Invasive coronary angiography remains the only acceptable technique for imaging coronary artery stenoses in the clinic, despite such disadvantages as its cost, the inconvenience to patients and its nonnegligible, if small, risk of complications. However, using multidetector CT to scan arteries may prove to be sensitive and specific enough to diagnose coronary artery disease. In a systematic review of the literature, Dr. Paul D. Stein of St. Joseph Mercy Oakland Hospital in Pontiac and his colleagues at Wayne State University in Detroit and at Oakland University in Rochester, all in Michigan, reported that the technique becomes more sensitive and specific enough with an increasing number of imaging slices. Among the 33 published studies that met the authors’ criteria, the use of four-, 16- and 64-slice CT for patient-based detection of significant coronary artery disease proved to have sensitivity averaging between 95 and 100 percent. Specificity averaged 84 percent with four- and 16-slice CT but 100 percent with 64-slice. There were not enough qualifying studies to indicate eight-slice CT results. CT has important limitations, however, including interference from coronary calcification and from stents, and poor resolution in morbidly obese patients and in patients with irregular heart rhythms or slow rates. The reviewers said that the timing and manner in which the advantages of CT over angiography should be exploited to benefit patients — higher speed and relatively lower cost and harmlessness — must be determined. With nearly 2 million angiograms performed annually, however, the cost benefit alone is worth pursuing. The authors describe their screening and selection process and discuss patient-based evaluations of significant coronary artery disease, alternative strategies for noninvasive imaging of the coronary arteries, and evaluations of CT imaging in proximal, middle and distal segments and in named arteries. (The American Journal of Medicine, March 2006, pp. 203-216.)