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

Abstract

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. 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 (CTDI_vol) from DECT was recorded and compared with the estimated CTDI_vol 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. For all 79 studies, actual median CTDI_vol 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 CTDI_vol 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). 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.