Correction of environmental magnetic fields for the acquisition of Nuclear magnetic relaxation dispersion profiles below Earth’s field

Vasileios Zampetoulas; David J. Lurie; Lionel M. Broche

doi:10.1016/j.jmr.2017.07.008

Correction of environmental magnetic fields for the acquisition of Nuclear magnetic relaxation dispersion profiles below Earth’s field

Vasileios Zampetoulas^* (Corresponding Author), David J. Lurie, Lionel M. Broche

^*Corresponding author for this work

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Abstract

T1 relaxation times can be measured at a range of magnetic field strengths by Fast Field-Cycling (FFC) NMR relaxometry to provide T1-dispersion curves. These are valuable tools for the investigation of material properties as they provide information about molecular dynamics non-invasively. However, accessing information at fields below 230 μT (10 kHz proton Larmor frequency) requires careful correction of unwanted environmental magnetic fields.

In this work a novel method is proposed that compensates for the environmental fields on a FFC-NMR relaxometer and extends the acquisition of Nuclear Magnetic Relaxation Dispersion profiles to 2.3 μT (extremely low field region), with direct application in the study of slow molecular motions. Our method is an improvement of an existing technique, reported by Anoardo and Ferrante in 2003, which exploits the non-adiabatic behaviour of the magnetisation in rapidly-varying magnetic fields and makes use of the oscillation of the signal amplitude to estimate the field strength. This increases the accuracy in measuring the environmental fields and allows predicting the optimal correction values by applying simple equations to fit the data acquired. Validation of the method is performed by comparisons with well-known dispersion curves obtained from polymers and benzene.

Original language	English
Pages (from-to)	38-46
Number of pages	8
Journal	Journal of Magnetic Resonance
Volume	282
Early online date	22 Jul 2017
DOIs	https://doi.org/10.1016/j.jmr.2017.07.008
Publication status	Published - Sept 2017

Bibliographical note

V.Z. acknowledges funding from EPSRC under grant number EP/J500045/1, “A UK Magnetic Resonance Basic Technology Centre for Doctoral Training”. Aspects of the work were funded by EPSRC grant EP/K020293/1, “Zero-Field MRI to Enhance Diagnosis of Neurodegeneration”. This project has also received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 668119, project “IDentIFY”. The authors are grateful to Mr. G.P. Ashcroft and Dr. W. Mathieson for providing access to the biological samples used.

Keywords

Fast Field-Cycling MRI
T1 dispersion
ultra-low field applications
MRI contrast

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10.1016/j.jmr.2017.07.008Licence: CC BY

Correction of environmental magnetic fields for the acquisition of Nuclear magnetic relaxation dispersion profiles below Earth’s field
2017 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Final published version, 1.48 MBLicence: CC BY

David Lurie
- School of Medicine, Medical Sciences & Nutrition, Medical Sciences - Emeritus Professor
Person: Honorary

Cite this

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title = "Correction of environmental magnetic fields for the acquisition of Nuclear magnetic relaxation dispersion profiles below Earth{\textquoteright}s field",

abstract = "T1 relaxation times can be measured at a range of magnetic field strengths by Fast Field-Cycling (FFC) NMR relaxometry to provide T1-dispersion curves. These are valuable tools for the investigation of material properties as they provide information about molecular dynamics non-invasively. However, accessing information at fields below 230 μT (10 kHz proton Larmor frequency) requires careful correction of unwanted environmental magnetic fields.In this work a novel method is proposed that compensates for the environmental fields on a FFC-NMR relaxometer and extends the acquisition of Nuclear Magnetic Relaxation Dispersion profiles to 2.3 μT (extremely low field region), with direct application in the study of slow molecular motions. Our method is an improvement of an existing technique, reported by Anoardo and Ferrante in 2003, which exploits the non-adiabatic behaviour of the magnetisation in rapidly-varying magnetic fields and makes use of the oscillation of the signal amplitude to estimate the field strength. This increases the accuracy in measuring the environmental fields and allows predicting the optimal correction values by applying simple equations to fit the data acquired. Validation of the method is performed by comparisons with well-known dispersion curves obtained from polymers and benzene.",

