Value and limitations of contrast-enhanced MR angiography in spinal arteriovenous malformations and dural arteriovenous fistulas

Case report: Surgical treatment and long-term successful outcome of a spinal intramedullary vascular malformation in a dog

A 3.5-year-old male intact Staffordshire terrier crossbreed dog was presented with a one-week history of progressive paraparesis with fecal and urinary incontinence. Neurological examination was consistent with a T3-L3 myelopathy. A magnetic resonance imaging study revealed the presence of a well-circumscribed hemorrhagic space-occupying lesion at the level of T12, suspected to be a vascular malformation, such as cavernoma or arteriovenous fistula, primary hematoma or hamartoma; less likely considerations included hemorrhagic inflammation or hemorrhagic primary or secondary neoplasia. A dorsal laminectomy, durotomy, and midline dorsal myelotomy were performed with a surgical microscope, and the vascular lesion was identified and removed. Histological examination of surgical samples yielded fibrin, hemorrhage, hematoidin pigment, and some neural tissue. Although a lining wall was visualized during surgery consistent with a vascular malformation, there was no histological confirmation of such a structure, hampering definitive classification of the lesion. There was no gross or histopathological evidence that would support a diagnosis of a hamartoma or benign neoplasia. The dog was paraplegic with intact nociception the day following surgery. Ambulation was recovered within 2 weeks. Progressive and complete recovery of neurological function was seen over the next 12 weeks. No recurrence of neurological dysfunction was seen over a 12-month follow-up period. Surgical treatment should be considered in dogs with spinal intramedullary vascular lesions which can have a successful long-term outcome.

High diagnostic performance of time-resolved MR angiography in spinal arteriovenous shunts

BACKGROUND AND PURPOSE

In comparison with the limited efficacy of conventional MR imaging and the invasiveness of catheter-based digital subtraction angiography (DSA), time-resolved MR angiography (TR-MRA) has been proposed as a promising examination for early diagnosis of spinal arteriovenous shunts (SAVSs). This paper aims to investigate the diagnostic performance of TR-MRA with scan parameters optimized for SAVSs evaluation in a large number of patients.

METHODS

One hundred patients with suspected SAVSs were enrolled. Each patient underwent preoperative TR-MRA with optimized scan parameters followed by DSA. The presence or absence of SAVS, the types and the angioarchitecture of SAVSs in the TR-MRA images were diagnostically analyzed.

RESULTS

Among the final 97 patients, 80 cases (82.5 %) were diagnosed and classified by TR-MRA as spinal cord arteriovenous shunts (SCAVSs; n = 22), spinal dural arteriovenous shunts (SDAVSs; n = 48), and spinal extradural arteriovenous shunts (SEDAVSs; n = 10). The agreement for classifying SAVSs between TR-MRA and DSA was excellent (κ = 0.91). The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA for the diagnosis of SAVSs were 100 % (95 % CI, 94.3-100.0 %), 76.5 % (95 % CI, 49.8-92.2 %), 95.2 % (95 % CI, 87.6-98.5 %), 100 % (95 % CI, 71.7-100.0 %), and 95.9 % (95 % CI, 89.9-98.4 %). The accuracy rates of TR-MRA for the detection of feeding arteries were 75.9 %, 91.7 %, and 80.0 % for SCAVSs, SDAVSs, and SEDAVSs respectively.

CONCLUSION

Time-resolved MR angiography showed excellent diagnostic performance for SAVSs screening. Additionally, this method can classify SAVSs and identify feeding arteries in SDAVSs with high diagnostic accuracy.

Spinal cord motor disorders

Spinal cord diseases are frequently devastating due to the precipitous and often permanently debilitating nature of the deficits. Spastic or flaccid paraparesis accompanied by dermatomal and myotomal signatures complementary to the incurred deficits facilitates localization of the insult within the cord. However, laboratory studies often employing disease-specific serology, neuroradiology, neurophysiology, and cerebrospinal fluid analysis aid in the etiologic diagnosis. While many spinal cord diseases are reversible and treatable, especially when recognized early, more than ever, neuroscientists are being called to investigate endogenous mechanisms of neural plasticity. This chapter is a review of the embryology, neuroanatomy, clinical localization, evaluation, and management of adult and childhood spinal cord motor disorders.

Conus medullary arteriovenous malformation mimicking intramedullary tumor: a case report

Background

Vascular malformation of the spine accounted for 3–4% of all intradural lesions. Spinal arteriovenous malformation (AVM) is often missed because of overlapping symptoms with other pathology and ambiguous imaging. Here, we report a conus medullary AVM that mimics intramedullary tumours either from clinical findings or MR imaging.

Case presentation

We report a 24-year-old man with left foot monoparesis, paresthesia, and intermittent claudication for the last 3 months. Magnetic resonance imaging revealed a strongly enhanced intramedullary lesion with a hypointense signal on T1-weighted images and a hyperintense signal on T2-weighted images without flow void, suggesting an intramedullary tumour of ependymoma. Left-sided hemilaminectomy was performed, revealing an AVM on conus medullary. Microsurgical resection was performed by subsequently ligating the arterial feeder and draining vein using a temporary clip. Improvement of neurological status without postoperative sequelae was noted.

Conclusions

Because of the similarity in epidemiology, symptoms, clinical progression, and imaging, suspicion of spinal AVM should remain. This case highlights that appropriate and meticulous surgical resection can preserve the patient's neurological function.

Imaging characteristics, misdiagnosis and microsurgical outcomes of patients with spinal dural arteriovenous fistula: a retrospective study of 32 patients

Background

Spinal dural arteriovenous fistula (SDAVF) is an extremely rare spinal vascular malformation. As SDAVF exhibits no specific clinical manifestations nor diverse imaging results, it is easily misdiagnosed, resulting in delayed treatment and irreversible neurological damage. Most patients were initially misdiagnosed, but there were few reports on reducing misdiagnosis.

Methods

A total of 32 consecutive patients, who presented to our institution (Shanghai Deji Hospital) with SDAVF between June 2013 and January 2016 were retrospectively analyzed. Data were collected on demographics, clinical presentation, imaging findings, follow-up, and clinical outcomes. The Aminoff-Logue scale (ALS) was used to assess clinical outcomes.

