Diffusion-weighted spectroscopy: A novel approach to determine macromolecule resonances in short-echo time 1H-MRS

✍ Scribed by N. Kunz; C. Cudalbu; V. Mlynarik; P. S. Hüppi; S. V. Sizonenko; R. Gruetter

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 450 KB
• Volume: 64
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.22490

✦ Synopsis

Abstract

Quantification of short‐echo time proton magnetic resonance spectroscopy results in >18 metabolite concentrations (neurochemical profile). Their quantification accuracy depends on the assessment of the contribution of macromolecule (MM) resonances, previously experimentally achieved by exploiting the several fold difference in T~1~. To minimize effects of heterogeneities in metabolites T~1~, the aim of the study was to assess MM signal contributions by combining inversion recovery (IR) and diffusion‐weighted proton spectroscopy at high‐magnetic field (14.1 T) and short echo time (=8 msec) in the rat brain. IR combined with diffusion weighting experiments (with δ/Δ = 1.5/200 msec and b‐value = 11.8 msec/μm^2^) showed that the metabolite nulled spectrum (inversion time = 740 msec) was affected by residuals attributed to creatine, inositol, taurine, choline, N‐acetylaspartate as well as glutamine and glutamate. While the metabolite residuals were significantly attenuated by 50%, the MM signals were almost not affected (<8%). The combination of metabolite‐nulled IR spectra with diffusion weighting allows a specific characterization of MM resonances with minimal metabolite signal contributions and is expected to lead to a more precise quantification of the neurochemical profile. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.