Pituitary 18F-FDG Uptake Correlates with Serum TSH Levels in Subjects with Diffuse Thyroid 18F-FDG Uptake

Yong Hyu Jeong, Dongwoo Kim, Jeong Won Lee, Yumie Rhee, Kee Hyun Nam, Mijin Yun, Chun Ki Kim

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Purpose This study was to evaluate the relationship among FDG uptake in the pituitary gland (FDGp), FDG uptake in the thyroid gland (FDGt), and serum thyroid-stimulating hormone (TSH) levels in patients with diffuse FDGt incidentally noted on positron emission tomography/computed tomography (PET/CT). Patients and Methods We retrospectively reviewed FDG PET/CT scans of 2,945 subjects who underwent health screening. Of these, 44 subjects had diffuse FDGt and available thyroid function tests. FDGt and FDGp were correlated with serum TSH. FDGp in 44 paired control subjects without FDGt and 15 thyroid cancer patients undergoing thyroid hormone withdrawal were additionally measured, and compared with FDGp in the 44 subjects with FDGt divided into 3 groups according to serum TSH levels. Results In the 44 subjects, there was a strong correlation found between FDGp and TSH (P < 0.001, r = 0.618). As well, there were statistically significant differences in FDGp between the low, normal, and high TSH groups (P < 0.001). FDGp in the paired control subjects was not different from that in the normal TSH group (P = 0.384), and FDGp in the TSH-stimulated thyroid cancer patients was not different from that in the high TSH group (P = 0.463). Conclusion We found a strong positive correlation between pituitary FDG uptake and serum TSH. Pituitary FDG uptake seems to hold an important clue to the functional status of the thyroid in subjects with diffuse thyroid FDG uptake. Furthermore, physiologic FDG uptake in the pituitary gland caused by hypothyroidism should not be confused with pathologic conditions such as macroadenoma or metastases.

Original languageEnglish
Pages (from-to)632-636
Number of pages5
JournalClinical nuclear medicine
Issue number8
Publication statusPublished - 2015 Aug 30

Bibliographical note

Publisher Copyright:
© 2015 Wolters Kluwer Health, Inc.

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging


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