Combination therapy of ezetimibe with a low-dose statin is occasionally used to avoid statin-related side effects in clinical practice among patients with atherosclerotic cardiovascular disease. This approach is equivalent to high-dose statin therapy to decrease LDL cholesterol level by >50%, allowing such patients to achieve LDL cholesterol target. However, it remains uncertain whether combination therapy with ezetimibe and low-dose statin verse high-dose statin monotherapy similarily suppress atherosclerotic plaque inflammation. This study is to compare high-dose rosuvastatin versus low-dose rosuvastatin plus ezetimibe on carotid plaque inflammation in patients with acute coronary syndrome using 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET) imaging.

Inclusion Criteria:

1. aged ≥ 19 years
2. acute coronary syndrome, carotid artery disease (diameter stenosis 20-50%), and at least one 18FDG uptake lesion in the carotid artery (target to background ratio (TBR) ≥ 1.6) by 18FDG PET/CT imaging
3. written consent

Exclusion Criteria:

1. previous history of carotid endarterectomy or stenting
2. schedule for cardiac or major surgery within the next 6 months
3. statin or ezetimibe therapy in the past 4 weeks
4. chronic disease needed to be treated with oral, intravenous, or intraarticular steroid
5. end-stage renal disease
6. chronic liver disease
7. history of cancers within the past 3 years
8. pregnant, breast-feeding or child-bearing potential
9. expected life expectancy within 2 years