Abstract：Objective: To explore the value of 18F-FDG PET/CT in the diagnosis of thyroid disease. Methods: Twenty-eight patients(13 male and 15 female, aged ranged from 25 to 84 years old) with pathological diagnosis of thyroid disease were retrospectively analyzed on 18F-FDG PET/CT. Surgical operation(26 cases) and fine-needle aspiration(2 cases) were performed on these patients, of whom 10 patients had more than one lesion in thyroid gland. Therefore, 8 malignant thyroid lesions and 31 benign thyroid lesions were included in the study. Results: Focal uptake and diffuse uptake were respectively shown in 7 thyroid cancer and 1 thyroid lymphoma. Of 31 benign thyroid lesions, both PET and CT were negative in 5, both PET and CT were positive in 9, PET was negative and CT was positive in 17. Nine benign thyroid lesions with increased FDG uptake comprised nodular goiter, follicular adenoma, Hashimoto’s thyroiditis, adenomatoid hyperplasia, chronic thyroiditis and subacute thyroiditis. The SUVmax was not correlated with maximum length and average density in thyroid cancer. There was no statistically significant difference on SUVmax between 8 malignant thyroid lesions and 9 benign thyroid lesions with high FDG uptake. The calcification did not show statistically significant difference between 8 malignant thyroid lesions and 31 benign thyroid lesions, but the sand-like calcification showed so. Conclusions: When PET/CT is used to evaluate the thyroid disease, only with SUV value can not discriminate malignant lesions from benign lesions and the sand-like calcification seen on CT may aid to identify thyroid cancer. The lesions with no FDG uptake and diffuse FDG uptake in thyroid gland are benign to a great extent, but the lesion with focal uptake in it is likely malignant. The former two are suggestive of follow-up with ultrasound, the latter is suggestive of fine-needle aspiration by ultrasound guidance.
2013, Vol. 24 
