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Understanding the physical relations governing the noise navigator
PURPOSE: The noise navigator is a passive way to detect physiological motion occurring in a patient through thermal noise modulations measured by standard clinical radiofrequency receive coils. The aim is to gain a deeper understanding of the potential and applications of physiologically induced the...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771522/ https://www.ncbi.nlm.nih.gov/pubmed/31317566 http://dx.doi.org/10.1002/mrm.27906 |
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author | Navest, R. J. M. Mandija, S. Andreychenko, A. Raaijmakers, A. J. E. Lagendijk, J. J. W. van den Berg, C. A. T. |
author_facet | Navest, R. J. M. Mandija, S. Andreychenko, A. Raaijmakers, A. J. E. Lagendijk, J. J. W. van den Berg, C. A. T. |
author_sort | Navest, R. J. M. |
collection | PubMed |
description | PURPOSE: The noise navigator is a passive way to detect physiological motion occurring in a patient through thermal noise modulations measured by standard clinical radiofrequency receive coils. The aim is to gain a deeper understanding of the potential and applications of physiologically induced thermal noise modulations. METHODS: Numerical electromagnetic simulations and MR measurements were performed to investigate the relative contribution of tissue displacement versus modulation of the dielectric lung properties over the respiratory cycle, the impact of coil diameter and position with respect to the body. Furthermore, the spatial motion sensitivity of specific noise covariance matrix elements of a receive array was investigated. RESULTS: The influence of dielectric lung property variations on the noise variance is negligible compared to tissue displacement. Coil size affected the thermal noise variance modulation, but the location of the coil with respect to the body had a larger impact. The modulation depth of a 15 cm diameter stationary coil approximately 3 cm away from the chest (i.e. radiotherapy setup) was 39.7% compared to 4.2% for a coil of the same size on the chest, moving along with respiratory motion. A combination of particular noise covariance matrix elements creates a specific spatial sensitivity for motion. CONCLUSIONS: The insight gained on the physical relations governing the noise navigator will allow for optimized use and development of new applications. An optimized combination of elements from the noise covariance matrix offer new ways of performing, e.g. motion tracking. |
format | Online Article Text |
id | pubmed-6771522 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-67715222019-10-03 Understanding the physical relations governing the noise navigator Navest, R. J. M. Mandija, S. Andreychenko, A. Raaijmakers, A. J. E. Lagendijk, J. J. W. van den Berg, C. A. T. Magn Reson Med Full Papers—Biophysics and Basic Biomedical Research PURPOSE: The noise navigator is a passive way to detect physiological motion occurring in a patient through thermal noise modulations measured by standard clinical radiofrequency receive coils. The aim is to gain a deeper understanding of the potential and applications of physiologically induced thermal noise modulations. METHODS: Numerical electromagnetic simulations and MR measurements were performed to investigate the relative contribution of tissue displacement versus modulation of the dielectric lung properties over the respiratory cycle, the impact of coil diameter and position with respect to the body. Furthermore, the spatial motion sensitivity of specific noise covariance matrix elements of a receive array was investigated. RESULTS: The influence of dielectric lung property variations on the noise variance is negligible compared to tissue displacement. Coil size affected the thermal noise variance modulation, but the location of the coil with respect to the body had a larger impact. The modulation depth of a 15 cm diameter stationary coil approximately 3 cm away from the chest (i.e. radiotherapy setup) was 39.7% compared to 4.2% for a coil of the same size on the chest, moving along with respiratory motion. A combination of particular noise covariance matrix elements creates a specific spatial sensitivity for motion. CONCLUSIONS: The insight gained on the physical relations governing the noise navigator will allow for optimized use and development of new applications. An optimized combination of elements from the noise covariance matrix offer new ways of performing, e.g. motion tracking. John Wiley and Sons Inc. 2019-07-17 2019-12 /pmc/articles/PMC6771522/ /pubmed/31317566 http://dx.doi.org/10.1002/mrm.27906 Text en © 2019 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—Biophysics and Basic Biomedical Research Navest, R. J. M. Mandija, S. Andreychenko, A. Raaijmakers, A. J. E. Lagendijk, J. J. W. van den Berg, C. A. T. Understanding the physical relations governing the noise navigator |
title | Understanding the physical relations governing the noise navigator |
title_full | Understanding the physical relations governing the noise navigator |
title_fullStr | Understanding the physical relations governing the noise navigator |
title_full_unstemmed | Understanding the physical relations governing the noise navigator |
title_short | Understanding the physical relations governing the noise navigator |
title_sort | understanding the physical relations governing the noise navigator |
topic | Full Papers—Biophysics and Basic Biomedical Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771522/ https://www.ncbi.nlm.nih.gov/pubmed/31317566 http://dx.doi.org/10.1002/mrm.27906 |
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