Fast adiabatic pulses

Details Fast adiabatic pulses Fast adiabatic pulses

1997-06-26

2000-07-25

Oda, Christine K.

Electricity: measuring and testing

Particle precession resonance

Using a nuclear resonance spectrometer system

324309, 324314, G01V 300

Patent

active

060940492

ABSTRACT:
New methods of generating optimal inversion pulses and adiabatic pulses in magnetic resonance imaging are disclosed. Trajectories, maximum sweep rates, and velocity profiles are used in defining an optimal pulse, over support regions. Adiabatic pulses are optimized by using the trajectory as a constraint of optimization, but selecting trajectories with velocity profiles, without using the adiabatic condition as a constraint for optimizing the velocity profile. A method or inverting MR spins substantially, independently of the pulse duration, by selecting a transition width between 1.4 and 1.9 and dividing that width by the pulse duration is disclosed; and A new method of inverting adiabatic, MR, amplitude modulated spins, with a trajectory defined by sin .alpha./cos .alpha., where .alpha.<0.9 and at least 50% of the trajectory is outside, in a z-x rotating frame of reference that rotates at the instantaneous frequency of the RF pulse is also taught.

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