Point Shear Wave Elastography by Acoustic Radiation Force Impulse Quantification in Comparison to Transient Elastography for the Noninvasive Assessment of Liver Fibrosis in Chronic Hepatitis C: A Prospective International Multicenter Study.

PURPOSE: The aim of the present prospective European multicenter study was to demonstrate the non-inferiority of point shear wave elastography (pSWE) compared to transient elastography (TE) for the assessment of liver fibrosis in patients with chronic hepatitis C. MATERIALS AND METHODS: 241 patients with chronic hepatitis C were prospectively enrolled at 7 European study sites and received pSWE, TE and blood tests. Liver biopsy was performed with histological staging by a central pathologist. In addition, for inclusion of cirrhotic patients, a maximum of 10 % of patients with overt liver cirrhosis confirmed by imaging methods were allowed by protocol (n = 24). RESULTS: Owing to slower than expected recruitment due to a reduction of liver biopsies, the study was closed after 4 years before the target enrollment of 433 patients with 235 patients in the 'intention to diagnose' analysis and 182 patients in the 'per protocol' analysis. Therefore, the non-inferiority margin was enhanced to 0.075 but non-inferiority of pSWE could not be proven. However, Paired comparison of the diagnostic accuracy of pSWE and TE revealed no significant difference between the two methods in the 'intention to diagnose' and 'per protocol' analysis (0.81 vs. 0.85 for F ≥ 2, p = 0.15; 0.88 vs. 0.92 for F ≥ 3, p = 0.11; 0.89 vs. 0.94 for F = 4, p = 0.19). Measurement failure was significantly higher for TE than for pSWE (p = 0.030). CONCLUSION: Non-inferiority of pSWE compared to TE could not be shown. However, the diagnostic accuracy of pSWE and TE was comparable for the noninvasive staging of liver fibrosis in patients with chronic hepatitis C.

Acoustic radiation force impulse imaging for non-invasive assessment of liver fibrosis in chronic hepatitis B.

Acoustic radiation force impulse (ARFI) imaging is a novel ultrasound-based elastography method that is integrated in a conventional ultrasound machine. It might provide an alternative method to transient elastography for the noninvasive assessment of liver fibrosis. While previous studies have shown comparable diagnostic accuracy of ARFI to transient elastography in chronic hepatitis C, the aim of the present prospective multicenter study was to evaluate ARFI for the assessment of liver fibrosis in chronic hepatitis B. ARFI imaging involves the mechanical excitation of tissue using short-duration acoustic pulses to generate localized displacements in tissue. The displacements result in shear-wave propagation which is tracked using ultrasonic, correlation-based methods and recorded in m/s. In the present international prospective study, patients infected with chronic hepatitis B received ARFI imaging, blood tests and if available transient elastography. The results were compared to liver biopsy as reference method analysed by a central pathologist. In 92 of 114 patients, a comparison of ARFI with transient elastography was possible. ARFI imaging and transient elastography correlated significantly with histological fibrosis stage. The diagnostic accuracy expressed as areas under ROC curves for ARFI imaging and transient elastography was 0.75 and 0.83 for the diagnosis of significant fibrosis (F ≥ 2), 0.93 and 0.94 for the diagnosis of severe fibrosis (F ≥ 3), and 0.97 and 0.93 for the diagnosis of liver cirrhosis, respectively. No significant difference was found between ARFI and transient elastography. ARFI imaging is a reliable ultrasound-based method for the assessment of advanced stages of liver fibrosis in chronic hepatitis B.