Computed-tomography-based radiomic nomogram for predicting the risk of indeterminate small (5–20 mm) solid pulmonary nodules

PURPOSE: This study aims to develop a diagnostic model that combines computed tomography (CT) images and radiomic features to differentiate indeterminate small (5–20 mm) solid pulmonary nodules (SSPNs). METHODS: This study retrospectively enrolled 413 patients who had had SSPNs surgically removed and histologically confirmed between 2017 and 2019. The SSPNs included solid malignant pulmonary nodules (n = 210) and benign pulmonary nodules (n = 203). The least absolute shrinkage and selection operator was used for radiomic feature selection, and random forest algorithms were used for radiomic model construction. The clinical model and nomogram were established using univariate and multivariable logistic regression analyses combined with clinical symptoms, subjective CT findings, and radiomic features. The area under the curve (AUC) of the receiver operating characteristic curve was used to evaluate the performance of the models. RESULTS: The AUC for the clinical model was 0.77 in the training cohort [n = 289; 95% confidence interval (CI): 0.71–0.82; P = 0.001] and 0.75 in the validation cohort (n = 124; 95% CI: 0.66–0.83; P = 0.016). The AUCs for the nomogram were 0.92 (95% CI: 0.89–0.95; P < 0.001) and 0.85 (95% CI: 0.78–0.91; P < 0.001), respectively. The radiomic score (Rad-score), sex, pleural indentation, and age were the independent predictors that were used to build the nomogram. CONCLUSION: The radiomic nomogram derived from clinical features, subjective CT signs, and the Rad-score can potentially identify the risk of indeterminate SSPNs and aid in the patient’s preoperative diagnosis.