FIG 3. The brain diffusion constants (circles) measured from distribution maps are plotted against age of the subjects. A linear fit to the data (solid line) is also shown (BD_av = 0.717 + 0.000421 x Age, r = 0.383, P < .05). Age dependency of the data is minimal. FIG 4. The diffusion constants determined from ROI measurements of the periventricular white matter (circles) are plotted against age of the subjects. There is a significant increase with respect to age. A linear fit to the data (solid line) is also shown (D_av = 0.718 + 0.000876 x Age, r = 0.406, P < .015)