CT vs SPECT: CT is the first-line test for the diagnosis and prognosis of stable coronary artery disease

Non-invasive cardiac imaging is pivotal in the diagnosis and prognosis of patients with stable CAD. Nuclear SPECT, PET, stress echocardiography and more recently cardiac magnetic resonance imaging have been utilized with excellent diagnostic accuracy. However, along with their inherent individual limitations, most modalities detect ischemia but lack the ability to define coronary anatomy or evaluate for subclinical atherosclerosis. A modality that not only accurately diagnoses obstructive CAD and also facilitates early identification of non-obstructive CAD may be of interest because it may allow for earlier aggressive risk factor modification and primary prevention. Cardiac computerized tomographic angiography (CCTA) has the potential to accurately detect or exclude luminal stenosis, as well as identify and quantify subclinical atherosclerosis in the absence if luminal narrowing. However CCTA, being a relatively a new modality, has less supporting evidence when compared to more mature modalities such as SPECT. Therefore, the question that begs to be addressed is whether CCTA can be utilized as a first line test in establishing the diagnosis and prognosis of CAD.