Advancing lung adenocarcinoma diagnosis using peri-nodular features: a CT radiomics study for determining invasiveness in sub-centimeter pure ground glass nodules.

Background: For sub-centimetre pure ground-glass nodules (pGGNs) in the lungs, accurately predicting their invasiveness remains a clinical challenge. This study aimed to assess the diagnostic value of peri-nodular radiomics features on enhanced computed tomography (CT) for predicting invasiveness, and develop a combined radiomics-clinical model to improve preoperative evaluation in early-stage lung adenocarcinoma (LUAD). Methods: This retrospective study analyzed patients with pathologically confirmed pGGNs from The Fourth Hospital of Hebei Medical University (training/internal validation: 309 nodules) and Xingtai People's Hospital (external validation: 38 nodules). Radiomics features were extracted from the nodule core and its surrounding 0-3 and 3-5 mm regions on CT scans. Feature selection was performed using the least absolute shrinkage and selection operator (LASSO) algorithm. Logistic regression was used to build predictive models for distinguishing non-invasive from invasive lesions. The dataset was split in a 7:3 ratio for training and internal validation. Model performance was assessed using the area under the receiver operating characteristic (ROC) curves (AUC) and decision curve analysis (DCA). A combined nomogram integrating radiomics and clinical features was also developed. Results: The combined intra-nodular and peri-nodular 0-3 mm radiomics model achieved the highest diagnostic performance in the validation set [AUC =0.847, 95% confidence interval (CI): 0.752-0.943], outperforming models based solely on intra-nodular (AUC =0.828) or peri-nodular features (AUC =0.800). The combined model further improved diagnostic accuracy (AUC =0.857), and DCA demonstrated its added clinical utility. A personalized nomogram incorporating RadScore and air bronchogram signs demonstrated potential clinical utility. Conclusions: Radiomics features from the peri-nodular 0-3 mm region significantly enhance the prediction of invasiveness in subcentimetric pGGNs. The combined radiomics-clinical model offers a promising tool for individualized decision-making in early-stage LUAD.