Diffusion‐weighted MRS of acetate in the rat brain. (10th August 2017)

• Record Type: Journal Article
• Authors: Dehghani, Masoumeh; Kunz, Nicolas; Lanz, Bernard; Yoshihara, Hikari A.I.; Gruetter, Rolf
• Is Part Of: NMR in biomedicine. Volume 30:Number 10(2017:Oct.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-10
• Subjects: acetate -- diffusion -- magnetic resonance spectroscopy -- metabolites -- rat brain -- volume of distribution; Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3768
• Languages: English
• ISSNs: 0952-3480

Abstract

Abstract : Acetate has been proposed as an astrocyte‐specific energy substrate for metabolic studies in the brain. The determination of the relative contribution of the intracellular and extracellular compartments to the acetate signal using diffusion‐weighted magnetic resonance spectroscopy can provide an insight into the cellular environment and distribution volume of acetate in the brain. In the present study, localized 1 H nuclear magnetic resonance (NMR) spectroscopy employing a diffusion‐weighted stimulated echo acquisition mode (STEAM) sequence at an ultra‐high magnetic field (14.1 T) was used to investigate the diffusivity characteristics of acetate and N‐ acetylaspartate (NAA) in the rat brain in vivo during prolonged acetate infusion . The persistence of the acetate resonance in 1 H spectra acquired at very large diffusion weighting indicated restricted diffusion of acetate and was attributed to intracellular spaces. However, the significantly greater diffusion of acetate relative to NAA suggests that a substantial fraction of acetate is located in the extracellular space of the brain. Assuming an even distribution for acetate in intracellular and extracellular spaces, the diffusion properties of acetate yielded a smaller volume of distribution for acetate relative to water and glucose in the rat brain. Abstract : The presence of acetate (Ace) resonance in 1 H spectra acquired at very large diffusion weighting, applied using a diffusion‐weighted stimulated echo acquisition mode (STEAM) sequence at 14.1 T, indicated restricted diffusion of Ace attributed to intracellular spaces. However, the significantly larger diffusion of Ace compared with N ‐acetylaspartate (NAA) suggests that a substantial fraction of Ace is located in the extracellular space of the brain. Assuming an even distribution for Ace in the intracellular and extracellular space, the diffusion properties of Ace yielded a smaller volume of distribution for Ace in rat brain compared with water and glucose