Abstract W P420: Impact of Embolization Therapy on Venous Congestion in Patients with Transverse-sigmoid Sinus Dural Arteriovenous Fistulas - A Semi-quantitative Susceptibility-weighted MRI study

Abstract

Background and Purpose: Dural arteriovenous fistulas (DAVFs) often provoke intracerebral hemorrhage (ICH) and progressive neurological deficits due to chronic venous congestion. Trans-arterial and/or trans-venous embolization (TAE/TVE) is known useful to dramatically improve cerebral hemodynamics. However, the methodology to non-invasively visualize venous congestion due to dAVFs has not been established yet. In this study, therefore, the authors evaluated the usefulness of susceptibility-weighted imaging (SWI) to evaluate the degree of venous congestion due to transverse-sigmoid sinus DAVF before and after TAE/TVE. Methods: This prospective study included totally 13 patients with transverse-sigmoid sinus DAVFs who underwent TAE/TVE in our hospital. SWI images were binarized and the number of pixels with the low intensity was automatically counted on each slice. Finally, the ratio of low-intensity pixels to total pixels on each slice was defined as the low intensity ratio (LIR). Results: Of 13 patients, 3 presented with ICH and two developed venous infarction. Cerebral angiography showed diffuse RLVD (retrograde leptomeningeal venous drainage) in four patients and PPP (pseudo-phlebitic pattern) in five. Before embolization, the mean LIR was 10.2±5.6%, ranging from 4.6 to 24%, being significantly higher than the control value (2.7±1.2%, n=5). Angiographical signs of venous congestion were closely related to high LIR values. Endovascular embolization markedly improved the sign of venous congestion on cerebral angiography in all patients. The LIR significantly decreased from 10.2±5.6% to 7.0±3.8% after TAE/TVE (P<0.05). None of them recurred cerebrovascular events due to DAVFs during a mean follow-up period of 20 months. Conclusions: The findings strongly suggest that SWI can non-invasively quantify venous congestion due to DAVFs with high sensitivity and provide reliable information on the efficacy of endovascular treatments.