If a sample contains liquid where at least part is confined or bounded, say in closed pores or vesicles, it is often possible to determine the bounded liquid fraction and bounded diameter, using the technique of measuring the diffusion distance as a function of time.

This may either be done using pulsed magnetic gradients, or in the static gradients found in the fringe field of a superconducting magnet.

These techniques works best for vesicle diameters in the range 0.1m to 10m.