Pulmonary nodule image quality and morphologic visualization with photon-counting detector CT: a scoping review

Objective To systematically map the available evidence on pulmonary nodule visualization quality using photon-counting CT (PCD-CT). Materials and methods This scoping review followed JBI methodology and PRISMA-ScR reporting standards. MEDLINE/PubMed, Embase, and Scopus were searched from January 2021 to January 2026. Studies evaluating pulmonary nodule visualization in adults or ex vivo human specimens using PCD-CT were included. Two reviewers independently screened records and extracted data; consistent with scoping review methodology, no formal risk-of-bias assessment was performed. Results Five studies (six records; 318 patients, mean age range 56–69 years) and 20 cadaveric lungs met the inclusion criteria. All studies used the same PCD-CT platform. Image quality: same-day comparisons showed superior subjective image quality with PCD-CT at 12%–18% lower radiation doses ( p < 0.001). Morphologic feature visualization: PCD-CT detected additional features in 34%–73% of subsolid nodules; ex vivo histological correlation demonstrated higher morphological concordance at 1024-matrix resolution. Nodule detection: ultra-low-dose PCD-CT maintained detection sensitivity of 0.94. Conclusion PCD-CT shows promise for improving pulmonary nodule visualization at reduced radiation doses. Evidence remains limited to single-center studies without clinical outcome validation, precluding implementation recommendations. Key Points Question Whether photon-counting detector CT improves image quality and morphologic characterization of pulmonary nodules compared with energy-integrating detector CT remains insufficiently mapped. Findings Photon-counting detector CT showed superior subjective image quality, additional morphologic features in 34%–73% of subsolid nodules, and 12%–18% lower doses versus energy-integrating detector CT. Relevance statement In single-center studies, photon-counting detector CT improved morphologic characterization of pulmonary nodules and reduced radiation exposure; clinical outcome validation is required before broad implementation.