Abstract: Background and purpose: Thymic epithelial tumor (TET) is the most common primary tumor in the anterior superior mediastinum with considerable histologic heterogeneity. This study aimed to compare the value of preoperative multi-slice spiral computed tomography (MSCT) signs and texture analysis based on computed tomography (CT) images in predicting World Health Organization (WHO) simplified pathological classification of TET. Methods: A total of 120 patients with pathologically confirmed TET in Fudan University Shanghai Cancer Center from Jan. 2011 to Jun. 2018 were retrospectively analyzed. According to the WHO simplified pathological classification, patients were divided into low-risk group (A1, AB, B1 thymoma) and high-risk group (B2, B3 thymoma and thymic adenocarcinoma). CT signs of each TET patient were evaluated and recorded. Texture feature extraction was performed on CT images of mediastinal window. Predictive models based on CT signs, texture features and the combination of them were developed with the least absolute shrinkage and selection operator (Lasso) regression. The predictive effectiveness of the model was evaluated by receiver operating characteristic (ROC) curve and compared with the area under curve (AUC). DeLong test was used to compare the diagnostic effectiveness of different prediction models. Results: A total of 120 patients with TET were enrolled in this study. Totally 11 CT signs and 14 texture features of each patient were recorded and extracted. CT model, texture model and the combination model were established. The AUCs of the three models in predicting low-risk group and high-risk group TET were 0.78, 0.80 and 0.88, respectively. The sensitivity was 86.4%, 88.1% and 93.2%, respectively. The specificity was 60.7%, 65.6% and 67.2%, respectively. And the accuracy was 70.8%, 74.2% and 80.0%, respectively. DeLong test showed that the combination model held the highest predictive efficiency (P<0.05). Conclusion: MSCT examination is the preferred imaging examination method for TET. Texture features can better reflect the micro-heterogeneity of TET than those obtained by naked eye evaluation. The combination of CT signs and texture features has more advantages in predicting the malignant degree of TET, and provides more comprehensive and accurate basis for clinical treatment and prognosis evaluation.

Key words:  , Thymic epithelial tumor, WHO pathological classification, Multi-slice spiral computed tomography, Texture analysis