Assessment of the effects of aerobic fitness on cerebrovascular function in young adults using multiple inversion time arterial spin labelling MRI

Abstract

The cross-sectional study investigated the effects of aerobic fitness on cerebrovascular function in the healthy brain. We quantified grey matter (GM) cerebral blood flow (CBF) and cerebrovascular reactivity (CVR), in a sample of young adults within a normal fitness range.Based on existing TCD and fMRI evidence, we predicted a positive relationship between fitness and resting GM CBF, and CVR. Exploratory hypotheses that higher ̇O 2peak would be associated with higher GM volume and cognitive performance were also investigated. 20 adults underwent a ̇O 2peak test and a battery of cognitive tests. All subjects 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. ROI analysis showed a non-significant negative correlation between whole-brain GM CBF and ̇O 2peak; r=-0.4, p=0.08, corrected p (p') =0.16 and a significant positive correlation between ̇O 2peak and voxelwise whole-brain GM CVR; r=0.62, p=0.003, p' =0.006. Voxelwise analysis revealed a significant inverse association between ̇O 2peak and resting CBF in the left and right thalamus, brainstem, right lateral occipital cortex, left intracalcarine cortex and cerebellum.The results of this study suggest that aerobic fitness is associated with lower CBF and greater CVR in young adults.

Effect of acute cardiovascular exercise on cerebral blood flow: A systematic review

“…Finally, arterial-spin labelling (ASL) magnetic resonance imaging is a non-invasive, quantitative method that relies on magnetically labeled arterial blood water protons as endogenous tracers to measure tissue perfusion (Steventon et al, 2020). ASL directly measures CBF by labeling inflowing water to tissue (Foster et al, 2019).…”

“…TCD does not directly measure CBF (Lipnick et al, 2018). Instead, TCD measures blood flow velocity as it does not consider vessel diameter (Foster et al, 2019). However, if the angle of insonation remains unchanged during imaging, changes in TCD velocities are likely to reflect changes in middle cerebral artery blood flow rate (Lipnick et al, 2018).…”

Assessment of the Effects of Aerobic Fitness on Cerebrovascular Function in Young Adults Using Multiple Inversion Time Arterial Spin Labeling MRI

“…This manuscript can be found as a preprint on BioRxiv at: https://www.biorxiv.org/content/10.1101/ 539072v1. This work first appeared in the lead author's thesis (Foster, 2017;Chapter 4) which can be accessed here: http://orca. cf.ac.uk/109647/.…”

Effect of Acute Cardiovascular Exercise on Cerebral Blood Flow: A Systematic Review

“…The difference in frequency between reflected and emitted waves, i.e., the Doppler shift frequency, reflects blood flow velocity (Purkayastha &Sorond, 2013). TCD measures blood flow velocity, rather than blood flow itself, as it does not consider vessel diameter (Foster et al, 2019).…”