Diffusion imaging with hyperpolarized 3He gas

We used MRI of hyperpolarized He-3 to demonstrate some novel aspects of gas diffusion, Two different techniques were used, First, a slice was burned into a one-dimensional image by inverting the spins in the slice and diffusion was studied by measuring the magnetization as it filled the depleted slice. A diffusion coefficient was determined by the fit of these data, Second, one-dimensional diffusion images were made using a Stejskal-Tanner PGSE method, This was done with and without a temperature gradient present, showing that the effect of temperature can be dynamically monitored by such diffusion images. (C) 1997 Academic Press.