Cerebrovascular 5D flow MRI

Area of Science:

• Cardiovascular Imaging
• Neuroimaging
• Medical Physics

Background:

• 4D flow MRI quantifies cardiac-induced blood flow in the brain.
• Respiration significantly modulates cerebral arterial and venous blood flow.
• Quantifying respiratory flow modulation (RFM) offers insights into vascular coupling and cerebral circulation.

Purpose of the Study:

• To develop and validate a 5D phase-contrast flow MRI framework for volumetric quantification of RFM.
• To assess the potential of this technique in understanding cerebral circulation dynamics.

Main Methods:

• A 5D flow MRI framework was developed, resolving velocity vector fields across cardiac and respiratory cycles.
• High spatial (0.82 mm isotropic) and cardiac (55 ms) resolutions were achieved.
• Deep learning methods were incorporated for image reconstruction and analysis, with a 20-minute acquisition time.

Main Results:

• The 5D framework was validated against 2D flow MRI in 10 healthy volunteers, showing high correlation (r=0.97, 0.90) for RFM quantification.
• Biases for mean velocity magnitude and amplitude RFM were minimal (0.09%, 1.77%).
• Full-field RFM quantification revealed significant intra-subject physiological variability.

Conclusions:

• Cerebrovascular 5D flow MRI enables comprehensive study of respiratory flow modulation.
• This technique holds significant potential for advancing the understanding of cerebral circulation.