Craniocervical dural fistula associated with cervical myelopathy: angiographic demonstration of normal venous drainage of the thoracolumbar cord does not rule out diagnosis.

We report a case of craniocervical dural arteriovenous fistula with perimedullary venous drainage associated with cervical myelopathy in which spinal angiography showed a normal venous phase after injection of the artery of Adamkiewicz. We conclude that because of the complex venous drainage of the spinal cord, a dural arteriovenous fistula with spinal drainage cannot be ruled out solely because a normal venous phase is seen in the lower part of the cord, as has previously been suggested.     

Arteriovenous fistulas at the cervicomedullary junction presenting with subarachnoid hemorrhage: six case reports with special reference to the angiographic pattern of venous drainage

BACKGROUND AND PURPOSE: Cases with spinal perimedullary arteriovenous fistulas (SPAVFs) or spinal dural arteriovenous fistulas (SDAVFs) at the cervicomedullary junction are rare. We performed a retrospective, angiographic study of 6 such patients to assess whether available angiographic data were predictive of the risk for hemorrhage. METHODS: We report 6 patients with arteriovenous fistulas at the cervicomedullary junction. All presented with subarachnoid hemorrhage (SAH). Angiography demonstrated that 4 of the 6 fistulas were SDAVFs fed by the meningeal branch of the vertebral artery; the other 2 were SPAVFs fed by the anterior spinal artery. Drainage was via the perimedullary vein of the cervicomedullary junction. RESULTS: An ascending venous route into the intracranial sinus was recognized in all 6 cases; in 3 the draining system contained varices. In 2 cases, the venous route was on the ventral side of the brain stem with drainage into the cavernous sinus. In 4 cases, the venous route was lateral at the brain stem with drainage into the inferior petrosal sinus. CONCLUSION: SPAVFs and SDAVFs at the cervicomedullary junction that manifest an ascending venous route into the intracranial sinus present an increased risk for SAH.     

Thrombosis of aggressive dural arteriovenous fistula after incomplete embolization

We report the cases of three patients diagnosed with dural arteriovenous fistula (DAVF) and cortical venous reflux (CVR). All were treated by transarterial endovascular embolization. Residual shunting and cortical venous drainage continued to be present at the end of the treatment procedure, despite the fact that during endovascular embolization glue penetration into the proximal venous component of the fistula had been achieved. Subsequently, follow-up angiography showed total obliteration of the fistulas and absent associated CVR. The fistulas were no longer opacified, and no additional treatment was performed. We demonstrate that residual aggressive DAVF may progress to total thrombosis if strategic deposition of the glue into the venous side has been achieved. Early follow-up angiogram is recommended prior to a planned complementary surgical approach.     

Embolization of dural cavernous fistulas via superior ophthalmic vein approach.

PURPOSETo present the results of our treatment of dural cavernous sinus fistulas with surgical exposure of the superior ophthalmic vein (SOV), retrograde venous catheterization, and coil embolization of the cavernous sinus.METHODSTwelve patients with dural cavernous sinus fistulas were treated via a retrograde transvenous SOV approach in our hospital during a 3-year period. All patients had been referred by ophthalmologists because of secondary glaucoma and decreased visual acuity. Angiography showed preferential venous drainage of the dural cavernous sinus fistulas to an enlarged ipsilateral SOV. A total of 13 SOV exposures were performed, one patient with bilateral fistulas required bilateral treatment. The vein was surgically exposed by an ophthalmologist and then catheterized. Platinum coils were delivered through a microcatheter at the fistula site and into the root of the SOV, until there was complete angiographic closure.RESULTSCatheterization and embolization were successful in 12 of the 13 patients, with complete angiographic occlusion of the fistula. Two patients with bilateral fistulas had transient worsening of symptoms on the contralateral side. Three patients required follow-up angiography. No early complications occurred, and late complications were minor in two cases. All patients except one with long-standing symptoms recovered premorbid visual acuity. At follow-up, 11 (92%) of the 12 embolized fistulas remained occluded.CONCLUSIONSRetrograde catheterization of the SOV and embolization of the cavernous sinus with coils is a direct, safe, and efficient way to occlude dural cavernous sinus fistulas.     

