Determination of fat and water content in vitro and in vivo by proton nuclear magnetic resonance

Abstract

AbstractProton NMR spectroscopy was performed on a series of pork samples containing varying proportions of fat and muscle and on a series of control and obese mice. Initial measurements were made using a 0.5 T (21 MHz) whole body imaging system and the results were expressed as the ratio of water and lipid hydrogen peak areas. With pork samples the NMR results correlated well with per cent water or lipid in the tissue (r = 0.99 for 20‐ and 50‐g samples). For the mice the correlation between per cent water or lipid in the body and the NMR measurement was 0.92. Subsequent measurements were made using a 4.7 T (200 MHz) imaging/spectrometer from which separate integral values were obtained for the water and lipid hydrogen peaks. The separation of the water and lipid peaks was 3.5 ppm. For pork samples measured with the 4.7 T system the correlation between the peak area and the amount of water or lipid in the sample was 0.997 with the standard error of the estimate being ±0.72 g for water and ±1.00g for lipid. NMR imaging was used to determine the relative amount of fat and muscle in a cross‐section of a control and an obese rat.