Journal of neurological disorders
The mechanisms of hyperintense vessel (HV) imaging using fluid-attenuated inversion recovery (FLAIR) have not been elucidated. However, stationary blood and slow antegrade or retrograde collateral flow distal to thromboembolic occlusion of a proximal artery has been suggested as possible explanations for HVs. Also, HVs on FLAIR sequences may be related to intra-luminal thrombi or emboli, which have also been observed using computed tomography (CT) scans indicating hyperdense middle cerebral artery (MCA) extension into the MCA branches of the Sylvian fissure (dot signs), especially in the case of erythrocyte-rich clot. But even if it looks like ‘dot sign’, it also can be the leptomeningeal collaterals other than the migration of thrombus from proximal occlusion. In the present report, we found that distal hyperattenuating vessels on unenhanced brain CT scans have similar shapes to HVs on FLAIR, and present at similar locations. We describe indicators of distal vessels on unenhanced brain CT, which were observed in areas of reduced edema on follow-up brain CT.