Fractional anisotropy (FA) is a scalar value between zero and one that describes the degree of anisotropy of a diffusion process. In simpler terms, it measures how directional the diffusion of water molecules is within tissue. FA is a crucial metric derived from Diffusion Tensor Imaging (DTI), a type of MRI technique. Higher FA values indicate more directional diffusion, which is often associated with organized and healthy tissue structures, such as nerve fibers in the brain.
