Patent ID: 7034533

Claim:
A method for generating a pulse sequence for operating a magnetic resonance imaging system for imaging a region of an object, wherein at least a portion of the region contains gas for at least a portion of the time required to apply said pulse sequence, said method comprising the steps of: (a) selecting spatial-encoding magnetic-field gradient waveforms to be approximately fully rephased, that is to have a zeroth moment approximately equal to zero, over the time period between pairs of successive RF pulses in said pulse sequence; (b) if desired, selecting spatial and/or spatial-spectral selection magnetic-field gradient waveforms associated with RF pulses in said pulse sequence to be approximately fully rephased; (c) if it is not desired to have approximately fully-rephased spatial or spatial-spectral selection magnetic-field gradient waveforms of step ‘b’, and/or it is desired to have spoiling magnetic-field gradients associated with refocusing RF pulses, setting the flip angles for said refocusing RF pulses approximately equal to 180°; (d) if a specific type of k-space trajectory is not required, optimizing said k-space trajectory to provide a low level of diffusion-induced signal attenuation throughout the acquisition for either a single-shot or multi-shot acquisition; and (e) selecting said spatial-encoding magnetic-field gradient waveforms to exclude as much as possible any time in said spatial-encoding magnetic-field gradient waveforms during which the gradient amplitude is zero.