Intraluminal Magnetic Resonance (MR) Findings of Dural Sinuses: Evaluation in Patients having Dural Arteriovenous Fistulas with Sinus Occlusion for Implications of Transvenous Embolization

Purpose Transcatheter angiography is the gold standard for evaluating the condition and anatomy of the dural sinuses in patients with arteriovenous fistulas (AVFs); however, the patency and intraluminal condition of the dural sinuses can also be evaluated on magnetic resonance imaging (MRI). The purpose of this study was to evaluate the usefulness of MRI for the diagnosis of sinus occlusion. Materials and Methods Thirty-one patients (19 males, 12 females; age range, 52-81 years) were diagnosed with dural arteriovenous fistulas (DAVFs) and surrounding dural sinus occlusion on transcatheter angiography. Twenty-three patients with transverse-sigmoid DAVFs showed ipsilateral transverse and/or sigmoid sinus occlusion, and eight patients with cavernous sinus DAVFs showed ipsilateral inferior petrosal sinus occlusion. The MR images were retrospectively evaluated, focusing on the signal intensity and contrast enhancement of the occluded sinuses. The accessibility of transvenous embolization through the occluded sinuses was also assessed. Results The occluded sinuses showed isointensity in 24 patients and hypointensity in six on T1-weighted imaging (T1WI); furthermore, they showed isointensity in seven patients, hyperintensity in 17, and heterogeneous hypoand hyperintensity in seven on T2-weighted imaging (T2WI). All occluded sinuses showed marked enhancement in the 14 patients in whom contrast-enhanced three-dimensional (3D)-T1WI was performed. Transvenous embolization was performed in 27 patients. An approach through the occluded sinuses was successful in 18 of these 20 patients. Conclusion The occluded sinuses showed various signal intensities on T1WI and T2WI, while all of the occluded sinuses showed homogeneous enhancement on contrast-enhanced T1WI.