Results

Of the 32 enrolled patients (3 females, mean age 59.1±3.8 years), 23 patients (71.9%) were misdiagnosed as acute myelitis (11 patients), intramedullary tumors (6 patients), lumbar disc herniation (4 patients), and other conditions (2 patients). All patients underwent surgical procedures under electrophysiological monitoring. Fistulas were found in all 32 patients and were successfully occluded. The mean follow-up period was 19.22±8.21 months (ranging from 2 weeks to 30 months). One year later, 20 patients underwent magnetic resonance imaging (MRI), and 14 showed no T2 edema, and the edema was relieved in 6 patients. A total of 10 patients underwent enhancement MRI and no enhancement signs were detected. Among the 27 patients with long-time follow-up, the fistula had no residual or recurrence, 21 patients showed decreased ALS scores (P<0.05). Six patients exhibited nonsignificant improvement. No aggravating patient was found. Prognosis differed significantly between patients with ALS <6 and those with ALS ≥6 (P<0.05).

Conclusions

Spinal angiography should be performed with full intubation, and microcatheter angiography can reduce misdiagnosis. SDAVF must be differentiated from acute myelitis, intramedullary tumor, and other spinal vascular malformations. Microsurgical treatment is effective with a low recurrence rate.

Arteriovenous malformations of the filum terminale: clinical characteristics, angioarchitecture, and management of a rare spinal vascular pathology

OBJECTIVE

The goal of this study was to describe clinical and neuroradiological features of arteriovenous malformations of the filum terminale (FT AVMs) and to present the authors’ diagnostic and therapeutic management in this rare disease.

METHODS

The presented cases were retrieved from a retrospectively collected database of all spinal vascular malformations treated between June 1992 and December 2021 at the Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen. Pretreatment and follow-up clinical and neuroradiological data were analyzed for this study.

RESULTS

Data in 15 patients with FT AVM with a mean age of 60 years were included, with an overall incidence of FT AVM of 19% among all spinal AVMs in our cohort. Twelve of 15 (80%) patients were men. Nonspecific but typical clinical and MR findings of thoracolumbar congestive myelopathy were found in all patients. Spinal MR angiography, performed in 10 patients, identified in all cases the arterialized FT vein as well as a lumbar/lumbosacral location of an AV shunt. Digital subtraction angiography (DSA) showed an arterial supply solely via the FT artery in 12/15 (80%) patients and via an additional feeder from the lumbosacral region in the other 3/15 (20%) patients. All patients were treated surgically. During 1-year follow-up, 2 patients presented with recurrent FT AVM due to further arterial supply from the lumbosacral region, and were treated surgically. Neurological status was improved in all patients within the 1-year follow-up, with marginal further changes during long-term follow-up.

CONCLUSIONS

Congestive myelopathy is the major pathological mechanism of symptoms in these patients, with no evidence for intradural bleeding. Missing the presence of possible multiple arterial supply of FT AVM during DSA may result in misdiagnosis and/or insufficient treatment. Due to the frequently prolonged course of FT artery, resection of the FT AVM may be a favorable treatment modality in comparison with endovascular treatment. Follow-up examinations are obligatory within the first 3 years after treatment, and further MR angiography and DSA examinations are indicated if congestive myelopathy persists.

Radiation Dose and Fluoroscopy Time of Diagnostic Angiography in Patients with Spinal Dural Arteriovenous Fistula

PURPOSE

Spinal dural arteriovenous fistulas (SDAVFs) represent the most common indication for a spinal angiography. The diagnostic reference level (DRL) for this specific endovascular procedure is still to be determined. This single-center study provides detailed dosimetrics of diagnostic spinal angiography performed in patients with SDAVFs.

METHODS

Retrospective analysis of all diagnostic spinal angiographies between December 2011 and January 2021. Only patients with an SDAVF who had baseline magnetic resonance angiography (MRA), diagnostic digital subtraction angiography (DSA), treatment and follow-up at this institution were included. Dose area product (DAP, Gy cm²) and fluoroscopy time were compared between preoperative and postoperative angiographies, according to SDAVF locations (common versus uncommon), MRA results at baseline (positive versus negative) and DSA protocols (low-dose, mixed-dose, normal-dose). The 75th percentile of the DAP distribution was used to define the local DRL.

RESULTS

A total of 62 spinal angiographies were performed in 25 patients with SDAVF. Preoperative angiographies (30/62, 48%) yielded a significantly higher DAP and longer fluoroscopy time when compared to postoperative angiographies (32/62, 53%) (p < 0.01). The local DRL was 329.41 Gy cm² for a nonspecific (n = 62), 395.59 Gy cm² for a preoperative and 138.6 Gy cm² for a postoperative spinal angiography. Preoperative angiography of uncommonly located SDAVFs yielded a significantly longer fluoroscopy time (p = 0.02). The MRA-based fistula detection had no significant impact on dosimetrics (p > 0.05). A low-dose protocol yielded a 61% reduction of DAP.

CONCLUSION

The results of the present study suggest novel DRLs for spinal angiography in patients with SDAVF. Dedicated low-dose protocols enable radiation dose optimization in these procedures.

Feasibility of Noninvasive Diagnosis of Spinal Vascular Diseases Using Time-Resolved Angiography With Stochastic Trajectories

Background and Purpose: To determine the feasibility of time-resolved angiography with stochastic trajectories (TWIST) in the diagnosis of spinal dural arteriovenous fistula (SDAVF) and perimedullary arteriovenous fistula (PAVF).

Methods: A total of 11 negative patients with TWIST examination were retrospective analyzed and then 18 patients with suspected spinal vascular diseases underwent TWIST. For negative patients, Adamkiewicz artery (AKA), great anterior radiculomedullary vein (GARV) and anterior spinal artery (ASA) were retrospective analyzed. In patients, the results of TWIST were compared with those of DSA.

Results: The displaying rates of the ASA, AKA and GARV in 11 negative patients were 100, 90.9, and 90.9%, respectively. The AKA and GARV were separated on TWIST. Of 18 patients, 11 and three were diagnosed with SDAVF and PAVF, respectively. The spinal cord vascular malformation diagnosed on TWIST was consistent with DSA with an excellent intermodality agreement (Kappa = 0.92, p < 0.001). The feeding artery and side of all 11 SDAVF patients were displayed on TWIST and the results were consistent with DSA. For PAVF patients, the feeding artery in two patients and the sides as displayed on TWIST were consistent with DSA.

