High Resolution Vessel Wall Imaging

The epidemiology of TOAST classification in Asian patients seems to differ due to the higher rates of large-artery atherosclerosis. The complex pathology of atherosclerosis could lead to recurrent stroke, including shear stress on the endothelium, disturbance of the flow, occlusion at the origin of the perforating artery, and other complications (plaque inflammation, plaque hemorrhage, plaque rupture) that could lead to stroke and recurrent stroke. Therefore, The exact determination of the etiology of stroke due to atherosclerosis is the most critical factor for treatment and prognostic. On the other hand, HR-MRI could be a useful imaging modality to evaluate the characteristics of plaque in stroke patients due to atherosclerosis stenosis, which will help us find out the etiology of stroke. Previous studies have demonstrated its prognosis value in predicting recurrent stroke in the same vascular territory. The investigators hypothesize that with an appropriate evaluation, HR-MRI could help to predict recurrent stroke in the same vascular territory in patients with high-risk plaque characteristics on HR-MRI. These findings could contribute to individual treatment according to etiology. The investigators intend to conduct a study to determine the correlation between plaque characteristics and recurrent stroke in the same vascular territory in ischemic stroke patients due to middle cerebral artery stenosis.

Atherosclerotic stenosis of the carotid and intracranial arteries is one of the leading causes of ischemic cerebrovascular events worldwide. Among these, intracranial atherosclerotic stenosis has an incidence rate of up to 46.6% in patients with ischemic stroke or transient ischemic attack (TIA) in China. The continuous advancement of high-resolution vascular wall imaging (HR-VWI) technology has enabled multi-dimensional imaging of the arterial walls of both intracranial and extracranial vessels. By suppressing intravascular flow, this technique allows clear visualization of the vascular wall morphology and signal characteristics, as well as the identification of plaque composition and assessment of vulnerable plaque features. However, due to the smaller size of intracranial atherosclerotic plaques, the image quality and effectiveness of current 3.0T high-resolution magnetic resonance imaging (MRI) are influenced by hardware and software limitations, as well as imaging parameters, making it difficult to accurately perform qualitative and quantitative analysis of intracranial and extracranial plaques. The advent of ultra-high field 5.0T MRI overcomes the limitations of 3.0T MRI in imaging, significantly improving the signal-to-noise ratio and allowing for clearer visualization of the signal characteristics of the arteria.