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.     

Identification of the feeding arteries of spinal vascular lesions via phase-contrast MR angiography with three-dimensional acquisition and phase display.

PURPOSETo determine whether identification of the feeding arteries of spinal vascular lesions with phase-contrast MR angiography benefits from the higher spatial resolution of three-dimensional (volume) acquisitions and flow-direction information provided by the phase reconstruction of two-dimensional acquisitions.METHODSFifteen patients with high- or low-flow spinal vascular lesions proved by spinal arteriography underwent MR angiography with phase-contrast techniques. Arteriographic and MR angiographic studies were reviewed to identify the arterial feeders of spinal vascular lesions.RESULTSOn modulus reconstructions of coronal 2-D or 3-D acquisitions, three of four arteries feeding high-flow lesions and three of 14 arteries feeding low-flow lesions were identified as hypertrophic vessels joining the parent intercostal or cervical arteries. Of 11 intradural veins draining dural arteriovenous fistulas, three were identified on coronal 2-D acquisitions and six on coronal 3-D acquisitions as vessels that coursed from a neural foramen to a midline tangle of vessels. Phase reconstruction showed ascending and descending flow patterns in two patients with intramedullary arteriovenous malformations, and diverging flow in perimedullary veins draining a hemangioblastoma. In nine patients with dural arteriovenous fistulas, phase reconstruction provided information as to the level of the arterial feeders. Phase reconstruction in coronal plane acquisitions also provided evidence of centripetal flow.CONCLUSIONThree-dimensional acquisitions and phase display of 2-D acquisitions improved the visibility of arterial pedicles of spinal vascular lesions at phase-contrast MR angiography.     

脊髓血管畸形的快速增强MRA与DSA诊断的比较研究

目的 评价椭圆形中心顺序(elliptic centric ordered)的快速增强磁共振血管成像(fastcontrast-enhanced MR angiography,CE-MRA)在脊髓血管畸形中的诊断和临床应用价值.方法 25例临床怀疑脊髓血管畸形的患者在1.5T MR机上接受了椭圆形中心顺序的快速CE-MRA检查,所有病例行选择性全脊椎动脉造影,18例施行了外科手术,其中2例术前行血管内栓塞,术后MRA随访了10例;以选择性全脊椎动脉造影为金标准,就病变诊断、供养动脉起源、供养动脉、瘘口或瘤巢、引流静脉和血管的图像质量(包括血管的连续性、强化程度和清晰度)进行MRA和DSA的比较.结果 经外科手术证实18例,包括脊髓动静脉畸形3例、髓周动静脉瘘5例、硬膜动静脉瘘7例、椎旁动静脉瘘1例、自发性椎管内硬膜外血肿2例;MRA显示脊髓血管畸形的诊断、供养动脉起源、供养动脉、瘤巢或瘘口、引流静脉与DSA的符合率分别为93.8%、92%、96.2%、100%和100%,MRA显示血管强化和清晰度类似于DSA(P＞0.05),DSA显示血管的连续性优于MRA(P＜0.05);9例MRA未见椎管内异常血管,与DSA完全符合.术后MRA随访的10例原异常血管未再显示.结论 椭圆形中心顺序的快速CE-MRA能够初步诊断脊髓血管畸形的亚型,能够显示脊髓血管畸形的供养动脉起源、供养动脉、瘤巢或瘘口、引流静脉,能够指导选择性脊椎动脉造影和手术治疗,是脊髓血管畸形术前诊断和术后随访的重要手段.     

Contrast-enhanced time-resolved MR angiography of spinal vascular malformations.