Conclusions: TWIST enables the differentiation of the spinal artery and vein and the differential diagnosis of SDAVF and PAVF.

Challenges in Diagnosis and Management of Previously Embolized Spinal Dural Arteriovenous Fistulae

BACKGROUND

Given the growing prevalence of initial endovascular treatment for type 1 spinal dural arteriovenous fistulae (dAVF), there are an increasing number of patients presenting with progressive symptoms related to recurrent previously embolized spinal dAVF. This study's goal was to identify demographic, clinical, and radiographic variables among patients who have failed embolization of type I spinal dAVF.

METHODS

A retrospective review of 24 consecutive surgeries for type I spinal dAVF performed by the senior author (A.D.L.) identified 5 patients who underwent open surgery for failed embolization. These 5 cases were reviewed for location of fistula, time from embolization to recurrence, preoperative functional status, fistulous point encountered at surgery, and clinical outcome of the patient at 3-month follow-up. A representative example case is reviewed in detail.

RESULTS

The median age at time of recurrence was 63 years (range 51-73 years). The median timing of embolization to recurrence of neurologic symptoms was 5 months (range 1-54) and to surgery 7 months (range 2-60 months). The level of the spinal dAVF was most frequently at T12-L1 (n = 3). Spinal magnetic resonance arteriography led to localization of the spinal dAVF in 2 patients and spinal catheter angiogram in 3 cases. All patients had definitive radiographic cure of the dAVF at last clinical follow-up.

CONCLUSIONS

The increased use of endovascular treatment of spinal dAVF has led to the treatment of refractory cases with a greater degree of surgical complexity. Open surgical ligation continues to provide the most definitive treatment outcomes for this complex spinal vascular entity.

The Top-100 most cited articles on dural arteriovenous fistula: A bibliometric analysis

Objective

Dural arteriovenous fistula (DAVF) is a rare pathological vascular lesion with variable clinical manifestations. Since 1968, several articles have been published to address spinal and cranial DAVFs. The aim of this study is to identify, analyse, and review the pertinent literature of the top-100 most cited articles on DAVFs published to date.

Methods

A title-specific, keyword-based search with no time restriction was performed in June 2020. The Scopus database was used to identify the top-100 most cited articles on DAVFs. The term “dural arteriovenous fistula” was used as a search keyword. The search results were arranged in descending order based on the total citation count. The top-100 articles were categorized into ten categories.

Results

Between 1968 and 2020, a total of 2298 articles were published on DAVFs. The top-100 most cited articles were published between 1983 and 2012. The total number of citations for the top-100 articles was 12393 (123 citations/article). Most articles (34%) were investigating the clinical aspect of DAVFs. The country contributing to the most impactful and highest volume of publications (46%) was the United States. The Mayo Clinic was the most active institute in contribution. Most articles (29%) were published by the Journal of Neurosurgery.

Conclusions

In the top-100 most cited articles on DAVF, most studies were published in neurosurgery/neuroradiology-dedicated journals. This bibliometric analysis identifies the publication trends and provides a comprehensive overview of the most influential articles addressing DAVFs.

Myelopathy secondary to an intramedullary arteriovenous malformation in a mature dog

A 2‐year‐old crossbreed dog was presented for evaluation of a 6‐week history of progressive paraparesis. Magnetic resonance imaging and computed tomography angiography of the thoracic and lumbar spinal cord disclosed multifocal, anomalous, small, vascular structures, distributed throughout the subarachnoid space of the included section of the spinal cord. An additional focal intramedullary lesion was identified extending from T9 to T10 to T12. Histopathological examination confirmed the presence of an intramedullary arteriovenous malformation affecting the thoracic spinal cord and leading to diffuse congestion and focal hemorrhages into the affected spinal cord.

Techniques for Imaging Vascular Supply of Peripheral Nerves

Few studies have been developed to map the vascular structures feeding peripheral nerves, with the majority using cadaveric models and inadequate sample sizes. Preliminary evidence, while limited, indicates that the mapping of these vessels may allow or preclude certain procedures in nerve reconstruction due to the location of essential arterial inflow to the vasa nervorum. This review evaluates the evidence regarding historical, current, and emerging techniques for visualizing these vascular structures in vivo and considers their potential application in peripheral nerve vasculature.

Long-Term Outcome of Patients with Spinal Dural Arteriovenous Fistula: The Dilemma of Delayed Diagnosis

BACKGROUND AND PURPOSE

The impact of various radiologic and clinical features on the long-term outcome in spinal dural arteriovenous fistulas is still unclear; thus, they are the purpose of this study.

MATERIALS AND METHODS

We retrospectively analyzed our medical data base for all patients treated for spinal dural arteriovenous fistula in our institution between 2006 and 2016. Patient age, neurologic status at the time of diagnosis, the duration of symptoms from onset to diagnosis, and follow-up information were evaluated. The extent of medullary T2WI hyperintensity, intramedullary contrast enhancement, and elongation of perimedullary veins on MR imaging at the time of diagnosis were additionally analyzed.

RESULTS

Data for long-term outcome analysis were available in 40 patients with a mean follow-up of 52 months (median, 50.5 months; range, 3-159 months). The mean age at the time of diagnosis was 69.27 ± 9 years (median, 71 years; range, 53-84 years) with a male predominance (n = 32; 80%). The mean duration of symptoms was 20.2 months (median, 10 months; range, 1-120 months). Shorter duration of symptoms at the time of diagnosis was significantly correlated with better outcome of symptoms (P < .05).

CONCLUSIONS

Spinal dural arteriovenous fistulas are characterized by interindividually variable clinical presentations, which make a determination of specific predictors for long-term outcome more difficult. Fast and sufficient diagnosis might result in a better outcome after treatment. The diagnosis of spinal dural arteriovenous fistula remains markedly delayed, reflecting an ongoing lack of knowledge and awareness among treating physicians of this rare-but-serious disease.

Treatment strategy and long-term outcome in patients with deep lumbosacral arteriovenous fistulas. A single center analysis in nineteen patients

OBJECTIVE

Deep lumbosacral dural arteriovenous fistulas (lsDAVF) are rare and present serious diagnostic and treatment difficulties. In our current analysis we present our treatment strategy and the long-term clinical outcome of nineteen patients with lsDAVF.

