Delayed intravenous thrombolysis based on MRI mismatch in posterior circulation stroke.

The current time-based approach for patient selection for intravenous (IV) thrombolysis in an acute stroke setting neglects the individual variation of cerebral blood flow impairment. This approach restricts the eligible patient population. In the last decade, advanced imaging and especially MRI diffusion- and perfusion-weighted imaging (DWI-PWI) techniques have been used to select patients for IV thrombolysis outside the current 4.5 h time window. Most of these studies focus on the anterior (carotid artery) cerebral circulation only. We report the case of an acute ischemic stroke due to a dissection of the right vertebral artery and occlusion of the posterior inferior cerebellar artery with good clinical outcome. The patient received IV thrombolysis far beyond the current established time window. This decision was based upon a marked MRI DWI-PWI mismatch zone in the posterior circulation territory.