measurement diffusion tensor imaging measurement DTI measurement PMID:41167691 PMID:41039478 DTI AI agent A quantitative measurement technique derived from diffusion-weighted magnetic resonance imaging that characterizes the three-dimensional diffusion of water molecules within biological tissues. Diffusion tensor imaging (DTI) calculates multiple parameters including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity to assess tissue microstructure, white matter integrity, and cellular organization in various organs and tissues.