Cardiac CT: present and future applications.

### Learning objectives Since its initial introduction about two decades ago, cardiac computed tomography (CCT) has rapidly evolved into one of the most versatile imaging modalities for evaluation of the cardiovascular system. Technical advances including prospective ECG gating, padding, variable pitch, weight-based lowering of tube potential (70 peak kilovoltage (kVp) in select patients) and iterative reconstruction algorithms have led to substantial improvement in image quality while reducing radiation exposure and contrast dose.1–3 Even though 64-slice systems are adequate for most CCT applications, 256-slice and 320-slice systems allow full volume acquisition in one to two cardiac cycles with superior image quality while significantly reducing radiation dose.4 ,5 Dual-source CT systems provide even higher temporal resolution virtually eliminating artefacts caused by high heart rates.6 More recently, multienergy CT has shown the potential for improved characterisation of atherosclerotic plaque and myocardial perfusion imaging.7 ,8 ### Coronary artery imaging #### Coronary artery calcification scoring Accurate quantification of the extent of coronary artery calcification can be performed using ECG-gated non-contrast CT with reasonably low radiation exposure. Coronary artery calcification scoring (CACS) is an established and extensively validated imaging biomarker for cardiovascular risk,9 allowing enhanced risk reclassification for the prediction of all-cause mortality and cardiac-specific mortality in asymptomatic subjects.10–12 The 2010 American College of Cardiology/American Heart Association guidelines recognise CACS as a Class IIa recommendation for screening of asymptomatic adults with intermediate risk (10–20%, 10 years based on Framingham Risk Score) and patients with diabetes; Class IIb recommendation for low-risk individuals (6–10%, 10 years risk) and for individuals who have a family history …