Volume imaging with MR phased arrays.

A volume MR phased array was constructed with two coils placed anteriorly and two coils posteriorly. Data acquired simultaneously from the four coils on a phantom were combined into a single image having a signal-to-noise ratio 80% better than that from the body coil. Additional comparisons of the four-coil phased array with a two-coil phased array and a Helmholtz pair having the same overall dimensions show how variations of signal amplitude and phase in the individual coils affect the composite SNR. Images of the male and female pelvis demonstrate how the improved SNR can be used to reduce the number of excitations, decrease the field of view, increase the echo time, or reduce the slice thickness.