Vibration-controlled transient elastography for noninvasive evaluation of liver steatosis.

Background: Nonalcoholic fatty liver disease (NAFLD) refers to a large spectrum of liver disorders and is the most common cause of metabolic liver disease. The current gold standard for diagnosing NAFLD is liver biopsy, which can lead to severe complications.

Purpose: Among the noninvasive diagnostic options, we chose to use a FibroScan and developed an algorithm applying the Voigt rheological model to assess the viscoelastic properties of the liver and evaluate its performance for the diagnosis of steatosis.

Methods: Twenty-two healthy volunteers and 20 patients with steatosis were included. For each subject, we used a modified FibroScan, whose data had been processed by our algorithm to separate the two viscoelastic components, stiffness μ, and viscosity η. The liver elasticity μFibroscan measured by the FibroScan was also recorded. Mann-Whitney tests and receiver operating characteristics (ROCs) curve analyses were performed to compare the parameters between the two groups, and Pearson's correlation coefficients were used to assess the correlations between the parameters.

Results: We found a good correlation between η and μFibroscan (r = 0.75), and poor correlations between μ and both η and μFibroscan (r = 0.33 and r = 0.03, respectively). We also showed that η and μFibroscan were higher in patients with steatosis compared to healthy volunteers, with area under the ROCs (AUROC) curve at 0.814 and 0.891, respectively. Conversely, μ was not different between the two groups (AUROC = 0.557).

Conclusions: Our novel method successfully separated the two viscoelastic properties of the liver, of which the parameter η is a sensitive indicator for steatosis.