title: The significance of alteration 2-[fluorine-18]fluoro-2-deoxy-(D)-glucose uptake in the liver and skeletal muscles of patients with hyperthyroidism.
abstract: OBJECTIVE
  Hyperthyroidism leads to an enhanced demand for glucose. The hypothesis of the study is that 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) can demonstrate the alteration of systemic glucose metabolism in hyperthyroidism patients by measuring the FDG standard uptake value (SUV) in liver and skeletal muscle.
  
  
  METHODS
  Forty-eight active hyperthyroidism patients and 30 control participants were recruited for the study. The intensity of FDG uptake in the liver and thigh muscles was graded subjectively, comprising three groups: group I, higher FDG uptake in the liver; group II, equal FDG uptake in the liver and muscles; and group III, higher FDG uptake in the muscles. Ten subjects with FDG PET scans at hyperthyroid and euthyroid status were analyzed. Serum levels of thyroxine (T4) and triiodothyronine (T3) correlated to the SUVs of the liver and muscles.
  
  
  RESULTS
  Forty-one patients (41/48, 85.4%) showed symmetrically increased FDG uptake in the muscles (22 in group I, 9 in group II, and 17 in group III). Group I patients were significantly older than group II (P = .02) and group III (P = .001) patients. The correlation coefficient between the serum T3, T4, and SUV levels in the muscles was significant (r = 0.47-0.77, P < .01), particularly in liver and muscle FDG uptake between hyperthyroid and euthyroid states. In the 30 control subjects, there was normal physiological FDG uptake in the liver and muscles.
  
  
  CONCLUSIONS
  In PET scans showing a pattern of decreased liver and increased skeletal muscle FDG uptake in hyperthyroidism patients, this change of FDG distribution is correspondence to the severity of hyperthyroidism status.
authors.affiliation: Department of Nuclear Medicine and PET Center, Shin Kong Wu Ho-Su Memorial Hospital, No. 95, Wen Chang RD., Shih Lin District, Taipei, Taiwan; School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan. Electronic address: M004149@ms.skh.org.tw.
authors.forename: Yen-Kung
authors.initials: YK
authors.lastname: Chen
authors.forename: Yen-Ling
authors.initials: YL
authors.lastname: Chen
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Tsui
authors.forename: Su-Chen
authors.initials: SC
authors.lastname: Wang
authors.forename: Ru-Hwa
authors.initials: RH
authors.lastname: Cheng
mesh_terms: D000328:Adult; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 2-[fluorine-18]fluoro-2-deoxy-d-glucose; liver; positron emission tomography; skeletal muscle; thyroid hormone