The objective of this study was to evaluate the relationship between fluorine-18-fluorodeoxyglucose (18F-FDG) uptake in the pituitary gland and serum thyroid-stimulating hormone (TSH) levels in differentiated thyroid cancer (DTC) patients on 18F-FDG PET/computed tomography (CT).
A total of 215 DTC patients and 215 age-paired and sex-paired healthy screening participants were included. DTC patients were divided into hypothyroid, euthyroid and subclinical hyperthyroid patients according to their serum TSH levels. The relationship between 18F-FDG uptake in the pituitary gland and serum TSH levels was evaluated the in DTC patients, and the pituitary 18F-FDG metabolism was compared in different thyroid status.
The standardized uptake value of pituitary (SUVp) in all 430 patients was directly correlated with serum TSH levels (r=0.479 and 0.432, all P<0.05). The SUVp in DTC patients was higher than that in 215 healthy participants (z=−10.4, P<0.05). No significant difference of SUVp was observed between euthyroid patients and healthy participants (P=0.145).
Our study established the positive correlation between pituitary 18F-FDG uptake and serum TSH. TSH values should be measured in patients with incidental pituitary uptake during 18F-FDG PET/CT. L-T4 replacement for DTC patients may well have the same feedback on the thyroid–pituitary axis as the physiologic thyroid status. The diffuse 18F-FDG uptake with normal CT or MRI appearance of the pituitary in patients with DTC indicates physiologic uptake.
aDepartment of Nuclear Medicine, XinHua Hospital, School of Medicine, Shanghai Jiaotong University
bDepartment of Nuclear Medicine, Tenth People’s Hospital of Tongji University, Shanghai, China
* Yingli Ding, Shuqi Wu and Jing Xu contributed equally to the writing of this article.
Correspondence to Chao Ma, MD, Department of Nuclear Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Kongjiang Road 1665, Shanghai 200092, China Tel: +86 021 2507 8593/+86 021 6630 2075; fax: +86 021 6630 3983; e-mails: email@example.com, firstname.lastname@example.org
Received June 6, 2018
Received in revised form September 26, 2018
Accepted October 8, 2018