Diagnosis of metabolic disease by imaging techniques

An increasing number of studies focus on fat distribution and its associations with metabolic risk, in interaction with genetics, environment and ethnicity, in children. The link between obesity and metabolic disease risk is driven by body fat distribution and ectopic fat deposition, but the only way to accurately visualize and quantify specific fat depots is state-of-the-art imaging techniques like computed tomography (CT) and magnetic resonance imaging (MRI). Recent advances in imaging techniques, especially in MRI, have made it possible to measure specific fat depots such as visceral abdominal fat (visceral adipose tissue [VAT]), subcutaneous abdominal fat (subcutaneous adipose tissue [SAT]) and ectopic fat depots including hepatic fat fraction (HFF), pancreatic fat fraction (PFF) and intramyocellular fat (IMCL fat. Abdominal as well as ectopic fat depots are present already in childhood and contribute to abnormal metabolic parameters, starting early in life. Visceral, hepatic and intramuscular fat seem to be interrelated but their patterns as well as their independent contribution on metabolic risk are not clear. Girls tend to accumulate more TBF and SAT during and after puberty, depositing fat preferentially in the gynoid and extremity regions. In contrast, pubertal and postpubertal boys tend to deposit more fat in the abdominal region, particularly in the VAT depot. Sexual maturation significantly influences TBF, VAT and SAT. Some ethnic-specific characteristics are also prevalent. Further research are needed in childhood obesity by using imaging techniques such as magnetic resonance imaging and computed tomography. These imaging methods can provide a better understanding of fat distribution and its relationships with metabolic risk, compared to less detailed fat and obesity assessment. However, studies on bigger samples and with a prospective character are warranted.