Evaluation of acoustic radiation force impulse imaging for determination of liver stiffness using transient elastography as a reference

AIM： To evaluate cut-off values and performance of acoustic radiation force impulse imaging （ARFI） using transient elastography [FibroScan （FS）] as a reference. METHODS： Six hundred and six patients were enrolled in this study.All patients underwent liver stiffness measurement with FS （FS-LS） and ARFI （with shear wave velocity quantification; ARFI-SWV） and the performance of ARFI in comparison to FS was determined. Sixtyeight patients underwent liver biopsy. RESULTS： Significantly higher success rates for the determination of liver stiffness were found using ARFI as compared to FS [604/606 （99.7%） vs 482/606 （79.5%）; P 〈 0.001]. ARFI-SWV correlated significantly with FS-LS （r = 0.920, P 〈 0.001）. ARFI-SWV increased significantly with the stage of fibrosis （1.09 ± 0.13 m/s for patients with no significant fibrosis （FS-LS 〈 7.6 kPa）; 1.46 ± 0.27 m/s for patients with significant liver fibrosis （7.6 〈 FS-LS ≤ 13.0 kPa）; and 2.55 ± 0.77 m/s for patients with liver cirrhosis （FS-LS 〉 13.0 kPa））. ARFI-SWV cut-off values were identified for no significant fibrosis （1.29 m/s; sensitivity 91.4% and specificity 92.6%） and for liver cirrhosis （1.60 m/s; sensitivity 92.3% and specificity 96.5%）. The optimal cut-off value for predicting liver fibrosis （F ≥ 2） was 1.32 m/s （sensitivity 87.0% and specificity 80.0%） and for liver cirrhosis （F4） 1.62 m/s （sensitivity 100% and specificity 85.7%）, for patients who underwent liver biopsy. An excellent inter-and intraobserver reproducibility was observed for ARFI-SWV determinations. CONCLUSION： An ARFI-SWV cut-off value of 1.29 m/s seems to be optimal for patients with no significant liver fibrosis and 1.60 m/s for patients with liver cirrhosis.