OBJECTIVE: The objective of this study was to investigate the usefulness of helical CT angiography in the evaluation of total anomalous pulmonary venous connections. MATERIALS AND METHODS: Fourteen patients with total anomalous pulmonary venous connections underwent helical CT angiography and subsequent three-dimensional (3D) reconstruction. They ranged in age from 3 days to 8 months (median age, 2.3 months) and in weight from 2.3 to 7.1 kg (median weight, 4.3 kg). The types of total anomalous pulmonary venous connections and the number of pulmonary veins were evaluated on axial and 3D images. Qualitative evaluations were performed for extent of pulmonary vascular enhancement and contrast- or motion-induced artifacts. RESULTS: In all patients, helical CT angiography correctly depicted total anomalous pulmonary venous connections. Seven cases were the supracardiac type, four cases were the cardiac type, one case was the infracardiac type, and two cases were the mixed type. The detection rate of the pulmonary vein in 3D reconstruction images (95-98%) was slightly lower than that of the pulmonary vein in the axial images (100%), but the difference between axial and 3D reconstruction images was not statistically significant (p > 0.1). No statistically significant differences were noted among 3D reconstruction images in the detection rates of the pulmonary vein (p > 0.1). The extent of contrast enhancement of the pulmonary vein was good or excellent in all patients. In five patients, there were contrast-induced artifacts that made some surrounding vascular distortion but did not interfere with the pulmonary vein analysis, except in one patient. Motion-induced artifacts were observed in nine patients. One of them had an obstacle in pulmonary vein analysis. CONCLUSION: The combination of axial and 3D images in helical CT angiography is helpful in the assessment of a total anomalous pulmonary venous connection containing the individual pulmonary vein, and this combination can be a good diagnostic tool in preoperative evaluation of neonates and infants with a total anomalous pulmonary venous connection.