The negative impact of treatment delays on the long-term neurological outcomes of spinal dural arteriovenous fistulas: a longitudinal cohort study.

OBJECTIVE: Dural arteriovenous fistulas are rare vascular malformations that affect the brain and spinal cord. Spinal dural arteriovenous fistulas (sdAVFs) are the most frequently encountered vascular malformation affecting the spinal cord. The object of this study was to evaluate the impact of treatment delays on the long-term neurological outcomes of either open surgical or interventional treatment of sdAVFs. METHODS: In this retrospective, population-based cohort study, the authors examined consecutive patients with diagnosed sdAVFs at a tertiary care center between 2005 and 2020. Patients were assessed using the Aminoff-Logue disability scale (ALS) at various time points including symptom onset, primary care visit, first specialist outpatient visit, as well as both short and long-term follow-ups. The postoperative long-term ALS gait and bladder grades constituted the primary outcomes of the study. RESULTS: Among the 34 patients included in the study, the median age was 65 years, and there was a male predominance (71%). Most lesions were in the lumbar region (47%). Significant worsening in ALS gait and bladder grades was observed preoperatively, followed by postoperative improvements (p < 0.05). There was no difference in outcomes between surgical and endovascular treatments. Older age (OR 1.10, 95% CI 1.03-1.17, p = 0.007), worse preoperative ALS gait grades (OR 5.12, 95% CI 2.18-12.4, p < 0.001), and longer time from first specialist outpatient visit to first treatment (OR 1.00, 95% CI 1.00-1.01, p = 0.040) were independently associated with worse long-term gait outcomes. Only the preoperative ALS bladder score was a predictor of worse long-term bladder function (OR 92.7, 95% CI 28.0-306.7, p < 0.001). CONCLUSIONS: Both surgical and endovascular treatments for sdAVFs led to significant neurological improvements. However, treatment delays were associated with less favorable long-term outcomes. Prompt diagnosis and early intervention prior to symptom progression may enhance recovery and help to preserve neurological function.

Intracranial dural arteriovenous fistulas: association with cerebral venous thrombosis, baseline aggressiveness, and clinical outcomes. A retrospective multicenter study on 263 consecutive patients and literature review.

OBJECTIVE: The pathogenesis of intracranial dural arteriovenous fistulas (icDAVFs) is controversial. Cerebral vein thrombosis (CVT) and venous hypertension are recognized predisposing factors. This study aimed to evaluate the incidence of association between icDAVF and CVT and describe baseline aggressiveness and clinical outcomes for icDAVFs associated with CVT. The authors also performed a literature review of studies reporting icDAVF associated with CVT. METHODS: Two hundred sixty-three consecutive patients in two university hospitals with confirmed icDAVFs were included. A double-blind imaging review was performed to determine the presence or absence of CVT close or distant to the icDAVF. Location, type (using the Cognard classification), aggressiveness of the icDAVF, clinical presentation, treatment modality, and clinical and/or angiographic outcomes at 6 months were also collected. All prior brain imaging was analyzed to determine the natural history of onset of the icDAVF. RESULTS: Among the 263 included patients, 75 (28.5%) presented with a CVT concomitant to their icDAVF. For 18 (78.3%) of 23 patients with previous brain imaging available, CVT preceding the icDAVF was proven (6.8% of the overall population). Former/active smoking (OR 2.0, 95% CI 1.079-3.682, p = 0.022) and prothrombogenic status (active inflammation or cancer/coagulation trouble) were risk factors for CVT associated with icDAVF (OR 3.135, 95% CI 1.391-7.108, p = 0.003). One hundred eighty-seven patients (71.1%) had a baseline aggressive icDAVF, not linked to the presence of a CVT (p = 0.546). Of the overall population, 11 patients (4.2%) presented with spontaneous occlusion of their icDAVF at follow-up. Seven patients (2.7%) died during the follow-up period. Intracranial DAVF + CVT was not associated with a worse prognosis (modified Rankin Scale score at 3-6 months: 0 [interquartile range {IQR} 0-1] for icDAVF + CVT vs 0 [IQR 0-0] for icDAVF alone; p = 0.055). CONCLUSIONS: This was one of the largest studies focused on the incidence of CVT associated with icDAVF. For 6.8% of the patients, a natural history of CVT leading to icDAVF was proven, corresponding to 78.3% of patients with previous imaging available. This work offers further insights into icDAVF pathophysiology, aiding in identifying high-risk CVT patients for long-term follow-up imaging. Annual imaging follow-up using noninvasive vascular imaging (CT or MR angiography) for a minimum of 3 years after the diagnosis of CVT should be considered in high-risk patients, i.e., smokers and those with prothrombogenic status.

