Ultra-Low-Dose Photon-counting Detector CT for Emphysema Assessment: A Head-to-Head Comparative Study with Low-Dose CT

< .001). There was excellent agreement between the two protocols for grading of visual CLE severity (weighted κ = 0.98) and paraseptal emphysema severity (κ = 0.96). The two protocols exhibited excellent agreement in LAV measurements across the lungs and for individual lung lobes (intraclass correlation coefficient range, 0.96-0.98). Visual CLE severity grades demonstrated good agreement with LAV measurements for both the LD (weighted κ = 0.73) and ULD (weighted κ = 0.75) protocols. Conclusion PCCT enables accurate visual and automated assessments of emphysema at a radiation dose equivalent to that of two chest radiographs without compromising image quality. © RSNA, 2026