How useful is computed tomography for screening for coronary artery disease? Noninvasive screening for coronary artery disease with computed tomography is useful.

The introduction of new ideas and concepts that lead to change in practice has always caused some degree of controversy, especially in medicine. At first glance, the concept of noninvasive imaging for calcium as a screen to identify patients at high risk for future coronary events would seem the most intense; however, one must only reflect on past controversies to gain an appropriate perspective. The controversy over radical mastectomy versus segmental resection or lumpectomy with radiation therapy has raged for the past 50 years, and only recently have data from the 20-year follow-up of a randomized trial comparing these forms of treatment been put forward.1,2 The process of establishing the chest roentgenogram as a standard diagnostic method in the diagnosis of respiratory disease spanned 30 years and was opposed by many of the leading physicians of the day, including Osler,3 who believed a good clinical examination was superior. In 1915, Crane4 stated that the chest roentgenogram that “claims a delicacy, rapidity and precision outranking the stethoscope and the percussion finger must expect to run a gauntlet of merciless criticism.” The chest roentgenogram largely came into general use in the 1930s, when it was recognized that 15% of the deaths in the United States were due to tuberculosis, and a massive screening process was instituted after World War II.5 Establishment of the chest roentgenogram as a diagnostic tool was based largely on the belief in technology and innovation; to date, however, no prospective randomized studies have been conducted to determine whether the chest roentgenogram has indeed affected the outcome of patients with cardiopulmonary diseases. Thankfully, the coronary artery calcium (CAC) examination has been placed under intense scrutiny, and although the construct and ethics of a prospective randomized study have yet to be decided, it is appropriate to review and discuss how it may help in treating patients with subclinical atherosclerosis and to determine its absolute predictive value and its relationship to the Framingham Risks score and National Cholesterol Education Panel Adult Treatment Panel III (NCEP ATP III) guidelines because it is the only noninvasive test available to evaluate insults to the arterial wall from all risk factors causing atherosclerosis. The concept of imaging coronary arteries for calcification in vivo arose shortly after the discovery of x-rays by scientists who demonstrated calcification within the coronary arteries but were limited by current technology.6–8 After publications by Habbe and Wright9 and Van der Straeten,10 Blankenhorn and Stern, in a landmark article, scientifically established the fact that calcification in the coronary arteries is directly related to atherosclerosis.9–13 Recent studies have confirmed