Applications and limitations of cardiac computed tomography in the evaluation of coronary artery disease.

Cardiac computed tomography angiography (CCTA) has rapidly emerged in recent years as a promising noninvasive imaging modality for the evaluation of coronary artery disease. This is predominantly because of its proven ability to exclude coronary stenosis in patients without a history of coronary artery disease and with a low-intermediate pre-test likelihood. There is also increasing data on the utility of CCTA in risk stratification and assessment of prognosis. However, it is important to realize the shortcomings of the current technology before advocating its widespread use. Importantly, the utility of CCTA is limited when an abnormal study is anticipated. Because of current limitations on spatial and temporal resolution, CCTA cannot precisely assess the degree of stenosis as compared with invasive coronary angiography. This tendency of CCTA to overestimate stenosis severity along with its the poor positive predictive value can lead to increased downstream testing including additional stress testing and unnecessary invasive coronary angiography. Moreover, despite improvements in technology, the radiation burden of CCTA in real-world clinical practice remains significant. To justify greater use of CCTA in the current healthcare environment, future studies need to demonstrate improvements in patient outcomes, better accuracy compared with established tests, and/or reductions in healthcare costs.