Preangiographic evaluation of spinal dural arteriovenous fistulas with elliptic centric contrast-enhanced MR Angiography and effect on radiation dose and volume of iodinated contrast material

BACKGROUND AND PURPOSE: The detection and localization of spinal dural arteriovenous fistulas (AVFs) remain diagnostic challenges. This study tested the hypothesis that elliptic centric contrast-enhanced MR angiography (MRA) can be used to detect spinal dural AVFs, predict the level of fistulas, and reduce the radiation dose and volume of iodinated contrast material associated with conventional angiography. METHODS: We examined 31 patients who presented with suspected spinal dural AVF between December 2000 and March 2004. All patients underwent MRA and conventional angiography. The effect of MRA on subsequent conventional angiography was assessed by analyzing total fluoroscopy time and volume of iodinated contrast material used. RESULTS: At angiography, spinal dural AVFs were diagnosed in 22 of 31 patients, and MRA depicted an AVF in 20 of the 22 patients. MRA findings correctly predicted a negative angiogram in seven of nine cases. Of the 20 true-positive MRA results, the level of the fistula was included in the imaging volume in 14. In 13 of these 14 cases, MRA results correctly predicted the side and the level of the fistula to within one vertebral level. Fluoroscopy time and the volume of contrast agent was reduced by more than 50% in the 13 patients with a spinal dural AVF in whom MRA prospectively indicated the correct level. CONCLUSION: Contrast-enhanced MRA can be used to detect spinal dural AVFs, predict the level of fistulas, and substantially reduce the radiation dose and volume of contrast agent associated with catheter spinal angiography.     

Peripheral spinal cord hypointensity on T2-weighted MR images: a reliable imaging sign of venous hypertensive myelopathy

BACKGROUND AND PURPOSE: MR findings reported in conjunction with spinal dural arteriovenous fistula (SDAVF) include cord swelling, increased T2 signal within the spinal cord, and parenchymal enhancement, each of which is nonspecific. Enlarged vessels on the cord surface, the most specific MR finding, is noted in only half of SDAVF patients. Nevertheless, we have frequently observed MR peripheral hypointensity of the spinal cord in SDAVF on T2-weighted images, which is not characteristic of nonvascular or nonhemorrhagic causes of myelopathy and which has not been described in association with SDAVF. We hypothesized that peripheral cord hypointensity might reliably suggest the diagnosis of SDAVF or other causes of venous hypertensive myelopathy. METHODS: We reviewed the MR findings in 11 consecutive cases of angiographically confirmed symptomatic SDAVF and in four cases of intracranial dural arteriovenous fistula with spinal drainage, a lesion that also causes spinal cord deficits mediated by venous hypertensive myelopathy. RESULTS: In each case, T2 hypointensity involving the cord periphery was present. This sign has not been previously described in association with either SDAVF or other causes of venous hypertensive myelopathy. It appears, however, to be a relatively constant imaging feature of SDAVF. CONCLUSION: In the absence of spinal hemorrhage, T2 hypointensity involving the periphery of the spinal cord suggests venous hypertensive myelopathy as a cause of spinal cord dysfunction.     

Comparison of Time-Resolved and First-Pass Contrast-Enhanced MR Angiography in Pretherapeutic Evaluation of Spinal Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE:Different MRA techniques used to evaluate spinal dural arteriovenous fistulas offer unique advantages and limitations with regards to temporal and spatial resolution. The purpose of this study was to compare the efficacy and interobserver agreement of 2 commonly used contrast-enhanced spinal MRA techniques, multiphase time-resolved MRA and single-phase first-pass MRA, in assessment of spinal dural arteriovenous fistulas.MATERIALS AND METHODS:Retrospective review of 15 time-resolved and 31 first-pass MRA studies in patients with clinical suspicion of spinal dural arteriovenous fistula was performed by 2 independent, blinded observers. DSA was used as the reference standard to compare the diagnostic performance of the 2 techniques.RESULTS:There were 10 cases of spinal dural arteriovenous fistula in the time-resolved MRA group and 20 in the first-pass MRA group. Time-resolved MRA detected spinal dural arteriovenous fistulas with sensitivity and specificity of 100% and 80%, respectively, with 100% correct-level localization rate. First-pass MRA detected spinal dural arteriovenous fistulas with sensitivity and specificity of 100% and 82%, respectively, with 87% correct-level localization rate. Interobserver agreement for localization was excellent for both techniques; however, it was higher for time-resolved MRA. In 5 cases, the site of fistula was not included in the FOV, but a prominent intradural radicular vein was observed at the edge of the FOV.CONCLUSIONS:Multiphase time-resolved MRA and single-phase first-pass MRA were comparable in diagnosis and localization of spinal dural arteriovenous fistulas and demonstrated excellent interobserver agreement, though there were more instances of ambiguity in fistula localization on first-pass MRA.

