Age-related and sex-specific reduction in cerebral arterial-venous cardiac pulse delay in functional magnetic resonance imaging

Motivation: Arterial-venous cardiac pulse delay is an informative marker of cerebral vascular compliance but is not easily accessible. Goal(s): Develop an automated fMRI processing technique to extract arterial-venous pulse delay and determine its relationship with age, biological sex, and vascular health metrics. Approach: Using fMRI's sensitivity to blood flow changes, we calculated the cardiac pulse delay between the large cerebral arteries and the superior sagittal sinus (SSS). Results: The fMRI-derived arterial-venous pulse delay was 77.8 ± 31.3 msec in participants aged 35-89. It decreased 3-4 msec for every decade of aging, was 10 msec faster in men than women, and increased with SSS volume. Impact: This work introduces a novel fMRI-based measure of cerebral arterial-venous pulse delay, providing an alternative tool sensitive to changes in vascular compliance. With the widespread accessibility of fMRI, this approach has applications for researching biomechanical changes in neurological conditions.