Intermolecular multiple-quantum magnetic resonance imaging

摘要

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.