title: Sonographic criteria predictive of benign thyroid nodules useful in avoiding unnecessary ultrasound-guided fine needle aspiration.
abstract: OBJECTIVE
  There has been no individual ultrasound feature of having high accuracy for diagnosis of thyroid malignancy. In this study, we aimed to establish feature-oriented criteria to characterize benign thyroid nodules that do not require ultrasound (US)-guided fine needle aspiration (FNA).
  
  
  METHODS
  We reviewed 374 patients with thyroid nodules who had undergone US-guided FNA at our institution (2005-2008). Thyroid nodules were classified into two groups: Category 1 (benign nodules that required follow-up 6-12 months later but not US-guided FNA); and Category 2 (indeterminate nodules or suspected carcinoma that required US-guided FNA). To test the validity, we reviewed 315 consecutive patients who had histologically proven thyroid carcinoma (n = 39) and randomly selected 40 of the 276 patients with benign nodules (2009-2010).
  
  
  RESULTS
  Of 374 nodules, 354 (95%) were benign and 20 (5%) malignant. On US, 260 nodules had no calcification, no increase in vascularity, well-defined margin, and no lymphadenopathy (Category 1). Using a combination of these four features, we were able to discriminate benign from indeterminate nodules or suspected malignant nodules with a sensitivity of 73%, and specificity and positive predictive value of 100%. Validity testing revealed that none of the 39 malignant thyroid nodules had all four US features. All Category 1 nodules (2005-2008) remained benign at the 3-years follow up.
  
  
  CONCLUSIONS
  The combination of four US features of Category 1 nodules is highly predictive of benign disease, and we could avoid unnecessary US-guided FNA in 69.5% of our patients using this combined features.
authors.affiliation: Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Shee-Yen
authors.initials: SY
authors.lastname: Tay
authors.affiliation: Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: cychencychen@gmail.com.
authors.forename: Chia-Yuen
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Radiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Wing P
authors.initials: WP
authors.lastname: Chan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: aspiration; biopsy; nodule; thyroid gland; ultrasound