Ultrasonography as a non-invasive tool for detection of nonalcoholic fatty liver disease in overweight/obese Egyptian children

Abstract

Introduction: Liver biopsy, although a gold standard in diagnosis of nonalcoholic fatty liver disease (NAFLD), is an invasive and expensive tool.

Aim: To assess the diagnostic accuracy of abdominal ultrasound in detecting NAFLD among a group of overweight/obese children having one or more liver abnormality (clinical hepatomegaly, raised ALT or echogenic liver parenchyma by ultrasound).

Methods: Seventy-eight overweight/obese children were referred to the Pediatric Hepatology Unit, Cairo University Pediatric Hospital, Egypt, for assessment for hepatic abnormalities. Out of the 78 children, 34 had one or more abnormality in the form of clinical hepatomegaly, raised alanine aminotransferase (ALT) and/or echogenic liver parenchyma by ultrasound. All 34 cases underwent liver biopsy for evaluation for NAFLD.

Results: Histological NAFLD was detected in 15 cases; 8 simple steatosis and 7 nonalcoholic steatohepatitis (NASH). Sonographic evaluation of hepatic parenchymal echogenicity revealed: 11 with grade 1 echogenicity, 12 with grade 2 and 9 with grade 3 while only 2 had normal liver echopattern. Ultrasonography was 100% sensitive and 100% specific in detecting histological NAFLD, while the positive predictive value (PPV) was 47% and negative predictive value (NPV) was 11%. After consolidating the included children into 2 groups: the first including normal and grade 1 echogenicity and the second including grades 2 and 3, the sensitivity of ultrasonography in detecting histological NAFLD was still 100%, while negative predictive value increased to 100% with an accuracy of 82%.

Conclusion: We conclude that ultrasonography is an important non invasive tool in assessment for NAFLD. Normal or grade 1 hepatic echogenicity can soundly exclude histological NAFLD and obviates the need for liver biopsy.