Abstract: In nuclear magnetic resonance imaging of the human brain or the like, multiple quantum coherences, such as intermolecular double quantum coherence (iDQC) between water molecules, are used for soft tissue contrast. A group of pulse sequences are used in which, (a) The standard &bgr;=&pgr;/2 pulse in the original CRAZED sequence is replaced with a &pgr;/3 pulse. The maximum signal derived from iDQCs is increased by a factor of 3{square root over (3)}/4. (b) The position of the acquisition window is adjusted, and a large acquisition window (small bandwidth) is used to sample a broad range of time-domain signals. (c) Receiver dynamic range is optimized. (d) A two-step phase cycle scheme for iDQC-encode gradients is designed to remove additional undesired coherence pathways.

Abstract: A magnetic imaging device, such as an MR scanner, is used to provide a modified three-dimensional gradient echo sequence having a spatial-spectral excitation in which phase-encoding lines are interleaved for the excitation of water and of fat. The phase-encoding lines are spaced by an interval equal to half of the repetition time. The resulting data are sorted for the reconstruction of water-only and fat-only images, which are realigned and combined to form water-fat combined images free of chemical shift artifacts.

Abstract: In nuclear magnetic resonance imaging of the human brain or the like, multiple quantum coherences, such as intermolecular double quantum coherence (iDQC) between water molecules, are used for soft tissue contrast. A group of pulse sequences are used in which, (a) The standard &bgr;=&pgr;/2 pulse in the original CRAZED sequence is replaced with a &pgr;/3 pulse. The maximum signal derived from iDQCs is increased by a factor of 3{square root}{square root over (3)}/4. (b) The position of the acquisition window is adjusted, and a large acquisition window (small bandwidth) is used to sample a broad range of time-domain signals. (c) Receiver dynamic range is optimized. (d) A two-step phase cycle scheme for iDQC-encode gradients is designed to remove additional undesired coherence pathways.