FIG 2. Decrease in the eigenvalues of the diffusion tensor during normal brain maturation is illustrated in five participants ranging in age from 31 gestational weeks (preterm) to 6 postnatal years. Diffusion-tensor imaging parameters are as in Figure 1, except for the preterm neonate, for whom the parameters were 3000/106/1 with four tetrahedrally oriented diffusion gradients (b = 800 s/mm²) and three orthogonally oriented diffusion gradients (b = 340 s/mm²). All images are transverse sections obtained at the level of the basal ganglia. All images are displayed with identical window and level settings to allow direct comparison of signal intensity across participants. The eigenvalues are rotationally invariant measures of the rate of water diffusion along each of the three principal axes of the diffusion tensor at each MR imaging voxel. _min (top row) is the eigenvalue with the smallest magnitude, _int (middle row) has intermediate values, and _max (bottom row) has the greatest magnitude.