What is the Role of Diffusion Weigh Magnetic Resonance Imaging in Evaluation of Thyroid Nodules?

This study aimed to compare ultrasonography (US), contrast-enhanced computed tomography (CCT) of the neck, and diffusion-weigh magnetic resonance imaging (DW-MRI) in differentiating between benign and malignant nodules while approaching to thyroid nodules, and to estimate sensitivity and specificity of these methods. On thyroid US, echogenicity, calcification, presence/absence of halo, nodule size being larger/smaller than 20 mm, and nodule nature (cystic/solid nature) were evaluated. Findings on CCT of the neck were grouped according to the heterogeneity/homogeneity, presence/absence of enhancement, and intensity. On DW-MRI, diffusion restriction was evaluated. The findings of these tests were compared with postoperative histopathological findings, and specificity and sensitivity of the tests in differentiating malignant and benign nodules were assessed. The study included 38 patients (34 females, 4 males). The sensitivity and specificity of DW-MRI were 20 and 75 %, respectively. Presence of a >20 mm nodule in thyroid US had the highest sensitivity, whereas thyroid fine-needle aspiration biopsy (FNAB) had the highest specificity in detecting malignancy. The sensitivities and specificities of CCT of the neck and DW-MRI appeared relatively low. Evaluation of thyroid US findings together with thyroid FNAB findings provided high specificity and sensitivity and yielded better results than findings of CCT of the neck and DW-MRI.