An Exploratory Study on the Relationship Between Cerebrovascular Reactivity and Intravenous Gadolinium-Based Contrast Agent (GBCA) Distribution in the Cerebrospinal Fluid (CSF)

Background: Intravenous gadolinium-based contrast agent (IV-GBCA)-based MRI has been widely used to study cerebrospinal fluid (CSF) circulation and clearance in the human brain. IV-GBCA can enter the CSF via the choroid plexus (CP) and parasagittal dura (PSD), but how these dynamics are coupled with cerebrovascular fluctuations is unclear. The goal of this study is to investigate the relationship between microvascular reactivity and CSF distribution in the human brain, which were measured with cerebrovascular reactivity (CVR) and IV-GBCA distribution in the CSF, respectively. Methods: CVR and IV-GBCA distribution in the CSF around the CP and PSD were measured in the same five healthy subjects (four males, one female; age 40 ± 16 years) during CO2 breathing using inflow-based vascular-space-occupancy (iVASO) MRI and dynamic susceptibility contrast in the CSF (cDSC) MRI, respectively. Results: Whole-brain arterial cerebral blood volume (CBVa) increases during CO2 breathing showed a strong negative correlation with GBCA concentration in CSF around the CP but a moderate positive (but not significant) correlation in CSF around the PSD. Conclusions: The finding of a differential relationship between CVR and IV-GBCA distribution in the CSF in different brain regions highlights the importance of accounting for microvascular function in neurofluids studies using IV-GBCA-based MRI.