Abstract T P368: Subcortical Calcification on CT as Diagnostic Sign of Transverse-Sigmoid Dural Arteriovenous Fistula With Cortical Venous Reflux

Abstract

Background: and purpose The annual mortality rate of the patients who had dural arteriovenous fistula (dAVF) with cortical venous reflux (CVR) is high without treatment and early diagnosis is considered desirable. However, diagnostic symptoms of dAVF with CVR are varied and sometimes non specific or chronic one such as tinnitus, headache, dizziness, dementia and so on, which causes of delay in diagnosis. We sought to determine the subcortical calcifications on computed tomography (CT) scans as the diagnostic sign of dAVF with CVR. Material and methods: In 119 consecutive patients diagnosed with dAVF by the cerebral angiographic findings, we reviewed for the prevalence of subcortical calcifications on CT, shunting sites and side of shunting and the presence of cortical venous reflux (CVR) on angiograms and clinical symptoms leading to the diagnosis (diagnostic symptoms). Results: Subcortical calcifications on CT scans were seen in 10 patients (8.4% of 119 patients with dAVF). All of them had dAVF of transverse-sigmoid sinus (TS-dAVF) with CVR. Prevalence of subcortical calcifications was significantly higher in patients with TS-dAVF (P<0.001) (21%, 10 of 48 patients) than in patients with other than TS-dAVF (0 of 71 patients), and significantly higher in patients with CVR (P<0.001) (19 %, 10 of 52 patients) than in patients without CVR (0%, 0 of 67 patients). Subcortical calcifications tended to limited in the posterior part of the same hemisphere as hemisphere with shunting and appeared to be curvilinear ones predominantly involving the cortico-medullary junction at the bottom of cerebral gyri. Prevalence of subcortical calcifications was significantly higher in patients with chronic or non specific symptom (P<0.001, 26 %, 8 of 31 patients) than those with acute or ophthalmic symptom (2%, 2 of 88 patients). Conclusion: Subcortical calcification on CT is a sign of TS-dAVF with CVR, specifically in patients who present chronic or non specific symptoms. Subcortical calcifications found in TS-dAVF could be caused by venous congestion due to long-lasting CVR without being noticed or diagnosed.