Quantitative Assessment Of Intrahepatic Fat Content With~1H MRS In Obese Children With Non-alcoholic Fatty Liver Disease

Objective:To quantitatively evaluate the clinical significance of intrahepatic fat (IHF) content with1H MRS in obese children with non-alcoholic fatty liver disease (NAFLD).Methods:A total of93obese and20healthy children matched in gender and age were enrolled consecutively in the study. Physical parameters, liver function, serum lipids, glycemic and insulin related parameters were measured and liver B-mode ultrasound (US) examination was performed for all of the cases. IHF content was quantified by1H magnetic resonance spectroscopy (1H MRS). Three subgroups were classified according to the conditional diagnostic criteria in obese children:simple obese children group, NAFLD-1group (US fatty liver and normal alanine aminotransterase) and NAFLD-2group (US fatty liver and elevated alanine aminotransterase). In addition, the healthy children who have no sign of fatty liver by US were selected as control group. Then we compared the variation of IHF content among these four groups, and analyzed the relationship of IHF content with other common clinic-laboratory parameters, and investigated the independent factors which could induce the increase of IHF content.Results:(1) IHF content measured by1H MRS was0.80%(0.4%～1.0%),2.9%(1.7%～4.3%),14.0%(7.2%～17.5%),18.8%(14.0%～29.1%) respectively in control group, simple obese children group, NAFLD-1group and NAFLD-2group, which showed a statistically significant with an upward trend.(2) In univariate correlation analyses, increased IHF content was positively correlated with waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), alanine aminotransferase (ALT), aspartate aminoreansferase (AST), gamma-glutamic acid transtetase (GGT), triglycerides (TG), low-density lipoprotein (LDL), OGTT2-hour plasma glucose (OGTT2hPG), fasting insulin (FINS),2-hour insulin (2hINS) and HOMA-IR; as well as negatively correlated with the decreased high-density lipoprotein (HDL).(3) By applying multivariate linear regression analyses, we identified three variables that independently induced the increase of IHF content:thickening WC, elevated OGTT2hPG and decreasing HDL.Conclusions:IHF content determined by1H MRS can reflected early hepatic fatty infiltration and closely related to the occurrence and progress of NAFLD in obese children. There was a significant correlation between most of common clinical laboratory parameters and IHF content. Finally, WC, OGTT2hPG and HDL are independent factors impacting IHF content.