Spinale durale arterioven?se Fisteln

Spinal dural arteriovenous fistulas are rare spinal vascular malformations which can cause progressive paraparesis and paraplegia if not treated. As symptoms are unspecific diagnosis is often delayed and clinical outcome is dependent on early therapy. While magnetic resonance imaging (MRI) is the first choice imaging procedure, selective spinal digital subtraction angiography is necessary to analyze the angioarchitecture and to plan the treatment. This article provides an overview on the epidemiology, etiology, clinical aspects and imaging features as well as therapeutic aspects of spinal dural arteriovenous fistulas. Knowledge of spinal vascular anatomy is the basis for understanding spinal dural arteriovenous fistulas.     

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 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.     

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.     

Fístulas arteriovenosas durales medulares: las malformaciones vasculares más frecuentes de la médula espinal

Spinal dural arteriovenous fistulas are produced by direct communication between the arterial and venous systems of the spinal cord, causing hypertension in the latter with spinal cord dysfunction. It is a rare pathology with unknown etiology and non-specific clinical symptoms that usually results in a delayed diagnosis. Often radiologists are the first to guide the disease towards an adequate diagnosis. Characteristic findings can be seen through MR or MR angiography, and may even locate the fistula in a high percentage of cases, although the pathology must be confirmed by spinal angiography. There are two treatment modalities: endovascular and surgical therapy. Endovascular treatment has improved in recent years with the advantages of a less invasive approach and is therefore usually chosen as primary therapy. In this article we review the main clinical manifestations, imaging findings and treatment of this pathology.     

Computed tomographic and digital subtraction angiography evaluation of ophthalmic-ethmoidal artery dural arteriovenous fistula

Ophthalmic-ethmoidal dural arteriovenous fistula (DAVFs) is a rare type of dural arteriovenous fistulas and usually presenting with spontaneous subarachnoid hemorrhage, subdural hemorrhage or ocular symptoms. We present a case of a 59-year old gentleman presenting with acute headache, vomiting and generalized weakness. CT study of the brain revealed a large left frontal hematoma and abnormal aneurysmal sac with dilated cortical vein, communicating with the superior sagittal sinus. Conventional angiography confirmed diagnosis of ruptured ophthalmic-ethmoidal DAVF, resulting in a frontal intra-axial hemorrhage. Anterior fossa DAVFs are extremely rare, difficult to diagnose and treat. CT angiography is initial method of diagnosis, but digital substruction angiography remains the gold standard of confirming dural fistulas.     

Double spinal dural arteriovenous fistulas

We present a patient with double spinal dural arteriovenous fistulas revealed by progressive myelopathy. Numerous dilated veins extending along the entire length of the spinal cord were found on MR imaging. Angiography showed a first spinal dural fistula at the level of T7 with descending venous drainage and a second spinal dural fistula at the level of T5 with ascending venous drainage. Both fistulas were cured by therapeutic embolization.     

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.     

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.     

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 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.     

Spinal Dural Arteriovenous Fistula: Imaging Features and Its Mimics

Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation, however it is still rare and underdiagnosed. Magnetic resonance imaging findings such as spinal cord edema and dilated and tortuous perimedullary veins play a pivotal role in the confirmation of the diagnosis. However, spinal angiography remains the gold standard in the diagnosis of SDAVF. Classic angiographic findings of SDAVF are early filling of radicular veins, delayed venous return, and an extensive network of dilated perimedullary venous plexus. A series of angiograms of SDAVF at different locations along the spinal column, and mimics of serpentine perimedullary venous plexus on MR images, are demonstrated. Thorough knowledge of SDAVF aids correct diagnosis and prevents irreversible complications.     

Association between lumbar epidural injection and development of acute paraparesis in patients with spinal dural arteriovenous fistulas

SUMMARY: We report 3 patients with previously undiagnosed spinal dural arteriovenous fistulas (SDAVFs), who developed acute paraparesis following lumbar epidural steroid injection. MR imaging demonstrated spinal cord T2 hyperintensity, edema and/or enhancement of the conus, and intradural enlarged vascular flow voids. Spinal angiography confirmed SDAVFs arising from pedicles remote from the sites of the epidural steroid injection. Fistulas were eliminated with either endovascular or combination endovascular and open surgical approaches, with subsequent partial resolution of paraparesis.     

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.     

Lumbar spinal dural arteriovenous fistula presenting with brainstem symptomatology: A case report

This report is about a rare case of a lumbar spinal dural arteriovenous fistula (DAVF) with distant brainstem symptoms of vertigo and ataxia. Brain magnetic resonance imaging (MRI) demonstrated a high signal abnormality in the lower pons, medulla, and cervico-medullary junction, presumably related to venous hypertension. Spinal MRI revealed markedly dilated veins along the dorsal aspect of the cord, while spinal angiography confirmed the presence of a lumbar spinal DAVF. Because lumbar DAVF may cause remote brainstem symptoms, spinal DAVF should be considered in the differential diagnosis of high signal MRI abnormalities localized in the brainstem. Properly extending the scanning range is essential in the diagnosis.     

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.     

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.     

Three cases of spinal dural AVF: evaluation with first-pass, gadolinium-enhanced, three-dimensional MR angiography

A first-pass, contrast-enhanced three-dimensional (3D) magnetic resonance (MR) angiography with short acquisition time was performed for three consecutive cases with suspected spinal arteriovenous fistula (AVF). This MR technique demonstrated the feeding arteries and draining veins of the spinal dural AVF, and was very useful for the definite diagnosis of the lesions as a disease with arteriovenous shunt. With this MR technique, we could localize the feeding artery and shunt before conventional angiography. J. Magn. Reson. Imaging 2000;12:949-952.     

Intracranial dural arteriovenous fistula with spinal medullary venous drainage

We report on a 46-year-old patient in whom an intracranial dural arteriovenous (AV) fistula, supplied by a branch of the ascending pharyngeal artery, drained into spinal veins and produced rapidly progressive symptoms of myelopathy and brainstem dysfunction including respiratory insufficiency. Magnetic resonance imaging studies demonstrated brainstem oedema and dilated veins of the brainstem and spinal cord. Endovascular embolization of the fistula led to good neurological recovery, although the patient had been paraplegic for 24 h prior to embolization. This case demonstrates the MRI characteristics of an intracranial dural AV fistula with spinal drainage and illustrates the importance of early diagnosis and treatment. Even paraplegia may be reversible, if angiography is performed and the fistula treated before ischaemic and gliotic changes become irreversible. Received: 25 May 1999; Revised: 25 January 2000; Accepted: 15 February 2000     

MR angiography of spinal vascular malformations.

PURPOSETo determine the potential and limitations of MR angiography in the evaluation of spinal vascular malformations.METHODSEleven consecutive patients with spinal vascular malformations proved with spinal selective arteriography underwent two-dimensional phase-contrast MR angiography.RESULTSAbnormal vessels within the spinal canal were identified with MR angiography in 10 patients. In 1 patient with a dural arteriovenous fistula no definite vascular abnormality was seen with MR angiography. Correlation of MR angiography with spinal selective arteriography showed that the former allowed identification of the arterial feeder in 3 patients with intramedullary arteriovenous malformations and 2 with perimedullary arteriovenous fistula, whereas the source of intradural draining vein was seen in only 2 of 6 patients with dural arteriovenous fistula.CONCLUSIONMR angiography is a promising complementary tool to MR imaging for detection and characterization of spinal vascular malformations.