Value of MRI and MRS fat measurements to complement conventional screening methods for childhood obesity

Abstract

Purpose To evaluate a protocol combining abdominal fat-water magnetic resonance imaging (MRI) and liver single voxel magnetic resonance spectroscopy (MRS) for studies of childhood obesity. Materials and Methods Six obese male children and five age-matched normal-weight controls underwent abdominal fat-water Dixon MRI based on a gradient echo sequence with multiple echo times and single voxel liver MRS at a field strength of 3T. The MRI/MRS data were compared with data previously acquired from an obese adult cohort and with anthropometric and blood parameters that are typically acquired for screening in childhood obesity. Results There was a very strong correlation (r=0.96) between the body mass index standard deviation score (BMI-SDS) and the subcutaneous fat volume fraction in the examined children, but only a moderate correlation (r=0.62) between the BMI-SDS index and the intraabdominal fat volume fraction, which is much lower in the obese children (5.3±1.1%) than in the obese adult cohort (19.4±2.9%). Furthermore, a significant difference between the two child cohorts was observed in the intrahepatic lipid (IHL) content as obtained with MRS (P=0.017). However, even the obese child cohort shows an IHL content that is 1-2 orders of magnitude lower (1.0±0.5%) than in the obese adult cohort (17.0±8.7%). Conclusion The proposed method was successfully applied in children and may complement traditional clinical screening methods for childhood obesity such as anthropometry and laboratory tests to better characterize the obesity-associated metabolic risk.