keywords = "Fast Field-Cycling MRI, T1 dispersion, ultra-low field applications, MRI contrast",

author = "Vasileios Zampetoulas and Lurie, {David J.} and Broche, {Lionel M.}",

note = "V.Z. acknowledges funding from EPSRC under grant number EP/J500045/1, “A UK Magnetic Resonance Basic Technology Centre for Doctoral Training”. Aspects of the work were funded by EPSRC grant EP/K020293/1, “Zero-Field MRI to Enhance Diagnosis of Neurodegeneration”. This project has also received funding from the European Union{\textquoteright}s Horizon 2020 research and innovation program under grant agreement No 668119, project “IDentIFY”. The authors are grateful to Mr. G.P. Ashcroft and Dr. W. Mathieson for providing access to the biological samples used.",

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AU - Zampetoulas, Vasileios

AU - Lurie, David J.

AU - Broche, Lionel M.

N1 - V.Z. acknowledges funding from EPSRC under grant number EP/J500045/1, “A UK Magnetic Resonance Basic Technology Centre for Doctoral Training”. Aspects of the work were funded by EPSRC grant EP/K020293/1, “Zero-Field MRI to Enhance Diagnosis of Neurodegeneration”. This project has also received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 668119, project “IDentIFY”. The authors are grateful to Mr. G.P. Ashcroft and Dr. W. Mathieson for providing access to the biological samples used.

PY - 2017/9

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N2 - T1 relaxation times can be measured at a range of magnetic field strengths by Fast Field-Cycling (FFC) NMR relaxometry to provide T1-dispersion curves. These are valuable tools for the investigation of material properties as they provide information about molecular dynamics non-invasively. However, accessing information at fields below 230 μT (10 kHz proton Larmor frequency) requires careful correction of unwanted environmental magnetic fields.In this work a novel method is proposed that compensates for the environmental fields on a FFC-NMR relaxometer and extends the acquisition of Nuclear Magnetic Relaxation Dispersion profiles to 2.3 μT (extremely low field region), with direct application in the study of slow molecular motions. Our method is an improvement of an existing technique, reported by Anoardo and Ferrante in 2003, which exploits the non-adiabatic behaviour of the magnetisation in rapidly-varying magnetic fields and makes use of the oscillation of the signal amplitude to estimate the field strength. This increases the accuracy in measuring the environmental fields and allows predicting the optimal correction values by applying simple equations to fit the data acquired. Validation of the method is performed by comparisons with well-known dispersion curves obtained from polymers and benzene.

AB - T1 relaxation times can be measured at a range of magnetic field strengths by Fast Field-Cycling (FFC) NMR relaxometry to provide T1-dispersion curves. These are valuable tools for the investigation of material properties as they provide information about molecular dynamics non-invasively. However, accessing information at fields below 230 μT (10 kHz proton Larmor frequency) requires careful correction of unwanted environmental magnetic fields.In this work a novel method is proposed that compensates for the environmental fields on a FFC-NMR relaxometer and extends the acquisition of Nuclear Magnetic Relaxation Dispersion profiles to 2.3 μT (extremely low field region), with direct application in the study of slow molecular motions. Our method is an improvement of an existing technique, reported by Anoardo and Ferrante in 2003, which exploits the non-adiabatic behaviour of the magnetisation in rapidly-varying magnetic fields and makes use of the oscillation of the signal amplitude to estimate the field strength. This increases the accuracy in measuring the environmental fields and allows predicting the optimal correction values by applying simple equations to fit the data acquired. Validation of the method is performed by comparisons with well-known dispersion curves obtained from polymers and benzene.

KW - Fast Field-Cycling MRI

KW - T1 dispersion

KW - ultra-low field applications

KW - MRI contrast

U2 - 10.1016/j.jmr.2017.07.008

DO - 10.1016/j.jmr.2017.07.008

M3 - Article

SN - 1090-7807

VL - 282

SP - 38

EP - 46

JO - Journal of Magnetic Resonance

JF - Journal of Magnetic Resonance

ER -

Correction of environmental magnetic fields for the acquisition of Nuclear magnetic relaxation dispersion profiles below Earth’s field

Abstract

Bibliographical note

Keywords

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