title: Ultrasonographic criteria for fine needle aspiration of nonpalpable thyroid nodules 1-2 cm in diameter.
abstract: OBJECTIVE
  To investigate the ultrasonographic (US) characteristics for nonpalpable thyroid nodules 1-2 cm in diameter and to evaluate the guideline for fine needle aspiration (FNA) in terms of US findings.
  
  
  METHODS
  Between June 2005 and November 2006, FNA was performed in 919 thyroid nodules by radiologists. Of these nodules, 51 malignant nodules and 72 benign nodules were finally included. All 123 nodules were analyzed by 3 radiologists if there were the following US characteristics: marked hypoechogenecity, hypoechogenecity, isoechogenecity, hyperechogenecity, microcalcification, coarse calcification, rim calcification, spiculated margin, taller-than-wide shape, irregular shape, hypoechoic rim and honeycomb appearance. The maximum diameters of nodules and thickness of hypoechoic rim were measured. US characteristics relevant as predictors were identified using a Chi-square or Fisher's exact test and odds ratio. We compared the diagnostic efficacy of 3 US criteria for FNA indication.
  
  
  RESULTS
  Microcalcification, taller-than-wide shape, marked hypoechogenecity, hypoechogenecity, coarse calcification, irregular shape and spiculated margin were significant characteristics of malignant nodules. Isoechogenecity, hypoechoic rim and honeycomb appearance was significant characteristics of benign nodules. Rim or arc calcification, hyperechogenecity and thickness of hypoechoic rim were insignificant. Among 3 US criteria for FNA indication, NFI showed the highest diagnostic efficacy, 98.0% in sensitivity, 75.0% in specificity and 150.0 in odds ratio.
  
  
  CONCLUSIONS
  As for nonpalpable thyroid nodules 1-2 cm in diameter, US characteristics are useful for differentiating between malignant and benign nodules. Malignant US characteristics and honeycombing appearance have significant value in selecting nodules for biopsy and reducing the frequency of the FNA procedure.
authors.affiliation: Department of Radiology, University of Louisville, 530 South Jackson Street, Louisville, KY 40242, USA. j0kim040@louisville.edu
authors.forename: Ji Yang
authors.initials: JY
authors.lastname: Kim
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Ki Ra
authors.initials: KR
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010173:Palpation / Q000706:statistics & numerical data*; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000453:epidemiology*