Improvements in performance time for simultaneous three-dimensional NMR imaging

Although the simultaneous collection of data from the whole of the volume of interest
offers some advantages in NMR imaging experiments it is not often used in practice.
This is largely because of the long imaging times involved. Two methods of reducing
total imaging time for 3D imaging experiments are presented. One involves restriction
of the sensitive volume to the volume of interest by selective excitation. The other involves
faster information collection which is achieved by repeatedly reforming an echo following
a single excitation. Images produced by the latter technique are presented and spatial
resolution and signal to noise ratio for both techniques are discussed.