Risk classification of thymoma based on multi-feature fusion in dynamic enhanced CT

Accurate classification of high-risk and low-risk thymomas is critical for guiding treatment strategies and assessing prognosis. Thymoma is the most common primary tumor of the anterior mediastinum. However, previous studies have limitations in comprehensively utilizing imaging data, particularly in combining radiomics and deep learning (DL) features for preoperative classification.

This study aimed to develop and validate a comprehensive model based on computed tomography (CT) imaging data (CSRT, Clinical Semantic, Radiomics, and Vision Transformer) to enhance the accuracy of preoperative high-risk and low-risk classification of thymomas and evaluate its application in non-invasive diagnosis.

This retrospective study included 360 patients with pathologically confirmed thymomas from three centers, with 274 cases (Centers A and B) used for model training and 86 cases (Center C) serving as an external validation set. CT images, including non-contrast enhanced CT (NECT) and contrast-enhanced CT (CECT), were used to extract radiomics features and ViT-based DL features, along with calculated Delta features (NECT minus CECT). Clinical semantic features were integrated, and key features were selected using t-tests and least absolute shrinkage and selection operator (LASSO) regression to construct the fusion model.

The CSRT model demonstrated excellent performance in the independent validation cohort, achieving an area under the receiver operating characteristic curve (AUC) of 0.835, an accuracy of 77.9%, a sensitivity of 78.4%, and a specificity of 77.1%. Calibration curves indicated high consistency between predictions and actual classifications. Through decision curve analysis, the model exhibited a high net benefit when the threshold probability exceeded 30%, confirming its clinical utility.

The CSRT model effectively differentiates between high-risk and low-risk thymomas preoperatively using CT imaging data. This non-invasive diagnostic tool supports individualized treatment strategies and enhances clinical decision-making, offering significant value for thymoma management by providing reliable classification above clinically relevant risk thresholds.