title: The value of acoustic radiation force impulse (ARFI) in the differential diagnosis of thyroid nodules.
abstract: OBJECTIVE
  The aim of this study was to investigate the value of shear wave velocity value (SWV) and shear wave velocity ratio (SWR) in differentiating between malignant and benign thyroid nodules using virtual touch tissue quantification (VTQ) of acoustic radiation force impulse (ARFI) technology.
  
  
  METHODS
  The SWV and SWR were analyzed in 155 thyroid nodules in 155 patients (93 benign and 62 malignant) and eighty normal thyroid glands. The diagnostic performance of SWV and SWR were compared.
  
  
  RESULTS
  The mean value of SWV of malignant nodules differed significantly from those of the benign nodules (6.34 ± 2.58 m/s vs. 2.15 ± 0.59 m/s, P<0.05) and the normal thyroid (1.96 ± 0.31 m/s, P<0.05). There was no statistically significant difference between the mean value of SWV of benign nodules and normal thyroid (P>0.05). The mean value of SWR of malignant nodules differed significantly from those of the benign nodules (2.99 ± 1.45 vs. 1.07 ± 0.34, P<0.05). The sensitivity, specificity, positive predictive values, negative predictive values and accuracy of SWV in differentiating between malignant and benign nodules were 96.80%, 95.70%, 93.75%, 97.80% and 96.13% respectively based on the cutoff point as 2.84 m/s. Those of SWR were 91.90%, 81.70%, 77.03%, 93.83% and 85.83% based on the cutoff point as 1.32. The diagnostic accuracy rate of SWV was statistically higher than that of SWR (P<0.05).
  
  
  CONCLUSIONS
  VTQ of ARFI technology provides the quantitative information of thyroid tissue elasticity and has high accuracy rate in differentiating between malignant and benign nodules. It is a useful complement for conventional ultrasonography.
authors.affiliation: Ultrasound Department, The Fourth Hospital of Hebei Medical University, No.12 Jiankang Road, Shijiazhuang 050011, China. Electronic address: 148126008@qq.com.
authors.forename: Feng-Juan
authors.initials: FJ
authors.lastname: Zhang
authors.forename: Ruo-Ling
authors.initials: RL
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000453:epidemiology*
keywords: Acoustic radiation force impulse; Thyroid nodules; Ultrasound; Virtual touch tissue quantification