Preliminary study of imaging infarct patterns and pathogenesis in patients with anterior circulation infarction

Objective To analyze imaging infarct patterns and features in patients with severe stenosis or occlusion of internal carotid artery （ICA） and middle cerebral artery （MCA）from the point of view of diffusion-weighted imaging （DWI） and to investigate the infarction related mechanism. Methods Eighty-eight patients with acute ischemic stroke who had moderate to severe ICA or MCA stenosis or occlusion confirmed by cerebral angiography were analyzed retrospectively. They were divided into ICA lesion and MCA lesion groups. The infarct patterns were classified as single and multiple according to DWI. The former were reclassified as perforating artery infarct （PAI）, pial infarct （PI）, watershed infarct, and large infarct. Results There were 11 types of infarct patterns in MCA territories. The DWI multi-infarct pattern accounted for 62.5% of all patients （55/88）. PI with watershed infarction appeared more often in the ICA lesion group （11/45, P=0. 040）, and PI with PAI appeared more often in the MCA lesion group （10/43, P = 0. 037）. Conclusions In patients with cerebral infarction associated with ICA or MCA severe stenosis or occlusion, most of them showed multi-infarct pattern,which suggested the mixed mechanisms such as embolization, hypoperfusion/impaired clearance of emboli, and local perforating branch occlusion were the main mechanisms of the occurrence of cerebral infarction. The main mechanism of cerebral infarction in the ICA lesion group was embolization combined with hypoperfusion/impaired clearance of emboli, while in the MCA lesion group was embolization combined with local perforating branch occlusion. Key words: Brain infarction;  Diffusion magnetic resonance imaging;  Angiography,digital subtraction