1. Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Takun, Taichung 406, Taiwan, ROC
2. Department of Cardiology, Taichung Armed Forces General Hospital, Taichung 411, Taiwan, ROC
3. Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan, ROC
4. Department of Radiology, Ningbo First Hospital, Ningbo 315012, Zhejiang, P. R. China
5. Department of Radiological Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand