title: Preoperative Lymph Node Staging by FDG PET/CT With Contrast Enhancement for Thyroid Cancer: A Multicenter Study and Comparison With Neck CT.
abstract: OBJECTIVE
  The purpose of this study was to compare lymph node (LN) staging using18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with contrast-enhancement (CE) PET/CT and contrast-enhanced neck CT (neck CT) in patients with thyroid cancer with level-by-level comparison with various factors.
  
  
  METHODS
  This was a retrospective multicenter study. A total of 85 patients were enrolled. Patients who underwent a preoperative evaluation by CE PET/CT and neck CT for thyroid cancer were enrolled. The gold standard for LN was the combination of surgical pathology and clinical follow-up. We compared CE PET/CT with neck CT using a level-by-level method. Factors, including age, sex, camera, arm position, tumor size, extra-thyroidal extension, tumor location, number of primary tumors, primary tumor maximum standardized uptake value, and the interval from scan to operation were also analyzed.
  
  
  RESULTS
  Overall accuracy was 81.2% for CE PET/CT and 68.2% for neck CT. CE PET/CT was more sensitive than neck CT (65.8% vs. 44.7%). Also, CE PET/CT showed higher negative predictive value (77.2% vs. 66.1%). CE PET/CT showed good agreement with the gold standard (weighted kappa [κ], 0.7) for differentiating N0, N1a, and N1b, whereas neck CT showed moderate agreement (weighted κ, 0.5). CE PET/CT showed better agreement for the number of levels involved with the gold standard (weighted κ, 0.7) than that of neck CT with the gold standard (weighted κ, 0.5). The accuracies for differentiating N0, N1a, and N1b were 81.2% for CE PET/CT and 68.2% for neck CT. Level-by-level analysis showed that CE PET/CT was more sensitive and has higher negative predictive value for detecting ipsilateral level IV and level VI LNs than neck CT. Other analyzed factors were not related to accuracies of both modalities.
  
  
  CONCLUSIONS
  CE PET/CT was more sensitive and reliable than neck CT for preoperative LN staging in patients with thyroid cancer.
authors.affiliation: Department of Nuclear Medicine, Chosun University Hospital, Gwangju, Korea.
authors.forename: Ari
authors.initials: A
authors.lastname: Chong
authors.affiliation: Department of Nuclear Medicine, Chosun University Hospital, Gwangju, Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Ha
authors.affiliation: Department of Nuclear Medicine, Chonbuk National University Hospital, Jeonju, Korea.
authors.forename: Yeon-Hee
authors.initials: YH
authors.lastname: Han
authors.affiliation: Department of Nuclear Medicine, Yeungnam University Medical Center, Daegu, Korea.
authors.forename: Eunjung
authors.initials: E
authors.lastname: Kong
authors.affiliation: Department of Nuclear Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea.
authors.forename: Yunjung
authors.initials: Y
authors.lastname: Choi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Chonbuk National University Medical School, Jeonju, Korea.
authors.forename: Ki Hwan
authors.initials: KH
authors.lastname: Hong
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Chosun University College of Medicine, Gwangju, Korea.
authors.forename: Jun-Hee
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.
authors.forename: Jung Mi
authors.initials: JM
authors.lastname: Park
keywords: Computed Tomography; Fluorodeoxyglucose F18; Positron-Emission Tomography; Thyroid Neoplasms