Normative cerebral microvascular blood flow waveform morphology assessed with diffuse correlation spectroscopy.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Physiology

Background:

• Cerebral blood flow pulsatility at cardiac frequency contains vital information on cerebrovascular health.
• Understanding normative waveform characteristics is crucial for assessing vascular function.

Purpose of the Study:

• To quantify normative features of microvascular cerebral blood flow waveforms in healthy adults.
• To investigate the sensitivity of these waveforms to changes in vascular tone.
• To identify potential sex-based differences in cerebral blood flow pulsatility.

Main Methods:

• Utilized diffuse correlation spectroscopy (DCS) for non-invasive quantification of cerebral blood flow.
• Analyzed waveform morphology, including area-under-the-curve and pulsatility index.
• Introduced controlled hypercapnia to assess responsiveness of vascular tone.

Main Results:

• Established normative values for cerebral blood flow pulsatility waveforms in 30 healthy adults.
• Demonstrated significant morphological changes in response to hypercapnia, indicating sensitivity to vascular tone.
• Observed distinct sex-based differences: females showed higher flow, greater area-under-the-curve, and lower pulsatility.
• Quantified normative cerebral critical closing pressure.

Conclusions:

• Microvascular cerebral blood flow pulsatility is a sensitive indicator of cerebrovascular health and vascular tone.
• Significant sex-based differences in cerebral blood flow dynamics exist.
• Normative data for cerebral critical closing pressure were established.