Quantifying the changes in oxygen extraction fraction and cerebral activity caused by caffeine and acetazolamide

Abstract

A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease. We aimed to measure the change in venous oxygen saturation (Y) before and after the intake of the vaso-dynamic agents caffeine and acetazolamide with high spatial resolution using susceptibility mapping. Caffeine and acetazolamide were administered on separate days to five healthy volunteers to measure the change in oxygen extraction fraction. The internal streaking artifacts in the susceptibility maps were reduced by giving an initial susceptibility value uniformly to the structure-of-interest, based on a priori information. Using this technique, Y for normal physiological conditions, post-caffeine and post-acetazolamide was measured inside the internal cerebral veins as Y = 69.1 ± 3.3%, Y = 60.5 ± 2.8%, and Y = 79.1 ± 4.0%. This suggests that susceptibility mapping can serve as a sensitive biomarker for measuring reductions in cerebro-vascular reserve through abnormal vascular response. The percentage change in oxygen extraction fraction for caffeine and acetazolamide were found to be +27.0 ± 3.8% and -32.6 ± 2.1%, respectively. Similarly, the relative changes in cerebral blood flow in the presence of caffeine and acetazolamide were found to be -30.3% and + 31.5%, suggesting that the cerebral metabolic rate of oxygen remains stable between normal and challenged brain states for healthy subjects.

Vascular effects of caffeine found in BOLD fMRI

“…gray matter), while the opposite was found in the white matter and lower part of the brain. Our results are consistent with previous ASL findings, which reported that decreasing CBF were widespread in the grey matter after caffeine intake (Buch et al 2017; Merola et al 2017). Compared to the delay map difference shown in Figure 5.a, we found that the regions of vessel constriction after caffeine intake overlap largely with the regions where the blood flow speed increases.…”

Improved sensitivity and temporal resolution in perfusion FMRI using velocity selective inversion ASL

“…even calibrated BOLD [2][3][4] and many longitudinal FMRI studies have used ASL acquisitions (for examples, see refs [5][6][7][8] ).…”

A robust multi-scale approach to quantitative susceptibility mapping

“…aging ( Acosta-Cabronero et al., 2016 ; Betts et al., 2016 ; Darki et al., 2016 ; Li et al., 2014 ; Persson et al., 2015 ), drug addiction ( Ersche et al., 2017 ), Alzheimer's disease ( Acosta-Cabronero et al., 2013 ; Ayton et al., 2017 ; Moon et al., 2016 ; van Bergen et al., 2016b ), Parkinson's disease ( Acosta-Cabronero et al., 2017 ; Guan et al., 2017 ; He et al., 2015 ), Huntington's disease ( Dominguez et al., 2016 ; van Bergen et al., 2016a ), neurodegeneration with brain iron accumulation ( Lobel et al., 2014 ), neuromuscular disease ( Acosta-Cabronero et al., In Press ; Costagli et al., 2016 ; Schweitzer et al., 2015 ), demyelinating disease ( Bian et al., 2016 ; Chen et al., 2014 ; Cronin et al., 2016 ; Li et al., 2016 ; Wisnieff et al., 2015 ; Zhang et al., 2016 ) and traumatic brain injury ( Liu et al., 2016 ). QSM has also been proposed for vascular monitoring both at single time points ( Fan et al., 2015 , 2016 ; Ozbay et al., 2015 ) or in combination with the MRI technique of arterial spin labelling to infer cerebral metabolic rates of oxygen extraction ( Buch et al., 2017 ; Zhang et al., 2018 ); and dynamically, using fast echo-planar acquisitions for functional MRI (fMRI) applications ( Balla et al., 2014 ; Bianciardi et al., 2014 ; Chen and Calhoun, 2015 ; Ozbay et al., 2016 ; Sun et al., 2017 ).…”