Evidence and Recommendations for Imaging Liver Fat in Children, Based on Systematic Review

Abstract

Background & Aims Fatty liver is a common problem in children, and increases their risk for cirrhosis, diabetes, and cardiovascular disease. Liver biopsy is the clinical standard for diagnosing and grading fatty liver. However, non-invasive imaging modalities are needed to assess liver fat in children. We performed a systematic review of studies that evaluated imaging of liver fat in children. Methods We searched PubMed for original research articles in peer-reviewed journals from January 1, 1982 through December 31, 2012 using the key words “imaging liver fat.” Studies included those in English, and those performed in children from birth to 18 y of age. To be eligible for inclusion, studies were required to measure hepatic steatosis via an imaging modality and a quantitative comparator as the reference standard. Results We analyzed 9 studies comprising 610 children; 4 studies assessed ultrasonography and 5 assessed magnetic resonance imaging (MRI). Ultrasonography was used in the diagnosis of fatty liver with positive predictive values of 47–62%. There was not a consistent relationship between ultrasound steatosis score and the reference measurement of hepatic steatosis. Liver fat as measurements by MRI or by spectroscopy varied with the methodologies used. Liver fat measurements by MRI correlated with results from histologic analyses, but sample size did not allow for assessment of diagnostic accuracy. Conclusions Available evidence does not support the use of ultrasonography for the diagnosis or grading of fatty liver in children. Although MRI is a promising approach, the data are insufficient to make evidence-based recommendations regarding its use in children for assessment of hepatic steatosis.

Lifestyle Interventions Including Nutrition, Exercise, and Supplements for Nonalcoholic Fatty Liver Disease in Children

“…In addition, elevated serum ALT, defined as two times the upper limit of normal, was shown in overweight and obese children to have a sensitivity of 57% and specificity of 71% for NAFLD [8]. Moreover, liver ultrasound evidence of steatosis has been shown to have a positive predictive value of only 47–62% for NAFLD [9]. The advanced MRI technique of proton density fat fraction has been shown to strongly correlate with hepatic steatosis, but there is not yet standardization for clinically appropriate cut-offs to determine NAFLD [10].…”

Accuracy of multiecho magnitude‐based MRI (M‐MRI) for estimation of hepatic proton density fat fraction (PDFF) in children

“…First, fatty liver disease prevalence in children is high (18–20), and so reliable methods to non-invasively assess fatty liver disease in children are needed. Ultrasound has been used to assess hepatic steatosis (21, 22), but a recent systematic review has shown that it has limited accuracy to diagnose and grade pediatric hepatic steatosis (23). Second, children are different from adults in important characteristics relevant to MRI including ability to tolerate MRI examinations, breath-holding capacity, and body habitus.…”

“…Second, children are different from adults in important characteristics relevant to MRI including ability to tolerate MRI examinations, breath-holding capacity, and body habitus. These characteristics influence the feasibility, technical optimization, and quality of MRI and may affect its diagnostic performance (23, 24). …”

The role of conventional ultrasound in pediatric chronic liver diseases

“…A systematic review conducted in 2014, based on the available studies in children, shows the positive predictive value of US to be between 47 to 62% in detecting and grading fatty liver in children. The sensitivity for revealing mild steatosis in adults is lower than for other grades, whereas high quality studies are lacking in children (16). Fibrosis and inflammation may also intensify liver echogenicity, but they are associated with liver enlargement more often than simple steatosis.…”