Noninvasive quantification of axon radii using diffusion MRI
Axon caliber plays a crucial role in determining conduction velocity and, consequently, in the timing and synchronization of neural activation. Noninvasive measurement of axon radii could have significant impact on the understanding of healthy and diseased neural processes. Until now, accurate axon...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2020-02-01
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| Series: | eLife |
| Subjects: | |
| Online Access: | https://elifesciences.org/articles/49855 |
| _version_ | 1811181030966558720 |
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| author | Jelle Veraart Daniel Nunes Umesh Rudrapatna Els Fieremans Derek K Jones Dmitry S Novikov Noam Shemesh |
| author_facet | Jelle Veraart Daniel Nunes Umesh Rudrapatna Els Fieremans Derek K Jones Dmitry S Novikov Noam Shemesh |
| author_sort | Jelle Veraart |
| collection | DOAJ |
| description | Axon caliber plays a crucial role in determining conduction velocity and, consequently, in the timing and synchronization of neural activation. Noninvasive measurement of axon radii could have significant impact on the understanding of healthy and diseased neural processes. Until now, accurate axon radius mapping has eluded in vivo neuroimaging, mainly due to a lack of sensitivity of the MRI signal to micron-sized axons. Here, we show how – when confounding factors such as extra-axonal water and axonal orientation dispersion are eliminated – heavily diffusion-weighted MRI signals become sensitive to axon radii. However, diffusion MRI is only capable of estimating a single metric, the effective radius, representing the entire axon radius distribution within a voxel that emphasizes the larger axons. Our findings, both in rodents and humans, enable noninvasive mapping of critical information on axon radii, as well as resolve the long-standing debate on whether axon radii can be quantified. |
| first_indexed | 2024-04-11T09:12:31Z |
| format | Article |
| id | doaj.art-50d3eb14eda84ed6a35ad974a565f3f0 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-11T09:12:31Z |
| publishDate | 2020-02-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-50d3eb14eda84ed6a35ad974a565f3f02022-12-22T04:32:28ZengeLife Sciences Publications LtdeLife2050-084X2020-02-01910.7554/eLife.49855Noninvasive quantification of axon radii using diffusion MRIJelle Veraart0https://orcid.org/0000-0003-0781-0420Daniel Nunes1https://orcid.org/0000-0001-8882-3228Umesh Rudrapatna2Els Fieremans3https://orcid.org/0000-0002-1384-8591Derek K Jones4Dmitry S Novikov5https://orcid.org/0000-0002-4213-3050Noam Shemesh6https://orcid.org/0000-0001-6681-5876Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal; Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, United States; imec-Vision Lab, Department of Physics, University of Antwerp, Antwerp, BelgiumChampalimaud Research, Champalimaud Centre for the Unknown, Lisbon, PortugalCUBRIC, School of Psychology, Cardiff University, Cardiff, United KingdomCenter for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, United StatesCUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom; Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, AustraliaCenter for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, United StatesChampalimaud Research, Champalimaud Centre for the Unknown, Lisbon, PortugalAxon caliber plays a crucial role in determining conduction velocity and, consequently, in the timing and synchronization of neural activation. Noninvasive measurement of axon radii could have significant impact on the understanding of healthy and diseased neural processes. Until now, accurate axon radius mapping has eluded in vivo neuroimaging, mainly due to a lack of sensitivity of the MRI signal to micron-sized axons. Here, we show how – when confounding factors such as extra-axonal water and axonal orientation dispersion are eliminated – heavily diffusion-weighted MRI signals become sensitive to axon radii. However, diffusion MRI is only capable of estimating a single metric, the effective radius, representing the entire axon radius distribution within a voxel that emphasizes the larger axons. Our findings, both in rodents and humans, enable noninvasive mapping of critical information on axon radii, as well as resolve the long-standing debate on whether axon radii can be quantified.https://elifesciences.org/articles/49855corpus callosumwhite matteraxon diameterdiffusion MRI |
| spellingShingle | Jelle Veraart Daniel Nunes Umesh Rudrapatna Els Fieremans Derek K Jones Dmitry S Novikov Noam Shemesh Noninvasive quantification of axon radii using diffusion MRI eLife corpus callosum white matter axon diameter diffusion MRI |
| title | Noninvasive quantification of axon radii using diffusion MRI |
| title_full | Noninvasive quantification of axon radii using diffusion MRI |
| title_fullStr | Noninvasive quantification of axon radii using diffusion MRI |
| title_full_unstemmed | Noninvasive quantification of axon radii using diffusion MRI |
| title_short | Noninvasive quantification of axon radii using diffusion MRI |
| title_sort | noninvasive quantification of axon radii using diffusion mri |
| topic | corpus callosum white matter axon diameter diffusion MRI |
| url | https://elifesciences.org/articles/49855 |
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