Most patients presenting with acute chest pain (ACP) at the emergency unit do not have any marked electrocardiogram abnormalities or known history of heart disease. Identifying the few patients who have, or will actually develop acute coronary syndrome in this group that is considered to be at low risk, is an actual clinical challenge for emergency department physicians. In these patients, the goal of complementary non-invasive morphological or functional imaging tests is to exclude heart disease. The diagnostic values of coronary CT angiography include a sensitivity of 96% and a negative likelihood ratio of 0.09, which are highly contributory to the diagnosis, and the integration of this imaging test into a decision tree algorithm appears to be the least expensive strategy with the best cost/effective ratio. Coronary CT angiography is indicated in the presence of ACP associated with an inconclusive electrocardiogram, in the absence of any other obvious diagnoses, when the ultrasensitive troponin assay is negative or the dynamic changes are modest, slow and/or inconclusive. Ideally, coronary CT angiography should be performed within 3 to 48hours after the initial consultation.