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

Abstract

Purpose: To demonstrate, at 9.4 T, that J-coupling interactions exhibited by lipid protons affects lipid composition determination with a point resolved spectroscopy (PRESS) sequence. Materials and Methods:Experiments were conducted on four oils (almond, corn, sesame, and sunflower), on visceral adipose tissue of a euthanized mouse, and on pure linoleic acid at 9.4 T. The 2.1, 2.3, and 2.8 ppm resonances were measured at multiple echo times (TEs) by a standard PRESS sequence and by a PRESS sequence consisting of narrow-bandwidth refocusing pulses designed to rewind the J-coupling evolution of the target peak protons in the voxel of interest. T 2 corrections were performed on both groups of data for the three peaks and lipid compositions for the oils and for the mouse tissue were determined. Lipid compositions were also calculated from a short-TE standard PRESS spectrum.Results: A chemical analysis of the samples was not performed; however, the oil compositions calculated from resonance peaks acquired with the PRESS sequence designed to minimize J-coupling effects, following T 2 relaxation correction, closely agreed with values in the literature, which was not the case for all of the compositions determined from the regular PRESS spectra. Conclusion:The presented work brings to attention the significance of J-coupling effects when calculating lipid compositions from localized proton spectra.

Hepatic lipid composition differs between ob/ob and ob/+ control mice as determined by using in vivo localized proton magnetic resonance spectroscopy

“…Due to J-coupling T 2 values obtained from PRESS experiments are smaller than those obtained when using the STEAM sequence [42,43], which might affect the accuracy of the intensity quantification. Based on literature data [43], we estimated that the effect of J-coupling modulation on I(0) values would be of the order of ±10%, which would translate into corresponding uncertainties regarding the parameters describing the lipid composition The conclusion regarding these parameters describing hepatic lipid composition is not affected by the deviation. Statistically significant differences between ob/ob and ob/?…”

In vivo proton magnetic resonance spectroscopy of liver metabolites in non-alcoholic fatty liver disease in rats: T2 relaxation times in methylene protons

“…Typically, spectra obtained from in vivo 1 H MRS of liver tissue show various lipid peaks as well as choline-containing compounds from the range of 0.9-5.3 ppm (Cheung et al, 2011;Ramamonjisoa et al, 2013). It has been suggested that these possess the characteristics and can be associated with specific lipid resonances (CH 3, 0.9 ppm; (CH 2 ) n, 1.3 ppm; CH 2 C¼CCH 2 , 2.1 ppm; ¼CCH 2 C¼, 2.8 ppm;CH¼CH, 5.3 ppm) (Lim et al, 2003;Gentile and Pagliassotti, 2008;Corbin et al, 2009;Cheung et al, 2011;Yahya et al, 2011;Gajdošík et al, 2014).…”

“…A recent study investigated the effect of J-coupling on the determination of lipid composition with T2 relaxation times using localized 1 H MRS (Yahya and Fallone, 2010;Yahya et al, 2011). T2 relaxation times were assessed using a standard PRESS sequence and narrowbandwidth PRESS sequence (Yahya et al, 2011;Gajdošík et al, 2014). The results were compared at resonances of 2.1, 2.3, and 2.8 ppm at multiple TEs (Yahya et al, 2011).…”

“…The J-coupling of lipid resonances cannot be easily analyzed and modeled (Hamilton et al, 2009). A recent study investigated the effect of J-coupling on the determination of lipid composition with T2 relaxation times using localized 1 H MRS (Yahya and Fallone, 2010;Yahya et al, 2011). T2 relaxation times were assessed using a standard PRESS sequence and narrowbandwidth PRESS sequence (Yahya et al, 2011;Gajdošík et al, 2014).…”

“…T2 relaxation times were assessed using a standard PRESS sequence and narrowbandwidth PRESS sequence (Yahya et al, 2011;Gajdošík et al, 2014). The results were compared at resonances of 2.1, 2.3, and 2.8 ppm at multiple TEs (Yahya et al, 2011). The T2 relaxation time of methylene protons was also determined from acquired spectra using a standard PRESS sequence (Oostendorp et al, 2006;Hamilton et al, 2009;Ramadan et al, 2010;Yahya et al, 2011).…”