Cardiac CT for CAD. Do we still need angiography?

Recent technological advances have led to a substantial increase in image quality in multi-detector computed tomography (MDCT). Over the last few years, there has been significant interest and controversy about the clinical application of CT angiography for the evaluation of the coronary anatomy in patients with suspected coronary artery disease (CAD). Unlike invasive coronary angiography, CT coronary angiography provides both visualization of the lumen and the coronary vessel wall. Calcified plaques can be detected without contrast administration and easily quantified. MDCT has largely replaced electron beam computerized tomography for calcium scoring. Growing evidence suggests that measurement of coronary calcium may be particularly valuable in therapy decisions for asymptomatic patients with an intermediate risk of coronary events. Recent studies have also shown an association between non-calcified coronary plaques and acute coronary syndromes in patients with stable angina. Contrast-enhanced CT coronary angiography provides a non-invasive alternative to intravascular ultrasound to evaluate coronary plaque morphology and severity. Contrast-enhanced CT has been extensively validated for the detection of coronary artery stenosis in symptomatic patients with known or suspected CAD. The number of non-evaluable cases has been reduced below 10% with the newest generation scanners. Although there is considerable enthusiasm, many doubts remain about the appropriate clinical indications of CT coronary angiography, even though most experts believe that the high negative predictive value of CT coronary angiography makes this test ideal for establishing or excluding coronary artery disease in patients with low-intermediate probability.