title: The use of dual-phase 18F-FDG PET in characterizing thyroid incidentalomas.
abstract: OBJECTIVE
  To examine the usefulness of dual-phase 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) for the evaluation of thyroid incidentalomas.
  
  
  METHODS
  In this retrospective study, cases with focal thyroid lesions seen incidentally at FDG PET in which the histopathological diagnosis was available and in which dual-phase FDG PET imaging was performed at 1 and 2 h after FDG injection were reviewed. In the included cases, the 1 and 2 h maximal standard uptake value (1-hour maximal SUV and 2-hour maximal SUV, respectively) and retention index (RI) were calculated, and the differences between benign and malignant thyroid incidentalomas were analysed. Receiver operating characteristic (ROC) analysis was performed to evaluate the ability of 1-hour maximal SUV, 2-hour maximal SUV, and RI to discriminate benign from malignant lesions.
  
  
  RESULTS
  A total of 39 patients (25 females, 14 males) with 45 lesions (17 malignant, 28 benign) were included. In malignant thyroid incidentalomas, the average 1-hour maximal SUV, 2-hour maximal SUV, and RI were 5.20, 5.72, and 7.67%, respectively, and in benign thyroid incidentalomas the values were 4.67, 4.97, and 7.38%, respectively. There were no significant differences in 1-hour maximal SUV, 2-hour maximal SUV, and RI between benign and malignant lesions. The area under the ROC curve did not differ from 0.5.
  
  
  CONCLUSIONS
  Dual-phase FDG PET is not useful for differentiating benign from malignant thyroid incidentalomas.
authors: Department of Nuclear Medicine, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan.
authors: Y-C
authors: YC
authors: Hsiao
authors: P-S
authors: PS
authors: Wu
authors: N-T
authors: NT
authors: Chiu
authors: W-J
authors: WJ
authors: Yao
authors: B-F
authors: BF
authors: Lee
authors: S-L
authors: SL
authors: Peng
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011230:Precancerous Conditions / Q000000981:diagnostic imaging / Q000473:pathology*; D011237:Predictive Value of Tests; D015995:Prevalence; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18