Incidental Detection of Thyroid Nodules at Magnetic Resonance Imaging of the Cervical Spine

The incidental detection of thyroid lesions in patients undergoing magnetic resonance (MR) imaging of the cervical spine was prospectively evaluated on 389 MR images. Sagittal images extended from the cranio-cervical junction to the upper thoracic level, and axial images from C3-4 to C7-T1 intervertebral levels. Twenty patients (5.1%) had a total of 26 thyroid nodules. Eighteen patients presented with a single dominant nodule, of whom 2 had a multinodular gland with a single dominant nodule (one had 3 and the other had 5 nodules). Two patients had diffusely enlarged gland without a dominant nodule. The mean size of the nodules was 11.6 mm. One thyroid nodule was detected at the C5-6 intervertebral level, 14 at the C6-7, and 11 at the C7-T1. T-2-weighted imaging was more useful than T-1-weighted imaging for the detection of thyroid nodules because of the hyperintense versus isointense appearance of the lesions. Thyroid carcinoma was identified at surgery in one patient. The detection rate was low compared with computed tomography with contrast medium and ultrasonography. Our results suggest that MR imaging has limited value for the detection of thyroid lesions and that the presence of such lesions cannot be denied based only on MR imaging of the cervical spine. However, asymptomatic thyroid lesions, including thyroid cancer, can be identified on MR images of the cervical spine, so we recommend that evaluation of these images should consider such lesions.