PATIENTS AND METHODS

We retrospectively analyzed our radiological and medical records for patients presenting with SDAVF between 1990 and 2018 at the University Hospital Aachen. We identified twenty patients with a lsDAVF. All patients were treated surgically. One patient died of pulmonary embolism three months after treatment and was excluded from our outcome analysis. Clinical data at time of admission, discharge, one year after discharge and at the last follow-up were evaluated according to modified Aminoff-Logue disability score (AL-score) for this analysis.

RESULTS

Mean age was 65 ± 7 years (median, 67; range, 53-78), sixteen patients (84 %) were male. After surgery, four patients developed a recurrent fistula in the same shunt zone and were re-treated microsurgically. Follow-up data one year after treatment was available in 15 patients. No relevant changes in AL-score were observed within this period. For the long-term follow-up analysis, data of 13 patients were available; 38.5 % of patients developed late functional deterioration.

CONCLUSION

In our cohort, patients with deep lumbosacral dural arteriovenous fistula had a higher risk of early recurrence compared to patients with thoracolumbar SDAVF, with a considerable percentage of late functional deterioration. Thus strict clinical and radiologic long-term follow-up examinations are recommended in those patients.

Spinal cord ischemia/infarct after cauda equina syndrome from disc herniation - A case study and literature review

Background

Spinal cord infarction is rare and occurs in 12/100,000; it represents 0.3%-2% of central nervous system infarcts. Here, we present a patient who developed recurrent bilateral lower extremity paraplegia secondary to spinal cord infarction 1 day after a successful L4-5 microdiscectomy in a patient who originally presented with a cauda equina syndrome.

Case Description

A 56-year-old patient presented with an acute cauda equina syndrome characterized by severe lower back pain, a right foot drop, saddle anesthesia, and acute urinary retention. When the lumbar magnetic resonance imaging (MRI) revealed a large right paracentral lumbar disc herniation at the L4-L5 level, the patient underwent an emergency minimally invasive right-sided L4-5 discectomy. Immediately, postoperatively, the patient regained normal function. However, 1 day later, while having a bowel movement, he immediately developed the recurrent paraplegia. The new lumbar MRI revealed acute ischemia and an infarct involving the distal conus medullaris. Further, workup was negative for a spinal cord vascular malformation, thus leaving an inflammatory postsurgical vasculitis as the primary etiology of delayed the conus medullaris infarction.

Conclusions

Acute neurologic deterioration after spinal surgery which does not neurologically correlate with the operative level or procedure performed should prompt the performance of follow-up MR studies of the neuraxis to rule out other etiologies, including vascular lesions versus infarctions, as causes of new neurological deficits.

Comparative Analysis of Volumetric High-Resolution Heavily T2-Weighted MRI and Time-Resolved Contrast-Enhanced MRA in the Evaluation of Spinal Vascular Malformations

BACKGROUND AND PURPOSE

Volumetric high-resolution heavily T2-weighted imaging or time-resolved contrast-enhanced MRA is used in the detection and characterization of spinal vascular malformations, though inherent trade-offs can affect their overall sensitivity and accuracy. We compared the efficacy of volumetric high-resolution heavily T2-weighted and time-resolved contrast-enhanced images in spinal vascular malformation diagnosis and feeder characterization and assessed whether a combined evaluation improved the overall accuracy of diagnosis.

MATERIALS AND METHODS

Twenty-eight patients with spinal vascular malformations (spinal dural arteriovenous fistula, spinal cord arteriovenous malformation, and perimedullary arteriovenous fistula) were prospectively enrolled. MR images were separately analyzed by 2 neuroradiologists blinded to the final diagnosis.

RESULTS

Both sequences demonstrated 100% sensitivity and 93.5% accuracy for the detection of spinal vascular malformations. Volumetric high-resolution heavily T2-weighted imaging was superior to time-resolved contrast-enhanced MR imaging for identification of spinal cord arteriovenous malformations (100% versus 90% sensitivity and 96.7% versus 93.5% accuracy), however, for the diagnosis of perimedullary arteriovenous fistula, time resolved contrast enhanced MRI was found to perform better than the volumetric T2 sequence (80% versus 60% sensitivity and 96.7% versus 93.5% accuracy). Both sequences showed equal sensitivity (100%) and accuracy (87%) for spinal dural arteriovenous fistulas. Combined evaluation improved the overall accuracy across all types of spinal vascular malformation. Volumetric high-resolution heavily T2-weighted imaging was superior or equal to time-resolved contrast-enhanced MR imaging for feeder identification of spinal dural arteriovenous fistulas for both observers (90.9% and 72.7% versus 72.7%), which improved to 90.9% when the sequences were combined. Time-resolved contrast-enhanced MR imaging performed better for major and total feeder identification of spinal cord arteriovenous malformation (80% versus 60%) and perimedullary arteriovenous fistula (80% versus 60%-80%).

CONCLUSIONS

Combined volumetric high-resolution heavily T2-weighted imaging and time-resolved contrast-enhanced MR imaging can improve the sensitivity and accuracy of spinal vascular malformation diagnosis, classification, and feeder characterization.

Diagnostic accuracy and efficiency of combined acquisition of low-dose time-resolved and single-phase high-resolution contrast-enhanced magnetic resonance angiography in a single session for pre-angiographic evaluation of spinal vascular disease

Background/Purpose

The purpose of this study was to evaluate the utility and efficacy of combined low-dose, time-resolved (TR) and single-phase high-resolution (HR) contrast-enhanced MRA (CE-MRA) as a pre-angiographic study for spinal vascular disease.

Materials and methods

Seventeen consecutive patients with suspected spinal vascular disease were retrospectively reviewed. All patients underwent combined low-dose TR CE-MRA and three-dimensional single-phase HR CE-MRA at 3 Tesla, followed by conventional spinal digital subtraction angiography (DSA) within 90 days. Six patients underwent additional spinal MRA and DSA for treatment follow-up. Spinal lesions were analyzed in terms of presence, disease type, laterality, spinal level, and number of arterial feeders.

