Characterization of regional differences in cerebral vascular response to breath holding usingBOLD fMRI

Abstract

Cerebrovascular reactivity (CVR) is a specific indicator of autoregulatory efficiency. Studies have demonstrated that CVR depends on the baseline vascular dilation status between groups. Within the brain, there also exist spatial variations in both the resting cerebral blood flow (CBF) and CVR across different cerebral regions. However, the relationship between the regional CBF and CVR remains unclear. Hence, the primary goal of this study was to investigate the relationship between the resting CBF using pseudocontinuous arterial spin labeling (pCASL) technique and CVR using blood oxygenation level‐dependent (BOLD) technique across different cerebral regions. Eleven male and 14 female young volunteers were recruited in this study. Each subject was asked to perform the breath‐holding challenge to evaluate CVR at 3 T. The resting CBF was measured using pCASL in each subject. The relationships between CBF and CVR across the lobes were evaluated using the Spearman's rank test. The results showed that, for both sexes, the frontal lobe had the maximal resting perfusion but minimal vascular response to hypercapnia, whereas the occipital lobe had the lowest baseline CBF but maximal reactivity to hypercapnia, suggesting low and high autoregulatory efficiencies at high and low resting CBF in the brain, respectively. Sex‐related differences were observed in CBF but not in CVR. These findings may be of clinical interest in the assessment of cerebrovascular reserve and regional‐dependent vascular diseases.

Lag-Optimized Blood Oxygenation Level Dependent Cerebrovascular Reactivity Estimates Derived From Breathing Task Data Have a Stronger Relationship With Baseline Cerebral Blood Flow

“…This difference could be driven by the fact they assessed CBF-CVR, as opposed to BOLD-CVR, which we discuss further in a subsequent section. A recent study ( Chen et al, 2021 ) with a sample of similar age to ours investigated sex differences in bCBF and BOLD-CVR, showing that female participants had higher bCBF (consistent with what we see in Supplementary Figure 2 ) but no difference in BOLD-CVR. However, they also reported a negative correlation between bCBF and BOLD-CVR, using average values from four different brain lobes (frontal, temporal, parietal, and occipital).…”

Cerebral hemodynamic response to caffeine: effect of dietary caffeine consumption

“…Twenty-six young participants (13 men, mean age 24.3 years, range [21][22][23][24][25][26][27][28][29] were included in this study. The average daily caffeine intake was assessed based on self-reports from the subjects.…”

“…This physiological property is defined as cerebrovascular reactivity (CVR), which is an important index for the vascular health. [24][25][26] CVR can be conveniently measured by inhalation of CO 2 gas 4,19,23,24 and breath-hold (BH) 27,28 while MRI signals are continuously recorded. CVR is not considered a new approach to estimate the dynamic properties of vessels in the caffeinated condition.…”

Macrovascular blood flow and microvascular cerebrovascular reactivity are regionally coupled in adolescence

“…59 This paper 59 provides a thorough commentary on other studies reporting positive correlations between baseline cerebral blood flow and BOLD CVR across individuals, 27,90,91 and the few reports of negative correlations between tissue-level blood flow and CVR amplitude. 92,93 Our findings provide evidence that CVR measured via BOLD fMRI is closely related to the inflow from upstream cerebral arteries. This is unsurprising, since large cerebral arteries are important determinants of microvascular pressure and perfusion, 89,94 which in turn influence arteriolar dilation capacity.…”

“…59 This paper 59 provides a thorough commentary on other studies reporting positive correlations between baseline cerebral blood flow and BOLD CVR across individuals, 27,90,91 and the few reports of negative correlations between tissue-level blood flow and CVR amplitude. 92,93…”