Point shear wave elastography by acoustic radiation force impulse (ARFI) of rare chronic liver disease such as autoimmune hepatitis (AIH) and overlap-syndrome

Purpose: Acoustic radiation force impulse (ARFI) elastography is a non-invasively method for evaluating liver fibrosis. Performance data on rare autoimmune liver diseases like autoimmune hepatitis (AIH) and overlap-syndrome are sparse. Therefore, ARFI shear wave velocities of the liver were ascertained and correlated with histological degree of fibrosis.

Material and methods: In a retrospective analysis, a total of 28 patients (21 female, 7 male, mean age 49 years, range: 19 – 74 years) with AIH (n = 19) and overlap-syndrome (n = 9) have been evaluated by use of ARFI elastography and histological degree of fibrosis by Ishak. A minimum of 7 measurements of the right hepatic lobe were obtained. The ARFI shear wave velocities are expressed as meters per second (m/s) and were calculated as the mean ± standard deviation (range).

Results: The mean ARFI values of all AIH patients showed 2.11 ± 1.01 m/s (range: 0.92 – 3.98 m/s) and correlated with the histological classification of fibrosis (r = 0.507, p < 0.05). The patients with an overlap-syndrome had an ARFI mean of 2.12 ± 0.74 m/s (range: 1.06 – 2.96 m/s), well correlating with the Ishak score (r = 0.813, p < 0.01).

The mean ARFI values of all patients correlated well with the Ishak fibrosis score (r = 0.611, p < 0.01). These shear wave velocities of all patients correlated also with patient age (r = 0.365, p < 0.05) and negatively with platelet count (r =-0.449, p < 0.01). The diagnosis of relevant fibrosis (Ishak ≥2) had a cutoff-value of 1.58 m/s with a sensitivity of 82.4% and a specificity of 81.8%.

Conclusion: Autoimmune liver diseases like AIH and overlap-syndrome revealed increased ARFI shear wave velocities values of the liver. Hepatic ARFI elastography correlated well with the degree of fibrosis and represents a helpful diagnostic adjuvant.