Effects of Dual-Energy Technique on Radiation Exposure and Image Quality in Pediatric Body CT.

OBJECTIVE: The purpose of this study was to assess the effects of dual-energy CT (DECT) on radiation exposure and image quality in pediatric body CT. MATERIALS AND METHODS: This retrospective study included 79 children (median age, 10.1 years; range, 12 days-18 years) who underwent thoracic or abdominal-pelvic CT or CT angiography with dual-energy technique between October 2014 and March 2015. The delivered volume CT dose index (CTDIvol) from DECT was recorded and compared with the estimated CTDIvol had the patient undergone scanning with a standard single-energy CT (SECT) protocol. Size-specific dose estimates were calculated for both DECT and SECT. Image quality was subjectively scored (scale, 1-4). For 16 of 79 patients who underwent both DECT and SECT, image contrast and noise were measured and contrast-to-noise ratio calculated. Parametric and nonparametric testing of independent and paired samples was performed. RESULTS: For all 79 studies, actual median CTDIvol and size-specific dose estimate were 3.7 and 5.9 mGy for DECT versus prescanning estimates of 4.4 and 7.7 mGy for SECT, resulting in 12.5% and 11.2% radiation exposure reduction (p < 0.01). Diagnostic image quality was achieved in all patients. In the 16-patient subset, the median CTDIvol values of DECT and SECT were 3.1 and 3.4 mGy (p < 0.05). Median noise was greater with DECT than with SECT (p < 0.01), but the mean contrast-to-noise ratios for the liver and portal vein were similar (liver, p = 0.32; portal vein, p = 0.21). CONCLUSION: In pediatric body CT, the use of DECT results in radiation exposures comparable to or less than those of SECT while maintaining contrast and contrast-to-noise ratio.