OBJECTIVES: To minimize radiation exposure during a multi-slice computed tomography (MSCT) examination in children with congenital heart disease (CHD), we assessed diagnostic value and the various applications of MSCT without electrocardiography (ECG)-gated image acquisition, including making plastic replicas by stereolithography. METHODS: Between 1997 and 2008, we performed 885 MSCT examinations in children with CHD. 3D images were reconstructed with differential color-coding of the arteries and veins. The vessel diameter was measured with CT attenuation profiles. Ventricular volumetry was initially validated by phantom experiment and followed by comparison with that of cine-angiography. Simulation for surgical operation was performed to evaluate the possibility of intracardiac rerouting in patients with double outlet right ventricle (DORV). Stereolithographic biomodels of CHDs were manufactured with MSCT imaging. RESULTS: Differential color-coding was able to provide accurate anatomical structure of CHD. The vessel diameter in MSCT well correlated with that obtained by angiography (r2=0.86). Based on the phantom experiments, ventricular volume was studied in patients with heart rate >120 beat/min. The ventricular volume in MSCT well correlated with taht obtained by cine-angiography (Y=0.77X, r2=0.98 for RV; Y=0.90X, r2=0.94, for LV). Simulative operation provided appropriate indication for biventricular repair in patients with DORV. Stereolithographic biomodels made of the both solid epoxy and flexible urethane were successfully manufactured by using multi-slice CT imaging, which reproduced fine anatomical structure and allowed simulation surgery. CONCLUSIONS: Non-ECG-gated MSCT angiography is applicable for precise anatomical diagnosis, ventricular volumetric study, and simulation surgery, and making stereolithography biomodels in children with CHD.