Comparison of Radiation Dose and Image Quality in Pediatric Abdominopelvic Photon-Counting Versus Energy-Integrating Detector CT

OBJECTIVE: Adoption of abdominal photon counting detector CT (PCD-CT) into clinical pediatric CT practice requires evidence that it provides diagnostic images at acceptable radiation doses. Thus, this study aimed to compare radiation dose and image quality of PCD-CT and conventional energy-integrating detector CT (EID-CT) in pediatric abdominopelvic CT. MATERIALS AND METHODS: This institutional review board-approved retrospective study included 147 children (median age 8.5 y; 80 boys, 67 girls) who underwent clinically indicated contrast-enhanced abdominopelvic PCD-CT between October 1, 2022 and April 30, 2023 and 147 children (median age 8.5 y; 74 boys, 73 girls) who underwent EID-CT between July 1, 2021 and January 1, 2022. Patients in the 2 groups were matched by age and effective diameter. Radiation dose parameters (CT dose index volume, CTDI vol ; dose length product, DLP; size-specific dose estimate, SSDE) were recorded. In a subset of 25 matched pairs, subjective image quality was assessed on a scale of 1 to 4 (1=highest quality), and liver attenuation, dose-normalized noise, and contrast-to-noise ratio (CNR) were measured. Groups were compared using parametric and/or nonparametric testing. RESULTS: Among the 147 matched pairs, there were no significant differences in sex ( P =0.576), age ( P =0.084), or diameter ( P =0.668). PCD-CT showed significantly lower median CTDI vol , DLP, and SSDE (1.6 mGy, 63.8 mGy-cm, 3.1 mGy) compared with EID-CT (3.7 mGy, 155.3 mGy-cm, 6.0 mGy) ( P< 0.001). In the subset of 25 patients, PCD-CT and EID-CT showed no significant difference in overall image quality for reader 1 (1.0 vs. 1.0, P =0.781) or reader 2 (1.0 vs. 1.0, P =0.817), or artifacts for reader 1 (1.0 vs. 1.0, P =0.688) or reader 2 (1.0 vs. 1.0, P =0.219). After normalizing for radiation dose, image noise was significantly lower with PCD-CT ( P <0.001), while CNR in the liver ( P =0.244) and portal vein ( P =0.079) were comparable to EID-CT. CONCLUSION: Abdominopelvic PCD-CT in children significantly reduces radiation dose while maintaining subjective image quality, and accounting for dose levels, has the potential to lower image noise and achieve comparable CNR to EID-CT. These data expand understanding of the capabilities of PCD-CT and support its routine use in children.