PURPOSE: The purpose of this work was to assess the potential and limitations of a contrast-enhanced time-resolved MR angiography technique for evaluation of spinal vascular malformations. METHOD: Two patients with intramedullary arteriovenous (AV) malformations and three patients with dural AV fistula underwent four serial acquisitions, every 17-20 s, of 20-32 coronal 1.5- to 2-mm-thick partitions with a fast 3D SPGR sequence after injection of 0.2-0.3 mmol/kg paramagnetic contrast agent. This was followed by coronal 3D and sagittal or coronal 2D phase contrast (PC) MR angiography. RESULTS: No spinal vessels were visualized in the first (baseline) series. In patients with intramedullary AV malformations, the arterial feeders, nidus, and perimedullary draining veins were visualized in the second (early) series. In the third (intermediate) series, the arterial feeder vanished, whereas the intercostal and lumbar veins appeared. In patients with dural AV fistula, abnormal intraspinal vessel appeared in the third series and persisted, although less conspicuous, in the fourth (late) series. Contrast-enhanced time-resolved MR angiography demonstrated the venous components of the lesion with better conspicuity than 3D PC MR angiography, whereas it was inferior for visualization of arterial feeders. Moreover, indirect identification of the level of the dural AV fistula was possible only on the phase display of the 2D PC MR angiography. CONCLUSION: Contrast-enhanced time-resolved MR angiography is a useful complement to PC MR angiography for the evaluation of spinal vascular malformation.     

Spinal cord vascular disease: characterization with fast three-dimensional contrast-enhanced MR angiography

BACKGROUND AND PURPOSE: Noninvasive characterization of spinal vascular lesions is essential for guiding clinical management, and several MR angiographic techniques have been applied in the past with variable results. The purpose of our study was to assess the potential of a dynamic 3D contrast-enhanced MR angiographic sequence to characterize spinal vascular lesions and to identify their arterial feeders and venous drainage. METHODS: A contrast-enhanced gradient-echo 3D pulse sequence providing angiographic information within 24 seconds was applied prospectively in 12 consecutive patients with a presumed spinal vascular lesion. The images were evaluated for visibility of the arterial feeder, and the results were compared with those of conventional angiography performed the next day. RESULTS: The MR angiographic findings proved that the lesions were correctly characterized as spinal arteriovenous malformations (AVMs) (n = 6), spinal dural arteriovenous fistulas (AVFs) (n = 3), a hemangioblastoma (n = 1), a teratoma (n = 1), and a vertebral hemangioma (n = 1). The arterial feeder was visible in all six AVMs and in the hemangioblastoma, corresponding to conventional angiographic findings. In two of three spinal dural AVFs, an enlarged draining medullary vein was seen within the neural foramen, providing correct localization. The third fistula could not be seen owing to reduced image quality from motion artifacts. CONCLUSION: Fast 3D contrast-enhanced MR angiography is a noninvasive technique with high accuracy in the characterization of spinal vascular disease. Visibility of the arterial pedicles corresponds well with that of digital subtraction angiography, facilitating the management of these patients.     

Dynamic MR angiography (MRA) of spinal vascular diseases at 3T

Spinal magnetic resonance angiography (MRA) is difficult to perform because of the size of the spinal cord vessels. High-field MR improves resolution and imaging speed. We examined 17 patients with spinal vascular diseases with dynamic contrast-enhanced three-dimensional MR sequences. In three patients, the artery of Adamkievicz could be seen; we could also detect all arteriovenous malformations and dural fistulas. MRA has the potential to replace diagnostic spinal angiography and the latter should be used only for therapeutic purposes.     

Dynamic gadolinium-enhanced MRI in the detection of spinal arteriovenous malformations

Arteriovenous fistulae and malformations (AVFs and AVMs) of the spinal cord are rare, potentially treatable causes of progressive disability. Although a variety of MRI abnormalities has been described, the diagnosis rests on the findings on selective spinal angiography.Collecting T2^*-weighted MR images during the passage of a gadolinium bolus gives information about perfusion and blood volume. We carried out dynamic MRI in seven patients with vascular abnormalities (5 dural AVFs, 1 intramedullary AVM, 1 cryptic angioma) and in two patients without an AVM. High resolution T1- and T2-weighted sagittal images of the whole spinal cord were first obtained using a multiarray receiver coil. Sagittal radiofrequency spoilt gradient echo images (GE34/25, flip angle 10⁰) were then obtained during bolus injection of gadolinium-DTPA. Abnormalities were seen in all seven patients with AVFs or AVMs. In the patient with an intramedullary AVM and four of the five with dural AVFs transient signal reduction was seen within the perimedullary venous plexus during passage of the bolus. The findings correlated well with those from selective spinal angiography. We conclude that dynamic MRI offers a useful adjunct to angiography and may localise an arteriovenous shunt when conventional MRI fails to do so. In combination with high-resolution imaging of the entire spinal cord the technique may make myelography redundant; it is simple, well tolerated and can be carried out without significant time penalty.     

