Quantitative cerebrovascular reactivity MRI in mice using acetazolamide challenge

Area of Science:

• Neuroimaging
• Cerebrovascular Research
• Preclinical MRI

Background:

• Cerebrovascular reactivity (CVR) assessment is crucial for understanding brain health.
• Current CVR methods in mice have limitations.
• Developing quantitative MRI techniques is essential for preclinical research.

Purpose of the Study:

• To develop and validate a quantitative MRI method for estimating cerebrovascular reactivity (CVR) in mice.
• To assess the cerebral vasodilatory response to acetazolamide (ACZ) using MRI.
• To establish a reliable method for regional CVR mapping in rodent models.

Main Methods:

• Utilized phase-contrast or pseudo-continuous arterial spin labeling MRI to measure cerebral blood flow (CBF).
• Determined vasodilatory input intensity via plasma ACZ levels measured by high-performance liquid chromatography.
• Investigated dose dependence and regional CVR variations, comparing ACZ injections to control experiments.

Main Results:

• CBF showed an exponential increase post-ACZ injection (time constant: 1.62 min).
• Plasma ACZ concentration increased linearly with dose (30-180 mg/kg), but CBF changes were not dose-dependent.
• Regional CVR analysis revealed higher reactivity in the isocortex compared to deep-brain regions.

Conclusions:

• Demonstrated the proof-of-principle for a novel quantitative CVR mapping technique in mice.
• The developed MRI method is feasible for preclinical cerebrovascular research.
• This technique allows for regional CVR assessment in rodent models.