Phase-offset multiplanar (POMP) volume imaging: a new technique.

Phase-offset multiplanar (POMP) imaging is a technique that excites several sections simultaneously for improved imaging efficiency. The centers of the reconstructed images from each of the POMP sections are offset from each other in the phase-encoding direction by means of view-dependent phase modulation of the radio-frequency (RF) excitation pulses and are placed adjacent to each other in the reconstruction. With a suitable reconstruction matrix size, the images can be made nonoverlapping and stored separately. At constant imaging time, signal-to-noise ratio (S/N), and resolution, POMP imaging produces a factor NP more sections than a conventional sequence but with a reduced field of view. Alternatively, imaging time may be increased by the factor NP to retain the same field of view but with the expected S/N advantage. The average RF power deposited by the 90 degrees composite RF pulse is greater by the factor Np, but the power for the 180 degrees pulse is unchanged. The POMP method is discussed and compared with three-dimensional and Hadamard techniques.