Results

Low-dose TR CE-MRA helped proper localization of subsequent HR CE-MRA in two patients with high or low level of the lesion. For initial detection of spinal vascular disease, sensitivity, specificity and accuracy of CE-MRA were 93.3% (n = 14/15), 100% (n = 3/3), and 94.4% (n = 17/18), respectively. In characterization of dural arteriovenous fistula (AVF), perimedullary AVF, spinal cord arteriovenous malformation (AVM), and extraspinal AVM, CE-MRA correctly characterized in 86.7% (n = 13/15) among the positive findings, and in 88.9% (n = 16/18) among the several patients including negative results. CE-MRA showed matched per-case localization of arterial feeders within 1 vertebral level in 80% (n = 12/15), and matched per-lesion localization in 78.3% (n = 18/23).

Conclusion

Combined low-dose TR CE-MRA and single-phase HR CE-MRA at 3 Tesla was an effective and accurate non-invasive tool for the pre-angiographic evaluation of spinal vascular diseases in a single session.

Double spinal dural arteriovenous fistulas

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVF) are usually solitary lesions. Synchronous and/or metachronous double SDAVF have rarely been reported in the literature. We report on three patients with double SDAVF and present our single center experience in the diagnostic and treatment management in these patients.

MATERIAL AND METHODS

We retrospectively revised our medical database for all patients who were diagnosed and treated in our center due to a SDAVF between 1990 and 2017. All data including demographics, clinical presentations, as well as radiological data were re-evaluated for this study.

RESULTS

Three (1.4%) of 209 consecutive patients with SDAVF presented double SDAVF with different arterial feeders and venous drainage patterns. All three patients were men. The mean age at time of diagnosis was 67.9 ± 10 years (median; 68, range: 53-82). Myelopathic symptoms were reported in all three cases. All three fistulas were located in the thoracolumbar region between T7 and L2. MRI/CE-MRA showed medullar T2-hyperintensity, intramedullary contrast-enhancement and dilatation of perimedullary veins in various extensions.

CONCLUSION

Double SDAVF are extremely rare and were found in 1.4% of patients in our series. The vast majority of the reported double SDAVF in the literature has been detected synchronously within an area of equal or less than three vertebral levels. Thus, whenever the SDAVF is identified, further injections of the fistula-zone neighbored segmental arteries might be recommended. However, due to the extremely low incidence of double SDAVF a complete spinal DSA is not indicated.

Spinal Epidural Arteriovenous Fistula with Perimedullary Venous Reflux: Clinical and Neuroradiologic Features of an Underestimated Vascular Disorder

BACKGROUND AND PURPOSE

The purpose of this study was to discuss the clinical and radiologic characteristics of spinal epidural arteriovenous fistulas (SEAVF) and demonstrate their specific angiomorphology in a single-center series.

MATERIALS AND METHODS

Thirteen consecutive patients were diagnosed with SEAVF at RWTH Aachen University Hospital between 2006 and 2018 and were included in this study. All patients had MR imaging and DSA before treatment; 10 of these 13 patients received contrast-enhanced MRA (CE-MRA).

RESULTS

The mean patient age was 72 ± 8 years. Paraparesis was present in 12 (92%) patients. Sphincter dysfunction and sensory symptoms were observed in 7 (54%) and 6 (46%) patients, respectively. The mean duration of symptoms was 6 ± 8 months. Congestive myelopathy on MR imaging was present in all patients. Prominent arterialized perimedullary veins were demonstrated in only 3 cases. CE-MRA revealed arterialized perimedullary veins and an arterialized epidural pouch in 9/10 (90%) patients, mostly located ventrolaterally. DSA demonstrated a multisegmental extension of the arterialized ventrolateral epidural pouch in 6 (46%) cases. An intradural radicular drainage vein was localized distant from the original fistula point in 3 (23%) patients.

CONCLUSIONS

Congestive myelopathy with an acute/subacute clinical course was the dominant finding in spinal epidural arteriovenous fistulas. CE-MRA is a powerful diagnostic tool for identifying arterialized perimedullary veins as well as an arterialized epidural pouch. While arterialized perimedullary veins frequently present with only mild enlargement and elongation in spinal epidural arteriovenous fistulas, the arterialized epidural pouch is frequently located ventrolaterally and may extend over several vertebral levels. DSA remains the criterion standard to precisely visualize a spinal epidural arteriovenous fistula and its intradural radicular drainage vein, which may be located distant from the fistulous point.

Clinical and Radiologic Characteristics of Deep Lumbosacral Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas located in the deep lumbosacral region are rare and the most difficult to diagnose among spinal dural arteriovenous fistulas located elsewhere in the spinal dura. Specific clinical and radiologic features of these fistulas are still inadequately reported and are the subject of this study.

MATERIALS AND METHODS

We retrospectively evaluated all data of patients with spinal dural arteriovenous fistulas treated and/or diagnosed in our institution between 1990 and 2017. Twenty patients with deep lumbosacral spinal dural arteriovenous fistulas were included in this study.

RESULTS

The most common neurologic findings at the time of admission were paraparesis (85%), sphincter dysfunction (70%), and sensory disturbances (20%). Medullary T2 hyperintensity and contrast enhancement were present in most cases. The filum vein and/or lumbar veins were dilated in 19/20 (95%) patients. Time-resolved contrast-enhanced dynamic MRA indicated a spinal dural arteriovenous fistula at or below the L5 vertebral level in 7/8 (88%) patients who received time-resolved contrast-enhanced dynamic MRA before DSA. A bilateral arterial supply of the fistula was detected via DSA in 5 (25%) patients.

CONCLUSIONS

Clinical symptoms caused by deep lumbosacral spinal dural arteriovenous fistulas are comparable with those of spinal dural arteriovenous fistulas at other locations. Medullary congestion in association with an enlargement of the filum vein or other lumbar radicular veins is a characteristic finding in these patients. Spinal time-resolved contrast-enhanced dynamic MRA facilitates the detection of the drainage vein and helps to localize deep lumbosacral-located fistulas with a high sensitivity before DSA. Definite detection of these fistulas remains challenging and requires sufficient visualization of the fistula-supplying arteries and draining veins by conventional spinal angiography.

Spinal dural arteriovenous fistulas: the most frequent vascular malformations of the spinal cord

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.

