Development and validation of a multimodal radiomics-serum biomarker model for diagnosing solid pulmonary nodules via machine learning.

Background: Globally, lung cancer is the most frequently diagnosed malignancy, for which solid pulmonary nodules (SPNs) are a common radiographic finding. Given the high false-positive rates of computed tomography (CT) screening, we aimed to develop a multimodal diagnostic model combining CT radiomics features and serum biomarkers via machine learning. Methods: This retrospective study included patients receiving both preoperative CT screening and serum biomarker testing. All pulmonary nodules (PNs) were divided into training and validation sets randomly at a ratio of 7:3. We developed a multimodal diagnosis model based on the CT radiomics and protein biomarkers of SPNs in the training cohort. The CT radiomics features were derived from the integration of traditional radiomics analysis methods and three-dimensional (3D) deep learning techniques. The accuracy of this multimodal diagnosis model for the prediction of SPNs was verified in the validation set. Model performances were evaluated in terms of the area under the curve (AUC), accuracy, positive predictive value (PPV), negative predictive value (NPV), decision curve analysis (DCA), and calibration curve. Results: Between February 2016 and December 2020, imaging data of 638 eligible PNs from CT scans of 633 different patients were collected. The multimodal model had satisfactory accuracy in differentiating benign and malignant SPNs in the training set [AUC =0.944; 95% confidence interval (CI): 0.924-0.964]. In the validation set, the multimodal model yielded an AUC of 0.926 (95% CI: 0.889-0.964), an accuracy of 0.885, an NPV of 0.812, and a PPV of 0.927. The multimodal model also significantly outperformed the single-modality diagnostic models, including the traditional radiomics CT model (AUC =0.843; 95% CI: 0.780-0.906), the serum biomarker model (AUC =0.783; 95% CI: 0.718-0.847), and the 3D deep learning model (AUC =0.820; 95% CI: 0.754-0.885) (all P values <0.01). Conclusions: This study developed a novel multimodal that demonstrated superior performance in classifying SPNs. It may thus enhance the diagnosis of benign and malignant lesions and provide support for clinical decision-making.