Can we rule out a spinal arteriovenous fistula using only MRI?: Yes, we can

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.

Spinal Dural Arteriovenous Fistula: A Review

Spinal dural arteriovenous fistula (SDAVF) is a rare disease, the etiology of which is not entirely clear. It is the most common vascular malformation of the spinal cord, comprising 60-80 % of the cases. The clinical presentation and imaging findings may be nonspecific and misleading, often mistaking it for other entities like demyelinating or degenerative diseases of the spine.This chapter describes the imaging findings, clinical signs, and symptoms of this disease and also the available treatment options according to the current literature.Angiography is still considered the gold standard for diagnosis; however, MRI/MRA is increasingly used as a screening tool. Modern endovascular techniques are becoming increasingly more effective in treating SDAVF offering a less invasive treatment option; however, they still lag behind surgical success rates which approach 100 %. The outcome of both treatment options is similar if complete obliteration of the fistula is obtained and depends mainly on the severity of neurological dysfunction before treatment.Heightened awareness by radiologists and clinicians to this rare entity is essential to make a timely diagnosis of this treatable disease. A multidisciplinary treatment approach is required in order to make appropriate treatment decisions.

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.

Vascular diseases of the spinal cord

Vascular disease affecting the spinal can cause substantial neurologic morbidity. Several vascular spinal cord ailments present as neurologic emergencies, and should thus be recognizable to the practicing neurologist. We review the epidemiology, presentation, management strategies, and prognosis of various pathologies, including infarction, dural arteriovenous fistula, arteriovenous malformation, cavernous malformation, compressive epidural hematoma, vasculitis, and genetic abnormalities.