Effects of lipid lowering by atorvastatin on carotid atherosclerotic plaque (ACAP) study: a randomized trial for analysis of qualitative change in carotid atherosclerrotic plaque with IB echo and Black Blood MRI

INTERVENTION: Atorvastatin Diet CONDITION: Carotid artery stenosis PRIMARY OUTCOME: The property change in carotid artery plaque after three and six months using IB echo and Black Blood MRI. SECONDARY OUTCOME: 1) The change of the serum lipid metabolism in six months: Serum total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides; 2) The change of the inflammatory marker in six months: serum high sensitivity CRP; 3) Ischemic attack in the territory of the internal carotid artery on the ipsilateral side INCLUSION CRITERIA: 1) Patients with mild hypercholesterolemia; TC<240mg/dL 2) Patients with carotid stenosis of 30 to 60% 3) Patients naive to lipid‐lowering medications at the study enrollement