Multidetector CT angiography in diagnosing type I and type IVA spinal vascular malformations

Multidetector CT (MDCT) angiography is an imaging technique that can provide high-resolution and high-contrast images; however, published reports of MDCT angiography in the evaluation of spinal vascular malformations are limited. We present 2 cases in which MDCT angiography led to diagnosis of a type I (spinal dural arteriovenous fistula) in one and type IVA (perimedullary spinal cord simple arteriovenous fistula fed by a single arterial feeder) spinal vascular malformation, both confirmed by conventional angiography. MDCT angiography can localize the feeding vessel and the fistula, thus greatly reducing the amount of time required for conventional angiography.     

64层螺旋CT血管成像诊断脊髓血管畸形的价值

目的 探讨64层螺旋CT 血管成像(CTA)对脊髓血管畸形的诊断价值.方法 经临床和MR检查拟诊为脊髓血管畸形的15例患者进行了CTA.所有患者均在1周内进行了DSA检查.其中4例行于术治疗.将CTA图像与DSA和手术所见进行对照,从判定畸形的类型、显示病变累及的范围、供血动脉、引流静脉和可能存在的瘘口等方面,对CTA图像进行评价.结果 15例脊髓血管畸形经DSA和手术确诊,分别为6例髓内动静脉畸彤、2例髓周动静脉瘘、3例硬脊膜动静脉瘘和4例Cobb综合征.CTA对15例患者的分类和对病变累及范围的判断与DSA结果一致.CTA清晰显示了病变的主要供血动脉和引流静脉.5例动静脉瘘中4例CTA判断的瘘口位置与DSA所见一敛,另1例为复杂血管畸形,瘘口难以辨别.CTA还清晰显示了4例Cobb综合征位于椎旁和皮下的畸形血管团.结论 64层螺旋CTA可以判定脊髓血管畸形的类型,快速、无创地显示其主要病变特征,可作为该病的筛查手段.     

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).     

MR of hereditary hemorrhagic telangiectasia: prevalence and spectrum of cerebrovascular malformations.

PURPOSEOur goal was to describe the prevalence and types of cerebral vascular malformations (CVMs) seen with MR imaging in patients with hereditary hemorrhagic telangiectasia (HHT).METHODSWe reviewed retrospectively the brain MR images of 184 consecutive patients with HHT. Catheter angiography was performed in 17 patients with CVMs detected on MR images.RESULTSMR imaging revealed 63 CVMs in 42 patients. Classic arteriovenous malformations (n = 10) had a conspicuous network of vessels with flow voids and enlarged adjacent pial vessels. Apparent venous malformations (n = 5) were best seen after administration of contrast material as a prominent vessel coursing through normal brain parenchyma. Indeterminate vascular malformations (n = 48) had a spectrum of appearances characterized by variable combinations of heterogeneous signal intensity, enhancement, or hemosiderin. Angiography in 17 patients revealed 47 CVMs. Forty-six were arteriovenous malformations (AVMs), including 25 CVMs not seen with MR imaging and 21 CVMs that by MR criteria included 8 AVMs and 13 indeterminate vascular malformations. Angiography confirmed 1 venous malformation seen with MR imaging but failed to detect 3 indeterminate lesions revealed by MR imaging.CONCLUSIONMR imaging of a large cohort of consecutive patients with HHT revealed a CVM prevalence of 23% (42/184). Most CVMs (48/63) have an atypical appearance for vascular malformations on MR images. Angiographic correlation suggests that MR imaging underestimates the prevalence of CVMs and that the majority of indeterminate CVMs, despite their variable MR appearance, are AVMs.     

