Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging
Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited fro...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2021-06-01
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| Series: | Frontiers in Physiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fphys.2021.639360/full |
| _version_ | 1819012235218911232 |
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| author | Julien Poublanc Reema Shafi Olivia Sobczyk Olivia Sobczyk Kevin Sam Daniel M. Mandell Lakshmikumar Venkatraghavan James Duffin James Duffin Joseph A. Fisher Joseph A. Fisher Joseph A. Fisher David J. Mikulis David J. Mikulis |
| author_facet | Julien Poublanc Reema Shafi Olivia Sobczyk Olivia Sobczyk Kevin Sam Daniel M. Mandell Lakshmikumar Venkatraghavan James Duffin James Duffin Joseph A. Fisher Joseph A. Fisher Joseph A. Fisher David J. Mikulis David J. Mikulis |
| author_sort | Julien Poublanc |
| collection | DOAJ |
| description | Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values. |
| first_indexed | 2024-12-21T01:40:49Z |
| format | Article |
| id | doaj.art-269635b053af44ee9aacd979b4139742 |
| institution | Directory Open Access Journal |
| issn | 1664-042X |
| language | English |
| last_indexed | 2024-12-21T01:40:49Z |
| publishDate | 2021-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physiology |
| spelling | doaj.art-269635b053af44ee9aacd979b41397422022-12-21T19:20:09ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2021-06-011210.3389/fphys.2021.639360639360Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume AveragingJulien Poublanc0Reema Shafi1Olivia Sobczyk2Olivia Sobczyk3Kevin Sam4Daniel M. Mandell5Lakshmikumar Venkatraghavan6James Duffin7James Duffin8Joseph A. Fisher9Joseph A. Fisher10Joseph A. Fisher11David J. Mikulis12David J. Mikulis13Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, CanadaJoint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, CanadaJoint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, CanadaDepartment of Anesthesia and Pain Management, University Health Network, Toronto, ON, CanadaDepartment of Radiology and Radiological Sciences, Johns Hopkins University, United StatesJoint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, CanadaDepartment of Anesthesia and Pain Management, University Health Network, Toronto, ON, CanadaDepartment of Anesthesia and Pain Management, University Health Network, Toronto, ON, CanadaDepartment of Physiology, University of Toronto, Toronto, ON, CanadaDepartment of Anesthesia and Pain Management, University Health Network, Toronto, ON, CanadaDepartment of Physiology, University of Toronto, Toronto, ON, CanadaInstitute of Medical Science, University of Toronto, Toronto, ON, CanadaJoint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, CanadaInstitute of Medical Science, University of Toronto, Toronto, ON, CanadaCerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values.https://www.frontiersin.org/articles/10.3389/fphys.2021.639360/fullcerebrovascular reactivityBOLDCO2speed of responseblood arrival timehealthy subjects |
| spellingShingle | Julien Poublanc Reema Shafi Olivia Sobczyk Olivia Sobczyk Kevin Sam Daniel M. Mandell Lakshmikumar Venkatraghavan James Duffin James Duffin Joseph A. Fisher Joseph A. Fisher Joseph A. Fisher David J. Mikulis David J. Mikulis Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging Frontiers in Physiology cerebrovascular reactivity BOLD CO2 speed of response blood arrival time healthy subjects |
| title | Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging |
| title_full | Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging |
| title_fullStr | Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging |
| title_full_unstemmed | Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging |
| title_short | Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging |
| title_sort | normal bold response to a step co2 stimulus after correction for partial volume averaging |
| topic | cerebrovascular reactivity BOLD CO2 speed of response blood arrival time healthy subjects |
| url | https://www.frontiersin.org/articles/10.3389/fphys.2021.639360/full |
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