Multidetector-row computed tomography to detect coronary artery disease: the importance of heart rate

Atherosclerosis resulting in coronary heart disease is a potentially preventable cause of death. Early non-invasive detection of unstable plaques in the coronary arteries may identify patients at risk for myocardial infarction, who can be aggressively treated to prevent cardiac events. The recent development of high-resolution 64-row CT scanners allows non-invasive high-quality visualization of ≥90% of the segments of coronary arteries within a few seconds. In addition, calcified, fibrous, and lipid-laden plaques can be differentiated. Strategies to optimize multidetector-row computed tomography (MDCT) imaging include careful choice of the reconstruction time point in the cardiac cycle, optimum contrast enhancement, and control of heart rate. When heart rate is >65 b.p.m., motion artifacts may compromise image quality. Thus, use of beta-blockers is recommended to control heart rate. Heart rate may also be slower and more consistent when a non-ionic, dimeric, iso-osmolar contrast medium (CM) rather than a hyper-osmolar ionic CM is used for image enhancement. When properly performed, advantages of MDCT for assessing coronary arteries include speed, information on the composition of atherosclerotic plaques, and no need for arterial access or hospitalization. Moreover, unlike angiography, MDCT can assess multiple potential causes of chest pain (heart attack, pulmonary embolism, aortic dissection) simultaneously.