Quantifying performance enhancements in photon-counting pediatric head CT: a direct comparison with energy-integrating CT

Background: Given the unique detector design, photon-counting detector CT (PCD-CT) systems may reduce dose and improve image quality in pediatric head CT. Objective: This retrospective study compared image noise characteristics, spatial resolution, and radiation dose between PCD-CT and energy-integrating detector CT (EID-CT) in pediatric non-contrast head CT exams. Clinical data was compared with results from phantom studies. Materials and methods: Radiation dose, image noise, and signal-to-noise ratio (SNR) differences were compared in matched clinical EID-CT vs. PCD-CT pairs from 162 full-dose and 33 low-dose pediatric head CT exams. Image noise, spatial resolution, and contrast-to-noise characteristics were also compared between EID-CT and PCD-CT using preclinical phantoms at different slice thicknesses. The ability of phantom scans to predict clinically observed performance changes between EID-CT and PCD-CT was also analyzed. Results: In full-dose pediatric head CT studies, PCD-CT demonstrated 24% lower noise and 18% higher SNR at equal slice thickness (both P < 0.001), as well as 2.3% lower CTDI_vol (P = 0.03). In low-dose cases, PCD-CT showed 20% lower noise, 13% higher SNR, and 12.5% lower CTDI_vol (all P < 0.001). Phantom studies closely agreed with clinical data and showed PCD-CT had ~ 19% lower image noise than EID-CT at the same dose and slice thickness using clinical scan and reconstruction parameters. Conclusion: Relative to EID-CT, PCD-CT offers similar noise texture with reduced noise magnitude at comparable or reduced radiation doses and thinner slices in pediatric head CT. When combined with improved spatial resolution, all these results point to the ability of PCD-CT to enhance imaging performance in pediatric head CT.