Resolve 3D choroid plexus structure and partitioned bidirectional cerebrospinal fluid flow with MRI

Motivation: Previous studies have not identified the high-resolution in vivo 3D structure of the choroid plexus or linked its unique ventricular localization to CSF flow hydrodynamics. Goal(s): We developed novel ultra-high-resolution MRI with 30 μm isotropic resolution to measure region-specific CSF flow in the ventricles using phase-contrast MRI. Approach: A head-implanted RF coil enhanced the SNR of MGE images, allowing for Gd-enhanced scanning in the ventricles. High-resolution PC-MRI mapped bidirectional CSF flow velocity in the free-space ventricle relative to the localization of ChP. Results: We estimated an ~20% volume fraction of ChP in the lateral ventricle and measured bidirectional CSF velocity at ~150-200 μm/s. Impact: Our findings clarify choroid plexus morphology and its crucial role in regulating bidirectional CSF flow dynamics. This study reveals novel CSF hydrodynamics controlled by ChP localization, informing therapeutic strategies to target ChP function in degenerative or hydrocephalic conditions.