Composition of adipose tissue and marrow fat in humans by 1H NMR at 7 Tesla

Abstract

Proton NMR spectroscopy at 7 Tesla (7T) was evaluated as a new method to quantify human fat composition noninvasively. In validation experiments, the composition of a known mixture of triolein, tristearin, and trilinolein agreed well with measurements by 1 H NMR spectroscopy. Triglycerides in calf subcutaneous tissue and tibial bone marrow were examined in 20 healthy subjects by 1 H spectroscopy. Ten well-resolved proton resonances from triglycerides were detected using stimulated echo acquisition mode sequence and small voxel (?0.1 ml), and T 1 and T 2 were measured. Triglyceride composition was not different between calf subcutaneous adipose tissue and tibial marrow for a given subject, and its variation among subjects, as a result of diet and genetic differences, fell in a narrow range. After correction for differential relaxation effects, the marrow fat composition was 29.1 6 3.5% saturated, 46.4 6 4.8% monounsaturated, and 24.5 6 3.1% diunsaturated, compared with adipose fat composition, 27.1 6 4.2% saturated, 49.6 6 5.7% monounsaturated, and 23.4 6 3.9% diunsaturated. Proton spectroscopy at 7T offers a simple, fast, noninvasive, and painless method for obtaining detailed information about lipid composition in humans, and the sensitivity and resolution of the method may facilitate longitudinal monitoring of changes in lipid composition in response to diet, exercise, and

Proton density water fraction as a biomarker of bone marrow cellularity: Validation in ex vivo spine specimens

“…Another finding from biochemical assay is that the lipid in bone marrow is essentially all in the form of triglyceride, in agreement with a previous study [15]. The Bland-Altman plot in Fig.…”

“…Panel A shows a Bland-Altman plot for the biochemical assays for triglyceride and total lipid; the very small difference between the two quantities indicates that, within error, all lipids in the samples are present as triglyceride. This finding is consistent with a previous study that reported that adipose tissue is predominantly triglyceride [15]. For the remainder of the study, the lipid and triglyceride are combined into an average Fat (%) content, defined in Methods.…”

Effect of J‐coupling on lipid composition determination with localized proton magnetic resonance spectroscopy at 9.4 T

“…It has been suggested that there may be a link between the composition of fatty tissue and the risk of suffering from such diseases (11,12). The amounts of saturated, monounsaturated, and polyunsaturated fatty acids composing a lipid can be determined from a high-resolution NMR (nuclear magnetic resonance) spectrum of the sample.…”

“…High-resolution NMR has been employed to identify the constituents of oils, animal fats, and extracts of rat adipose tissue (13)(14)(15)(16). Recently, in vivo MRS measurements of rodents (12,17,18) and humans (11) have been performed at high field strengths to calculate adipose tissue composition from the areas of the 2.1 ppm, 2.3 ppm, and 2.8 ppm (diallylic protons) proton lipid peaks. Previous studies (11,12,18) utilized the popular PRESS (point resolved spectroscopy) (19,20) pulse sequence for spatial localization.…”

“…Recently, in vivo MRS measurements of rodents (12,17,18) and humans (11) have been performed at high field strengths to calculate adipose tissue composition from the areas of the 2.1 ppm, 2.3 ppm, and 2.8 ppm (diallylic protons) proton lipid peaks. Previous studies (11,12,18) utilized the popular PRESS (point resolved spectroscopy) (19,20) pulse sequence for spatial localization. During the PRESS echo time, TE, the signal of each lipid resonance decays due to transverse relaxation according to a T 2 constant characteristic of the protons contributing to that peak.…”