To assess the value of conventional ultrasound combined with contrast-enhanced ultrasound in the differential diagnosis of benign and malignant partially cystic thyroid nodules (PCTNs).

The clinical data and ultrasound images of 135 patients with 159 PCTNs who were treated at the First Medical Center of PLA General Hospital from January 2016 to December 2018 were analyzed retrospectively. There were 109 benign nodules, including 94 nodular goiters and 15 adenomas, and 50 malignant nodules, including 47 papillary carcinomas, 2 medullary carcinoma, and 1 undifferentiated carcinoma. A binary logistic regression model was established with pathological results as the response variables and ultrasonic characteristics as the independent variables, and the ability of the model for predicting benign and malignant nodules was evaluated.

A total of four features were entered into the logistic regression model, including calcification, boundary, solid part morphology, and enhanced uniformity. The sensitivity, specificity, and accuracy of the logistic regression model were 86.0%, 94.5%, and 80.5% respectively, and the area under the ROC curve was 0.902 (95% confidence interval: 0.845-0.944).

The logistic regression model of routine ultrasound combined with contrast-enhanced ultrasound is helpful in the differential diagnosis of benign and malignant thyroid PCTNs.