Increased image noise and radiation dose in pediatric high pitch cardiac CTA using photon counting detector CT compared to energy integrating detector CT.

Background Previous studies have shown improved image quality in pediatric cardiac imaging using photon-counting detector CT (PCDCT). However, these studies did not evaluate image quality and radiation dose when utilizing the full spectral capabilities of PCDCT scanners. Objective To compare image quality and radiation dose between high pitch cardiac CT using full spectral PCDCT and dual source energy-integrating detector CT (EIDCT). Methods This retrospective, IRB-approved study analyzed high pitch cardiac CTs from January 2021 to October 2023 in pediatric patients (< 18 years). Patients were scanned using either PCDCT with full spectral technique (“QuantumPlus”) or EIDCT. Radiation doses were measured by CT dose index (CTDI) and dose-length product (DLP). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also calculated, and image quality was assessed using a 5-point Likert scale. Statistical analysis included unpaired T-test, Shapiro-Wilk test, Mann-Whitney test, and kappa coefficients for interrater agreement. Results 200 patients were evaluated, with 100 scanned on PCDCT and 100 on EIDCT. Most patients (148/200) were ≤ 12 months of age. CNR was similar between groups for both age groups. In patients ≤ 12 months, SNR was only significantly higher at the teres muscles for EIDCT (p < 0.0001). Radiation doses were significantly higher for PCDCT across both age groups (p < 0.0001). Conclusion High pitch cardiac CT with PCDCT using spectral processing resulted in higher radiation doses and lower SNR in infants compared to EIDCT.