Measurement of Liver Stiffness with 2D-Shear Wave Elastography (2D-SWE) in Bariatric Surgery Candidates Reveals Acceptable Diagnostic Yield Compared to Liver Biopsy

Background Nonalcoholic fatty liver disease (NAFLD) is common among severely obese patients. Two-dimensional shear wave elastography (2D-SWE) has been validated as a noninvasive diagnostic tool for liver stiffness measurement. However, the technical feasibility and accuracy of this method in severely obese patients are still under debate. Objective We aimed to assess the diagnostic accuracy of 2D-SWE in bariatric surgery candidates in comparison with the gold standard liver biopsy. Methods Ninety severely obese candidates for bariatric surgery were included. Liver stiffness was measured using 2D-SWE 14 days before liver biopsy. Liver biopsy was taken on the day of surgery. The area under the receiver operating curve (AUROC) was calculated for the staging of liver fibrosis. Results 2D-SWE was performed in 97.3% of patients successfully. Histologic stages of fibrosis (F0-F4) were detected in 34.2%, 36%, 6.3%, 3.6%, and 0.9% of patients, respectively. The AUROC for 2D-SWE was 0.77 for F1, 0.72 for F2, 0.77 for F3, and 0.70 for F4. In univariate analysis, 2D-SWE values were correlated with BMI, waist circumference, NAFLD activity score (NAS), and steatosis, whereas these components did not affect liver stiffness in multivariate analysis. Conclusion Two-dimensional shear wave elastography of the liver can be feasible and has good accuracy in severely obese candidates for bariatric surgery. Therefore, 2D-SWE may be a good option for assessing liver fibrosis, especially in the early stages of fibrosis to lessen complications of surgery in this population. However, this method should be applied on a larger scale for late stage of fibrosis.