Long-term treatment outcomes and natural course of low-grade intracranial dural arteriovenous fistulas.

OBJECTIVE: In contrast to high-grade dural arteriovenous fistula (dAVF), low-grade dAVF is mainly associated with tinnitus and carries a low risk of morbidity and mortality. It remains unclear whether the benefits of active interventions outweigh the associated risk of complications in low-grade dAVF. METHODS: The authors conducted a retrospective single-center study that included all consecutive patients diagnosed with an intracranial low-grade dAVF (Cognard type I and IIa) during 2012-2022 with DSA. The authors analyzed symptom relief, symptomatic angiographic cure, treatment-related complications, risk for intracerebral hemorrhage (ICH), and mortality. All patients were followed up until the end of 2022. RESULTS: A total of 81 patients were diagnosed with a low-grade dAVF. Of these, 48 patients (59%) underwent treatment (all primary endovascular treatments), and 33 patients (41%) did not undergo treatment. Nine patients (19%) underwent retreatments. Angiographic follow-up was performed after median (IQR) 7.7 (6.1-24.1) months by means of DSA (mean 15.0, median 6.4 months, range 4.5-83.4 months) or MRA (mean 29.3, median 24.7 months, range 5.9-62.1 months). Symptom control was achieved in 98% of treated patients after final treatment. On final angiographic follow-up, 73% of patients had a completely occluded dAVF. There were 2 treatment-related complications resulting in 1 transient (2%) and 1 permanent (2%) neurological complication. One patient showed recurrence and progression of a completely occluded low-grade dAVF to an asymptomatic high-grade dAVF. No cases of ICH- or dAVF-related mortality were found in either treated patients (median [IQR] follow-up 5.1 [2.0-6.8] years) or untreated patients (median [IQR] follow-up 5.7 [3.2-9.0] years). CONCLUSIONS: Treatment of low-grade dAVF provides a high rate of symptom relief with small risks for complications with neurological sequela. The risks of ICH and mortality in patients with untreated low-grade dAVF are minimal. Symptoms may not reveal high-grade recurrence, and radiological follow-up may be warranted in selected patients with treated low-grade dAVF. An optimal radiographic follow-up regimen should be developed by a future prospective multicenter registry.

Microsurgical versus endovascular treatment of ethmoidal dural arteriovenous fistulas: systematic review and meta-analysis with a single-center case series.

OBJECTIVE: Ethmoidal dural arteriovenous fistulas (DAVFs) are often associated with cortical venous drainage (CVD) and a higher incidence of hemorrhage compared with DAVFs in other locations. They may be treated with open surgical disconnection or with endovascular treatment (EVT). In this systematic review and meta-analysis, the authors compare the outcomes of ethmoidal DAVFs treated with open microsurgery versus EVT and report four additional cases of ethmoidal DAVFs treated with open microsurgery in their institution. METHODS: A literature search of the PubMed and Scopus databases was conducted between December 2021 and May 2022 to identify relevant articles published between 1990 and 2021 using the PRISMA guidelines. References were reviewed and screened by two authors independently, and disagreements were resolved through consensus. Exclusion criteria included non-English-language studies, those with an incorrect study design, those reporting DAVFs in a nonethmoidal location, and studies whose outcomes were not stratified based on DAVF location. Inclusion criteria were any studies reporting on ethmoidal DAVFs treated by either microsurgery or EVT. A risk of bias assessment was performed using the Newcastle-Ottawa Scale. The authors performed a pooled proportional meta-analysis to compare patient outcomes. RESULTS: Twenty studies were included for analysis. Of 224 patients, 142 were treated with surgery, while 103 were treated with EVT. Seventy percent (148/210) of the patients were symptomatic at presentation, with hemorrhage being the most common presentation (48%). CVD was present in 98% of patients and venous ectasia in 61%. The rates of complete DAVF obliteration with surgery and EVT were 89% and 70%, respectively (95% CI -30% to -10%, p < 0.03). Twenty percent (21/103) of endovascularly treated fistulas required subsequent surgery. Procedure-related complications occurred in 10% of the surgical cases, compared with 13% of the EVT cases. The authors' case series included 4 patients with ethmoidal DAVFs treated surgically with complete obliteration, without any postoperative complications. CONCLUSIONS: The complete obliteration rates of ethmoidal DAVF appear to be higher and more definitive with microsurgical intervention than with EVT. While complication rates between the two procedures seem similar, patients treated with EVT may require further interventions for definitive treatment. The limitations of this study include its retrospective nature, the quality of studies included, and the continued evolving technologies of EVT. Future studies should focus on the association between venous drainage pattern and the proclivity toward venous ectasia or rate of hemorrhage at presentation.

