Comparative analysis of lung-RADS 2022 and Fleischner's 2017 guidelines

Pulmonary nodules are among the most frequent findings on chest CT scans, creating challenges in balancing early detection with the avoidance of overdiagnosis. This brief communication compares the Fleischner Society 2017 and Lung-RADS 2022 guidelines for management of single solid nodules in high-risk adults. Although these guidelines are designed for distinct clinical contexts, high-risk individuals often undergo diagnostic CT scans outside screening pathways, resulting in variation in follow-up strategies and management. We conducted a focused comparative analysis of both systems, examining follow-up recommendations for solid nodules ≤5 mm, 8 mm, and ≥9 mm. Both systems mostly align for nodules ≤5 mm, while Lung-RADS recommends earlier PET/CT evaluation for nodules >8 mm and a higher threshold for biopsy than Fleischner. These differences can influence surveillance intensity, timing of diagnosis, and resource utilization when screening eligible patients undergo diagnostic CT outside structured LDCT programs. Recognizing that this ambiguity arises from clinical workflow rather than from conceptual conflict between guidelines may help radiologists apply each framework more appropriately and reduce uncertainty in high-risk patients encountered outside formal screening pathways.