Looking into the functional architecture of the brain with diffusion MRI

Water diffusion magnetic resonance imaging (dMRI) allows tissue structure to be probed and imaged on a microscopic scale, providing unique clues to the fine architecture of neural tissues and to changes associated with various physiological and pathological states, such as acute brain ischaemia. Because diffusion is anisotropic in brain white matter, reflecting its organization in bundles of fibres running in parallel, dMRI can also be used to map the orientation in space of the white matter tracks in the brain, opening a new window on brain connectivity and brain maturation studies. This article provides an introduction to the key physical concepts that underlie dMRI, and reviews its potential applications in the neurosciences and associated clinical fields.