Obesity and fat quantification in lean tissues using three-point Dixon MR imaging.
BACKGROUND
It has been suggested that increased hepatic and intramuscular fat is associated with insulin resistance, and that increased pancreatic fat is related to impaired insulin secretion.


OBJECTIVE
We postulated that in obese nondiabetic teenagers insulin levels would be directly related to increases in intramuscular and hepatic fat and inversely related to increases in pancreatic fat.


METHODS
MRI was used to assess the percentage of fat in the liver, muscle and pancreas in 15 healthy Mexican-American girls, 14-17 years old, with body mass indexes (BMIs) ranging from 17.7 kg/m(2) to 46 kg/m(2).


RESULTS
Strong correlations were observed between BMI and fat content in the liver, muscle, and pancreas (r(2)s between 0.50 and 0.89; P<0.003). Serum insulin levels were closely associated with fat measures in the muscle and liver (r(2s)=0.63 and 0.29, and P=0.001 and P=0.023, respectively). In contrast to our hypothesis, fat content in the pancreas was also directly related to insulin secretion (r(2)=0.74; P=0.001).


CONCLUSIONS
We conclude that in nondiabetic teenagers, obesity is associated with an increased accumulation of fat in the pancreas without impairment of insulin secretion.
Kovanlikaya
Arzu
A
Department of Radiology, Children's Hospital of Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027, USA.
Mittelman
Steven D
SD
Ward
Andrette
A
Geffner
Mitchell E
ME
Dorey
Frederick
F
Gilsanz
Vicente
V
D000273:Adipose Tissue / Q000033:anatomy & histology*; D000293:Adolescent; D015992:Body Mass Index; D005234:Fatty Liver / Q000175:diagnosis; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009132:Muscles; D009765:Obesity; D010179:Pancreas