title: Diagnostic value of 18F-FDG PET/CT in patients with TENIS syndrome: correlation with thyroglobulin levels.
abstract: OBJECTIVE
  The aim of the study was to disclose the place of (18)F-FDG PET/CT to predict recurrent disease in patients with differentiated thyroid cancer (DTC), negative radioiodine whole-body scan (WBS) and high serum thyroglobulin (Tg).
  
  
  METHODS
  Seventy-one patients who underwent total thyroidectomy followed by radioactive iodine ablation and had negative radioiodine WBS but elevated Tg levels underwent PET/CT. They were followed up for 6-50 months (median 23) for the occurence of recurrent disease as detected by either clinical findings, other imaging modalities or histopathological examination. The place of PET/CT findings at baseline to predict the presence of recurrent disease was evaluated. Correlation between PET/CT findings and Tg levels was examined and a threshold for Tg level above which the predictive value of PET/CT was highest was determined.
  
  
  RESULTS
  PET/CT was positive for recurrent disease in 38 (53.5%) patients. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT to predict the occurence of recurrent disease at follow-up were 68.8, 78.3, 86.8, 54.5 and 71.9%, respectively. The sensitivity, accuracy and PPV of PET/CT increased with increasing Tg levels. The highest diagnostic accuracy of PET/CT, with a sensitivity of 76.2% and a specificity of 100% to detect recurrent disease appeared to be at a Tg level greater than 29 ng/mL.
  
  
  CONCLUSIONS
  Our findings suggest that (18)F-FDG-PET/CT is a valuable tool to predict the occurence of recurrent disease in patients with DTC, negative WBS and elevated Tg levels. PET/CT positivity has been shown to be strongly and positively correlated with Tg levels in this patient subset.
authors.affiliation: Department of Nuclear Medicine, Ataturk Training and Research Hospital, Bilkent, Ankara, 06530, Turkey, ecingi@yahoo.com.
authors.forename: Elif
authors.initials: E
authors.lastname: Özdemir
authors.forename: Nilufer
authors.initials: N
authors.lastname: Yildirim Poyraz
authors.forename: Sefika Burcak
authors.initials: SB
authors.lastname: Polat
authors.forename: Seyda
authors.initials: S
authors.lastname: Turkolmez
authors.forename: Reyhan
authors.initials: R
authors.lastname: Ersoy
authors.forename: Bekir
authors.initials: B
authors.lastname: Cakir
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D013577:Syndrome; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000145:classification / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin