Assessment of the Effects of Aerobic Fitness on Cerebrovascular Function in Young Adults Using Multiple Inversion Time Arterial Spin Labeling MRI
Catherine Foster, Jessica J. Steventon, Daniel Helme, Valentina Tomassini, Richard G. Wise
Abstract
This cross-sectional study investigated the effects of aerobic fitness on cerebrovascular function in the healthy brain. Grey matter cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were quantified in a sample of young adults within a normal fitness range. Based on existing Transcranial Doppler ultrasound and fMRI evidence, a positive relationship between fitness and resting grey matter CBF, and CVR was predicted. Exploratory hypotheses that higher V ̇O2peak would be associated with higher GM volume and cognitive performance were also investigated. 20 adults underwent a V ̇O2peak test and a battery of cognitive tests. All subjects also underwent an MRI scan where multiple inversion time (MTI) pulsed arterial spin labelling (PASL) was used to quantify resting CBF and CVR to 5% CO2. Region of interest analysis showed a non-significant inverse correlation between whole-brain grey matter CBF and V ̇O2peak; r=-0.4, p=0.08, corrected p (p’) =0.16 and a significant positive correlation between V ̇O2peak and whole-brain averaged grey matter CVR; r=0.62, p=0.003, p’ =0.006. Voxel-wise analysis revealed a significant inverse association between V ̇O2peak and resting CBF in the left and right thalamus, brainstem, right lateral occipital cortex, left intra-calcarine cortex and cerebellum. The results of this study suggest that aerobic fitness is associated with lower CBF and greater CVR in young adults.