Spinal vascular malformations

Spinal vascular malformations are rare diseases that consist of true inborn cavernomas and arteriovenous malformations (including perimedullary fistulae, glomerular and juvenile AVMs) and presumably acquired dural arteriovenous fistulae. This review article gives an overview of the imaging features both on MRI and angiography, the differential diagnoses, the clinical symptomatology and the potential therapeutic approaches to these diseases. It is concluded that MRI is the diagnostic modality of first choice in suspected spinal vascular malformation and should be complemented by selective spinal angiography. Treatment in symptomatic patients offers an improvement in the prognosis, but should be performed in specialized centers. Patients with spinal cord cavernomas and perimedullary fistulae type I are surgical candidates. Dural arteriovenous fistulae can either be operated upon or can be treated by an endovascular approach, the former being a simple, quick and secure approach to obliterate the fistula, while the latter is technically demanding. In spinal arteriovenous malformations, the endovascular approach is the method of first choice; in selected cases, a combined therapy might be sensible.     

Spontaneous resolution of low-flow spinal arteriovenous fistulas

Purpose

Spinal vascular anomalies with arteriovenous blood shunting include spinal arteriovenous malformations (SAVMs) and spinal arteriovenous fistulas (SAVFs), which are distinguished by the presence or absence of an interposed nidus. SAVFs can be further characterized based on their location (perimedullary, dural, or extradural) and flow pattern (high-flow versus low-flow shunts). The spontaneous resolution of a spinal vascular malformation, i.e., the complete disappearance—in the absence of therapeutic measures—of a lesion previously identified by angiography, seems to represent an exceptional phenomenon.

Methods

This study retrospectively analyzed seven patients with spontaneously resolving spinal vascular malformations observed by the senior author between January 2008 and April 2017.

Results

A total of 143 spinal vascular malformations were angiographically evaluated during the considered time period, including nine spontaneously resolving SAVFs in six patients, seven spinal epidural fistulas, and two spinal dural arteriovenous fistula.

Conclusion

The “spontaneous” resolution of spinal vascular malformations appears to selectively involve SAVFs. While vessel wall alterations previously documented on the venous side of SAVFs may play an important role in the regression of these lesions, angiography seems to represent a significant contributing factor, probably through the prothrombotic properties of nonionic contrast agents.

     

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.     

MR imaging and MR angiography in the evaluation of pulsatile tinnitus.

PURPOSE1) To evaluate the scope of imaging findings seen with spin-echo MR and MR angiography (MRA) in patients with pulsatile tinnitus; 2) to determine whether MRA adds additional imaging information (to that provided by spin-echo MR) necessary for determining the cause of pulsatile tinnitus; and 3) to suggest MR and MRA imaging techniques for evaluation of patients with pulsatile tinnitus.METHODSForty-nine patients with pulsatile tinnitus were evaluated with MR and MRA. Seventeen of these patients had conventional angiography.RESULTSVascular lesions or paraganglioma were demonstrated in 28 patients. Of these 28 lesions, the majority were seen best (46%) or only (36%) on MRA. The spectrum of lesions detected included dural arteriovenous fistula (nine), extracranial arteriovenous fistula (three), paraganglioma (five), jugular bulb variants (three), aberrant internal carotid artery (one), internal carotid artery stenosis (one), tortuous internal carotid artery (one), carotid dissection with pseudoaneurysm (one), stenosis of the transverse sinus (two), and arteriovenous malformation (two).CONCLUSIONSMRA, in conjunction with spin-echo imaging, markedly enhances the ability of MR to diagnose the lesions responsible for pulsatile tinnitus.     

Intra-arterial digital subtraction angiography of the spinal cord

Digital subtraction angiography (DSA) of the spinal cord was performed in 6 patients using selective intra-arterial injections of contrast material. Two arteriovenous malformations of the spinal cord, 1 dural fistula, and 1 case of multiple hemangioblastomas were studied. Contrast and spatial resolution were satisfactory for defining normal and abnormal vascularity while reducing examination time, contrast dosage, patient discomfort, and film cost. The only significant limitation was misregistration artifacts seen on lateral views encompassing the diaphragm.     

Venous congestion: an MR finding in dural arteriovenous malformations with cortical venous drainage.

