Non-stenotic intracranial arteries have atherosclerotic changes in acute ischemic stroke patients: a 3T MRI study

Introduction: The aim of this study is to evaluate the degree of atherosclerotic changes in intracranial arteries by assessing arterial wall thickness using T1-weighted 3D-turbo spin echo (3D-TSE) and time-of-flight MR angiography (TOF-MRA) in patients with acute ischemic stroke as compared with unaffected controls. Methods: Thirty-three patients with acute ischemic stroke and 36 control patients were analyzed. Acute ischemic stroke patients were divided according to TOAST classification. At both distal internal carotid arteries and basilar artery without stenosis, TOF-MRA was used to select non-stenotic portion of assessed arteries. 3D-TSE was used to measure the area including the lumen and wall (Area_Outer) and luminal area (Area_Inner). The area of the vessel wall (Area_VW) of assessed intracranial arteries and the ratio index (RI) of each patient were determined. Results: Area_Inner, Area_Outer, Area_VW, and RI showed good inter-observer reliability and excellent intra-observer reliability. Area_Inner did not significantly differ between stroke patients and controls (P = 0.619). However, Area_Outer, Area_VW, and RI were significantly larger in stroke patients (P < 0.001). The correlation coefficient between Area_Inner and Area_Outer was higher in the controls (r = 0.918) than in large vessel disease patients (r = 0.778). RI of large vessel disease patients was significantly higher than that of normal control, small vessel disease, and cardioembolic groups. Conclusion: In patients with acute ischemic stroke, wall thickening and positive remodeling are evident in non-stenotic intracranial arteries. This change is more definite in stroke subtype that is related to atherosclerosis than that in other subtypes which are not.