Intracranial atherosclerotic disease is the most common cause of ischemic stroke that is directly attributed to the progression or rupture of intracranial high-risk plaque in Asia. Many studies mainly from Euro-American population with a focus on extracranial carotid plaque have fully demonstrated the advantages of intensive statin therapy on stabilizing or reversing plaque burden, reversing plaque composition presenting that lipid-rich necrotic core (LRNC) is gradually replaced by fibrous tissue, and even reversing pattern of arterial remodeling to reduce the occurrence of cerebrovascular events. Yet, direct evidence of the effect of intensive statin therapy on intracranial atherosclerotic plaques is lacking and the effect of statin intensity and duration on intracranial plaque burden and composition is still unclear. High resolution magnetic resonance imaging (HRMRI) is a new and non-invasive technique that enable to assess the morphologic characteristics of vascular wall and plaque composition of intracranial artery. Based on above discussion, the investigators conduct this study to further determine the effect of intensive statin in ischemic stroke with intracranial atherosclerotic plaques.