DURAL SINUS THROMBOSIS - LONG-TERM FOLLOW-UP BY MAGNETIC-RESONANCE-IMAGING

Ten consecutive patients with superior sagittal (SSS. n = 7) and/or lateral (LS. n = 8, bilateral in 3) sinus thrombosis had control magnetic resonance imaging (MRI) performed 6 months after clinical onset. Abnormal signals were still noted in 4 out of 7 cases of SSS thrombosis and in 8 out of 11 cases of LS thrombosis. In only 3 patients follow-up MR] was entirely normal. Persistent abnormalities were usually more limited in length, involving only a part of the sinus. Compared with initial MRI, the signal from the affected sinus was often heterogeneous but predominantly isointense on T1-weighted images and hyperintense or isointense to brain parenchyma on T2-weighted images. A marked decrease in the size of LS was noted in 4 patients. One patient developed dural arteriovenous fistula. Six patients with persistent signal abnormalities at 6 months had control MRIs 6-12 months later. Little change was observed compared with MRI performed at 6 months. MRI results were consistent with angiographic data in the patients who had both examinations. The persistence of MR] abnormalities long after (up to 18 months) dural sinus thrombosis must be kept in mind to avoid erroneous diagnosis of acute dural sinus thrombosis.