Short echo time ¹H MRSI of the human brain at 3T with adiabatic slice‐selective refocusing pulses; reproducibility and variance in a dual center setting

Abstract

Purpose: To assess the reproducibility of 1 H-MR spectroscopic imaging (MRSI) of the human brain at 3T with volume selection by a double spin echo sequence for localization with adiabatic refocusing pulses (semi-LASER). Materials and Methods:Twenty volunteers in two different institutions were measured twice with the same pulse sequence at an echo time of 30 msec. Magnetic resonance (MR) spectra were analyzed with LCModel with a simulated basis set including an experimentally acquired macromolecular signal profile. For specific regions in the brain mean metabolite levels, within and between subject variance, and the coefficient of variation (CoV) were calculated (for taurine, glutamate, total N-acetylaspartate, total creatine, total choline, myo-inositol þ glycine, and glutamate þ glutamine).Results: Repeated measurements showed no significant differences with a paired t-test and a high reproducibility (CoV ranging from 3%-30% throughout the selected volume). Mean metabolite levels and CoV obtained in similar regions in the brain did not differ significantly between two contributing institutions. The major source of differences between different measurements was identified to be the between-subject variations in the volunteers. Conclusion:We conclude that semi-LASER 1 H-MRSI at 3T is an adequate method to obtain quantitative and reproducible measures of metabolite levels over large parts of the brain, applicable across multiple centers.

Multi‐center reproducibility of neurochemical profiles in the human brain at 7 T

“…The average concentrations of quantified metabolites reported in this study matched reasonably well with recently reported values that were obtained from the same brain regions (4,6,8,24-27). In all 108 analyzed spectra, 10 (in WM) – 11 (in GM) metabolites were quantified with an average CRLB of less than 20%.…”

“…The increased accuracy in detection of neurochemical profiles at UHF is supported by the lower CoV compared to other studies (8,10,25,26,28-33). This suggests that metabolites involved in inhibitory and excitatory neurotransmission, such as NAAG, Glu and Gln, can now be detected with higher accuracy.…”

“…Several other studies have investigated the variation in the level of metabolites in the human brain using MRS on lower field strengths (≤3T) (8,10,26,27) and on UHF at a single site (4-6,11). The increased accuracy in detection of neurochemical profiles at UHF is supported by the lower CoV compared to other studies (8,10,25,26,28-33).…”

Characterisation of tissue-type metabolic content in secondary progressive multiple sclerosis: a magnetic resonance spectroscopic imaging study

“…Our findings for the concentrations of choline, creatine and Glx in NAWM compared with GM are consistent with previous studies in healthy controls [12, 16, 17]. …”

Clinical Proton MR Spectroscopy in Central Nervous System Disorders

“…The spectrum of disorders for which (172,173). Importantly, standard clinical hardware generates reproducible MR spectroscopy data from the human brain in a multicenter setting provided spectroscopy at 3.0 T (174), and coefficients of variance less than 10% were reported for tNAA, tCr, tCho, and mIns with MR spectroscopic imaging at 3.0 T Acknowledgments: The initiative for the MRS Consensus paper was proposed by Risto Kauppinen, MD, PhD, in the MR spectroscopy session of the 8th Biennial Minnesota Workshop on High and Ultra-high Field Imaging held in Minneapolis, Minn, in October 2011.…”