Use of Amplitude and Frequency Transformations to Generate Adiabatic Pulses of Wide Bandwidth and Low RF Power Deposition
✍ Scribed by Jun Shen
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 215 KB
- Volume
- 112
- Category
- Article
- ISSN
- 1064-1866
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✦ Synopsis
An amplitude transformation of adiabatic pulses stated presized. Despite these efforts, the overall RF power deposition viously [Baum et al., Phys. Rev. A 32, 3435-3447 (1985)] is genercan still be very high, since a sophisticated pulse sequence alized using the Bloch equations. Both amplitude and frequency with proper localization may require up to more than 30 transformations are used to create new adiabatic pulses of wide half-passage pulses (4). Therefore, it is very desirable to bandwidth and low RF power deposition. Several adiabatic pulses further reduce the power deposited by these adiabatic pulses (including the tanh/tan pulse used for construction of BIR-4, without sacrificing performance.
SSAP, and BISEP pulses) are transformed into new pulses. These
It has been shown previously (11), using a trajectory new pulses are demonstrated numerically and experimentally to argument, that for on-resonance magnetization, the perforoperate at a significantly lower RF power level while maintaining mance of an amplitude-modulated and phase-modulated the same performance or over a wider bandwidth while using the pulse can be duplicated by a different pulse obtained through same RF power. They are expected to be useful for in vivo NMR experiments, especially for applications involving wide frequency an amplitude transformation. For on-resonance magnetizadispersion and pulse sequences composed of many adiabatic halftion, the hyperbolic secant pulse (2, 12) was shown to be passage pulses.