Acoustic radiation force impulse (ARFI) imaging measures liver stiffness (LS), which significantly correlates with the stage of liver fibrosis in treatment-naive patients with chronic hepatitis B (CHB).

We aimed to prospectively assess the clinical usefulness of ARFI during long-term antiviral therapy in CHB.

Seventy-one CHB patients were consecutively recruited and paired liver biopsies were performed in 27 patients. LS was assessed by ARFI semiannually during entecavir therapy.

LS gradually decreased with treatment and continued to decrease after normalization of alanine aminotransaminase. Overall, 97.2% patients achieved improvement of LS, whereas 19.7% patients had more than 30% reduction in LS values between baseline and week 104. Multivariate linear regression analysis showed that the degree of LS reduction significantly correlated with the baseline levels of LS value, platelet and cholinesterase. In the 27 patients who underwent paired liver biopsies, LS significantly correlated with stage of fibrosis and inflammatory grade at baseline. LS values decreased more significantly in patients with fibrosis regression than those with static histological fibrosis.

In CHB patients, LS assessed by ARFI was gradually reduced during antiviral therapy. Longitudinal monitoring of LS may be a promising noninvasive assessment of fibrosis regression during long-term antiviral therapy in CHB. Further large sample studies are needed.