Spinal dural arteriovenous fistulas (SDAVFs) represent an abnormal connection between a radiculomeningeal artery and a radicular vein, typically on the dural sleeve adjacent to the nerve root. The arterialized radicular vein causes regurgitation of blood flow to the perimedullary venous plexus, resulting in increased venous pressure and congestion.¹ Although SDAVFs are a treatable cause of myelopathy,² the diagnosis remains challenging because the clinical and conventional MR imaging features are nonspecific. As a result, misdiagnosis and delay in diagnosis are common, which may result in additional disability.³MRA is useful for confirming the diagnosis and for localizing SDAVFs to expedite DSA.^4,5 DSA is ultimately the “criterion standard” for diagnosis of this condition, but the number of injections and the time required to perform this study can be reduced with the knowledge of the level involved, provided by MRA. The contrast-enhanced spinal MRA techniques useful for evaluation of SDAVFs are broadly of 2 types: first-pass and time-resolved. These differ with regards to temporal and spatial resolution. The purpose of this study was to compare the efficacy and interobserver agreement of multiphase time-resolved MRA (TR-MRA) and single-phase first-pass MRA (FP-MRA) in assessment of SDAVFs.     

Intracranial dural fistulas with exclusive perimedullary drainage: the need for complete cerebral angiography for diagnosis and treatment planning

Three patients are presented with slowly progressive tetraparesis caused by an intracranial dural arteriovenous fistula with exclusive perimedullary venous drainage. MR imaging showed a swollen cervicothoracic cord with central myelopathy and dilated perimedullary veins. Bilateral vertebral angiography initially failed to demonstrate the fistulas, and diagnosis was established with external carotid angiography. All 3 patients were successfully treated with glue embolization, 1 after failed surgical exploration. Angiographic cure of the fistula resulted in clinical cure in 1 patient and stabilization in 2 patients.     

Carotid-cavernous sinus fistulas and venous thrombosis

Radiographic signs of cavernous sinus thrombosis were found in eight consecutive patients with an angiographic diagnosis of carotid-cavernous sinus fistula; six were of the dural type and the ninth case was of a shunt from a cerebral hemisphere vascular malformation. Diagnostic features consisted of filling defects within the cavernous sinus and its tributaries, an abnormal shape of the cavernous sinus, an atypical pattern of venous drainage, and venous stasis. Progression of thrombosis was demonstrated in five patients who underwent follow-up angiography. Because of a high incidence of spontaneous resolution, patients with dural-cavernous sinus fistulas who show signs of venous thrombosis at angiography should be followed conservatively.     

Intraarterial digital subtraction angiography of spinal arteriovenous malformations

Intraarterial digital subtraction angiography (DSA) in two patients with spinal dural arteriovenous fistulas demonstrated the major feeding arteries and the venous drainage of the respective malformations. However, the dural component of the malformations--which distinguishes them from intradural malformations--could not be recognized, nor was normal cord vasculature demonstrated. In a patient with an intradural arteriovenous malformation (AVM), only major arterial feeders were demonstrated. Intraarterial DSA provides essential anatomic information with an increased margin of safety in spinal AVMs, but supplemental selective arteriography, conventional or digital, also is currently required.     

Phase-contrast MR angiography of vascular malformations of the spinal cord at 0.5 T.

Preliminary experience with phase-contrast magnetic resonance (MR) angiography at 0.5 T applied in 12 cases of vascular malformations of the spinal cord is reported. There were six intramedullary arteriovenous malformations (AVMs), four perimedullary fistulas, and two dural arteriovenous fistulas with perimedullary drainage, all proved with x-ray angiography. The small size of the vessels and their location within a bony structure presented a technical challenge. Serpentine vascular signal patterns were identified within the spinal canal in all cases, showing good correlation with the x-ray angiographic pattern. Relative to spin-echo images, MR angiograms allowed better visualization of the venous drainage. The nidus of intramedullary AVMs was more difficult to recognize. The ability to manipulate the velocity-encoding value allows better characterization of flow speed. The results underline the two dimensions of the phase-contrast technique, which provides both anatomic images and dynamic information about vascular malformations. MR angiography does not replace selective x-ray angiography, which is indispensable for therapeutic strategy (endovascular procedure or surgery), but it can be considered a valuable alternative to x-ray angiography during follow-up.     

