In a mean follow-up period of 2.8 years, the overall complete occlusion rate was 85.5 % (78 % for the benign group and 89.5 % for the aggressive group) and clinical cure and/or improvement rate of 93 %. The operative mortality was zero, and permanent neurologic morbidity was 2.3 %. In 73 % of our cases, N-butyl cyanoacrylate (NBCA) was used as the only or main embolic material. Endovascular embolization is the treatment of choice for CDAVF. High rates of good anatomical and clinical results, associated with very low operative complication rate can be achieved with few embolization sessions. Although mastering of a permanent embolic material is important, the therapeutic strategy should be individulized and not material based.

Silicone models as basic training and research aid in endovascular neurointervention--a single-center experience and review of the literature.

The rapid development and wider use of neurointerventional procedures have increased the demand for a comprehensive training program for the trainees, in order to safely and efficiently perform these procedures. Artificial vascular models are one of the dynamic ways to train the new generation of neurointerventionists to acquire the basic skills of material handling, tool manipulation through the vasculature, and development of hand-eye coordination. Herein, the authors present their experience regarding a long-established training program and review the available literature on the advantages and disadvantages of vascular silicone model training. Additionally, they present the current research applications of silicone replicas in the neurointerventional arena.

Persistent ventral ophthalmic artery associated with supraclinoid internal carotid artery aneurysm: case report and review of the literature.

A persistent ventral ophthalmic artery arising from the A1 segment of the anterior cerebral artery associated with an ipsilateral asymptomatic supraclinoid internal carotid artery (ICA) aneurysm is extremely rare. This variation and association were thoroughly documented by digital substraction angiography (DSA) and 3-dimensional rotational angiography (3DRA) in a 49-year-old female with polycystic kidney disease. A short review of the related literature is also presented.

Unassisted and multiple microcatheter coiling of distal basilar aneurysms: Outcomes and literature review.

PURPOSE: The best treatment for distal basilar artery aneurysms is controversial. We aimed to review our single-centre experience with coil embolisation of aneurysms at this location and compare it with the surgical and endovascular literature. METHODS: Forty-two aneurysms in a distal basilar location in 42 consecutive patients (15 ruptured and 27 unruptured) were treated endovascularly from 2010 to 2015. Unassisted single and multiple microcatheter coil embolisation alone was used in all cases. We studied our immediate and long-term anatomical results, operative complications, and outcome. RESULTS: The immediate angiographic results showed complete occlusion in 34 (81%), a neck remnant in seven (16.6%) and a residual aneurysm in one patient (2.4%). There were two thromboembolic events (4.7%) without clinical sequelae; therefore, the operative morbidity and mortality were zero.Three patients with ruptured aneurysms (7.1%) died due to complicated vasospasm. Thirty-nine patients (93%) had clinical and MR imaging follow-up (mean 32.3 months ± 18.6, range from 12 to 66 months). There was recanalization in 30.8% with a retreatment rate of 15.3% and no new bleedings. The aneurysm size was the most important predictor of early anatomical outcome and recurrence. CONCLUSION: Unassisted and multiple microcatheter coiling is a safe treatment for distal basilar aneurysms. Early anatomical results and recurrence depend on the aneurysm size. Morbidity and mortality are lower and recurrence rates are higher in comparison with clipping or other adjunctive endovascular techniques.

Impact of fMRI-guided advanced DTI fiber tracking techniques on their clinical applications in patients with brain tumors.

INTRODUCTION: White matter tractography based on diffusion tensor imaging has become a well-accepted non-invasive tool for exploring the white matter architecture of the human brain in vivo. There exist two main key obstacles for reconstructing white matter fibers: firstly, the implementation and application of a suitable tracking algorithm, which is capable of reconstructing anatomically complex fascicular pathways correctly, as, e.g., areas of fiber crossing or branching; secondly, the definition of an appropriate tracking seed area for starting the reconstruction process. Large intersubject, anatomical variations make it difficult to define tracking seed areas based on reliable anatomical landmarks. An accurate definition of seed regions for the reconstruction of a specific neuronal pathway becomes even more challenging in patients suffering from space occupying pathological processes as, e.g., tumors due to the displacement of the tissue and the distortion of anatomical landmarks around the lesion. METHODS: To resolve the first problem, an advanced tracking algorithm, called advanced fast marching, was applied in this study. The second challenge was overcome by combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) in order to perform fMRI-guided accurate definition of appropriate seed areas for the DTI fiber tracking. In addition, the performance of the tasks was controlled by a MR-compatible power device. RESULTS: Application of this combined approach to eight healthy volunteers and exemplary to three tumor patients showed that it is feasible to accurately reconstruct relevant fiber tracts belonging to a specific functional system. CONCLUSION: fMRI-guided advanced DTI fiber tracking has the potential to provide accurate anatomical and functional information for a more informed therapeutic decision making.

