OBJECTIVETo compare the diagnostic performance of prospective electrocardiogram (ECG)-triggered computed tomography coronary angiography (CTCA) versus retrospective ECG-gated CTCA.

METHODSPatients with suspected coronary artery disease divided into two groups which underwent 64-slice CTCA with prospective ECG-triggered or retrospective ECG-gated scanning (n = 100 each, HR < or = 65 bpm). Multi-planar reconstruction (MPR), curved-planar reconstruction (CPR), maximum intensity projection (MIP) and volume rendering (VR) were made to demonstrate the coronary arteries. The image quality was defined as excellent, good and poor by motion and stair-step artifacts. Individual radiation exposure dose was estimated from the dose-length product.

RESULTSThe mean effective radiation dose of prospective ECG-triggered CTCA [(2.81 +/- 0.48) mSv] was significantly lower than that of retrospective ECG-gated CTCA [(10.16 +/- 1.09) mSv, P < 0.01]. Segments of diagnostic image quality (95.2%, 1165/1224) and non-diagnostic coronary segments (4.8%, 59/1224) in prospective ECG-triggered group were similar as those of retrospective ECG-gated group (94.1%, 1186/1261 and 5.9%, 75/1261, all P > 0.05).

CONCLUSIONThough the radiation exposure dose required is significantly lower, the diagnostic performance of prospective ECG-triggered 64 slice CTCA is comparable with that of retrospective ECG-gated 64 slice CTCA on patients with stable heart rates up to 65 bpm.