Spinal vascular malformations: MR angiography after treatment

PURPOSE: To evaluate the role of magnetic resonance (MR) angiography in the assessment of spinal vascular malformation therapy. MATERIALS AND METHODS: Thirty-four patients with spinal vascular malformations (30 dural arteriovenous fistulas, two perimedullary arteriovenous fistulas, and two intramedullary arteriovenous malformations) underwent MR angiography and MR imaging before and after endovascular or surgical treatment. RESULTS: MR angiography showed residual flow in perimedullary vessels in seven patients with dural fistula after embolization with liquid adhesive. In all seven, treatment failure was confirmed with arteriography. Long-lasting disappearance of flow in perimedullary vessels was demonstrated at MR angiography in 22 patients with dural fistula. MR imaging demonstrated normalization of spinal cord volume in 16 of 22 patients and signal intensity on T2-weighted images in three patients. Disappearance of cord enhancement was observed in five of 21 patients and of perimedullary enhanced vessels in six of 13 patients. In one additional patient with dural fistula treated with embolization, early posttreatment MR angiography showed disappearance of flow in perimedullary vessels, which reappeared at follow-up and was consistent with reopening of a small residual fistula. Posttreatment MR angiography demonstrated transient reduction of flow in the nidus in two patients with intramedullary malformations treated with embolization. Permanent disappearance of flow in the perimedullary vessel was seen after endovascular treatment in two patients with perimedullary fistula. CONCLUSION: MR angiography is more sensitive than MR imaging in depicting residual or recurrent flow in peri- or intramedullary vessels, which indicates patency of the vascular malformation.     

Dynamic 3D MR angiography of intra- and extracranial vascular malformations at 3T: a technical note

Time-resolved, contrast-enhanced 3D MR angiography combined with parallel imaging at 3T was applied to an intracranial arteriovenous malformation, a dural arteriovenous fistula, and an extracranial facial arteriovenous malformation. The temporal resolution was one image every 1.5 seconds. Arterial feeders were depicted in all three cases. Early venous drainage was observed in the intracerebral arteriovenous malformation and the dural arteriovenous fistula, but not in the facial arteriovenous malformation. All findings were concordant with conventional angiography.     

Intracranial dural arteriovenous fistulas with spinal venous drainage: relation between clinical presentation and angiographic findings.

PURPOSETo investigate why some patients with an intracranial dural arteriovenous fistula (DAVF) with spinal venous drainage have myelopathy and others do not.METHODSWe reviewed the clinical and radiologic data for 12 patients who had a DAVF with spinal venous drainage diagnosed at our institutions from 1982 to 1995.RESULTSSix patients had progressive spinal cord indications of disease (patients with myelopathy) and six others (patients without myelopathy) had cerebral indications (five had intracranial hemorrhage and one had a seizure). Cerebral angiography showed a posterior fossa DAVF with spinal venous drainage in all cases. The clinical presentation of DAVFs with spinal venous drainage was compared with the extent of the drainage. In patients without myelopathy, the spinal venous drainage exited the intradural canal via the cervical medullary-radicular veins and was therefore limited to the cervical perimedullary veins. In patients with myelopathy, no medullary-radicular vein was seen, and the venous drainage descended along the perimedullary veins of the entire spinal cord toward the conus medullaris.CONCLUSIONWe found an exact relation between clinical presentation and venous drainage of DAVFs with spinal venous drainage. Patients had no myelopathy when the venous drainage was limited to the cervical cord; myelopathy was present when the venous drainage descended toward the conus medullaris.     

Endovascular treatment for dural arteriovenous fistula of the anterior condylar vein with unusual venous drainage: report of two cases

We report 2 patients with dural arteriovenous fistula of the anterior condylar vein in which the patients presented with rare clinical symptoms related to unusual venous drainage patterns. The first patient had progressive myelopathy and showed venous drainage into the anterior spinal vein. The second had ocular signs and showed retrograde drainage into the superior ophthalmic vein. Complete cure was attained by transarterial glue injection in the first patient and transvenous coil embolization in the latter.     

