A computed tomography scan application to evaluate adiposity in a minipig model of human obesity

The aim of the present study was to describe and validate a computed tomography (CT) method to analyse adiposity distribution in Göttingen minipigs. Adiposity was evaluated in two groups of minipigs. In group 1 (n 8), measurements were performed before and after the induction of obesity. In group 2 (n 7), animals were fed rations designed to obtain heterogeneous adiposity before analyses. CT acquisitions were associated with anatomical, ultrasonography and body chemical measurements. Our CT method was based on acquisition of a single slice at a fixed anatomical landmark, calculation of individual X-ray density ranges for CT values and delineation of the three main adipose compartments (subcutaneous adipose tissue, SAT; retroperitoneal adipose tissue, RAT; and visceral adipose tissue, VAT). Our validation measures showed that the CT-scan method was accurate, sensitive and reliable. The CT data were found to be correlated with body weight, abdominal perimeter, ultrasonography, anatomical measurements and body chemical composition (from r 0.84 to 0.93, P < 0.001 for all), with a pitfall concerning the precise estimation of VAT. With increased body weight, the amount of adipose tissue increased and the relative proportion of SAT increased, whereas the relative proportion of RAT and VAT decreased (P < 0.001 for all). Adiposity measured by CT, and especially SAT, was found to be negatively correlated with insulin sensitivity (r 0.54, P < 0.05). In conclusion, a precise evaluation of the adipose compartments in minipigs was done by CT. Therefore, the use of Göttingen minipigs is relevant to further investigate the relationship between the different adipose tissues and obesity.