Comparison of methods for spectral alignment and signal modelling of GABA-edited MR spectroscopy data

TitleComparison of methods for spectral alignment and signal modelling of GABA-edited MR spectroscopy data
Publication TypeJournal Article
Year of Publication2021
AuthorsRideaux R, Mikkelsen M, Edden RAE
JournalNeuroimage
Volume232
Pagination117900
Date Published2021 May 15
ISSN1095-9572
KeywordsData Analysis, Databases, Factual, gamma-Aminobutyric Acid, Gray Matter, Humans, Magnetic Resonance Spectroscopy, Models, Neurological
Abstract

Many methods exist for aligning and quantifying magnetic resonance spectroscopy (MRS) data to measure in vivo γ-aminobutyric acid (GABA). Research comparing the performance of these methods is scarce partly due to the lack of ground-truth measurements. The concentration of GABA is approximately two times higher in grey matter than in white matter. Here we use the proportion of grey matter within the MRS voxel as a proxy for ground-truth GABA concentration to compare the performance of four spectral alignment methods (i.e., retrospective frequency and phase drift correction) and six GABA signal modelling methods. We analyse a diverse dataset of 432 MEGA-PRESS scans targeting multiple brain regions and find that alignment to the creatine (Cr) signal produces GABA+ estimates that account for approximately twice as much of the variance in grey matter as the next best performing alignment method. Further, Cr alignment was the most robust, producing the fewest outliers. By contrast, all signal modelling methods, except for the single-Lorentzian model, performed similarly well. Our results suggest that variability in performance is primarily caused by differences in the zero-order phase estimated by each alignment method, rather than frequency, resulting from first-order phase offsets within subspectra. These results provide support for Cr alignment as the optimal method of processing MEGA-PRESS to quantify GABA. However, more broadly, they demonstrate a method of benchmarking quantification of in vivo metabolite concentration from other MRS sequences.

DOI10.1016/j.neuroimage.2021.117900
Alternate JournalNeuroimage
PubMed ID33652146
PubMed Central IDPMC8245134
Grant ListK99 EB028828 / EB / NIBIB NIH HHS / United States
P41 EB015909 / EB / NIBIB NIH HHS / United States
R01 EB016089 / EB / NIBIB NIH HHS / United States
R01 EB023963 / EB / NIBIB NIH HHS / United States