International Circulation: Cardiac CT offers a better， cost-effective approach to diagnose heart diseases especially for the patients with chest pain. Do you think it is also useful for myocardial perfusion imaging? Dr. Ruehm: I think there is information about myocardial perfusion available which has been underutilized in the past. Coronary CTA for is certainly able to provide information about myocardial perfusion in addition to the display of coronary artery morphology.