title: Application of acoustic radiation force impulse imaging for the evaluation of focal liver lesion elasticity.
abstract: BACKGROUND
  Acoustic radiation force impulse (ARFI) imaging is a new elastography method for the evaluation of tissue stiffness. This study aims to evaluate the performance of ARFI in noninvasive assessment of the tissue stiffness of focal liver lesion (FLL) and to explore its potential value in the differential diagnosis of FLL.
  
  
  METHODS
  ARFI was performed in 140 patients with 154 FLLs, which included 28 hemangiomas (ANGIs), 14 focal nodular hyperplasias (FNHs), 61 hepatocellular carcinomas (HCCs), 39 metastases and 12 cholangiocellular carcinomas (CCCs). Virtual touch tissue quantification (VTTQ) values were obtained, analyzed and compared. The area under the receiver operating characteristic curve (AUROC) and optimal cut-off values were obtained using a receiver operating characteristic (ROC) curve analysis to assess diagnostic performance. All cases were definitively diagnosed using histopathology, CT, MRI or contrast-enhanced ultrasound.
  
  
  RESULTS
  The VTTQ median values of ANGI, FNH, HCC, metastasis and CCC were 1.30, 1.80, 2.52, 3.08 and 3.89 m/s, respectively. A significant increase in the VTTQ values of different lesions was observed: ANGI<FNH<HCC<InvalidTagstasis<CCC (P<0.001). The AUROC (95% CI) of VTTQ values was 0.94 (0.90-0.98) for ANGI, 0.91 (0.87-0.96) for malignant lesions and 0.87 (0.79-0.94) for CCC. The sensitivity and specificity for ANGI (86.5%, 89.3%, respectively), malignancy (81.3%, 92.9%, respectively), and CCC (91.7%, 72.5%, respectively) were associated with VTTQ cut-off values of 1.76, 2.22 and 3.00 m/s, respectively.
  
  
  CONCLUSIONS
  ARFI can accurately and objectively assess the elasticity of lesions by obtaining the shear wave elastic value of FLL with VTTQ. Therefore, ARFI is a novel, simple, noninvasive and useful diagnostic method for the characterization of FLL.
authors.affiliation: Department of Ultrasound, Third Xiangya Hospital, Central South University, Changsha 410013, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhou
authors.forename: Shuang-Ming
authors.initials: SM
authors.lastname: Tian
authors.forename: Ying
authors.initials: Y
authors.lastname: Qian
authors.forename: Jin
authors.initials: J
authors.lastname: Deng
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D001650:Bile Duct Neoplasms; D001653:Bile Ducts, Intrahepatic; D001706:Biopsy; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology*; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology*; D003287:Contrast Media; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques; D005260:Female; D020518:Focal Nodular Hyperplasia / Q000000981:diagnostic imaging / Q000473:pathology*; D006391:Hemangioma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000556:secondary; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D003287:Contrast Media