We investigated the causes and mechanisms driving acute border zone infarctions using diffusion-weighted imaging (DWI).

We analyzed DWI in 104 patients (male: 72 years, female: 32 years, age range: 44 to 84 years) with acute border zone infarction. The DWI patterns were classified as follows: pattern A- An acute border zone infarction combined with multiple small disseminated cortical infarctions, pattern B- An acute border zone infarction only.

The most common cause of acute border zone infarctions was extracranial internal carotid artery (ICA) stenosis (45 cases, 43%). Other causes included middle cerebral artery stenosis (22 cases, 21%), intracranial ICA stenosis (14 cases, 13%), unknown, (12 cases 12%), iatrogenic (6 cases, 6%) and cardiogenic (5 cases, 5%), respectively. The most common pattern for DWI was pattern A (83 cases, 80%). We performed a transcranial Doppler in 7 of 75 cases (11%), and found at least 1 embolic pulse.

The most common pattern of DWI for acute border zone infarctions was pattern A. We propose that the mechanisms driving acute border zone infarctions are emboli coupled with hypoperfusion.