Ultrahigh-resolution, whole-brain MAP-MRI in vivo using the NexGen 7T scanner

Motivation: To assess the potential of high-resolution diffusion propagator imaging in human subjects Goal(s): To measure diffusion propagators with submillimeter spatial resolution and whole-brain coverage in healthy volunteers by leveraging the capabilities of the NexGen 7T MRI scanner Approach: We designed an efficient protocol to acquire in vivo data with strong diffusion sensitization and high tissue sensitivity. We estimated the 3D net displacements of water molecules diffusing in tissue using mean apparent propagator (MAP) MRI. Results: MAP-derived microstructural parameters revealed cortical laminar patterns in multiple brain regions. Variations in cortical diffusion anisotropy revealed laminar pattern discontinuities that may correlate with boundaries between cortical areas. Impact: Ultrahigh resolution MAP-MRI could improve the neuroradiological assessment of cortical and subcortical gray matter and the early detection of neurodegenerative diseases. It could enable direct segmentation of cortical cytoarchitectonic domains and advance our ability to map connections between cortical layers.