Rare association between spinal dural arteriovenous fistulas and dysraphisms: Report of two cases and review of the literature with a focus on pitfalls in diagnosis and treatment

Spinal vascular malformations are uncommon yet important spinal pathologies commonly classified in congenital and acquired lesions. Spinal lipomas consist of three subtypes: intramedullary lipomas, lipomyelo(meningo)celes and lipomas of the filum. Although the association of spinal arteriovenous malformations (AVM) with other congenital anomalies is well known, the coexistence of dural arteriovenous fistulas (AVF) and tethered spinal cord is exceptionally rare and only eight cases have been reported. We present two cases from our institution and speculate on the possible origin of such a rare but insidious association. We review the current literature with a focus on possible pitfalls in diagnosis and treatment.

Magnetic Resonance Imaging and Clinical Features in Acute and Subacute Myelopathies

Differential diagnosis of acute and subacute transverse myelopathy includes inflammatory, infectious, vascular, metabolic and paraneoplastic etiologies. Information on the diagnostic approach to transverse myelopathy with regard to daily clinical practice is provided. The differentiation between five lesion patterns on magnetic resonance imaging (MRI) in myelitis may be helpful: (1) longitudinal extensive transverse myelitis, (2) short segment ovoid or peripherally located, (3) "polio-like", (4) granulomatous and (5) segmental with rash. A correlation with these imaging features is supported if the clinical course and neurological symptoms are known. Although the mean interval from onset to nadir of symptoms in spinal cord infarction is 1 h, an overlap with a fulminant course of myelitis is possible, and impaired diffusion may also occur in acute inflammatory processes. As a result, laboratory testing, including aquaporin-4 antibodies and cerebrospinal fluid analysis, is crucial for the correct interpretation of imaging findings. Moreover, the discrimination of acute complete and acute partial transverse myelitis is advantageous in order to identify diverse entities, the latter often being a precursor to multiple sclerosis. Additional brain imaging is mandatory in suspected demyelinating, infectious, neoplastic and systemic autoimmune disease. A symmetrical lesion pattern restricted to individual tracts or dorsal columns indicates subacute combined degeneration of the spinal cord and, in addition to deficiency syndromes, a paraneoplastic etiology should be considered.

Arterial Hypertension Is Associated with Symptomatic Spinal Dural Arteriovenous Fistulas

OBJECTIVE

To determine possible systemic factors that may induce or be associated with the pathogenesis and pathologic course of spinal dural arteriovenous fistulas (SDAVFs), the most common type of arteriovenous disorder of the spinal cord and its meninges.

METHODS

We assessed the role of possible systemic (vascular) risk factors (arterial hypertension, diabetes mellitus, fat metabolism disorders, and nicotine dependence) by comparing the prevalence of these risk factors in an SDAVF cohort of 59 patients with the prevalence in the general population.

RESULTS

Age-corrected prevalence of arterial hypertension in the SDAVF cohort was significantly higher than in the general population (P < 0.001). Prevalence of diabetes mellitus (P = 0.150.), nicotine dependence (P = 0.561), adiposity (P = 0.217), and fat metabolism disorders (P = 0.125) did not differ from prevalence of comparable cohorts in the general population.

CONCLUSIONS

Our results and data from the literature suggest that arterial hypertension may play an important role in the development of SDAVF-related symptoms or the development of SDAVFs in the presence of other predisposing factors.

Clinical utility of optimized three-dimensional T1-, T2-, and T2*-weighted sequences in spinal magnetic resonance imaging

This article reviews the clinical utility of 3D magnetic resonance imaging (MRI) sequences optimized for the evaluation of various intraspinal lesions. First, intraspinal tumors with hypervascular components and arteriovenous malformations (AVM) are clearly shown on contrast-enhanced (CE)-3D T1-weighted gradient-echo (GE) sequences with high spatial resolution. Second, dynamic CE-3D time-resolved magnetic resonance angiography (MRA) shows delineated feeding arteries of intraspinal AVM or arteriovenous fistula (AVF), greatly aiding subsequent digital subtraction angiography (DSA). Third, 3D multiecho T2*-weighted GE sequences are used to visualize intraspinal structures and spinal cord lesions and are sensitive to the magnetic susceptibility of intraspinal hemorrhages. Three-dimensional balanced steady-state free precession (SSFP) and multishot 3D balanced non-SSFP sequences produce contiguous thin images with high signal-to-noise ratio (SNR) in short scanning times. Intraspinal cystic lesions and small nerve-root tumors in subarachnoid space can be viewed using 3D balanced SSFP. Spinal cord myelomalacia and cord compression can be evaluated on fat-suppressed multishot 3D balanced non-SSFP. Finally, a 3D T2-weighted fast spin-echo (FSE) sequence with variable flip angle (FA) refocusing pulse improves through-plane spatial resolution over conventional 2D T2-weighted FSE sequences while matching image contrast.

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.

Dynamic contrast-enhanced magnetic resonance angiography for the localization of spinal dural arteriovenous fistulas at 3T

OBJECTIVE

This study was undertaken to evaluate the accuracy of dynamic contrast-enhanced magnetic resonance angiography (DCE-MRA) in the precise location and demonstration of fistulous points in spinal dural arteriovenous fistulas (SDAVFs).

METHODS

Fifteen patients (14 men, 1 woman; age range: 40-78 years; mean: 55.5 years) harboring SDAVF who underwent preoperative DCE-MRA and spinal digital subtraction angiography (DSA) between January 2012 and January 2015 were evaluated retrospectively. Two reviewers independently evaluated the level and side of the arteriovenous fistula and feeding artery on 3T DCE-MRA and DSA images. The accuracy of DCE-MRA was assessed by comparing its findings with those from DSA and surgery in each case.

RESULTS

All 15 patients underwent DCE-MRA and DSA. DSA was unsuccessful in two patients due to technical difficulties. All cases were explored surgically, guided by the DCE-MRA. Surgery confirmed that 14 AVF sites were located in the thoracic spine, 5 in the lumbar spine, and 1 in the cervical spine. The origin of the fistulas and feeding arteries was accurately shown by DCE-MRA in 11 of the 15 patients. DCE-MRA also detected dilated perimedullary veins in all 15 patients. Overall, DCE-MRA facilitated DSA catheterization in 10 cases. In six patients, the artery of Adamkiewicz could be observed. In 15 out of 20 fistulas (75%), both readers agreed on the location on DCE-MRA images, and the κ coefficient of the interobserver agreement was 0.67 (95% confidence interval [CI], 0.16-0.87). In 13 of 16 shunts (75%), the DCE-MRA consensus findings and DSA findings coincided. The intermodality agreement was 0.77 (95% CI: 0.35-0.92).