Disruption of the blood-brain barrier by intra-arterial administration of papaverine: a technical note.

INTRODUCTION: Various endovascular techniques can be used to treat cerebral vasospasm after aneurysmal subarachnoid haemorrhage (SAH) including intra-arterial administration of vasodilator drugs such as papaverine or nicardipine and balloon dilatation of the affected vessel segment. Papaverine is known to have side effects, and we report a possible new one. MATERIALS AND METHODS: After the treatment of cerebral vasospasm in a SAH patient by intra-arterial administration of papaverine into the left posterior cerebral artery, severe mesencephalic extravasation of blood and contrast media was detected. RESULTS: After reviewing the literature, the authors conclude that interruption of the blood-brain barrier by papaverine most likely combined with a secondary hyperperfusion phenomena, and perhaps a direct toxic effect on brain tissue was the mechanism of this major complication. CONCLUSION: In treating vasospasm in areas with a high density of perforating arteries, especially in the posterior circulation, papaverine should be used cautiously because a safe regimen has yet to be established. In this situation, alternative agents such as calcium channel blockers could be considered, but evidence-based data are still missing.

Thrombophilia Due to Factor V and Factor II Mutations and Formation of a Dural Arteriovenous Fistula: Case Report and Review of a Rare Entity.

Genetic mutations underlying thrombophilia are often recognized in patients with thromboembolic episodes. However, the clinical and therapeutic implications of such findings often remain unclear. We report the first case of a dural arteriovenous fistula (DAVF) in a patient with a combined factor II and factor V Leiden mutation. A 40-year-old man presented with a large left temporal and intraventricular hemorrhage. An initial angiogram showed thrombosis of the left sigmoid sinus but no evidence of a vascular malformation. One year after the hemorrhage, an angiographic study showed the appearance of a right DAVF. During the follow-up period, the patient was found to harbor heterozygosity for a mutation of factor V and a mutation of factor II. Recognition of the patient's thrombophilia led to prolonged oral anticoagulation therapy to reduce the risk of a recurrent thrombotic episode. Despite the increased risk of bleeding, the therapy was considered justified. DAVFs may occur after sinus thrombosis in patients with combined factor II and factor V mutations. This observation indicates the association of multiple hematological disorders with DAVFs in individual patients. Moreover, it raises the clinical conundrum of how to manage patients with thrombophilia, intracranial hemorrhage, and DAVFs.

Correlation between the efferent venous drainage of the tumor and peritumoral edema in intracranial meningiomas: superselective angiographic analysis of 25 cases.

OBJECT: The extent of peritumoral brain edema (PTBE) associated with meningiomas can be highly variable. The authors studied the correlation between the development of efferent venous drainage from the tumor and the degree of PTBE that occurs in intracranial meningiomas. METHODS: Twenty-five patients with 27 intracranial supratentorial meningiomas were investigated to identify the correlation between the efferent venous drainage system of the tumor and peritumoral edema. The overall mean age of the patients was 54 years. Seventeen patients (68%) were female and eight (32%) were male. All patients underwent magnetic resonance imaging and digital subtraction angiography. In each meningioma, superselective angiography of the dominant feeding artery was performed, including the late venous phase to evaluate the development of the tumor's draining vein. An edema index (EI) was introduced to serve as an objective means by which to judge the extent of PTBE. Eleven meningiomas (41%), in which the mean EI was 0.14 +/- 0.10, clearly showed dominant draining veins originating from the tumor itself. In the other 16 meningiomas (59%), superselective angiography demonstrated no efferent venous drainage from the tumor, which could account for this group's mean EI value of 1.49 +/- 1.05 (p < 0.001). CONCLUSIONS: The current results suggest that hypoplasia of the efferent draining vein from the meningioma itself contributes to PTBE formation. The development of an efferent venous system mitigates against the formation of PTBE. Intratumoral venous congestion can be considered the main cause of PTBE in meningiomas.