Effectiveness of diffusion-weighted magnetic resonance imaging (DW-MRI) in the differentiation of thyroid nodules.

Background: The aim was to investigate which of two different b values (b 500 s/mm² and b 800 s/mm²) are more effective in the differentiation of benign-malignant nodules using Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI).

Materials and methods: Patients presenting with a preoperative diagnosis of nodular goiter or multinodular goiter were included in this study. These patients underwent neck MRI examinations, and their cases were analyzed retrospectively. A total of 26 patients were included in the study. A total of 46 nodules meeting the study criteria were examined. Measurements were performed on Apparent Diffusion Coefficient (ADC) maps of patients at two different b values (b 500 s/mm² and b 800 s/mm²), and the results were compared with histopathological findings.

Results: Out of a total of 46 nodules, 37 were identified as benign, and 9 as malignant based on histopathological analysis. The mean ADC value at b 500 was lower in malignant nodules (1259.65 ± 328.13) compared to benign nodules (19037.48 ± 472.74). Similarly, the mean ADC value at b 800 was lower in malignant nodules (1081.72 ± 200.23) compared to benign nodules (1610.44 ± 418.06). When a cut-off value of 1.1 × 10^- 3 was accepted for the differentiation of pathology, the sensitivity for distinguishing pathology with ADC values at b 500 was 83.3%, with a specificity of 90.0%, and for ADC values at b 800, the sensitivity was 71.4%, with a specificity of 89.7%.

Conclusion: DW-MRI without the need for contrast agent administration is a useful method in the differentiation of benign-malignant thyroid nodules.