JHA410H1 Lecture Notes - Lecture 3: Diffusion Mri, White Matter, One Direction
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Lecture 3: diffusion tensor imaging: b diffusion weighting factor, d diffusion term or coefficient, adc apparent diffusion coefficient. What is diffusion: random movement of molecules through whatever media (independent of gravity, random microscopic movement of molecules due to thermal collisions. Spreading of ink is due to thermal motion of its molecules. Shape of ink on paper reveals something about the structure of the paper. If shape is circular, diffusion is equal in every direction isotropic diffusion. If shape is elongated along one axis but not others, diffusion in one direction anisotropic diffusion. Water should diffuse around fat (not through or part of fat) We can display information gained into orientation of the fat in the brain. Bundles of white matter displayed (characterize white matter/fat) It is impossible to extract information about diffusion from a single signal. Allows us to estimate the extent of diffusion happening in the brain: this is achieved by.