OBJECTIVE To apply the retrospective ECG-gating to the 16-row MSCT scan of intrathoracic vessels. METHODS Fourty-eight patients underwent MSCT with a new 16-row scanner (Sensation 16-Siemens) for the study of the great intrathoracic vessels. In group 1 (33 patients) a retrospectively ECG-gated protocol was applied; in the control-group 2 (15 patients) a conventional MSCT protocol for thoracic imaging was applied. Images were scored regarding 1) the presence or absence of artefacts determined by breath-hold, beam hardening and mis-triggering; 2) the visualisation (optimal, mild and poor) of great intrathoracic vessels (aorta, pulmonary arteries and veins); 3) the visualisation (presence or absence) of proximal, mid and distal coronary arteries (left main, left anterior descending, circumflex, and right coronary artery). RESULTS Ascending aorta showed motion artefacts in 3 (20%) cases in group 2 and none in group 1. In group 1, proximal LAD, CX, and RCA were assessable in 94%, 91%, and 91%, respectively. Left main coronary artery was assessable in 32 (97%) and 10 (67%) cases for group 1 and 2, respectively. In group 2, proximal segments of left anterior descending (LAD), circumflex (CX), and right coronary artery (RCA), were almost not assessable. CONCLUSIONS The retrospectively ECG-gated 16-row MSCT provides more information regarding ascending aorta and coronary arteries.