Abstract
Objective. Acoustic radiation force impulse imaging (ARFI) is a non-invasive method for the quantification of liver stiffness. We aimed to develop standards for the measuring procedure and studied the impact of different measuring sites. Materials and Methods. ARFI was tested in a tissue phantom and in 50 healthy volunteers. In addition, 116 patients with chronic liver disease underwent ARFI. The results were compared with histological staging (non-viral liver disease) and transient elastography (hepatitis C). ARFI diagnostic performance was evaluated with receiver operating characteristic curves. Results. ARFI results were not normally distributed in >20% of cases. Deep inspiration significantly increased ARFI values by 13% (p < 0.05). The mean shear-wave velocity in healthy individuals was 1.28 ± 0.19 m/s in the left liver lobe and 1.15 ± 0.17 m/s in the right liver lobe (p < 0.001). Similarly, in 79/116 patients with chronic liver disease a significant difference of shear-wave velocity between both liver lobes was detected. The histological staging correlated with ARFI results of the biopsy site (r = 0.661, p < 0.001) in non-viral liver disease (n = 47). The mean shear-wave velocity in cases with F1 and F2 fibrosis was increased in the left compared with the right liver lobe (2.1 ± 0.73 m/s vs. 1.75 ± 0.89 m/s, p = 0.041). Similar results were obtained in patients with hepatitis C (n = 69). Conclusion. Our study strengthens the necessity for definition of examination standards and demonstrates the usefulness of ARFI in non-viral liver disease. Interlobe variations of liver stiffness demand further investigation.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.