Correlation between ultrasound and histologic findings of fatty liver changes among non-alcoholic obese Patients

الملخص

Background: Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of liver disease in western countries. We aim to evaluate sensitivity, specificity and predictive values of ultrasound in diagnosing NAFLD’s patterns among morbidly obese patients. Methods:45 morbidly obese patients undergoing sleeve gastrectomy were prospectively studied. They underwent true cut liver biopsy during the surgery. Classification of histological patterns was based on the NIH-sponsored NASH Clinical Research Network NAFLD Activity Score (NAS). Prior to surgery, patients had an assessment for fatty liver changes by ultrasound (4 grades). The findings from histology (being the gold standard test) and ultrasound (being the test in question) were compared. Results: 71% were females (32/45). Mean age was 35 (range: 17-58), mean BMI was 43 (range: 35-52). The prevalence of NAFLD histologically was 91.8%. 19/45 patients (39%) had non-alcoholic steatohepatitis (NASH) on histology. Ultrasound’s sensitivity, specificity and positive predictive value in diagnosing NAFLD were 85%, 50% and 95%; respectively. While its sensitivity, specificity and positive predictive value in diagnosing NASH were 100%, 28% and 43%; respectively. There was significant correlation between ultrasound grades and each of steatosis histologic grades (P<0.001), NAS (score) (P<0.001) and the presence of NASH (P<0.001). Conclusion: US has demonstrated a good sensitivity for NAFLD and very high sensitivity for NASH in morbidly obese patients, which makes it a good screening test for hepatic steatosis in obese indivsuals. Because of its high negative predictive value, US can be completely relied on to rule out NASH, maybe with no need for further confirmatory investigations.