Diffusion-Weighted MR Imaging Findings of Cortical Vein Thrombosis at 3 T

Diagnosis of cortical vein thrombosis (CVT) on the basis of clot hyperintensity on diffusion-weighted imaging (DWI) has been reported as limited. Our aim was to evaluate different DWI findings of CVT either in isolated form or in combination with sinus thrombosis.

In this review-board-approved study, patients with the diagnosis of CVT on magnetic resonance venography (MRV) between 2004 and 2011 were evaluated, and 13 patients with 26 CVT (3 isolated and 23 combined CVT) sites were recruited. The evaluated DWI findings were as follows: (1) the hyperintense clot signal (CS) itself, and (2) clot susceptibility signal (CSS) that appears next to the CVT. Two blinded radiologists evaluated the data. Kappa (κ) statistics was applied for interobserver agreement.

Both readers reported CS within the vascular clot itself in 6 of 26 (23%) CVT sites on DWI. CSS was reported in 16 of 26 (61.5%) CVT sites by reader 1, and in 14 of 26 (54%) of the CVT sites by reader 2. At four CVT sites with thrombosed veins on MRV, both readers reported no DWI findings. When both CS and CSS were evaluated together, reader 1 reported a positive DWI finding in 22 of 26 (84%) of the CVT sites, and reader 2 reported in 20 of 26 (79%) of the sites. κ Statistics showed a very good agreement (κ: 0.87).

Besides the hyperintense CS, with additional evaluation of the presence of CSS, DWI can provide an additional clue in CVT patients and may suggest its diagnosis, which is important in clinically unsuspected patients.