Coronary CT angiography (CCTA)

Coronary CT angiography (CCTA) uses multi-detector computed tomography with intravenous iodinated contrast to produce three-dimensional images of the coronary arteries, enabling assessment of both luminal stenosis and plaque composition — including non-calcified, low-attenuation (lipid-rich) plaques that are not visible on unenhanced calcium scoring. In the SCOT-HEART randomised trial (n=4,146), CCTA-guided management reduced fatal and non-fatal myocardial infarction by 41% over five years compared with standard care, partly through reclassification of risk and initiation of preventive therapy. Modern CCTA delivers effective radiation doses of approximately 1–5 mSv with iterative reconstruction, substantially lower than earlier protocols; CT-derived fractional flow reserve (CT-FFR) extends the examination to haemodynamic significance assessment without invasive catheterisation. CCTA differs from coronary artery calcium (CAC) scoring: CAC quantifies calcified plaque burden only, while CCTA reveals the full atherosclerotic plaque landscape including non-calcified disease.