Use of a single-scan Lung-RADS for pulmonary nodule assessment in resource-limited clinical settings

Lung carcinoma remains the leading cause of cancer-related mortality worldwide, with a similar high burden in Asia. While Lung-RADS v2022 was developed to standardize lung cancer screening using low-dose CT (LDCT), its reliance on follow-up imaging limits feasibility in low-resource settings.

To evaluate the diagnostic performance of Lung-RADS v2022 applied to a single baseline CT scan for pulmonary nodule characterization.

Baseline CT scans from 79 participants in the National Lung Screening Trial (NLST) were reviewed by two radiologists using Lung-RADS v2022. Nodules were classified as benign (categories 1-3) or malignant (categories 4A-4X). Histopathological diagnosis or ≥2 years of CT stability was taken as the reference standard. Diagnostic performance was assessed using cross-tabulation, logistic regression, and ROC analysis.

The cohort comprised 45 men and 34 women (mean age: 62.9 years). Using single-scan Lung-RADS, sensitivity was 72% and specificity 90.7%, with overall accuracy of 84.8% and AUC of 0.79. Positive and negative predictive values were 78.3% and 87.5%, respectively. Chi-square analysis showed significant correlation between Lung-RADS categories and final diagnoses (p < 0.0001). The multivariate logistic regression model achieved sensitivity of 76.1%, specificity of 90.7%, and AUC of 0.92.

Lung-RADS retains diagnostic value when applied to baseline scans alone, though with reduced sensitivity compared to longitudinal use. Spiculated margins and size >7 mm were the most robust predictors of malignancy. These findings support the applicability of single-scan Lung-RADS in resource-limited settings lacking follow-up CT access.