[Differences in CT findings between embolic and thrombotic cerebral artery occlusion of the internal carotid arterial system]

Abstract

Two hundred and one patients with embolic (EM) and 107 with thrombotic (TH) cerebral arterial occlusion of the internal carotid arterial system were subjected to the study. Diagnoses of EM and TH were made with our own diagnostic criteria, based on clinical and angiographic informations but not on CT findings, as previously described. Well-marginated hypodense areas in multiple vascular territories were observed only in patients with EM (13.9%). The following CT findings were more frequently seen in EM than in TH; a) a hypodense area involving the cortex, b) a sharply-marginated lesion, c) a shift of the mid-line structures and d) hemorrhagic infarction. Patients with TH were more frequently accompanied with watershed infarction, or infarct in the basal ganglia and/or deep white matter than those with EM. Watershed zone between cortical and perforating arteries was involved only by TH. Deep-seated infarct, however, was more likely to be embolic rather than thrombotic in nature, if it was sharply-marginated and accompanied with surrounding brain edema. Differences in CT findings of EM and TH appeared to reflect those of pathogenetic mechanisms such as rapidity of occlusive process, sites of occlusion, routes and availabilities of collateral circulation, presence of reopening of the previously occluded artery, etc. In the present study, it can be concluded that there is distinctive differences in CT findings between EM and TH, indicating the usefulness in differentiation of two diagnostic subtypes in the acute stage of cerebral infarction.