title: 18F-fluorodeoxyglucose positron emission tomography does not predict malignancy in thyroid nodules cytologically diagnosed as follicular neoplasm.
abstract: OBJECTIVE
  The objective of this study was to evaluate the usefulness of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting malignancy in thyroid nodules cytologically diagnosed as follicular neoplasm.
  
  
  METHODS
  A total of 46 patients with thyroid nodules larger than 1 cm in diameter cytologically diagnosed as follicular neoplasm at Asan Medical Center (Seoul, Korea) were included. FDG-PET images were taken in all patients before surgical resection, and the maximum standardized uptake value (SUVmax) of each nodule was measured.
  
  
  RESULTS
  FDG-PET showed hypermetabolic activity of all nodules compared with normal thyroid tissue. Thirty-six patients underwent surgery, whereas 10 refused immediate operation. Fifteen patients had cancer: 11 with follicular and two each with Hürthle cell and follicular variants of papillary cancer. Twenty-one patients had benign nodules: 11 follicular adenomas, eight adenomatous hyperplasias, and two Hürthle cell adenomas. SUVmax did not differ significantly between malignant and benign nodules (3.6 +/- 3.5 vs. 3.4 +/- 3.2; P = 0.83) or among subtypes of benign nodules (P = 0.23). However, SUVmax differed significantly among subtypes of malignant nodules (P = 0.02).
  
  
  CONCLUSIONS
  On FDG-PET, the glucose metabolic activities of benign thyroid follicular nodules were as high as those of malignant nodules. These findings suggest that FDG-PET has limited value for selecting candidates for surgery among patients cytologically diagnosed as follicular neoplasm.
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea.
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Ryu
authors.forename: Tae Yong
authors.initials: TY
authors.lastname: Kim
authors.forename: Won Bae
authors.initials: WB
authors.lastname: Kim
authors.forename: Gui Young
authors.initials: GY
authors.lastname: Kwon
authors.forename: Gyungyub
authors.initials: G
authors.lastname: Gong
authors.forename: Dae Hyuk
authors.initials: DH
authors.lastname: Moon
authors.forename: Seong Chul
authors.initials: SC
authors.lastname: Kim
authors.forename: Suck Joon
authors.initials: SJ
authors.lastname: Hong
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shong
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose