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Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast

The pulsatility of blood flow through cerebral arteries is clinically important, as it is intrinsically associated with cerebrovascular health. In this study we outline a new MRI approach to measuring the real-time pulsatile flow in cerebral arteries, which is based on the inflow phenomenon associat...

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Autores principales: Whittaker, Joseph R., Fasano, Fabrizio, Venzi, Marcello, Liebig, Patrick, Gallichan, Daniel, Möller, Harald E., Murphy, Kevin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8802674/
https://www.ncbi.nlm.nih.gov/pubmed/35110991
http://dx.doi.org/10.3389/fnins.2021.795749
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author Whittaker, Joseph R.
Fasano, Fabrizio
Venzi, Marcello
Liebig, Patrick
Gallichan, Daniel
Möller, Harald E.
Murphy, Kevin
author_facet Whittaker, Joseph R.
Fasano, Fabrizio
Venzi, Marcello
Liebig, Patrick
Gallichan, Daniel
Möller, Harald E.
Murphy, Kevin
author_sort Whittaker, Joseph R.
collection PubMed
description The pulsatility of blood flow through cerebral arteries is clinically important, as it is intrinsically associated with cerebrovascular health. In this study we outline a new MRI approach to measuring the real-time pulsatile flow in cerebral arteries, which is based on the inflow phenomenon associated with fast gradient-recalled-echo acquisitions. Unlike traditional phase-contrast techniques, this new method, which we dub dynamic inflow magnitude contrast (DIMAC), does not require velocity-encoding gradients as sensitivity to flow velocity is derived purely from the inflow effect. We achieved this using a highly accelerated single slice EPI acquisition with a very short TR (15 ms) and a 90° flip angle, thus maximizing inflow contrast. We simulate the spoiled GRE signal in the presence of large arteries and perform a sensitivity analysis. The sensitivity analysis demonstrates that in the regime of high inflow contrast, DIMAC shows much greater sensitivity to flow velocity over blood volume changes. We support this theoretical prediction with in-vivo data collected in two separate experiments designed to demonstrate the utility of the DIMAC signal contrast. We perform a hypercapnia challenge experiment in order to experimentally modulate arterial tone within subjects, and thus modulate the arterial pulsatile flow waveform. We also perform a thigh-cuff release challenge, designed to induce a transient drop in blood pressure, and demonstrate that the continuous DIMAC signal captures the complex transient change in the pulsatile and non-pulsatile components of flow. In summary, this study proposes a new role for a well-established source of MR image contrast and demonstrates its potential for measuring both steady-state and dynamic changes in arterial tone.
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spelling pubmed-88026742022-02-01 Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast Whittaker, Joseph R. Fasano, Fabrizio Venzi, Marcello Liebig, Patrick Gallichan, Daniel Möller, Harald E. Murphy, Kevin Front Neurosci Neuroscience The pulsatility of blood flow through cerebral arteries is clinically important, as it is intrinsically associated with cerebrovascular health. In this study we outline a new MRI approach to measuring the real-time pulsatile flow in cerebral arteries, which is based on the inflow phenomenon associated with fast gradient-recalled-echo acquisitions. Unlike traditional phase-contrast techniques, this new method, which we dub dynamic inflow magnitude contrast (DIMAC), does not require velocity-encoding gradients as sensitivity to flow velocity is derived purely from the inflow effect. We achieved this using a highly accelerated single slice EPI acquisition with a very short TR (15 ms) and a 90° flip angle, thus maximizing inflow contrast. We simulate the spoiled GRE signal in the presence of large arteries and perform a sensitivity analysis. The sensitivity analysis demonstrates that in the regime of high inflow contrast, DIMAC shows much greater sensitivity to flow velocity over blood volume changes. We support this theoretical prediction with in-vivo data collected in two separate experiments designed to demonstrate the utility of the DIMAC signal contrast. We perform a hypercapnia challenge experiment in order to experimentally modulate arterial tone within subjects, and thus modulate the arterial pulsatile flow waveform. We also perform a thigh-cuff release challenge, designed to induce a transient drop in blood pressure, and demonstrate that the continuous DIMAC signal captures the complex transient change in the pulsatile and non-pulsatile components of flow. In summary, this study proposes a new role for a well-established source of MR image contrast and demonstrates its potential for measuring both steady-state and dynamic changes in arterial tone. Frontiers Media S.A. 2022-01-17 /pmc/articles/PMC8802674/ /pubmed/35110991 http://dx.doi.org/10.3389/fnins.2021.795749 Text en Copyright © 2022 Whittaker, Fasano, Venzi, Liebig, Gallichan, Möller and Murphy. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Whittaker, Joseph R.
Fasano, Fabrizio
Venzi, Marcello
Liebig, Patrick
Gallichan, Daniel
Möller, Harald E.
Murphy, Kevin
Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title_full Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title_fullStr Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title_full_unstemmed Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title_short Measuring Arterial Pulsatility With Dynamic Inflow Magnitude Contrast
title_sort measuring arterial pulsatility with dynamic inflow magnitude contrast
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8802674/
https://www.ncbi.nlm.nih.gov/pubmed/35110991
http://dx.doi.org/10.3389/fnins.2021.795749
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