Imaging Cerebrospinal Fluid Transport by Contrast-Enhanced Magnetic Resonance Imaging via Intraventricular Infusion in Rodents.

Intraventricular (ICV) cannulation enables the delivery of exogenous tracers or therapeutic agents directly into the lateral ventricle, the origin of the cerebrospinal fluid (CSF) circulation pathway. Infused molecules are transported by CSF bulk flow through the ventricular compartments to the subarachnoid space and subsequently enter the brain parenchyma via the perivascular space. However, conventional ICV cannulation methods typically use ferromagnetic cannulas, which are incompatible with MRI studies and therefore require infusion to be performed outside the scanner and removal of the cannula prior to imaging. The time required for animal transport and imaging setup often results in the loss of the initial, and arguably most critical, phase of tracer transport. Here, we describe an MRI-compatible ICV cannulation and infusion protocol for rodents that supports continuous, in-scanner tracer delivery during dynamic MRI acquisition. The infusion line is constructed entirely from non-magnetic materials, enabling uninterrupted image acquisition within a single session. This approach is well-suited for dynamic contrast-enhanced MRI studies of CSF dynamics, glymphatic transport, solute clearance, and intrathecal drug delivery.