Retrograde cortical and deep venous drainage in patients with intracranial dural arteriovenous fistulas: comparison of MR imaging and angiographic findings

BACKGROUND AND PURPOSE: We assessed MR imaging, specifically contrast-enhanced three-dimensional (3D) magnetization-prepared rapid gradient-echo (MP-RAGE), in evaluating retrograde venous drainage in patients with intracranial dural arteriovenous fistulas (dAVFs) that may result in catastrophic venous infarction or hemorrhage. METHODS: Twenty-one patients with angiographically proved dAVFs underwent nonenhanced spin-echo (SE) and fast SE imaging, 3D fast imaging with steady-state precession, and enhanced SE and 3D MP-RAGE imaging. Retrograde venous drainage was categorized as cerebral cortical, deep cerebral, posterior fossa medullary, ophthalmic, or spinal venous. We assessed retrograde venous drainage and graded its severity. MR imaging and angiographic severities were correlated. Sensitivity, specificity, and accuracy were calculated to evaluate the diagnostic utility of each technique compared with conventional angiography. We retrospectively correlated angiograms and MR images. RESULTS: Enhanced 3D MP-RAGE and T1-weighted SE images had higher diagnostic accuracy higher than nonenhanced images, especially when retrograde drainage involved cerebral cortical, posterior fossa, and spinal veins. Correlation of severity for enhanced MP-RAGE images and enhanced T1-weighted images with angiograms was good to excellent and better than that with nonenhanced images. All sequences had low diagnostic accuracy when drainage was via deep cerebral veins. On retrospective review, 3D MP-RAGE images showed two thrombotic inferior petrosal sinuses. CONCLUSION: Enhanced MR images were superior to nonenhanced images in assessing retrograde venous drainage in intracranial dAVFs. Enhanced 3D MP-RAGE is superior to enhanced T1-weighted SE imaging for determining the route and severity of venous reflux because of its increased spatial resolution and ability to contiguously delineate the venous system.     

Double spinal dural arteriovenous fistulas: case report and review of the literature

Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation. It mainly affects men after the fifth decade and is usually an acquired lesion with an unknown etiology. We report on a patient with the unusual finding of two separate SDAVFs at the level of L1 on the right and L2 on the left side. Initial selective spinal digital subtraction angiography (DSA) was terminated with demonstration of a SDAVF at the level of L1 but incomplete demonstration of all segmental arteries. Due to a recurrent deterioration of the patients neurological status, and persistent pathological vessels seen on MRI, a second spinal DSA was performed 6 years later, demonstrating the second fistula at the level of L2 on the left side with a separate venous drainage pattern. A retrospective analysis of the angiographic films suggested that both fistulas had already been present 6 years previously. This conclusion is justified because of a transient and faint opacification of the left L2 fistula demonstrated on the films after injection of the right L2 segmental artery. We conclude that in the case of incomplete angiography and persistent clinical and MR findings not only reopening of the treated SDAVF has to be taken into account but also the existence of a second fistula. Since this is the first case of a double fistula in our series of 129 SDAVFs, and given the few reported cases of double SDAVFs, we do not think that completion of selective spinal DSA has to be postulated routinely after a fistula has been found. However, repeat angiography should be performed in patients who continue to deteriorate, fail to improve with persisting MRI pathologies, or demonstrate delayed deterioration after a period of improvement.     

经静脉入路海绵窦内液体胶联合弹簧圈栓塞海绵窦区硬脑膜动静脉瘘

目的探讨应用经静脉入路联合液体胶和弹簧圈介入栓塞海绵窦区硬脑膜动静脉瘘的方法和策略。方法回顾性分析应用经静脉入路联合液体胶和弹簧圈栓塞治疗的8例海绵窦区硬脑膜动静脉瘘患者,包括瘘口的血管构筑学、治疗方法和疗效。结果所有患者均采用经静脉入路液体胶联合弹簧圈栓塞,其中经面静脉-眼上静脉入路1例,经岩下窦入路7例。8例均临床治愈,患者术后即刻造影提示瘘口完全消失。除术后早期头痛外无其他介入相关并发症。临床随访3个月～3年,患者无临床症状复发。结论经静脉入路应用液体胶联合弹簧圈介入栓塞对于海绵窦区硬脑膜动静脉瘘是安全、有效且经济的治疗方法 。     

Endovascular treatment of dural fistulas with the venous outflow of laterocavernous sinus

Objective

To report our findings concerning the laterocavernous sinus (LCS) drainage of dural fistulas, focusing our attention on the important implications in treatment of the LCS, which is one of the principal drainage pathways of the superficial middle cerebral vein (SMCV).

