Riedel's Thyroiditis in Multifocal Fibrosclerosis: CT and MR Imaging Findings

A, Enhanced CT of the neck shows an enlarged and hypodense thyroid gland surrounding the trachea and compressing the esophagus. Note the small piece of normal enhancing thyroid tissue (arrow).

B and C, T1-weighted (560/25/2 [TR/TE/excitations]) unenhanced (B) and fast spin-echo T2-weighted (3800/96/3) (C) MR images of the neck showing the enlarged and diffusely hypointense thyroid gland with a small piece of thyroid tissue with normal intensity (arrow).

D, T1-weighted (560/25/2) MR image after administration of gadolinium shows an extremely diminished enhancement of most of the thyroid gland. Note the anteriorly located normal thyroid tissue with normal homogenous enhancement (arrow).