Identification of sanctuary sites: A digital map of the anterior cerebral artery territory associated with anterior cerebral artery occlusion.

Abstract

Background/Aim: The territory of the anterior cerebral artery (ACA) has been previously defined by cadaveric injection studies in subjects without stroke disease. However, the potential compensatory capacity of inter-territorial leptomeningeal anastomoses (LA) between the ACA, posterior cerebral artery (PCA) and middle cerebral artery (MCA) may modify this topography in stroke patients. We have created a digital atlas of the ACA territory associated with occlusion of the ACA and its branches on CT or MR angiography. Method(s): We manually segmented the perfusion deficit (defined by Tmax) on CT perfusion, and infarcts on T2-weighted images and linearly registered the images onto a standard brain template. The probability of infarction at each voxel was calculated by averaging the segmented MR images Comparison of the perfusion topography with infarct topography at a voxel level enabled identification of sanctuary sites, with a low probability of infarction. Result(s): 25 patients (male=11), median age of 74 years (IQR, 62 to 77 years), median admission NIHSS 4 (IQR 2,8). Regions with the highest probability of infarction were located anteriorly within the anterior cingulate gyrus (0.32) and superiorly within superior frontal gyrus (0.28), likely due to poor collateral blood supply. Sanctuary sites included the paracentral lobule (0.04) and precuneus (0.04) superomedially, the precentral gyrus (0.04) and post central gyrus (0.04) superolaterally and inferomedially, the posterior cingulate gyrus (0.04) Conclusion(s): Following stroke disease, potential rescue by inter-territorial LA plays an important role in supporting salvage of penumbral tissue posterolaterally, thereby reducing the risk of infarction of important motor and somatosensory regions.