CONCLUSIONS

Our DCE-MRA studies benefited from the use of a high-field 3T MR imaging unit and reliably detected and localized the SDAVF and feeding arteries. As experience with this technique grows, it may be possible to replace DSA with DCE-MRA if surgery is the planned treatment.

Impact of non-contrast enhanced volumetric MRI-based feeder localization in the treatment of spinal dural arteriovenous fistula

BACKGROUND

The preoperative localization of the feeder of spinal dural arteriovenous fistula (SDAVF) could simplify the diagnostic spinal angiographic procedure. Localization by non-contrast-enhanced MRI-based techniques is an attractive option. However, the usefulness of such an approach for evaluation of SDAVF has not yet been reported.

OBJECTIVE

To study the impact of non-contrast MRI-based feeder localization, followed by targeted spinal angiography, in the evaluation of SDAVF before endovascular intervention.

MATERIALS AND METHODS

Prospectively collected data were analyzed and the level of the feeder was localized preoperatively. The procedural time for targeted spinal angiography was calculated and compared with that of a historical cohort, who underwent routine spinal angiographic examination before the study period. Follow-up MRI was carried out to assess the reliability of this model for detection of occasional metachronous lesions that might be missed with this approach.

RESULTS

Seven patients underwent targeted spinal angiography during the study. The feeder level was accurately identified in five patients and was localized to one vertebral level in six patients. The correlation between MRI and DSA was statistically significant. The number of spinal levels assessed was fewer and overall procedure time was significantly shorter compared to historical cohort (58 min vs 162 min, respectively; p<0.001). Intervention was coupled with targeted angiography in two patients. Follow-up MRI demonstrated flow voids in one patient, who had recurrent fistula at one vertebral level below the previously embolized feeder.

CONCLUSIONS

The non-contrast MRI-based localization technique can reliably detect the level of feeder and help in therapeutic planning of SDAVF. The localization techniques potentially shorten the angiographic procedure and may facilitate simultaneous endovascular definitive treatment. Inclusion of follow-up MRI may be useful for detection of synchronous or metachronous lesions if a targeted approach is adopted. Additionally, this helps to identify failed endovascular therapy.

Novalis Stereotactic Radiosurgery for Spinal Dural Arteriovenous Fistula

The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system.

Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe

OBJECT

The object of this study was to evaluate the accuracy of fast 3D contrast-enhanced spinal MR angiography (MRA) using a manual syringe contrast injection technique for detecting and evaluating spinal arteriovenous shunts (AVSs).

METHODS

This was a retrospective study of 15 patients and 20 spinal MRA and catheter angiography studies. The accuracy of using spinal MRA to detect spinal AVS, localize shunts, and discriminate the subtype and dominant arterial feeder of the AVS were studied.

RESULTS

There were 14 pretherapeutic and 6 posttherapeutic follow-up spinal MRA and catheter spinal angiography studies. The spinal AVS was demonstrated in 17 of 20 studies. Spinal MRA demonstrated 100% sensitivity for detecting spinal AVS with no false-negative results. A 97% accuracy rate for AVS subtype discrimination and shunt level localization was achieved using this study's diagnostic criteria. The detection of the dominant arterial feeder was limited to 9 of these 17 cases (53%).

CONCLUSIONS

The fast 3D contrast-enhanced MRA technique performed using manual syringe contrast injection can detect the presence of a spinal AVS, locate the shunt level, and discriminate AVS subtype in most cases, but is limited when detecting small arterial feeders.

Utility of 3D SPACE T2-weighted volumetric sequence in the localization of spinal dural arteriovenous fistula

OBJECTIVE The aim of this study was to investigate the utility of a heavily T2-weighted volumetric MRI sequence (3D sampling perfection with application-optimized contrasts using different flip-angle evolutions [SPACE]) in the feeder localization of spinal dural arteriovenous fistula (SDAVF). METHODS Patients who were diagnosed with SDAVF and who had 3D SPACE source images available for review were identified from a retrospective review of medical records. A total of 16 patients were identified, and MR images were analyzed separately by 2 blinded observers. The accuracy of the observation and interobserver agreement were measured by Kendall's tau and kappa statistics. RESULTS The site of fistula was accurately predicted by Observers 1 and 2 in 81% and 88% of cases, respectively, which improved to 94% when the level was considered within 1 vertebral level. The observer agreement with gold-standard angiography and interobserver agreement were found to be highly significant (p < 0.0001). CONCLUSIONS The 3D SPACE MRI sequence is valuable in the precise detection of the site of SDAVF. It may help to tailor digital subtraction angiography and thereby reduce the radiation exposure, contrast load, and study time.

ACR Appropriateness Criteria Myelopathy

Patients presenting with myelopathic symptoms may have a number of causative intradural and extradural etiologies, including disc degenerative diseases, spinal masses, infectious or inflammatory processes, vascular compromise, and vertebral fracture. Patients may present acutely or insidiously and may progress toward long-term paralysis if not treated promptly and effectively. Noncontrast CT is the most appropriate first examination in acute trauma cases to diagnose vertebral fracture as the cause of acute myelopathy. In most nontraumatic cases, MRI is the modality of choice to evaluate the location, severity, and causative etiology of spinal cord myelopathy, and predicts which patients may benefit from surgery. Myelopathy from spinal stenosis and spinal osteoarthritis is best confirmed without MRI intravenous contrast. Many other myelopathic conditions are more easily visualized after contrast administration. Imaging performed should be limited to the appropriate spinal levels, based on history, physical examination, and clinical judgment. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Spinal cord ischemia: aetiology, clinical syndromes and imaging features

INTRODUCTION

The purpose of this study was to analyse MR imaging features and lesion patterns as defined by compromised vascular territories, correlating them to different clinical syndromes and aetiological aspects.

METHODS

In a 19.8-year period, clinical records and magnetic resonance imaging (MRI) features of 55 consecutive patients suffering from spinal cord ischemia were evaluated.

