title: Factors associated with positive F-18 flurodeoxyglucose positron emission tomography before thyroidectomy in patients with papillary thyroid carcinoma.
abstract: BACKGROUND
  The role for pre-thyroidectomy (pre-Tx) imaging with F-18 flurodeoxyglucose (FDG) positron emission tomography (PET), FDG PET-computed tomography (CT), in differentiated thyroid cancer is controversial as is the significance of positive and negative FDG uptake in this setting. We reviewed the records of patients with papillary thyroid carcinoma (PTC) who had pre-Tx FDG PET-CT to determine whether FDG uptake was associated with features noted on pre-Tx ultrasonography (US) and parameters determined after post-Tx.
  
  
  METHODS
  Patients were selected for a retrospective review of their records if they had a total Tx with central lymph node dissection for PTC and pre-Tx FDG PET-CT and US between 2006 and 2009. Sixty patients who met these criteria were studied. Patients who had a history of head and neck irradiation, surgery, or sclerotherapy with ethanol in the last 3 months were excluded. The clinicopathologic factors-age, sex, size, tumor-node-metastasis (TNM) staging, the presence of extrathyroidal extention, multifocality, cervical lymph node metastases (CLNM), Hashimoto thyroiditis, and US characteristics-were evaluated to determine whether they were associated with positive pre-Tx FDG uptake.
  
  
  RESULTS
  Forty-three (71.6%) of patients in the study had positive FDG uptake. Larger tumors and the presence of CLNM were associated with a greater likelihood of positive FDG uptake. The sensitivity, specificity, positive predictive value, and negative predictive value for CLNM detection by FDG PET-CT showed low statistical values. When considering the excellence of US for evaluating a thyroid nodule size and the presence of CLNM, the clinical value of pre-Tx FDG PET-CT is comparatively limited.
  
  
  CONCLUSIONS
  Pre-Tx FDG PET is not recommended for routine use in patients with PTC.
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Bum Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Seong-Jang
authors.initials: SJ
authors.lastname: Kim
authors.forename: In Joo
authors.initials: IJ
authors.lastname: Kim
authors.forename: Kyounjune
authors.initials: K
authors.lastname: Pak
authors.forename: Keunyoung
authors.initials: K
authors.lastname: Kim
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000000981:diagnostic imaging*; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009333:Neck; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D013965:Thyroidectomy; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18