Minor Ischemic Stroke With Intracranial Atherosclerosis:a High Resolution Magnetic Resonance Imaging Study

Objective: To explore the characteristics of intracranial atherosclerosis and the possible pathogenesis of minor ischemic stroke by 3.0T high resolution magnetic resonance imaging(HR-MRI).Methods: The imaging and clinical features of intracranial atherosclerosis in patients were retrospectively analyzed.The complete clinical data of patients were collected,and the stenosis rate was judged on TOF-MRA axial images.The number of plaques,plaque enhancement,plaque hyperintensity and plaque morphology were counted on HR-T1 WI axial images.Results: A total of 69 eligible patients were screened out.43 of them had high signal intensity on diffusion weighted imaging(DWI)and the National Institutes of Health Stroke Scale(NIHSS)score less than 3 at admission was classified as minor ischemic stroke group.In addition,among 43 patients with minor stroke,22 had anterior circulation infarction,15 had posterior circulation infarction and 6 had mixed infarction.Among them,mild stroke with perforator artery disease was the most common,but there was no significant difference(P=0.154).26 patients were classified as non-stroke group without high signal intensity on DWI.There were no significant differences in age,sex,smoking,alcohol consumption,hypertension,diabetes,hyperuricemia,hyperlipidemia,hyperhomocysteinemia,stroke history and clinical risk factors of coronary heart disease between the two groups(P >0.05).A total of 170 segments of blood vessels and 294 plaques were included in the study.There were significant differences in plaque number(P=0.035),plaque enhancement(P <0.001)and plaque signal(P=0.027)between the two groups,but there was no significant difference in plaque shape and stenosis degree between the two groups(P value was 0.304 and 0.457,respectively).Conclusion: The plaque number,plaque enhancement and plaque signal of intracranial atherosclerosis are closely related to minor ischemic stroke,which may be related to arterio-arterial embolism,perforator vascular lesions and mixed lesions caused by vulnerable plaques.The degree of intracranial vascular stenosis and plaque morphology are not significantly related to the occurrence of minor ischemic stroke,which might be caused by the establishment of collateral circulation and the compensatory correlation of blood flow dynamics.