HASHIMOTO THYROIDITIS - CORRELATION OF MR-IMAGING SIGNAL INTENSITY WITH HISTOPATHOLOGIC FINDINGS AND THYROID-FUNCTION TEST-RESULTS

PURPOSE: To assess the clinical usefulness of magnetic resonance (MR) imaging of the thyroid gland in Hashimoto thyroiditis. MATERIALS AND M ETHODS: Signal intensity ratios on spin-echo T1-, proton-density-, and T2-weighted images were measured prospectively in 37 patients with Ha shimoto thyroiditis (33 women, four men; mean age, 51 years) and in 10 patients with thyroid lymphoma (six women, four men; mean age, 68 yea rs). Signal intensity ratios were correlated with histopathologic find ings and thyroid function test results with stepwise regression analys is. Diagnosis of lymphoma with signal intensity ratios was compared wi th morphologic diagnosis by using receiver operating characteristic cu rves. RESULTS: A proton-density-weighted signal intensity ratio of 1.5 4 or higher indicated hypothyroidism (R = .445, P = .008; 29% sensitiv ity [two of seven patients]). A T2-weighted signal intensity ratio of 5.08 or higher suggested advanced glandular destruction (R = .677, P < .001). Diagnosis by each observer was better than diagnosis with sign al intensity ratios. CONCLUSION: MR imaging results can reflect thyroi d function and histopathologic findings in the thyroid gland and help discriminate malignant lymphoma from Hashimoto thyroiditis.