title: Thyroid imaging reporting and data system for US features of nodules: a step in establishing better stratification of cancer risk.
abstract: OBJECTIVE
  To develop a practical thyroid imaging reporting and data system (TIRADS) with which to categorize thyroid nodules and stratify their malignant risk.
  
  
  METHODS
  The institutional review board approved this retrospective study, and the requirement to obtain informed consent for the review of images and records was waived. From May to December 2008, ultrasonographically (US)-guided fine-needle aspiration biopsy (FNAB) was performed in 3674 focal thyroid nodules in 3414 consecutive patients. The study included the 1658 thyroid nodules (≥1 cm in maximum diameter at US) in 1638 patients (1373 women, 265 men) for which pathologic diagnosis or follow-up findings were available. Univariate and multivariate analyses with generalized estimating equations were performed to investigate the relationship between suspicious US features and thyroid cancer. A score for each significant factor was assigned and multiplied by the β coefficient obtained for each significant factor from multivariate logistic regression analysis. Scores for each significant factor were then added, resulting in an equation that fitted the probability of malignancy in thyroid nodules. The authors evaluated the fitted probability by using a regression equation; the risk of malignancy was determined according to the number of suspicious US features.
  
  
  RESULTS
  The following US features showed a significant association with malignancy: solid component, hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. As the number of suspicious US features increased, the fitted probability and risk of malignancy also increased. Positive predictive values according to the number of suspicious US features were significantly different (P < .001).
  
  
  CONCLUSIONS
  Risk stratification of thyroid malignancy by using the number of suspicious US features allows for a practical and convenient TIRADS.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
authors.forename: Kyung Hwa
authors.initials: KH
authors.lastname: Han
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Son
authors.forename: So Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Hyun Kyung
authors.initials: HK
authors.lastname: Jung
authors.forename: Ji Soo
authors.initials: JS
authors.lastname: Choi
authors.forename: Bo Mi
authors.initials: BM
authors.lastname: Kim
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D014463:Ultrasonography / Q000706:statistics & numerical data*; D055815:Young Adult