Initial experience of 3 tesla apparent diffusion coefficient values in differentiating benign and malignant thyroid nodules

Purpose: To evaluate the role of diffusion‐weighted magnetic resonance imaging (DWMRI) in differentiating benign and malignant thyroid nodules using a 3 Tesla (T) MRI scanner. Materials and Methods: Twenty‐eight nodules in 25 patients and 14 healthy control cases were included in the study. DWMRI was acquired with 6 b values with a 3T MRI scanner. The apparent diffusion coefficient (ADC) values of the nodules were calculated from reconstructed ADC map images and were compared with the final histopathological diagnoses. Results: The mean ADC value of the benign nodules was 1548 ± 353.4 (×10 −6 mm 2 /s), and the mean ADC of the malignant nodules was 814 ± 177.12 (×10 −6 mm 2 /s). The normal thyroid tissue had a mean ADC value of 1323.43 ± 210.35 × 10 −6 mm 2 /s (958–1689 × 10 −6 mm 2 /s) in the healthy control group. The ADC values were significantly different among the three groups ( P = 0.001). An ADC value of 905 × 10 −6 mm 2 /s was determined to be the cutoff value for differentiating benign and malignant nodules, with 90% (55.5–98.3) sensitivity and 100% (81.3–100.0) specificity. Conclusion: This study suggests that the ADC values of nodules measured with a 3T MRI scanner could help in differentiating benign thyroid nodules from malignant nodules. J. Magn. Reson. Imaging 2013;37:1077–1082. © 2012 Wiley Periodicals, Inc.