Photon-counting CT versus Energy-integrating Detector CT Performance for Various BMI and Tumor Sizes in Lung Cancer.

Background Data on the detection of enhancement-related malignant features and applicable scenarios for low-dose ultrahigh-resolution photon-counting CT (PCCT) in lung cancer are lacking. Purpose To compare the benefits of PCCT versus energy-integrating detector (EID) CT at contrast-enhanced chest CT for different populations with lung cancer. Materials and Methods This prospective study enrolled 459 consecutive participants with lesions who underwent either low-dose contrast media PCCT (1 mL/kg at 2 mL/sec) or standard-dose EID CT (1.2 mL/kg at 3 mL/sec) from June to December 2024. The EID CT group was selected using propensity score matching. Images were reconstructed into five section thicknesses (PCCT: 5 mm, 1 mm, 0.4 mm; EID CT: 5 mm, 1 mm). Adverse reactions and contrast-induced acute kidney injury were recorded. Lesion image quality, malignant radiologic features, diagnostic confidence, and subgroup (body mass index [calculated as weight in kilograms divided by height in meters squared], tumor size) were analyzed using a five-point Likert scale. Statistical data were compared using one-way analysis of variance and post hoc comparisons. Results Among 200 participants after propensity score matching (mean age, 61.66 years ± 9.60 [SD]), PCCT reduced radiation and iodine exposure by 66.34% (effective dose, 1.36 mSv vs 4.04 mSv) and 26.57% (iodine load, 20.62 mg vs 28.08 mg; P < .001), respectively, lowering adverse reactions and contrast-induced acute kidney injury (2% [two of 100 participants] vs 9% [nine of 100], P = .03; 1% [one of 100] vs 7% [seven of 100], P = .03). PCCT at 0.4 mm showed higher detection and diagnostic confidence for enhancement-related malignant features (PCCT vs EID CT, 291-340 findings vs 194-255 findings [Likert 5 {IQR, 4-5} vs Likert 3 {IQR, 3-4}]; P < .001) and yielded higher overall image quality (Likert 5 [IQR, 5-5]; P < .05) in normal weight participants and structures within enhanced lesions of less than or equal to 3 cm (Likert 4 [IQR, 3-4] vs Likert 3 [IQR, 3-3]; P < .001). Conclusion PCCT reduced radiation exposure, adverse reactions, and contrast-induced acute kidney injury compared with EID CT. With a 0.4-mm section thickness, PCCT improved overall image quality, detection of enhancement-related malignant features, and diagnostic confidence, making it suitable for various body mass index and small lesions (T1 stage). © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.