Objective To investigate the reasons of artifacts in 64-slice spiral CT coronary angiography.Methods One hundred patients with diagnosed or suspected coronary artery disease underwent retrospectively ECG-gated 64-slice spiral CT coronary angiogruphy.Maximum intensity projection(MIP),muhiplanar reformation(MPR)and volume rendering technique(VRT)were reconstructed.The reasons of artifacts were assessed by two experienced radiologists.Results A total of 1347 segments(1347/1500,89.8%)were reviewed,the artifacts were found in 192 segments(14.2%).Breath movement was the moat common artifact(124/192).and the other reasons included fast rate and irregular rhythm of the heart beat (42/192).while the phase mismatch was the third reason(22/192).Conclusions The common artifacts of 64-slice spiral CT coronary angiography includes breath movement,fast rate and irregular rhythm of heart beat and phage mismatch.Breath-holding control,low rate and regular rhythm of heart beat,muhiphage reconstruction are suggested for the accurate diagnosis.