Dural arteriovenous fistula in the setting of cerebral venous sinus thrombosis and COVID-19 infection.

OBJECTIVE: The aim of this study was to examine the presence of concurrent venous thrombosis and COVID-19 infections in patients with dural arteriovenous fistulas (dAVFs). METHODS: An analysis of all patients diagnosed with dAVF via cerebral angiography by the senior author was conducted, with special attention given to the presence of cerebral venous sinus thrombosis (CVST) and COVID-19 infection. General demographics, clinical presentation, presence of CVST, and COVID-19 infection status were reported. RESULTS: A total of 30 patients with dAVFs were included in this study. Three patients were diagnosed with COVID-19 (10%), with one of these patients developing CVST (33%) at 6 months postinfection. Of the 27 patients not infected with COVID-19, one was diagnosed with a likely chronic CVST at the time of presentation of dAVF (4%). A total of 11 case reports and 3 retrospective studies describing patients diagnosed with CVST at or after diagnosis of dAVFs have been reported in the literature. The incidence of dAVFs in patients with CVST has been reported as 2.4%, and the incidence of dAVF has reportedly increased five- to tenfold since the COVID-19 pandemic. CONCLUSIONS: COVID-19 infections may pose as an emerging risk factor for the development of CVST and subsequent dAVF development. To the authors' knowledge, this study presents the first cases in the literature describing a temporal relationship between COVID-19 and development of a dAVF with CVST. The effect of both COVID-19 and associated vaccines should be further assessed in future studies to examine its impact as an effect modifier on the association of dAVF and CVST.

Simultaneous Parkinsonism and Dementia as Initial Presentation of Intracranial Dural Arteriovenous Fistulas: A Systematic Review.

BACKGROUND: Intracranial dural arteriovenous fistulas (IDAVFs) are abnormal vascular connections between dural arteries and various venous structures within the brain. IDAVFs, rarely present with parkinsonism and dementia concurrently, making this a unique and underexplored clinical scenario. To the best of our knowledge, this is the first systematic review to comprehensively analyze cases of IDAVFs manifesting as both parkinsonism and dementia. METHODS: We assessed databases from inception to September 18, 2023. We identified studies describing patients with IDAVFs initially presenting with dementia or parkinsonism. Inclusion criteria encompassed case reports and case series, while excluding review articles, guidelines, technical notes, comments, conference abstracts, and editorials. RESULTS: The systematic search resulted in the initial screening of 383 studies, with 33 articles meeting the inclusion criteria. Among these, 29 were case reports, often describing 3 or fewer patients. From the remaining 4 case series, data pertinent to patients presenting both parkinsonism and dementia were selectively extracted, yielding a total study population of 43 patients. The anatomical distribution of IDAVFs within this cohort was diverse, with the transverse and sigmoid sinuses being the most common locations. Although most of these patients received endovascular therapy, a few underwent microsurgical occlusion or combined surgical and endovascular treatment. CONCLUSIONS: IDAVFs presenting with both parkinsonism and dementia represent a rare clinical entity. This systematic review provides valuable insights into the clinical characteristics, treatment options, and outcomes for such cases. However, additional research involving larger cohorts is essential to better comprehend the underlying mechanisms and establish standardized therapeutic guidelines.

A Case of Extremely Rapid Progression in Foix-Alajouanine Syndrome.

