Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T

PURPOSE: To detect neuronal activity–evoked pH changes by amide proton transfer–chemical exchange saturation transfer (APT‐CEST) MRI at 7 T. METHODS: Three healthy subjects participated in the study. A low‐power 3‐dimensional APT‐CEST sequence was optimized through the Bloch‐McConnell equations. pH...

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Autores principales: Khlebnikov, Vitaliy, Siero, Jeroen C.W., Bhogal, Alex A., Luijten, Peter R., Klomp, Dennis W.J., Hoogduin, Hans
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5900917/
https://www.ncbi.nlm.nih.gov/pubmed/29154463
http://dx.doi.org/10.1002/mrm.27013
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author Khlebnikov, Vitaliy
Siero, Jeroen C.W.
Bhogal, Alex A.
Luijten, Peter R.
Klomp, Dennis W.J.
Hoogduin, Hans
author_facet Khlebnikov, Vitaliy
Siero, Jeroen C.W.
Bhogal, Alex A.
Luijten, Peter R.
Klomp, Dennis W.J.
Hoogduin, Hans
author_sort Khlebnikov, Vitaliy
collection PubMed
description PURPOSE: To detect neuronal activity–evoked pH changes by amide proton transfer–chemical exchange saturation transfer (APT‐CEST) MRI at 7 T. METHODS: Three healthy subjects participated in the study. A low‐power 3‐dimensional APT‐CEST sequence was optimized through the Bloch‐McConnell equations. pH sensitivity of the sequence was estimated both in phantoms and in vivo. The feasibility of pH–functional MRI was tested in Bloch‐McConnell‐simulated data using the optimized sequence. In healthy subjects, the visual stimuli were used to evoke transient pH changes in the visual cortex, and a 3‐dimensional APT‐CEST volume was acquired at the pH‐sensitive frequency offset of 3.5 ppm every 12.6 s. RESULTS: In theory, a three‐component general linear model was capable of separating the effects of blood oxygenation level–dependent contrast and pH. The Bloch‐McConnell equations indicated that a change in pH of 0.03 should be measurable at the experimentally determined temporal signal‐to‐noise ratio of 108. However, only a blood oxygenation level–dependent effect in the visual cortex could be discerned during the visual stimuli experiments performed in the healthy subjects. CONCLUSIONS: The results of this study suggest that if indeed there are any transient brain pH changes in response to visual stimuli, those are under 0.03 units pH change, which is extremely difficult to detect using the existent techniques. Magn Reson Med 80:126–136, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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spelling pubmed-59009172018-04-23 Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T Khlebnikov, Vitaliy Siero, Jeroen C.W. Bhogal, Alex A. Luijten, Peter R. Klomp, Dennis W.J. Hoogduin, Hans Magn Reson Med Full Papers—Imaging Methodology PURPOSE: To detect neuronal activity–evoked pH changes by amide proton transfer–chemical exchange saturation transfer (APT‐CEST) MRI at 7 T. METHODS: Three healthy subjects participated in the study. A low‐power 3‐dimensional APT‐CEST sequence was optimized through the Bloch‐McConnell equations. pH sensitivity of the sequence was estimated both in phantoms and in vivo. The feasibility of pH–functional MRI was tested in Bloch‐McConnell‐simulated data using the optimized sequence. In healthy subjects, the visual stimuli were used to evoke transient pH changes in the visual cortex, and a 3‐dimensional APT‐CEST volume was acquired at the pH‐sensitive frequency offset of 3.5 ppm every 12.6 s. RESULTS: In theory, a three‐component general linear model was capable of separating the effects of blood oxygenation level–dependent contrast and pH. The Bloch‐McConnell equations indicated that a change in pH of 0.03 should be measurable at the experimentally determined temporal signal‐to‐noise ratio of 108. However, only a blood oxygenation level–dependent effect in the visual cortex could be discerned during the visual stimuli experiments performed in the healthy subjects. CONCLUSIONS: The results of this study suggest that if indeed there are any transient brain pH changes in response to visual stimuli, those are under 0.03 units pH change, which is extremely difficult to detect using the existent techniques. Magn Reson Med 80:126–136, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. John Wiley and Sons Inc. 2017-11-20 2018-07 /pmc/articles/PMC5900917/ /pubmed/29154463 http://dx.doi.org/10.1002/mrm.27013 Text en © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine 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 Full Papers—Imaging Methodology
Khlebnikov, Vitaliy
Siero, Jeroen C.W.
Bhogal, Alex A.
Luijten, Peter R.
Klomp, Dennis W.J.
Hoogduin, Hans
Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title_full Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title_fullStr Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title_full_unstemmed Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title_short Establishing upper limits on neuronal activity–evoked pH changes with APT‐CEST MRI at 7 T
title_sort establishing upper limits on neuronal activity–evoked ph changes with apt‐cest mri at 7 t
topic Full Papers—Imaging Methodology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5900917/
https://www.ncbi.nlm.nih.gov/pubmed/29154463
http://dx.doi.org/10.1002/mrm.27013
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