Fig. 5

Baseline tracer evolution. Parenchymal tracer concentration after (from left to right) 1, 3, 8 and 24 h of diffusion in (from top to bottom) sagittal, transverse and coronal planes. Initially, most of the tracer is found in inferior regions. At 24 h, tracer has penetrated substantially into the gray matter, but not into the deep, central regions