Bilateral watershed infarct
The non-contrast CT brain shown is from a patient with bilateral watershed infarct. Here, chronic ischaemic changes can be seen along the external or cortical watershed zones (Figures 1 and 2). These “borderzones” is where the terminal vasculature of the anterior cerebral artery and middle cerebral artery meet as well as where the middle cerebral artery and posterior cerebral artery meet. Watershed infarcts are commonly due to hypotension with or without underlying severe arterial stenosis or occlusion.