Since starting the chest pain protocol another diagnostic imaging technology has become more widespread used, 64-slice CT angiography. This technology utilizes a fast CT scanner and involves administration of a contrast agent, but avoids the invasiveness of a heart catheterization. The accuracy of detection of CAD and its exclusion is very high as compared with angiography (6). Although minimally invasive, the CT angiogram does involve a radiation dose similar to that used with stress nuclear testing, approximately 900 to 1100 mrem (6) and the iodine contrast used may cause contrast nephropathy, especially in diabetics and those with already impaired renal function. The use of this technology provides an opportunity to find subjects with normal coronary arteries with accuracy close to as high as for invasive coronary angiography. To date, this population has been hard to study, since subjects with a normal stress test rarely will undergo more invasive studies.