Background and aims: Acoustic Radiation Force Impulse (ARFI) shear wave imaging is a noninvasive method of assessment of the liver to detect fibrosis in patients with chronic hepatitis and nonalcoholic fatty liver disease (NAFLD). The aim of this retrospective study was to investigate whether noninvasive measurement of shear wave velocity (SWV) by ARFI shear wave imaging has a potential usefulness for detection of fibrosis secondary to NAFLD in patients with morbid obesity.
Methods: Twenty-eight morbidly obese patients were included in this study. NAFLD and fibrosis were classified according to the nonalcoholic steatohepatitis (NASH) Clinical Research Network NAFLD activity score. SWV was quantified by ARFI imaging. Component steatosis, inflammation and ballooning scores, and fibrosis staging were correlated with SWV, and diagnostic accuracy of ARFI for fibrosis was assessed.
Results: There was a decrease in mean SWV with increasing hepatic steatosis (P = .057). The SWV showed a significant negative correlation (r = -0.417, P = .011) with steatosis grade. The mean SWV was neither significantly different nor correlating with the obesity classes based on body mass index (BMI), steatosis grades, inflammation grades, ballooning grades, and fibrosis stages of NAFLD. Receiver operating characteristic analysis showed no significant area under curve for diagnosis of fibrosis using SWV. Valid SWV could be acquired in all subjects; however, only 21.42% fulfilled the interquartile range criterion.
Conclusion: ARFI SWV values do not correlate with fibrosis on liver biopsy in morbidly obese patients and lack accuracy for diagnosis. Discordant values may be related to higher BMI and increasing hepatic steatosis.