RESULTS

Aetiologies of infarcts were arteriosclerosis of the aorta and vertebral arteries (23.6%), aortic surgery or interventional aneurysm repair (11%) and aortic and vertebral artery dissection (11%), and in 23.6%, aetiology remained unclear. Infarcts occurred in 38.2% at the cervical and thoracic level, respectively, and 49% of patients suffered from centromedullar syndrome caused by anterior spinal artery ischemia. MRI disclosed hyperintense pencil-like lesion pattern on T2WI in 98.2%, cord swelling in 40%, enhancement on post-contrast T1WI in 42.9% and always hyperintense signal on diffusion-weighted imaging (DWI) when acquired.

CONCLUSION

The most common clinical feature in spinal cord ischemia is a centromedullar syndrome, and in contrast to anterior spinal artery ischemia, infarcts in the posterior spinal artery territory are rare. The exclusively cervical location of the spinal sulcal artery syndrome seems to be a likely consequence of anterior spinal artery duplication which is observed preferentially here.

Clinical application and diagnostic value of noninvasive spinal angiography in spinal vascular malformations

OBJECTIVE

The purpose of this study was to explore the value of computed tomographic (CT) spinal angiography with 256-slice CT and fast dynamic contrast-enhanced 3-dimensional magnetic resonance angiography (MRA) at 3.0 T in the diagnosis of spinal vascular malformations.

METHODS

Seventeen patients who presented with suspected spinal vascular diseases by initial magnetic resonance and clinical findings all underwent CT spinal angiography. Among these, 10 patients underwent MRA, 15 patients underwent digital subtraction angiography (DSA) within 3 to 5 days, and 8 patients finally underwent surgical treatment.

RESULTS

Computed tomographic angiography examination clearly showed the abnormal vascular lesions in 16 of the 17 patients, including 7 patients with the diagnosis of spinal dural arteriovenous fistula, 7 patients with perimedullary arteriovenous fistula, and 2 patients with spinal arteriovenous malformations. The results were consistent with the diagnosis of DSA or surgery. One patient was poorly diagnosed. The fistulas could be seen in 12 patients; feeding arteries were correctly displayed in 12 patients. The fistulas and feeding arteries were accurately shown in 7 of 10 patients by MRA; DSA results were also negative in the other 3 patients.

CONCLUSIONS

Spinal angiography with 256-slice CT and contrast-enhanced MRA at 3.0 T can clearly show the extent of spinal vascular malformations, feeding arteries, and fistulas. They are safe, noninvasive, as well as rapid and can shorten the time of DSA diagnosis and treatment.

Value of prominent flow voids without cord edema in the detection of spinal arteriovenous fistulae

PURPOSE

To determine the prevalence of spinal dural arteriovenous fistulae (SDAVF) in patients presenting with prominent vascular flow voids on imaging without other imaging findings suggestive of SDAVF.

METHODS

We retrospectively identified patients from January 1, 2005 to March 1, 2012 who underwent spinal angiography for suspected SDAVF with prominent vascular flow voids on prior imaging. We excluded patients with other major spinal pathology or other imaging findings of SDAVF including cord hyperintensity, enhancement, or expansion. We calculated the proportion of patients with positive findings for SDAVF on angiography and evaluated the prevalence of SDAVF for this finding alone and in correlation with clinical findings.

RESULTS

18 patients underwent spinal angiography for prominent flow voids on imaging without other spinal pathology or imaging findings of SDAVF. Three had a SDAVF detected on angiography. The prevalence of SDAVF in this population was low, only 17% (95% CI 6-39%). All of the patients with positive angiography findings had myelopathy, increasing the prevalence to 100% if the additional clinical finding of myelopathy was present.

CONCLUSIONS

Prominent flow voids without other imaging findings suggestive of SDAVF is poorly predictive of the presence of a SDAVF, unless myelopathy is present clinically.

MRI and MRA of spinal cord arteriovenous shunts

The purpose of this review is to describe the diagnostic criteria for spinal cord arteriovenous shunts (SCAVSs) when using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), and to discuss the extent to which the different MRI and MRA sequences and technical parameters provide the information that is required to diagnose these lesions properly. SCAVSs are divided into four groups according to location (paraspinal, epidural, dural, or intradural) and type (fistula or nidus); each type of lesion is described. SCAVSs are responsible for neurological symptoms due to spinal cord or nerve root involvement. MRI is usually the first examination performed when a spinal cord lesion is suspected. Recognition of the image characteristics of vascular lesions is mandatory if useful sequences are to be performed-especially MRA sequences. Because the treatment of SCAVSs relies mainly on endovascular therapies, MRI and MRA help with the planning of the angiographic procedure. We explain the choice of MRA sequences and parameters, the advantages and pitfalls to be aware of in order to obtain the best visualization, and the analysis of each lesion.

Comparison of surgical and endovascular approach in management of spinal dural arteriovenous fistulas: A single center experience of 27 patients

Background:

Spinal dural arteriovenous fistula (SDAVF) is a rare spinal vascular malformation with an annual incidence of 5-10 cases per million. The data on efficacy, recurrence rates and complications of endovascular versus surgical treatment of SDAVF is limited.

Methods:

We conducted a retrospective chart review of 27 adult patients with a diagnosis of SDAVF and who underwent treatment at Duke University Hospital between January 1, 1993 and December 31, 2012. We compared the outcome measures by Aminoff–Logue score (ALS) in patients who underwent treatment with endovascular embolization versus surgical ligation of fistula. We compared complication rates, recurrence rates as well as data on long-term follow up in these patients.

Results:

Out of 27 patients in the study, 10 patients underwent endovascular embolization (Onyx was used in 5 patients and NBCA in 5 patients) as the first line therapy. Seventeen patients underwent surgical ligation as initial therapeutic modality. Patients in both groups showed significant improvement in clinical status (ALS) after treatment. One patient in endovascular group developed spinal infarction due to accidental embolization of medullary artery. Three patients in embolization group had recurrence of fistula during the course of follow up requiring surgical ligation. Two patients in surgical group developed local wound infection. None of the patients in surgical group had recurrence of fistula during the course of follow up.

Conclusions:

Endovascular embolization and surgical ligation are effective treatment strategies for SDAVF. Our observations show that surgical ligation may offer permanent cure without any recurrence. Endovascular approach is associated with higher incidence of recurrence, especially with use of onyx.