Abstract
A new class of nuclear magnetic resonance (NMR) pulses that provides simultaneous spatially selective inversion of nuclear spins in two dimensions following a single pulse application is described and demonstrated. The two-dimensional selective pulses consist of a single square- or amplitude-modulated π rf pulse applied in the presence of an amplitude-modulated magnetic field gradient that reorients through the two dimensions during the rf pulse. For example, square and Gaussian rf pulses produce sharply peaked sombrero-, egg-carton-, and stalagmite-shaped profiles of spin inversion in the xz plane when applied in the presence of a gradient that rotates or describes a figure eight in the xz plane. The theoretical profiles, computed by numerical integration of the Bloch equation, are in good agreement with experimental results obtained by incorporating the pulses into a conventional NMR imaging sequence. The pulses are directly applicable to restricted field-of-view high-resolution imaging for the amelioration of aliasing signal artifacts, and when combined with one-dimensional localized phosphorus (31P) chemical shift spectroscopy techniques that employ surface detection coils, should permit complete three-dimensionally localized 31P NMR spectroscopy. The π pulses provide similar two-dimensional spatial selectivity of the transverse nuclear magnetization when used for refocusing Hahn spin echoes.
Original language | English (US) |
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Pages (from-to) | 4284-4290 |
Number of pages | 7 |
Journal | Journal of Applied Physics |
Volume | 62 |
Issue number | 10 |
DOIs | |
State | Published - 1987 |
Externally published | Yes |
ASJC Scopus subject areas
- Physics and Astronomy(all)