MEASUREMENT OF LIVER STIFFNESS WITH SHEAR WAVE ELASTOGRAPHY (SWE) IN BARIATRIC SURGERY CANDIDATES REVEALED ACCEPTABLE DIAGNOSTIC YIELD COMPARED TO LIVER BIOPSY

Background and Aim: we aimed to assess the diagnostic accuracy of Shear Wave Elastography (SWE) as a non-invasive tool by comparing it with that of liver biopsy as the standard test in bariatric surgery candidates.Methods: Background: Non-alcoholic fatty liver disease (NAFLD) is a prevalent condition among severely obese patients. It can gradually progress to liver fibrosis. Shear Wave Elastography (SWE) has been validated as a noninvasive diagnostic tool for liver stiffness measurement in a wide range of liver disorders associated with fibrosis. However, technical feasibility and accuracy of this method are still under debate in severely obese patients. Methods: A total of 111 severely obese candidates for bariatric surgery were recruited. Liver stiffness was measured using SWE fourteen 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. Liver biopsy was considered as the gold standard. Results: The stages of fibrosis were numbered from 1 to 4 based on increasing severity of fibrosis. They were detected in 65.8%, 10.8%, 4.5% and 0.9% of patients, respectively. As the fibrosis stage progressed, the median Liver Stiffness Measurement (LSM) increased on 2D-SWE. Patients with a higher fibrosis stage exhibited LSMs with markedly higher median values than those of subjects with less severe fibrosis (all p-values < 0.05). AUROC for SWE was 0.77 for F1; 0.72 for F2; 0.77 for F3 and 0.70 for F4.Conclusion: Non-invasive LSM with SWE is a viable option in severely obese patients. Using SWE, patients with NASH could be distinguished from those with NAFLD. Finally, SWE may be considered as a diagnostic tool in clinical evaluation before bariatric surgery.

Keywords:

bariatric surgery , liver stiffness , morbid obesity , elastography