Intra-abdominal fat: Comparison of computed tomography fat segmentation and bioimpedance spectroscopy

Background
Intra-abdominal fat is an important factor in determining insulin resistance and the metabolic syndrome, and thus the risk of diabetes and ischaemic heart disease. Computed tomography (CT) fat segmentation represents a defined method of quantifying intra-abdominal fat, with attendant radiation risks. Bioimpedance spectroscopy may offer a method of assessment without any risks to the patients. A comparison is made of these 2 methods.
Methods
This was a preliminary study of the utility of multifrequency bioimpedance spectroscopy of the midabdomen as a measure of intra-abdominal fat, by comparison with fat segmentation of an abdominal CT scan in the −30 to −190 HU range.
Results
There was a significant (P < 0.01) correlation between intra-abdominal fat and mid-upper arm circumference, as well as the bioimpedance parameter, the R/S ratio. Multivariate analysis showed that these were the only independant variables and allowed the derivation of a formula to estimate intra-abdominal fat: IAF = 0.02 × MAC − 0.757 × R/S + 0.036.
Conclusions
Circumabdominal bioimpedance spectroscopy may prove a useful method of assessing intra-abdominal fat, and it may be suitable for use in studies to enhance other measures of body composition, such as mid-upper arm circumference.