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Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T

Laminar fMRI at ultra-high magnetic field strength is typically carried out using the Blood Oxygenation Level-Dependent (BOLD) contrast. Despite its unrivalled sensitivity to detecting activation, the BOLD contrast is limited in its spatial specificity due to signals stemming from intra-cortical asc...

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Autores principales: Kashyap, Sriranga, Ivanov, Dimo, Havlicek, Martin, Huber, Laurentius, Poser, Benedikt A., Uludağ, Kâmil
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075193/
https://www.ncbi.nlm.nih.gov/pubmed/33901230
http://dx.doi.org/10.1371/journal.pone.0250504
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author Kashyap, Sriranga
Ivanov, Dimo
Havlicek, Martin
Huber, Laurentius
Poser, Benedikt A.
Uludağ, Kâmil
author_facet Kashyap, Sriranga
Ivanov, Dimo
Havlicek, Martin
Huber, Laurentius
Poser, Benedikt A.
Uludağ, Kâmil
author_sort Kashyap, Sriranga
collection PubMed
description Laminar fMRI at ultra-high magnetic field strength is typically carried out using the Blood Oxygenation Level-Dependent (BOLD) contrast. Despite its unrivalled sensitivity to detecting activation, the BOLD contrast is limited in its spatial specificity due to signals stemming from intra-cortical ascending and pial veins. Alternatively, regional changes in perfusion (i.e., cerebral blood flow through tissue) are colocalised to neuronal activation, which can be non-invasively measured using Arterial Spin Labelling (ASL) MRI. In addition, ASL provides a quantitative marker of neuronal activation in terms of perfusion signal, which is simultaneously acquired along with the BOLD signal. However, ASL for laminar imaging is challenging due to the lower SNR of the perfusion signal and higher RF power deposition i.e., specific absorption rate (SAR) of ASL sequences. In the present study, we present for the first time in humans, isotropic sub-millimetre spatial resolution functional perfusion images using Flow-sensitive Alternating Inversion Recovery (FAIR) ASL with a 3D-EPI readout at 7 T. We show that robust statistical activation maps can be obtained with perfusion-weighting in a single session. We observed the characteristic BOLD amplitude increase towards the superficial laminae, and, in apparent discrepancy, the relative perfusion profile shows a decrease of the amplitude and the absolute perfusion profile a much smaller increase towards the cortical surface. Considering the draining vein effect on the BOLD signal using model-based spatial “convolution”, we show that the empirically measured perfusion and BOLD profiles are, in fact, consistent with each other. This study demonstrates that laminar perfusion fMRI in humans is feasible at 7 T and that caution must be exercised when interpreting BOLD signal laminar profiles as direct representation of the cortical distribution of neuronal activity.
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spelling pubmed-80751932021-05-05 Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T Kashyap, Sriranga Ivanov, Dimo Havlicek, Martin Huber, Laurentius Poser, Benedikt A. Uludağ, Kâmil PLoS One Research Article Laminar fMRI at ultra-high magnetic field strength is typically carried out using the Blood Oxygenation Level-Dependent (BOLD) contrast. Despite its unrivalled sensitivity to detecting activation, the BOLD contrast is limited in its spatial specificity due to signals stemming from intra-cortical ascending and pial veins. Alternatively, regional changes in perfusion (i.e., cerebral blood flow through tissue) are colocalised to neuronal activation, which can be non-invasively measured using Arterial Spin Labelling (ASL) MRI. In addition, ASL provides a quantitative marker of neuronal activation in terms of perfusion signal, which is simultaneously acquired along with the BOLD signal. However, ASL for laminar imaging is challenging due to the lower SNR of the perfusion signal and higher RF power deposition i.e., specific absorption rate (SAR) of ASL sequences. In the present study, we present for the first time in humans, isotropic sub-millimetre spatial resolution functional perfusion images using Flow-sensitive Alternating Inversion Recovery (FAIR) ASL with a 3D-EPI readout at 7 T. We show that robust statistical activation maps can be obtained with perfusion-weighting in a single session. We observed the characteristic BOLD amplitude increase towards the superficial laminae, and, in apparent discrepancy, the relative perfusion profile shows a decrease of the amplitude and the absolute perfusion profile a much smaller increase towards the cortical surface. Considering the draining vein effect on the BOLD signal using model-based spatial “convolution”, we show that the empirically measured perfusion and BOLD profiles are, in fact, consistent with each other. This study demonstrates that laminar perfusion fMRI in humans is feasible at 7 T and that caution must be exercised when interpreting BOLD signal laminar profiles as direct representation of the cortical distribution of neuronal activity. Public Library of Science 2021-04-26 /pmc/articles/PMC8075193/ /pubmed/33901230 http://dx.doi.org/10.1371/journal.pone.0250504 Text en © 2021 Kashyap et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Kashyap, Sriranga
Ivanov, Dimo
Havlicek, Martin
Huber, Laurentius
Poser, Benedikt A.
Uludağ, Kâmil
Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title_full Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title_fullStr Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title_full_unstemmed Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title_short Sub-millimetre resolution laminar fMRI using Arterial Spin Labelling in humans at 7 T
title_sort sub-millimetre resolution laminar fmri using arterial spin labelling in humans at 7 t
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075193/
https://www.ncbi.nlm.nih.gov/pubmed/33901230
http://dx.doi.org/10.1371/journal.pone.0250504
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