Magnetic Resonance Imaging Findings of Spinal Arteriovenous Fistulas: Focusing on Localization of Fistulas and Differentiation between Spinal Dural and Perimedullary Arteriovenous Fistulas

Abstract

Purpose: To investigate the MRI findings of spinal arteriovenous fistulas (AVFs) to predict their locations and types. Materials and Methods: Patients who underwent spinal angiography for suspected spinal AVF between April 2003 and April 2013 were enrolled. Spine MRIs were analyzed by two radiologists in consensus focusing on the distribution patterns of flow void pial vessels (FVPVs): longitudinal distribution pattern along the spinal level (even or uneven, with description of the most crowded level in uneven cases) and axial distribution pattern in relation to the cord (ventral, dorsal or co-dominance). Spinal angiography served as the reference standard for the locations and types of fistulas. Results: Thirty two patients (M:F=24:8, mean age, 53 years

range, 2–74 years) were included. There were 18 patients with spinal dural AVFs (SDAVFs), seven with perimedullary AVFs, four with epidural AVFs, and three diagnosed as normal. In 12 of 15 longitudinally uneven AVFs, the most crowded levels of FVPVs ± ≤two-level corresponded to the true fistulous level. While dorsal dominance was predominant in SDAVFs (13/18), ventral dominance was major in perimedullary AVFs (5/7) (P < 0.01). Conclusion: Fistulous levels may be predicted to be within the most crowded level of FVPVs ± two-level. The dorsal dominance pattern of FVPVs favors SDAVFs while the ventral dominance pattern suggests perimedullary type.