| Arterial pulsatility is linked to cerebral small vessel damage and neurodegeneration, but measuring cerebrovascular pulsatility in humans has largely been impeded by the skull. This thesis describes a method that generates cerebrovascular pulsatility maps based on resorting blood-oxygenation level dependent (BOLD) volumes according to their cardiac cycle position. Sensitivity of this method was tested using 20 minutes of moderate-intensity exercise as an acute physiological stressor in 45 healthy adolescents. Further examinations evaluated the influence of repetition time (TR) and echo time (TE) via simulation and multi-echo data, respectively. There were global, tissue-specific, and region-specific decreases in cerebrovascular pulsatility 20 minutes following exercise cessation. Cardiac-related pulsatility detection was comparable over a range of TR and TE values, with highest detection during rapid TRs (≤300ms) or shorter TE (~14ms). These results suggest that cardiac-related fMRI may represent a potent and easily adoptable method of mapping cerebrovascular pulsatility influences with voxel-wise specificity. |
