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Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T

The combination of functional MRI (fMRI) and MRS is a promising approach to relate BOLD imaging to neuronal metabolism, especially at high field strength. However, typical scan times for GABA edited spectroscopy are of the order of 6‐30 min, which is long compared with functional changes observed wi...

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Autores principales: Hendriks, Arjan D., Fracasso, Alessio, Arteaga de Castro, Catalina S., Gosselink, Mark W.J.M., Luijten, Peter R., Petridou, Natalia, Klomp, Dennis W.J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5887933/
https://www.ncbi.nlm.nih.gov/pubmed/29442388
http://dx.doi.org/10.1002/nbm.3890
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author Hendriks, Arjan D.
Fracasso, Alessio
Arteaga de Castro, Catalina S.
Gosselink, Mark W.J.M.
Luijten, Peter R.
Petridou, Natalia
Klomp, Dennis W.J.
author_facet Hendriks, Arjan D.
Fracasso, Alessio
Arteaga de Castro, Catalina S.
Gosselink, Mark W.J.M.
Luijten, Peter R.
Petridou, Natalia
Klomp, Dennis W.J.
author_sort Hendriks, Arjan D.
collection PubMed
description The combination of functional MRI (fMRI) and MRS is a promising approach to relate BOLD imaging to neuronal metabolism, especially at high field strength. However, typical scan times for GABA edited spectroscopy are of the order of 6‐30 min, which is long compared with functional changes observed with fMRI. The aim of this study is to reduce scan time and increase GABA sensitivity for edited spectroscopy in the human visual cortex, by enlarging the volume of activated tissue in the primary visual cortex. A dedicated setup at 7 T for combined fMRI and GABA MRS is developed. This setup consists of a half volume multi‐transmit coil with a large screen for visual cortex activation, two high density receive arrays and an optimized single‐voxel MEGA‐sLASER sequence with macromolecular suppression for signal acquisition. The coil setup performance as well as the GABA measurement speed, SNR, and stability were evaluated. A 2.2‐fold gain of the average SNR for GABA detection was obtained, as compared with a conventional 7 T setup. This was achieved by increasing the viewing angle of the participant with respect to the visual stimulus, thereby activating almost the entire primary visual cortex, allowing larger spectroscopy measurement volumes and resulting in an improved GABA SNR. Fewer than 16 signal averages, lasting 1 min 23 s in total, were needed for the GABA fit method to become stable, as demonstrated in three participants. The stability of the measurement setup was sufficient to detect GABA with an accuracy of 5%, as determined with a GABA phantom. In vivo, larger variations in GABA concentration are found: 14‐25%. Overall, the results bring functional GABA detections at a temporal resolution closer to the physiological time scale of BOLD cortex activation.
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spelling pubmed-58879332018-04-12 Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T Hendriks, Arjan D. Fracasso, Alessio Arteaga de Castro, Catalina S. Gosselink, Mark W.J.M. Luijten, Peter R. Petridou, Natalia Klomp, Dennis W.J. NMR Biomed Research Articles The combination of functional MRI (fMRI) and MRS is a promising approach to relate BOLD imaging to neuronal metabolism, especially at high field strength. However, typical scan times for GABA edited spectroscopy are of the order of 6‐30 min, which is long compared with functional changes observed with fMRI. The aim of this study is to reduce scan time and increase GABA sensitivity for edited spectroscopy in the human visual cortex, by enlarging the volume of activated tissue in the primary visual cortex. A dedicated setup at 7 T for combined fMRI and GABA MRS is developed. This setup consists of a half volume multi‐transmit coil with a large screen for visual cortex activation, two high density receive arrays and an optimized single‐voxel MEGA‐sLASER sequence with macromolecular suppression for signal acquisition. The coil setup performance as well as the GABA measurement speed, SNR, and stability were evaluated. A 2.2‐fold gain of the average SNR for GABA detection was obtained, as compared with a conventional 7 T setup. This was achieved by increasing the viewing angle of the participant with respect to the visual stimulus, thereby activating almost the entire primary visual cortex, allowing larger spectroscopy measurement volumes and resulting in an improved GABA SNR. Fewer than 16 signal averages, lasting 1 min 23 s in total, were needed for the GABA fit method to become stable, as demonstrated in three participants. The stability of the measurement setup was sufficient to detect GABA with an accuracy of 5%, as determined with a GABA phantom. In vivo, larger variations in GABA concentration are found: 14‐25%. Overall, the results bring functional GABA detections at a temporal resolution closer to the physiological time scale of BOLD cortex activation. John Wiley and Sons Inc. 2018-02-14 2018-04 /pmc/articles/PMC5887933/ /pubmed/29442388 http://dx.doi.org/10.1002/nbm.3890 Text en © 2018 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Research Articles
Hendriks, Arjan D.
Fracasso, Alessio
Arteaga de Castro, Catalina S.
Gosselink, Mark W.J.M.
Luijten, Peter R.
Petridou, Natalia
Klomp, Dennis W.J.
Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title_full Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title_fullStr Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title_full_unstemmed Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title_short Maximizing sensitivity for fast GABA edited spectroscopy in the visual cortex at 7 T
title_sort maximizing sensitivity for fast gaba edited spectroscopy in the visual cortex at 7 t
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5887933/
https://www.ncbi.nlm.nih.gov/pubmed/29442388
http://dx.doi.org/10.1002/nbm.3890
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