It is well understood that diabetes mellitus (DM) causes various micro- and macrovascular complications. Among them, coronary heart diseases (CHDs) claim most mortality, and diabetes has been considered as "CHD equivalent". Furthermore, the risk of CHD has been noticed to increase in the pre-diabetic stage, suggesting the development of CHD may start in a rather early stage of the disease. Thus, early detection of CHD in diabetic patients seems to be important. However, currently exam methods for CHD in diabetic patients seemed to have their limitations.