The visualisation and quantification of human gastrointestinal fat distribution with MRI: a randomised study in healthy subjects

• Published in: British journal of nutrition Vol. 115; no. 5; pp. 903 - 912
• Main Authors: Liu, Dian, Parker, Helen L., Curcic, Jelena, Schwizer, Werner, Fried, Michael, Kozerke, Sebastian, Steingoetter, Andreas
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 14.03.2016
• Subjects: Body Mass Index; correlation; Correlation coefficient; creaming; Cross-Over Studies; Dietary Fats - administration & dosage; Dietary Fats - metabolism; Digestion; Digestive system; droplet size; Emulsions; experimental design; Female; functional foods; Functional foods & nutraceuticals; Gastric Emptying; Gastrointestinal Contents; gastrointestinal system; Gastrointestinal tract; Gastrointestinal Tract - metabolism; Healthy Volunteers; Humans; Innovative Techniques; least squares; Magnetic Resonance Imaging; Male; NMR; Nuclear magnetic resonance; Oils & fats; Reproducibility of Results; separation; Single-Blind Method; Studies; Young Adult; Lipid emulsions; MRI; Water–fat separation; Gastric physiology; Gastrointestinal function; Healthy subjects; Biophysics of fat digestion; IDEAL iterative decomposition with echo asymmetry and least squares estimation; FCV fat content volume; GI gastrointestinal; TCV total content volumes
• DOI: 10.1017/S0007114515005188
• ISSN: 0007-1145; 1475-2662

We aimed to study the fate of fat during digestion. For this purpose, we validated and investigated the non-invasive quantification of gastric and duodenal fat emptying and emulsion processing (creaming and phase separation) using the MRI method iterative decomposition with echo asymmetry and least squares estimation (IDEAL). In total, twelve healthy subjects were studied on two separate visits in a single-blind, randomised, cross-over design study. IDEAL was utilised to repeatedly acquire quantitative fat fraction maps of the gastrointestinal tract after infusion of one of two fat emulsions: E1 (acid stable, droplet size 0·33 mm) and E4 (acid unstable, 0·38 mm). In vitro and in vivo validation was carried out using diluted emulsion and gastric content samples, respectively, and resulted in Lin’s concordance correlation coefficients of 1·00 (95 % CI 0·98, 1·00) and 0·91 (95 % CI 0·87, 0·94), respectively. Fat fraction maps and intragastric emulsion profiles enabled the identification of features of intraluminal phase separation and creaming that were not visible in conventional MRI. Gastric fat emptying was faster for E4 compared with E1 with a difference of 2·5 (95 % CI 1·9, 3·1) ml/h. Duodenal content volumes were larger for E1 than for E4 with a difference of 4·9 (95 % CI 3·9, 8·5) ml. This study demonstrated that with IDEAL it was possible (1) to visualise the intragastric and duodenal fat distribution and (2) to quantify the differences in emptying, phase separation and creaming of an acid-stable and an acid-unstable emulsion. This method has potential to bridge the gap between current in vitro digestive models and in vivo behaviour and to be applied in the development of effective functional foods.