PURPOSETo present the MR findings of intracranial dural arteriovenous malformations with cortical venous drainage, emphasizing the parenchymal changes.METHODSConventional MR and x-ray angiograms in 13 patients with dural arteriovenous malformations and cortical venous reflux were reviewed. The site of the shunt, location of the venous reflux, and presence of venous stenosis were assessed on the angiograms. Parenchymal changes, dilated vessels, and venous occlusive disease were assessed on MR.RESULTSOn MR, 10 of the 13 patients (77%) had dilated pial vessels. Two patients had hydrocephalus. Two patients presented with parenchymal bleeds, one with a subdural component, both remote from the nidus. Two patients presented with subarachnoid hemorrhage. One patient had a parenchymal bleed 9 months after presentation. Venous occlusion was evident on MR in 2 patients. Diffuse white matter edema in the cerebellar or cerebral hemispheres was present on MR in 4 patients and correlated with neurologic deficits. In 2 of these 4 patients, gadolinium enhancement was seen in the periphery of the involved hemisphere.CONCLUSIONSOn MR a surplus of pial vessels suggests a dural arteriovenous malformation with cortical venous drainage. The MR finding of white matter edema deep in the cerebral or cerebellar hemispheres is direct evidence of a venous congestion.     

Spinal dural arteriovenous fistula localization with a technique of first-pass gadolinium-enhanced MR angiography: initial experience

Nine patients with initial magnetic resonance (MR) imaging and clinical findings suggestive of spinal dural arteriovenous fistula (AVF) underwent spinal MR angiography with an autotriggered elliptic centric ordered three-dimensional gadolinium-enhanced technique (hereafter, this MR angiographic technique) before conventional intraarterial angiography. In all nine patients, findings with this MR angiographic technique correctly and precisely localized the spinal dural AVF. Observer error resulted in one case in which the site of the fistula was not prospectively reported but was easily identified retrospectively on the spinal MR angiogram.     

Intracranial dural arteriovenous fistulas: evaluation with combined 3D time-of-flight MR angiography and MR digital subtraction angiography

OBJECTIVE: The purpose of this study was to compare the diagnostic utility of 3D time-of-flight (TOF) MR angiography and MR digital subtraction angiography in patients with angiographically proven moderate- to high-flow intracranial dural arteriovenous fistula. MATERIALS AND METHODS: Two neuroradiologists, unaware of patients' histories and angiographic findings, retrospectively reviewed 17 MR angiograms with 3D TOF MR angiography and MR digital subtraction angiography in 15 patients with dural arteriovenous fistula and also reviewed 35 MR angiograms in control patients without findings of dural arteriovenous fistula on angiography. Disagreements were resolved by consensus. RESULTS: In patients with dural arteriovenous fistula, source images of 3D TOF MR angiography showed two abnormal findings: multiple high-intensity curvilinear or nodular structures adjacent to the sinus wall and high-intensity areas in the venous sinus. Findings of multiple high-intensity structures adjacent to the sinus wall were observed in all cases of dural arteriovenous fistula. Findings of high-intensity areas in the venous sinus were observed in 13 of 17 cases of dural arteriovenous fistula. Findings of multiple high-intensity structures adjacent to the sinus wall were not observed in any control subjects. Findings of high-intensity areas within the venous sinus were observed in five of 35 control subjects. Findings of MR digital subtraction angiography showed early filling of the venous sinus, suggestive of dural arteriovenous fistula, in 13 of 15 patients with dural arteriovenous fistula. Sensitivity and specificity of multiple high-intensity structures adjacent to the sinus wall, high-intensity areas in the venous sinus, and early filling of the venous sinus were 100% and 100%, 76% and 86%, and 87% and 100%, respectively. Although 3D TOF MR angiography failed to show the findings of retrograde cortical venous drainage and venous sinus occlusion, MR digital subtraction angiography clearly showed both findings in all five subjects. CONCLUSION: A protocol including both 3D TOF MR angiography (source images) and MR digital subtraction angiography allowed the diagnosis of moderate- to high-flow dural arteriovenous fistula. In addition, cortical venous drainage was reliably noted in a small subset of patients.