Perivascular cerebrospinal fluid inflow matches interstitial fluid efflux in anesthetized rat brains

This dataset contains all MRI from the paper: "Perivascular cerebrospinal fluid inflow matches interstitial fluid efflux in anesthetized rat brains". It consists of dynamic contrast-enhanced MRI after infusion of tracers in the cerebrospinal fluid (CSF) in the cisterna magna. The paper details the quantification of CSF inflow into brain tissue based on these data and validation data.

data/Gd-DTPA contains data from the main experiment: T2-imaging to measure pial perivascular space cross-sectional area and dynamic contrast-enhanced MRI after infusion of Gd-DTPA in CSF to track CSF flow around and into the brain.
data/GadospinP contains data from a validation experiment with a larger tracer molecule to validate that the observed flow velocity was not affected by diffusion effects of infusion artefacts.
data/high_res_T2 contains data from a validation experiment to test how the imaging sequence affects the measured pial perivascular space cross-sectional area.
data/template contains an anatomical template described here: https://doi.org/10.1016/j.jconrel.2023.01.054. The file 'input_sources.nii.gz' contains the template-space definition of the subarachnoid-space territory of the middle cerebral arteries used in the calculation of the CSF perfusion territory of the middle cerebral artery (Fig. 3 in the paper).

code/python contains python scripts to produce quantitative DCE-MRI time series, i.e. 4D tracer concentration images.
code/matlab contains Matlab scripts implementing the calculations necessary to produce the results described in the paper.

Abstract:
Waste solutes are cleared from the brain via outflow of interstitial fluid (ISF). Blood-brain-barrier water secretion and inflow of cerebrospinal fluid (CSF) via perivascular channels have been suggested as potential fluid sources to replace outflowing ISF. To assess the role of CSF inflow in brain clearance, we measured both CSF inflow and ISF outflow in ketamine/dexmedetomidine anesthetized rats. We used magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) to track tracer flows after infusion in CSF or ISF. CSF inflow was estimated at 0.5-0.7 µl·g-1·min-1 using either direct observation of perivascular flow or compartment modelling. ISF outflow was estimated at 0.47±0.05 µl·g-1·min-1 after intraparenchymal infusion. Our observations indicate that under the anesthetic condition examined, inflowing CSF is sufficient to replace outflowing ISF, that perivascular flow and CSF inflow to interstitium are dominated by convection, and that diffusion and convection both contribute to tracer transport within the brain parenchyma.