Perfusion MRI of acute stroke

Abstract

Perfusion-weighted magnetic resonance imaging (PWI) describes MRI techniques that visually depict hemodynamic conditions at the microvascular level. This is in contrast to other vascular MR imaging techniques, notably magnetic resonance angiography (MRA) that depict the flow of blood in larger, macroscopically visible vessels. Ischemic damage to brain tissue is caused most directly by impairments in microvascular perfusion, rather than by events occurring in large vessels. Therefore, PWI offers the ability to guide acute stroke therapy by identifying regions of brain tissue that are directly threatened by impaired perfusion, though not yet irreversibly damaged, and consequently may be rescued by timely initiation of thrombolytic or neuroprotective therapy. © 2011 Springer-Verlag Berlin Heidelberg.