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Objective To assess quantitative and subjective image quality and radiation dose for abdominal enhanced CT with low tube voltage and low-concentration iodinated contrast agent in children. Methods Forty-eight patients were randomized to one of the two protocols: group A (n=24, mean age 46.96±44.65months, mean weight 15.71±9.11kg, BMI 16.48±2.40kg/m2) and group B (n=24, mean age 41.33±44.59months, mean weight 18.15±17.67kg, BMI 17.50±3.73kg/m2). Group A: 80kVp tube voltage, 270mgI/ml contrast agent (Visipaque, GE Healthcare), and images were reconstructed using 70% ASIR. Group B: 100kVp tube voltage, 370mgI/ml contrast agent (Iopamiro, Bracco), and images were reconstructed using 50% ASIR. The volume of contrast agent was 1.30 ml/kg in both Groups A and B. The degree of enhancement and noises in the abdominal aorta in arterial phase (AP) and portal vein in portal venous phase (PVP) were measured; while the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for abdominal aorta (AO) and portal vein (PV) were calculated. A five point scale was used to subjectively evaluate image quality and image noise by two radiologists with more than 10 years experience. DLP (mGy-cm) and CTDIvol (mGy) were calculated. Objective measurements and subjective quality scores for the two groups were compared using paired t test and Mann-Whitney U test, respectively. Results There was no significant difference in age, weight or BMI between the two groups (all p >0.5). The iodine load in Group A (5517.3±3197.2mgI) was 37% lower than that in Group B (8772.1±8474.6mgI), although there was no significant difference between them (p=0.111). And the DLP, CTDIvol for Group A were also lower than Group B, but were not statistically significant (DLP, 104mGy-cm ±45.81 vs.224.5 mGy-cm±45.83; CTDIvol, 1.44 mGy±0.50 vs.2.08 mGy±1.87, all p >0.05). The mean arterial and portal venous enhancement (255.33HU±83.42, 146.41HU±23.45) and the noises (AP 14.96HU±2.09, PVP 16.30HU±3.21), CNRs (AO 14.54±7.12, PV 5.07±1.73) and SNRs (AO 20.76±6.76, PV 12.43±3.24) for Group A were similar with those (enhancement 226.55HU±77.71, 138.69HU±33.22; noises 14.92HU±3.12, 15.36HU±3.48; CNRs 12.96±7.14, 5.16±2.28; SNRs 19.13±7.30, 12.69±4.22) in Group B were similar (all p>0.05). The mean score on quality of arterial phase (AP) and portal venous phase (PVP) images in Group B with scores of 4.31±0.53 and 4.35±0.52, while scores of 4.29±0.51 and 4.25±0.51 were obtained in Group A, there were no statistically significant difference between the two groups. Conclusion The scanning protocol using low tube voltage (80kVp) together with 70% ASIR and low-concentration iodinated contrast agent (270mgI/mL) enables 37% reduction in iodine load and 30% reduction in radiation dose while maintaining compatible image quality.