Methods

Consecutive 32 patients with dural fistulas treated endovascularly between 2005 and 2008 were reviewed. Seven patients had angiographic features such as dural fistulas draining with SMCV via LCS. Clinical records for these 7 patients were focused to determine their presenting symptoms, angiographic features, endovascular treatments, and clinical outcomes.

Results

Over 3 years, 7 patients had 7 dural fistulas drained with SMCV via LCS were treated. Six-vessel angiography confirmed the presence of the dural fistulas. All fistulas were Cognard Type III featured by leptomeningeal veins drainage. One fistula involving the lesser sphenoid wing and 6 fistulas involving CS were supplied by external carotid artery branches with or without dural branches of the internal carotid artery. LCS was identified as a contiguous to SMCV drainage in these cases. One patient was treated with transvenous coil embolization alone, two with transvenous a combination of Onyx and coil embolization, and 4 with transarterial embolization. An angiographic obliteration and clinical cure was achieved in all patients. Complication was local hair loss due to X-ray radiation in one patient.

Conclusion

It is very important to diagnose the presence of LCS in dural fistulas during the diagnostic angiography. It is believed that the knowledge of LCS might be relevant for the understanding and treatment of dural fistulas involving the LCS.     

Normal Venous Phase Documented during Angiography in Patients with Spinal Vascular Malformations: Incidence and Clinical Implications

BACKGROUND AND PURPOSE:A key angiographic sign observed in patients with spinal vascular malformations is the absence of a normal venous phase. While this finding alone is often believed to rule out a lesion impacting the perimedullary venous drainage, the observation of a venous phase in several patients with vascular malformations led us to reconsider the validity of that sign.MATERIALS AND METHODS:Eighty-one patients with 6 spinal arteriovenous malformations, 16 perimedullary arteriovenous fistulas, 61 spinal epidural or dural AVFs, and 1 paravertebral AVF (2 patients had multiple lesions) were reviewed. The venous phase was defined as normal, absent, or indeterminate. The venous phase timing was analyzed in patients with spinal dural or epidural AVFs.RESULTS:The existence of a venous phase could not be determined for technical reasons in 23 patients. A venous phase was documented in 25 of 58 patients (43%), including 16 of 49 vascular malformations (40.0%) with perimedullary venous drainage. Twelve of the 30 patients (40.0%) with dural or epidural AVFs had a normal venous phase, appearing, on average, 10.1 seconds and best visualized 15.0 seconds after opacification of the artery of Adamkiewicz.CONCLUSIONS:A normal venous phase was observed in 43% of patients with spinal vascular malformations, and within an acceptable delay (<18 seconds) in 40% of slow-flow AVFs. While it remains an important angiographic sign, the observation of a normal venous phase cannot be used to exclude the presence of a vascular malformation or justify interrupting a diagnostic spinal angiogram.

Spinal digital subtraction angiography (SpDSA) is the criterion standard imaging technique for the evaluation of the spinal vasculature and remains essential for the diagnosis and management of spinal vascular malformations (SVMs).¹ The practice of SpDSA requires a sound understanding of the vascular anatomy of the spinal cord, notably its venous system.^2,3 A key angiographic sign observed in patients with SVMs is the absence of a normal venous phase, a phenomenon first reported in 2 cases of spinal dural arteriovenous fistulas (SDAVFs).² It was later suggested that a spinal angiogram could be terminated when “a normal venous phase is visualized and the veins correspond to the defects on the myelogram,” an approach based on the assumption that “if the venous phase of the spinal circulation is normal, this alone rules out DAVF [dural AVF] as the cause of the patient''s symptoms.”⁴ While MR imaging has now supplanted myelography in the work-up of spinal vascular anomalies, the notion that the angiographic pursuit of an SVM can stop after the documentation of a normal venous phase is still widely accepted, though at times more cautiously. Some authors have, for example, suggested that a normal venous phase “usually”⁵ or “reportedly”⁶ allows terminating a diagnostic angiogram or that it only makes the “diagnosis of a fistula less likely.”⁷ To our knowledge, there is, so far, only 1 reported instance of a normal venous phase associated with a vascular malformation draining into the perimedullary system, but this case involved a cranial dural arteriovenous fistula rather than an SVM.⁸Several observations of a morphologically normal venous phase associated with lesions involving the perimedullary venous system have pushed us to reconsider the validity of this angiographic sign. The spinal venous phase was, therefore, evaluated in 81 patients diagnosed with an SVM in our practice during a 5-year period, with particular attention paid to SDAVFs and spinal epidural arteriovenous fistulas (SEAVFs).