Foix-Alajouanine syndrome is a rare cause of spinal dural arteriovenous fistula that can cause irreversible myelopathy and paraplegia if not treated promptly. The complex nature of this pathology often leads to missed or delayed diagnosis regardless of broad workups executed. We present a symptomatically classic Foix-Alajouanine 68-year-old patient with an accelerated progression reaching stages of severe myelopathy in less than a year. Even with endovascular intervention, our patient was unable to recover neurologically. Including appropriate spinal imaging early in the workup for Foix-Alajouanine syndrome is necessary to halt or treat this disease process.

Endovascular embolisation of posterior condylar canal dural arteriovenous fistula.

We describe a rare case of dural arteriovenous fistula (dAVF) of the posterior condylar canal in a man in his 30s who presented with recent onset headache and neck pain and subsequently acute intracranial haemorrhage. Radiological workup showed a medulla bridging vein draining dAVF of the right posterior condylar canal supplied by a meningeal branch of the right occipital artery. A dilated venous sac was seen compressing over cerebellar tonsil on the right side. There was acute haemorrhage in the posterior fossa and fourth ventricle. He was successfully managed with transarterial endovascular embolisation via a supercompliant balloon microcatheter without any complication. The balloon microcatheter effectively prevented reflux of the liquid embolic agent into the parent artery and vasa nervosa of lower cranial nerves.

Dural arteriovenous fistula presenting with recurrent focal status epilepticus and lateralised periodic epileptiform discharges.

BACKGROUND: Dural arteriovenous fistulae (dAVF) are relatively infrequently encountered, and status epilepticus (SE) and lateralised periodic discharges (LPDs) on electroencephalography (EEG) have only rarely been associated with these arteriovenous malformations. METHODS: We present a patient with recurrent presentations with focal SE, aphasia and other focal deficits of cortical function and ictal and peri-ictal LPDs on serial EEG, who was shown to have a left hemispheric dAVF associated with left transverse and sigmoid sinus thrombosis. Seizures proved refractory to four anti-seizure medications but became more amenable to control after successful embolisation of the dAVF, with subsequent resolution of the focal cortical deficits. We discuss the co-occurrence of SE and LPDs with dAVF and review previously reported cases with this rare association. CONCLUSIONS: Our report supports a causative relationship between dAVF and focal SE, manifesting as ictal LPDs on EEG, and highlights the importance of active dAVF management in achieving seizure control. The relatively good patient outcome contrasts to the few similar case reports. Whilst rare, it is important to consider dAVF as a potentially treatable condition underlying new-onset seizures, including SE.

Transarterial Embolization of Anterior Cranial Fossa Dural AVFs as a First-Line Approach: A Single-Center Study.

BACKGROUND AND PURPOSE: Endovascular treatment has been increasingly used for anterior cranial fossa dural AVFs. Evidence on the safety and efficacy of different endovascular treatment strategies is limited. We report clinical and angiographic outcomes of patients with anterior cranial fossa dural AVFs who underwent treatment using transarterial embolization with n-BCA as a first-line approach. MATERIALS AND METHODS: Consecutive patients undergoing treatment for anterior cranial fossa dural AVFs at the Amsterdam University Medical Centers between 2010 and 2023 were retrospectively included. Transarterial embolization was used as a first-line approach, while transvenous treatment and surgery were used in cases of unsuccessful transarterial embolization. Treatment was evaluated on the basis of the angiographic cure rate, procedural complications, and clinical outcome. RESULTS: Fourteen patients were included with 15 anterior cranial fossa dural AVFs. All patients underwent primary endovascular treatment (12 transarterial, 1 transvenous, and 1 combined). Complete occlusion using only transarterial embolization was reached in 69% of patients (9/13), while the overall complete occlusion by endovascular treatment was reached in 79% of patients (11/14). Navigation and embolization were performed through the ophthalmic artery in 13 patients, with no procedural complications. Visual acuity was preserved in all patients. Three patients underwent an operation after failed endovascular treatment. All patients had complete anterior cranial fossa dural AVF occlusion at follow-up. CONCLUSIONS: Treatment of anterior cranial fossa dural AVFs using transarterial embolization with n-BCA as a first-line approach is a safe and feasible first-line treatment strategy. No visual complications due to embolization through the ophthalmic artery occurred in this study.

Concomitant Thoracic Spinal Dural Arteriovenous Fistula and Spinal Cavernous Malformation.

