Abstract: Objective · To investigate the value of 3.0-T MR diffusion-weighted imaging (DWI) combined with dynamic contrast-enhanced MR imaging (DCE-MRI) in the differential diagnosis of benign and malignant thyroid nodules. Methods · A total of 65 patients with thyroid nodules confirmed by operation and pathology in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from January 2018 to October 2019 were retrospectively analyzed. All patients underwent 3.0-T MRI scan, including routine MRI, DWI (b value was 0, 1 000 s/mm2) and DCE-MRI examination before operation. The apparent diffusion coefficient (ADC) values and DCE-MRI parameters were measured. Stepwise Logistic regression model was used to analyze the independent predictors of benign and malignant nodules, and receiver operator characteristic curve was used to analyze the diagnostic efficacy of the combined model. Results · Compared with the malignant thyroid nodules, the ADC value of the benign thyroid nodules was higher and the time to peak was earlier (both P<0.05). Stepwise Logistic regression analysis showed that ADC value and time to peak were independent predictors of benign and malignant nodules. The area under the curve of combined model of ADC values and time to peak for differentiating benign and malignant thyroid nodules was 0.93, the sensitivity was 82.4%, and the specificity was 100%. Conclusion · ADC value and time to peak are important parameters to distinguish benign and malignant thyroid nodules, and their combined model may be helpful for clinical diagnosis and provide reference for preoperative diagnosis.

Key words: thyroid nodule, magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), dynamic contrast-enhanced imaging