Abstract: Objective To explore the value of spiral dynamic enhanced CT in differentiating benign and malignant myxoid soft tissue tumors. Methods The clinical and CT data of 147 patients(52 males and 95 females)with myxoid soft tissue tumors diagnosed by pathology in Qilu Hospital of Shandong University from August 2016 to March 2020 were retrospectively analyzed. The patients were divided into the benign group(n=59)and malignant group(n=88). The plain and tri-phasic dynamic enhanced CT features of tumors were evaluated and recorded by two radiologists, including the maximum/minimum diameter, boundary and shape of lesions, distribution and amount of myxoid or solid part, calcification and liquefaction necrosis within the tumor, enhanced blood vessel, and CT values of myxoid and solid components during the plain and enhanced CT phases. Patients age, gender, location of lesions, and CT features were analyzed to assess the differential diagnostic value. After variables were screened with the variance inflation coefficient(VIF), a multivariable Logistic regression prediction model was established, including the model 0 based on multiple fractional polynomial(MFP)model, model 1 with all variables and model 2 based on akakike information criteria(AIC), the receiver-operating characteristic(ROC)curve was drawn to evaluate the effectiveness of the models. Results Patients age, location of lesions, maximum/minimum diameter, tumor boundary, tumor shape, tumor calcification, enhanced vessels in tri-phasic scanning and solid part on plain CT were statistically different between benign and malignant tumors(P<0.05). The Logistic regression prediction model had certain value in the differentiation of benign and malignant tumors(Model 0: OR=29.714 3, AUC=0.867 8; Model 1: OR=37.142 9, AUC=0.874 6; Model 2: OR=9.730 8, AUC=0.833 6). Conclusion The Logistic regression prediction model based on spiral CT features and clinical data of patients can be used to differentiate benign and malignant myxoid soft tissue tumors.

Key words: Spiral CT, Myxoid degeneration, Tumor, Benign or malignant, Prediction model