Changes in liver stiffness using acoustic radiation force impulse imaging in patients with obstructive cholestasis and cholangitis.

BACKGROUND: Acoustic radiation force impulse imaging is used to assess stages of liver fibrosis. The aim of our study was to evaluate liver stiffness changes in patients with biliary obstruction with or without sclerosing cholangitis after biliary drainage. METHODS: A total of 71 patients were enrolled in this prospective study (cohort N=51, control group N=20); 51 patients with obstructive cholestasis, indicated for endoscopic retrograde cholangiography, received stiffness measurement by acoustic radiation force impulse imaging before and 1-2 days after endoscopic retrograde cholangiography. Seventeen patients with obstructive cholestasis had primary or secondary sclerosing cholangitis. Forty one patients had a follow-up acoustic radiation force impulse imaging measurement after 3.0 ± 9.31 weeks. RESULTS: In all patients with obstructive cholestasis, stiffness decreased significantly after biliary drainage (p<0.001). The main decrease was observed within 2 days after endoscopic retrograde cholangiography (1.92-1.57 m/s, p<0.001) and correlated with the decrease of bilirubin and alkaline phosphatase (p=0.04 and p=0.002, respectively). In patients with sclerosing cholangitis, the initial decrease of stiffness after biliary drainage was weaker than in those without (2.1-1.85 m/s vs. 1.81-1.43 m/s, p=0.016). CONCLUSION: Acoustic radiation force impulse imaging elastography shows that liver stiffness is increased by biliary obstruction, and decreases after endoscopic retrograde cholangiography irrespective of the aetiology. In patients with sclerosing cholangitis the reduction in stiffness after biliary drainage is impaired.