Both spinal dural arteriovenous fistula (SDAVF) and spinal cavernous malformation (SCM) are uncommon vascular malformations. To our knowledge, such a case of SDAVF concomitant with SCM has not been reported. We encountered a case of a 55-year-old man who had weakness and numbness in both lower extremities. Magnetic resonance imaging showed a round-shape lesion identified as a cavernous malformation in the middle segment of the thoracic spine, with spinal edema and obvious flow voids. Diagnostic angiography revealed an SDAVF fed by the right T7 radicular artery with venous drainage. The intramedullary venous hypertension due to fistula was suspected of inducing the formation of SCM. This case may provide new insight into the pathogenesis of SCM.

Sinus reconstruction therapy for superior sagittal sinus dural arteriovenous fistula caused by parasagittal meningioma invasion: a case report.

A dural arteriovenous fistula (dAVF) involving the superior sagittal sinus (SSS) is relatively rare, and its clinical course is usually aggressive. Its concomitance with a tumor has rarely been reported. Here, we present a case of SSS dAVF due to meningioma invasion, which was treated with sinus reconstruction and endovascular embolization. A 75-year-old man who had undergone tumor resection for parasagittal meningioma 4 years prior presented with intra-ventricular hemorrhage. Computed tomography angiography and magnetic resonance imaging revealed recurrent tumor invasion into the SSS causing occlusion. Cerebral angiography revealed multiple shunts along the occluded segment of the SSS, diffuse deep venous congestion, and cortical reflux. Borden type 3 SSS dAVF was diagnosed. We first performed direct tumor resection, followed by stenting for the occluded SSS and partial embolization of the shunts. After a 6-month interval, transvenous occlusion of the SSS was performed along the stent, resulting in complete obliteration of the dAVF. Sinus reconstruction therapy was effective in the immediate improvement of venous hypertension, obtaining the access route to the fistulas, and eradicating the shunts.

Dural Arteriovenous Fistulas With or Without Cerebral Venous Thrombosis: A Cross-Sectional Analysis of 511 Patients.

BACKGROUND AND OBJECTIVES: Recent studies suggest a bidirectional relationship of dural arteriovenous fistula (DAVF) with cerebral venous thrombosis (CVT). We aimed to compare the characteristics of patients with DAVF with or without CVT and to analyze the risk factors for the coexistence of CVT in a DAVF population. METHODS: A total of 511 adult patients with DAVF were enrolled consecutively in our hospital from February 2019 through November 2022. Demographic data, clinical manifestations, and imaging characteristics were reviewed in detail. The patients with DAVF were divided into two groups: DAVF with CVT (DAVF-CVT) group and without CVT (DAVF alone) group. Univariate logistic regression and multivariate logistic regression were used to analyze the risk factors for the coexistence of CVT and DAVF. RESULTS: CVT was found in 19.8% of patients with DAVF. In univariate analysis, compared with the DAVF-alone group, the DAVF-CVT group was more likely to have tinnitus ( P = .001), blurred vision ( P < .001), visual field loss ( P = .001), focal neurological deficits ( P = .002), seizures ( P = .008), and cognitive impairment ( P = .046) and less likely to have spinal cord/brain stem dysfunction ( P = .004). In addition, there were significant differences in age ( P = .009), sex ( P = .019), the occurrence of venous cerebral infarction ( P = .001), and DAVF location ( P < .001) between the two groups. Furthermore, multivariate analysis showed that blurred vision, venous cerebral infarction, large sinus DAVF, and multiple DAVF were risk factors for the coexistence of CVT in patients with DAVF, with the odds ratio of 2.416 (95% CI 1.267-4.606, P = .007), 6.018 (95% CI 1.289-28.100, P = .022), 5.801 (95% CI 2.494-13.496, P < .001), and 5.640 (95% CI 2.122-14.989, P = .001), respectively. CONCLUSION: CVT occurred in approximately one fifth of patients with DAVF. Blurred vision, venous cerebral infarction, large sinus DAVF, and multiple DAVF may be the risk factors for predicting the coexistence of CVT in patients with DAVF.

An isolated Sinus Intracranial Dural Arteriovenous Fistula with Unusual Drainage Pattern.

Isolated sinus dural arteriovenous fistulas (DAVFs) involve a dural sinus with occlusion on both sides of the diseased sinus segment. Because of venous drainage refluxing from the isolated sinus into the cortical veins, all isolated sinus DAVFs are Borden type III or Cognard type Ⅲ/Ⅳ. Venous drainage typically involves temporo-occipital cortical veins or the superior petrosal sinus and tributaries of the petrosal vein. However, drainage veins involving the perimedullary venous system are extremely rare. Here, we present a case of Cognard type V isolated sinus DAVF successfully treated with balloon catheter and Onyx.

