Correlation of the lesion pattern of internal border zone infarction with atherosclerosis and outcome a retrospective case series study

Objective To investigate the correlation of the lesion pattern of internal border zone infarction （IBZI） with atherosclerosis and outcome. Methods Eighty-one patients with IBZI were retrospectively divided into a simple IBZI group and a mixed IBZI group （combined with other infarct patterns） according to diffusion-weighted imaging （DWI）. The clinical characteristics were compared between the 2 groups. And then, the mixed IBZI group was further divided into 3 subgroups： IBZI ＋ pial infarct （PI）, IBZI ＋ perforating artery infarct （PAI）, and IBZI ＋ PI ＋ PAl. They were compared with the simple IBZI group respectively.Results There were no significant differences in the clinical characteristics, such as age, hyperten- sion, and the numbers of patients with stent implantation between the simple IBZI group and the mixed IBZI group. The proportions of severe stenosis and occlusion of internal carotid artery （ICA） and/or middle cerebral artery （MCA） （P =0. 009） and MCA lesions （P =0. 032） in the mixed IBZI group were significantly higher. Among the patients with MCA lesions, the severe stenosis in the simple IBZI group was significantly more than that in the mixed IBZI group （P =0. 042）, while the occlusive lesions in the mixed IBZl group were significantly more than those in the simple IBZI group （P = 0. 022）. The short-term （within 7 days） exacerbation （P = 0. 039） and poor outcome at 90 days （modified Rankin Scale 〉 3） in the mixed IBZI group （P=0.030） were significantly higher than those in the simple IBZI group. The subgroup analysis showed that the proportions of the short-term exacerbation （P = 0. 001 ） and poor outcome in patients at 90 days （P = 0. 010） in the IBZI ＋ PI ＋PAI subgroup were significantly higher than those in the simple IBZI group. Conclusions The IBZI patients combined with other infarct patterns often exist severe cerebrovascular stenosis and occlusion, and their clinical outcome was poorer. For patients with MCA lesions, the mixed IBZI occurred more in patients with MCA occlusion, and the simple IBZI occurred more in patients with severe MCA stenosis. Key words: Brain infarction;  Carotid artery diseases;  Carotid artery, internal;  Middle cerebral artery;  clinical features;  Magnetic resonance imaging;  Diffusion magnetic resonance imaging Magnetic resonance angiography;  Angiography, digital subtraction