title: The in vivo J-difference editing MEGA-PRESS technique for the detection of n-3 fatty acids.
abstract: In this study, we present a method for the detection of n-3 fatty acid (n-3 FA) signals using MRS in adipose tissue in vivo. This method (called oMEGA-PRESS) is based on the selective detection of the CH3 signal of n-3 FA using the MEGA-PRESS (MEshcher-GArwood Point-RESolved Spectroscopy) J-difference editing technique. We optimized the envelope shape and frequency of spectral editing pulses to minimize the spurious co-editing and incomplete subtraction of the CH3 signal of other FAs, which normally obscure the n-3 FA CH3 signal in MR spectra acquired using standard PRESS techniques. The post-processing of the individual data scans with the phase and frequency correction before data subtraction and averaging was implemented to further improve the quality of in vivo spectra. The technique was optimized in vitro on lipid phantoms using various concentrations of n-3 FA and examined in vivo at 3 T on 15 healthy volunteers. The proportion of n-3 FA estimated by the oMEGA-PRESS method in phantoms showed a highly significant linear correlation with the n-3 FA content determined by gas chromatography. The signal attributed to n-3 FA was observed in all subjects. Comparisons with the standard PRESS technique revealed an enhanced identification of the n-3 FA signal using oMEGA-PRESS. The presented method may be useful for the non-invasive quantification of n-3 FA in adipose tissue, and could aid in obtaining a better understanding of various aspects of n-3 FA metabolism.
authors.affiliation: MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors.forename: Antonín
authors.initials: A
authors.lastname: Skoch
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Tošner
authors.forename: Milan
authors.initials: M
authors.lastname: Hájek
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D015992:Body Mass Index; D002849:Chromatography, Gas; D015525:Fatty Acids, Omega-3 / Q000032:analysis*; D006801:Humans; D008043:Linseed Oil / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D019047:Phantoms, Imaging; D010938:Plant Oils / Q000737:chemistry; D050151:Subcutaneous Fat / Q000737:chemistry; D000074242:Sunflower Oil
chemical_list: D015525:Fatty Acids, Omega-3; D010938:Plant Oils; D000074242:Sunflower Oil; D008043:Linseed Oil
keywords: J-difference editing; MEGA-PRESS; in vivo MRS; n-3 fatty acids; oMEGA-PRESS