A large proportion of patients with sudden cardiac death or nonfatal myocardial infarction (MI) had no prior symptom, which emphasizes the importance of early detection and treatment of the underlying subclinical coronary atherosclerosis before they happen. However, there are no powerful screening methods to detect subclinical coronary atherosclerosis until recently. Traditional CAD risk factors, treadmill exercise test, and EBCT are known to have limited power to detect subclinical coronary atherosclerosis and predict future cardiac events.