DefinePK

Abstract

Border zone or watershed infarcts are ischemic lesions that occur at the junction of  two non anastomosing major cerebral arterial territories, constituting approximately 10% of all brain in­farcts. Two types of border zone infarcts (BZI) are recognized: Supra tentorial and infra tentorial. Supra tentorial BZI are further of two types; external (cortical) and internal (subcortical). Their pathophysiology has not yet been fully elucidated, but a commonly accepted hypothesis holds that in­ternal BZI are caused mainly by hemodynamic com­promise, whereas external BZI are believed to result from embolism but not always with associated hypoperfusion. Various imaging modalities have been used to determine the presence and ex­tent of hemodynamic compromise or misery perfusion in association with BZI. Several advanced techniques (e-g, diffusion and perfusion magnetic resonance imaging and computed tomography, positron emission tomography) can be useful for identifying the pathophysiology, making an early clinical diagnosis and predicting the outcome.