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

Abstract

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