Simultaneous Cerebral Blood Flow and Cerebrovascular Reactivity Obtained From Novel Multi-Band Multi-Echo...

Area of Science:

• Neuroimaging
• Cerebrovascular Physiology

Background:

• Assessing cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) is crucial for understanding brain health.
• Existing methods for measuring CBF and CVR have limitations in spatial and temporal resolution.
• Multi-band pseudo-continuous arterial spin labeling (M2-PCASL) is a novel MRI technique with potential for improved measurements.

Purpose of the Study:

• To evaluate the reliability of CBF and CVR measurements using a novel M2-PCASL sequence combined with hypercapnia.
• To identify factors influencing CBF variability.
• To assess the effect of different carbon dioxide (CO2) concentrations on CVR estimates.

Main Methods:

• Nine participants underwent test-retest M2-PCASL scans at 3T with a hypercapnic challenge.
• Intraclass correlation coefficient (ICC) was used to assess reliability at whole brain, ROI, and voxel levels.
• Linear mixed-effect models and t-tests were employed to analyze CBF variability and CO2 concentration effects on CVR.

Main Results:

• The M2-PCASL sequence demonstrated good to excellent reliability (ICC > 0.81) for baseline CBF and BOLD CVR in whole brain, gray matter (GM), and white matter (WM) after smoothing.
• Fair to moderate reliability was observed for CBF CVR in GM (ICCs between 0.42 and 0.55).
• Head motion was significantly associated with CBF temporal signal-to-noise ratio (SNR), and CO2 concentrations (5% vs. 8%) yielded similar BOLD CVR estimates.

Conclusions:

• The M2-PCASL sequence with hypercapnia provides reliable estimates of baseline CBF and BOLD CVR.
• This novel technique offers enhanced spatial and temporal resolutions compared to existing methods.
• M2-PCASL enables non-invasive and comprehensive assessment of cerebrovascular health.