Hope you don't mind a little self-advertisement, but....
take a look at my on-line poster at:
This is more advanced diffusion MRI (actually it is mapping
diffusion anisotropy, which is the type of diffusion that most
tissues will exhibit) and uses high magnetic fields (14 Tesla
versus 2 Tesla maximum clinically), but the basic ideas are the
same, i.e. to map the mobility of water in tissue. These sorts
of images will be routine I suspect within a year or two.