Wavelet brain angiography suggests arteriovenous pulse wave phase locking.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Cranial blood volume must remain constant despite variations in arterial and venous blood proportions during the cardiac cycle.
• A hypothesis suggests extraluminal information exchange between cerebral arterial and venous circulations facilitates this regulation.

Purpose of the Study:

• To introduce and validate novel wavelet angiography methods for resolving individual vascular pulse waves (PWs) in the brain.
• To investigate the coordination between arterial and venous PWs and their relationship with brain pulse motion.

Main Methods:

• Development of a vascular PW cine imaging method using cross-correlated wavelets with high frequency and temporal resolution.
• Acquisition of high-frame-rate angiographic data from human (optical) and piglet (ultrasound) brains.
• Exploitation of angiographic time-of-flight to differentiate arterial and venous circulation.

Main Results:

• The developed method successfully resolved individual arterial and venous PWs in human and piglet brains.
• Arterial and venous PWs were found to be phase-locked with distinct phase relationships to brain pulse motion.
• Observed coordination is consistent with pulse motion-mediated regulation of arterial and venous PWs.

Conclusions:

• The findings support the hypothesis of coordinated arterial and venous pulse wave activity in regulating cranial blood volume.
• This coordination, mediated by brain pulse motion, suggests a potential role for cerebrospinal fluid in ventricular regulation.