title: Thyroid incidentalomas detected on 18F-fluorodeoxyglucose-positron emission tomography/computed tomography: Thyroid Imaging Reporting and Data System (TIRADS) in the diagnosis and management of patients.
abstract: BACKGROUND
  Our aim was to evaluate the role of the Thyroid Imaging Reporting and Data System (TIRADS) in the risk stratification of thyroid incidentalomas detected on (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography ((18)F-FDG-PET/CT) scans.
  
  
  METHODS
  Eighty-seven thyroid nodules in 84 patients showing incidentally detected increased uptake on (18)F-FDG-PET/CT who also had ultrasonography (US)-guided fine needle aspiration performed were included. On review of the US images, a TIRADS category was assigned to each thyroid nodule based on the number of suspicious US features. The correlation between the TIRADS category and the standard uptake values (SUV) on (18)F-FDG-PET/CT were calculated and compared.
  
  
  RESULTS
  Of the 87 thyroid nodules, 47 (54%) were benign, and 40 (46%) were malignant. The malignancy rate of the TIRADS categories were as follows: 9% for category 3, 15% for category 4a, 39% for category 4b, 72% for category 4c, and 100.0% for category 5. Combining the TIRADS with the SUV showed increased specificity and positive predictive value but decreased sensitivity and negative predictive value compared with TIRADS alone (all P < .05). The area under the receiver operating characteristics curve value of TIRADS was the greatest, comparable with the combined TIRADS and SUV (0.737 to 0.724, P = .788).
  
  
  CONCLUSIONS
  TIRADS may be applied in the risk stratification of thyroid incidentalomas detected on (18)F-FDG-PET/CT. Considering the high malignancy rate of thyroid incidentalomas showing increased (18)F-FDG uptake, ultrasonography-guided fine needle aspiration is mandatory even if there are no suspicious features present on US.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Nuclear Medicine, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea.
authors.forename: Arthur
authors.initials: A
authors.lastname: Cho
authors.affiliation: Biostatistics Collaboration Unit, Medical Research Center, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea.
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University, College of Medicine, Seoul, South Korea. Electronic address: docjin@yuhs.ac.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis*; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012372:ROC Curve; D011873:Radiology Information Systems; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D018570:Risk Assessment; D016606:Thyroid Nodule / Q000145:classification / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18