Non-invasive evaluation of liver fibrosis using transient elastography

(A) Position of probe and explored volume (Imaging from Echosens). (B) Shear wave propagation velocity according to the severity of hepatic fibrosis (Metavir score). The elastic modulus E expressed as E=3ρV², where V is the shear velocity and ρ is the mass density (constant for tissues): the stiffer the tissue, the faster the shear wave propagates. Hence, for absent fibrosis (F0), velocity is 1.0m/s and elasticity is 3kPa, whereas for cirrhosis (F4) velocity is 3.0m/s and elasticity is 27kPa. Adapted from Sandrin et al. [13].

Distribution of liver stiffness values in 429 healthy subjects without overt causes of liver disease and normal liver enzymes, according to the presence or the absence of metabolic syndrome. Adapted from Roulot et al. [25].

Box-plots of liver stiffness values for each fibrosis stage (Metavir). Because of the wide range of FS values for F4, the vertical axis is in logarithmic scale. Adapted from (A) Ziol et al. [18] and (B) Castera et al. [17].

Proposed algorithm for clinical practice combining FibroScan and Fibrotest as first-line assessment of hepatic fibrosis in patients with chronic hepatitis C. Adapted from Castera et al. [17].

(A) Relationship between liver stiffness and portal pressure in a cohort of 124 HCV-infected liver transplant recipients who underwent 129 paired hepatic venous pressure gradient (HVPG) and liver stiffness measurements. Patients are grouped according to the HVPG value (x axis): normal portal pressure (HVPG<6mmHg), mild portal hypertension (HVPG=6–9.9mmHg), and clinically significant portal hypertension (HVPG⩾10mmHg). Adapted from Garcia-Samanego & Forns [56]. (B) Linear regression analysis between HVPG and liver stiffness values in 61 HCV patients. Adapted from Vizzutti et al. [52].

Clinical significance of liver stiffness cut-offs in chronic liver diseases. When liver stiffness values range between 2.5 and 7kPa, mild or absent fibrosis is likely, whereas when liver stiffness values are above 12.5kPa, cirrhosis is likely.