Prevalence and Characteristics of Intracranial Aneurysms in Hereditary Hemorrhagic Telangiectasia.

BACKGROUND AND PURPOSE: The association between hereditary hemorrhagic telangiectasia and intracranial aneurysms remains controversial. This study evaluated the prevalence and characteristics of intracranial aneurysms in patients with hereditary hemorrhagic telangiectasia with brain vascular malformations. MATERIALS AND METHODS: Between 2007 and 2021, patients enrolled in the Brain Vascular Malformation Consortium with definite hereditary hemorrhagic telangiectasia, the presence of brain vascular malformations, and available angiographic studies of the brain were retrospectively reviewed. Angiographic features of intracranial aneurysms and their relationship to coexisting brain vascular malformations were analyzed. We also examined the association between baseline clinical features and the presence of intracranial aneurysms. RESULTS: One hundred eighty patients were included. A total of 14 intracranial aneurysms were found in 9 (5%) patients, and 4 intracranial aneurysms were considered flow-related aneurysms. Patients with intracranial aneurysms were significantly older than patients without intracranial aneurysms (mean, 48.1 [SD, 18.2] years versus 33.5 [SD, 21.0] years; P = .042). If we excluded flow-related intracranial aneurysms, the prevalence of intracranial aneurysms was 3.3%. All intracranial aneurysms were in the anterior circulation, were unruptured, and had an average maximal diameter of 3.9 (SD, 1.5) mm. No intracranial aneurysms were found in pediatric patients with hereditary hemorrhagic telangiectasia. No statistically significant correlation was observed among other baseline demographics, hereditary hemorrhagic telangiectasia features, and the presence of intracranial aneurysms. CONCLUSIONS: The prevalence of intracranial aneurysms in this large cohort study is comparable with that in the general population and might be increased slightly due to hemodynamic factors associated with shunting brain vascular malformations.

The 'corkscrew' sign: an indirect MRI hint for intracranial venous hypertension.

Dural arteriovenous fistulas (DAVFs) are intracranial vascular abnormalities in which one or more meningeal arteries shunt into a venous structure, either a cortical vein or a venous sinus, causing cerebral venous hypertension and risk of haemorrhage. Imaging diagnosis and characterisation are of paramount importance to grade the haemorrhagic risk and direct management. Non-invasive vascular neuroimaging might pose a diagnostic suspicion, but invasive catheter digital subtraction angiography (DSA) is usually required. We present the case of a patient with an atypical acute cerebral haemorrhage in which admission imaging with CT angiography (CTA) and MR angiography (MRA) was unremarkable, while advanced morphological MR with susceptibility-weighted imaging (SWI) revealed specific findings suggesting unilateral chronic venous hypertension. Successively, DSA detected a small DAVF that was treated with endovascular embolization. This case report raises awareness on subtle but important conventional imaging findings that suggest the presence of an AV shunt, to avoid misdiagnosis and delayed treatment.

Prevalence of Developmental Venous Anomalies in Association with Sporadic Cavernous Malformations on 7T MRI.

BACKGROUND AND PURPOSE: The etiology of sporadic cavernous malformations is not well-understood. However, recent evidence suggests that they may arise from a developmental venous anomaly. The goal of this study was to evaluate the prevalence of developmental venous anomalies associated with sporadic cavernous malformations using 7T MR imaging. MATERIALS AND METHODS: We retrospectively identified patients with a sporadic cavernous malformation imaged with 7T MR imaging between August 2019 and July 2022. Two raters determined whether a developmental venous anomaly was associated with each malformation. RESULTS: The study included 59 patients with a total of 61 cavernous malformations. Of the sixty-one, 44 (72%) had an associated developmental venous anomaly. An associated anomaly was most common for cavernous malformations in the brainstem (88%) compared with the cerebral hemispheres or cerebellum (60%-67%). CONCLUSIONS: By means of high-quality 7T imaging, most patients with a sporadic cavernous malformation were found to have an associated developmental venous anomaly. These findings support the hypothesis that cavernous malformations may arise secondary to hemodynamic abnormalities.