Patients

The Institutional Review Board of Shanghai Ninth People’s Hospital approved this retrospective study, and the requirement for informed consent was waived. The following criteria were adopted for patient selection: 1) primary thyroid tumor; 2) patients underwent both conventional DWI and ultrasound scan before treatment; 3) masses with short axis ≥ 10 mm; 4) magnetic resonance (MR) images could be acquired and interpreted. Through a comprehensive search of our institutional medical report database from July 2017 to January 2019, we identified 100 patients (mean age, 49 years; range, 23–79 years) with 137 nodules (mean short axis, 18 mm; range, 5–76 mm). The final diagnoses based on histopathological results in 137 nodules, and the diagnostic results of DWI and ultrasound were compared.