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Updated: Mar 12, 2026
Evaluation of the Cognitive Performance of Hypertensive Patients with Silent Cerebrovascular Lesions
Published on: April 23, 2021
Cerebrovascular reactivity and white matter integrity
Kevin Sam1, Boris Peltenburg1, John Conklin1
1From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada.
Objective:
To compare the diffusion and perfusion MRI metrics of normal-appearing white matter (NAWM) with and without impaired cerebrovascular reactivity (CVR).
Methods:
Seventy-five participants with moderate to severe leukoaraiosis underwent blood oxygen level-dependent CVR mapping using a 3T MRI system with precise carbon dioxide stimulus manipulation. Several MRI metrics were statistically compared between areas of NAWM with positive and negative CVR using one-way analysis of variance with Bonferroni correction for multiple comparisons.
Results:
Areas of NAWM with negative CVR showed a significant reduction in fractional anisotropy by a mean (SD) of 3.7% (2.4), cerebral blood flow by 22.1% (8.2), regional cerebral blood volume by 22.2% (7.0), and a significant increase in mean diffusivity by 3.9% (3.1) and time to maximum by 10.9% (13.2) (p < 0.01), compared to areas with positive CVR.
Conclusions:
Impaired CVR is associated with subtle changes in the tissue integrity of NAWM, as evaluated using several quantitative diffusion and perfusion MRI metrics. These findings suggest that impaired CVR may contribute to the progression of white matter disease.
Insights
Impaired cerebrovascular reactivity (CVR) is linked to subtle white matter changes. These diffusion and perfusion MRI findings suggest CVR may influence white matter disease progression.
Area of Science:
- Neuroimaging
- White Matter Diseases
- Cerebrovascular Physiology
Background:
- Leukoaraiosis, a common finding in aging and cerebrovascular disease, affects white matter integrity.
- Cerebrovascular reactivity (CVR) reflects the brain's ability to modulate blood flow in response to stimuli.
- Assessing CVR is crucial for understanding white matter health and disease progression.
Purpose of the Study:
- To compare diffusion and perfusion magnetic resonance imaging (MRI) metrics in normal-appearing white matter (NAWM) between individuals with and without impaired CVR.
- To investigate the relationship between CVR status and quantitative MRI markers of white matter tissue integrity.
Main Methods:
- Seventy-five participants with moderate to severe leukoaraiosis underwent functional MRI for CVR mapping using a 3T system and CO2 manipulation.
- Blood oxygen level-dependent (BOLD) CVR mapping was performed.
- Diffusion and perfusion MRI metrics of NAWM were statistically compared between areas with positive and negative CVR.
Main Results:
- Areas of NAWM with impaired CVR (negative CVR) exhibited significantly reduced fractional anisotropy, cerebral blood flow, and regional cerebral blood volume.
- Conversely, areas with negative CVR showed significantly increased mean diffusivity and time to maximum.
- These differences were statistically significant (p < 0.01).
Conclusions:
- Impaired CVR is associated with subtle yet significant alterations in the microstructural integrity of normal-appearing white matter.
- Quantitative diffusion and perfusion MRI metrics can detect these changes.
- These findings suggest that impaired CVR may be a contributing factor to the progression of white matter diseases.
