Diffusion imaging is a technique used in neuroimaging to study the movement of water molecules in the brain. By measuring the diffusion of water in different directions, researchers can infer the structural organization of white matter fibers and identify changes in these structures due to various neurological conditions or diseases. Diffusion imaging is particularly useful in studying conditions such as stroke, multiple sclerosis, and traumatic brain injury, as well as in mapping the connections between different regions of the brain.