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Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight
A subset of long-duration spaceflight astronauts have experienced ophthalmic abnormalities, collectively termed spaceflight-associated neuro-ocular syndrome (SANS). Little is understood about the pathophysiology of SANS; however, microgravity-induced alterations in intracranial pressure (ICP) due to...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7545196/ https://www.ncbi.nlm.nih.gov/pubmed/33083526 http://dx.doi.org/10.1038/s41526-020-00119-3 |
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author | Rohr, Jesse J. Sater, Stuart Sass, Austin M. Marshall-Goebel, Karina Ploutz-Snyder, Robert J. Ethier, C. Ross Stenger, Michael B. Martin, Bryn A. Macias, Brandon R. |
author_facet | Rohr, Jesse J. Sater, Stuart Sass, Austin M. Marshall-Goebel, Karina Ploutz-Snyder, Robert J. Ethier, C. Ross Stenger, Michael B. Martin, Bryn A. Macias, Brandon R. |
author_sort | Rohr, Jesse J. |
collection | PubMed |
description | A subset of long-duration spaceflight astronauts have experienced ophthalmic abnormalities, collectively termed spaceflight-associated neuro-ocular syndrome (SANS). Little is understood about the pathophysiology of SANS; however, microgravity-induced alterations in intracranial pressure (ICP) due to headward fluid shifts is the primary hypothesized contributor. In particular, potential changes in optic nerve (ON) tortuosity and ON sheath (ONS) distension may indicate altered cerebrospinal fluid dynamics during weightlessness. The present longitudinal study aims to provide a quantitative analysis of ON and ONS cross-sectional areas, and ON deviation, an indication of tortuosity, before and after spaceflight. Ten astronauts undergoing ~6-month missions on the International Space Station (ISS) underwent high-resolution magnetic resonance imaging (MRI) preflight and at five recovery time points extending to 1 year after return from the ISS. The mean changes in ON deviation, ON cross-sectional area, and ONS cross-sectional area immediately post flight were −0.14 mm (95% CI: −0.36 to 0.08, Bonferroni-adjusted P = 1.00), 0.13 mm(2) (95% CI −0.66 to 0.91, Bonferroni-adjusted P = 1.00), and −0.22 mm(2) (95% CI: −1.78 to 1.34, Bonferroni-adjusted P = 1.00), respectively, and remained consistent during the recovery period. Terrestrially, ONS distension is associated with increased ICP; therefore, these results suggest that, on average, ICP was not pathologically elevated immediately after spaceflight. However, a subject diagnosed with optic disc edema (Frisen Grade 1, right eye) displayed increased ONS area post flight, although this increase is relatively small compared to clinical populations with increased ICP. Advanced quantitative MRI-based assessment of the ON and ONS could help our understanding of SANS and the role of ICP. |
format | Online Article Text |
id | pubmed-7545196 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-75451962020-10-19 Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight Rohr, Jesse J. Sater, Stuart Sass, Austin M. Marshall-Goebel, Karina Ploutz-Snyder, Robert J. Ethier, C. Ross Stenger, Michael B. Martin, Bryn A. Macias, Brandon R. NPJ Microgravity Article A subset of long-duration spaceflight astronauts have experienced ophthalmic abnormalities, collectively termed spaceflight-associated neuro-ocular syndrome (SANS). Little is understood about the pathophysiology of SANS; however, microgravity-induced alterations in intracranial pressure (ICP) due to headward fluid shifts is the primary hypothesized contributor. In particular, potential changes in optic nerve (ON) tortuosity and ON sheath (ONS) distension may indicate altered cerebrospinal fluid dynamics during weightlessness. The present longitudinal study aims to provide a quantitative analysis of ON and ONS cross-sectional areas, and ON deviation, an indication of tortuosity, before and after spaceflight. Ten astronauts undergoing ~6-month missions on the International Space Station (ISS) underwent high-resolution magnetic resonance imaging (MRI) preflight and at five recovery time points extending to 1 year after return from the ISS. The mean changes in ON deviation, ON cross-sectional area, and ONS cross-sectional area immediately post flight were −0.14 mm (95% CI: −0.36 to 0.08, Bonferroni-adjusted P = 1.00), 0.13 mm(2) (95% CI −0.66 to 0.91, Bonferroni-adjusted P = 1.00), and −0.22 mm(2) (95% CI: −1.78 to 1.34, Bonferroni-adjusted P = 1.00), respectively, and remained consistent during the recovery period. Terrestrially, ONS distension is associated with increased ICP; therefore, these results suggest that, on average, ICP was not pathologically elevated immediately after spaceflight. However, a subject diagnosed with optic disc edema (Frisen Grade 1, right eye) displayed increased ONS area post flight, although this increase is relatively small compared to clinical populations with increased ICP. Advanced quantitative MRI-based assessment of the ON and ONS could help our understanding of SANS and the role of ICP. Nature Publishing Group UK 2020-10-08 /pmc/articles/PMC7545196/ /pubmed/33083526 http://dx.doi.org/10.1038/s41526-020-00119-3 Text en © The Author(s) 2020 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Article Rohr, Jesse J. Sater, Stuart Sass, Austin M. Marshall-Goebel, Karina Ploutz-Snyder, Robert J. Ethier, C. Ross Stenger, Michael B. Martin, Bryn A. Macias, Brandon R. Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title | Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title_full | Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title_fullStr | Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title_full_unstemmed | Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title_short | Quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
title_sort | quantitative magnetic resonance image assessment of the optic nerve and surrounding sheath after spaceflight |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7545196/ https://www.ncbi.nlm.nih.gov/pubmed/33083526 http://dx.doi.org/10.1038/s41526-020-00119-3 |
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