Objective: The aim of our study was to present the prevalence of thyroid nodules we incidentally
discovered by routine Magnetic Resonance Imaging (MRI) of the cervical spine, to
evaluate their clinical significance, and to discuss the current clinical approach to incidental thyroid
Methods: We retrospectively evaluated the cervical spinal MRI studies of 512 patients. Thyroid
glands were evaluated for morphologic and signal characteristics and examined for the presence of
nodule(s). The nodules with a maximum diameter of 5 mm or more were taken into analysis.
Results: Of 512 MRI studies, 254 revealed incidental thyroid nodule(s) (49.6%). The mean maximum
nodule diameter was 7.48±2.92 mm. Thirty-eight of 254 incidental thyroid nodules were radiologically
reported, 35 reported nodules were evaluated by US, and 22 were further analyzed by
fine needle aspiration cytology. The final diagnosis of 11 aspirated nodules was an adenomatous
nodule, whereas 3 were papillary thyroid carcinoma. One of the patients with papillary thyroid carcinoma
was a 32-year-old man with a nodule with a maximum diameter of 7 mm.
Conclusion: Incidental thyroid nodule is a frequent non-spinal lesion detected by routine cervical
spinal MRI. The 3-tiered system which is recommended in the clinical approach to incidental thyroid
nodules may miss some clinically significant thyroid nodules. We suggest the criteria of this
system to be re-evaluated and modified if necessary. In addition, we would like to emphasize the
need for a guideline for radiologists for reporting incidental thyroid nodules on MRI on the basis of
a standard clinical approach.