Clinical Feasibility of MR Elastography in Patients With Biliary Obstruction.

Objective: The purpose of this study is to evaluate the clinical effect of liver stiffness measured using MR elastography (MRE) in patients with cholestasis due to biliary obstruction.
Materials and Methods: In this retrospective study, 69 consecutive patients with no history of diffuse liver disease who underwent pancreaticobiliary imaging with MRE were included. Quantitative MRI parameters (i.e., liver stiffness, apparent diffusion coefficient, R2*, and proton density fat fraction) and laboratory results (i.e., aspartate aminotransferase, alanine aminotransferase, and total bilirubin levels) were measured. Patients were classified as having either normal bilirubin (group A; n = 49) or hyperbilirubinemia (group B; n = 20). Continuous variables were compared using the independent t test or Mann-Whitney U test. Correlation between parameters was analyzed using the Pearson correlation coefficient. The ROC curve analysis was used to evaluate the diagnostic performance and clinical effect of MRE.
Results: Liver stiffness was significantly higher in group B (mean ± SD, 3.8 ± 0.7 kPa) than in group A (2.8 ± 0.5 kPa) (p < 0.001); there were no differences in other MRI parameters. There were positive correlations between liver stiffness and total bilirubin (r = 0.609; p < 0.001), aspartate aminotransferase (r = 0.376; p = 0.001), and alanine aminotransferase (r = 0.285; p = 0.017) levels. There was a negative correlation between the degree of biliary decompression 1 week after bile drainage and liver stiffness (r = -0.71; p = 0.003). The sensitivity and specificity for predicting biliary decompression were 83.3% and 100%, respectively, at a liver stiffness cutoff of 4.0 kPa.
Conclusion: Liver stiffness measured by MRE increases as cholestasis increases and can be a predictive factor for the sufficiency of biliary decompression after biliary drainage.