Evidence of Incoherent Fluids Flow in the Human Brain from Multidimensional Intravoxel Incoherent Motion MRI

Motivation: The human brain contains multiple fluid compartments, including blood, cerebrospinal fluid (CSF), and tissue water. While microvascular perfusion is well-studied using intravoxel incoherent motion (IVIM), evidence on flow in other fluid compartments remains limited. Goal(s): To develop in vivo multi-dimensional MRI methods to investigate potential contributions of CSF movements in the IVIM regime. Approach: We implemented MADCO-accelerated joint T1-Diffusion and T2-Diffusion measurements to resolve subvoxel heterogeneities of IVIM components in living human brains. Results: Analysis of T1-Diffusion and T2-Diffusion correlation spectra revealed distinct signatures of CSF flow in addition to microvascular perfusion, particularly in the subarachnoid space. Impact: This multidimensional MRI approach reveals multiple pseudo diffusion components in the living human brain beyond traditional IVIM measurements, providing a novel framework to characterize distinct fluid dynamics and potentially advance our understanding of brain fluid transport systems.