Current and future applications of magnetic resonance imaging and spectroscopy of the brain in hepatic encephalopathy

Figure 3 Principles of diffusion: A water molecule in an unconstrained environment would move randomly and equally in all directions; isotropic diffusion (A). The probability of motion can be defined by the radius ‘r’, of the spherical range of motion. Diffusion in an ordered environment such as the white matter will assume an elliptical range of motion (B and C). Three eigenvalues, λ₁, λ₂ and λ₃ define the shape and three eigenvectors v₁, v₂ and v₃ define the orientation of the ellipsoid.