RE: Liver Shear-Wave Velocity to Diagnose Hepatic Fibrosis in Patients with Chronic Viral Hepatitis B.

We have read with interest the article by Liu et al. (1) in a recent issue of the Korean Journal of Radiology, in which they concluded that liver shear-wave velocity and serum fibrosis were markers to diagnose hepatic fibrosis in patients with chronic hepatitis B. We thank the authors for their invaluable contribution. However, we would like to offer some minor criticism from a methodological view point.

First, in the present study, the measurements of Acoustic Radiation Force Impulse (ARFI) were performed in the right liver lobe through the intercostal space in the left lateral decubitis position with the right arm elevated above the head (1). In contrast, Uslu et al. (2) demonstrated that subcostal approach to the liver parenchyma was significantly superior to intercostal approach for the evaluation of stiffness. ARFI measurements through the subcostal space result in better pressure transmission to the liver parenchyma and thus, would have determined the elasticity of liver more accurately than the intercostal approach.

Second, the length of the biopsy material was at least 15 mm in present study. Bedossa et al. (3) recommend 40 mm long biopsy as an optimal specimen for accurate evaluation of liver fibrosis. Additionally, at least 5 pieces of the portal tracts were included in the present study; whereas, American Association of Study of Liver Disease guidelines recommend greater than 11 portal tracts (4). It would have been relevant, if the authors had mentioned these limitations in the study.

Third, Trovato et al. (5) showed that ARFI of the spleen correlates with fibrosis staging and could potentially be an additional tool for the diagnosis of liver fibrosis. The study would have been strengthened, if the authors had evaluated their patients according to spleen measurements of these techniques.