Magnetic resonance system and operating method for flow artifact reduction in slab selective space imaging

摘要

In a SPACE (Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) or equivalent magnetic resonance imaging pulse sequence, the dephasing gradient is generated (activated) so as to occur immediately in front of the second refocusing pulse, thereby eliminating the long time duration that occurs in conventional SPACE or equivalent sequences between excitation and readout. This long time duration has been identified as a source for flow-related artifacts that occur in images reconstructed from data acquired according to conventional SPACE or equivalent sequences. By eliminating this long time duration, such flow-related artifacts are substantially reduced, if not eliminated.

主权项

1. A method for generating a magnetic resonance image, comprising:
operating a magnetic resonance image data acquisition unit according to an imaging pulse sequence comprising an excitation radio-frequency (RF) pulse and a plurality of refocusing RF pulses temporally following said excitation RF pulse, said plurality of refocusing RF pulses including a first refocusing RF pulse and a second refocusing RF pulse; also operating said magnetic resonance image data acquisition unit in said imaging pulse sequence to shorten a time between dephasing of signals and readout of magnetic resonance data, by activating no dephasing gradient between said excitation RF pulse and said first refocusing RF pulse, and by activating a dephasing gradient in a readout direction between said first refocusing RF pulse and said second refocusing RF pulse and, not until after said second refocusing RF pulse, activating a readout gradient in said readout direction and, during said readout gradient, reading out magnetic resonance data from an object, animal or human subject, with a substance therein exhibiting a flow, exposed to said imaging pulse sequence in said magnetic resonance data acquisition unit; and supplying said magnetic resonance data to a computerized processor and, in said computerized processor, reconstructing a magnetic resonance image from said magnetic resonance data that is substantially free of artifacts related to said flow because of the shortened time between said dephasing gradient and reading out said magnetic resonance data with said readout gradient, and making said magnetic resonance image available as a data file at an output of said computerized processor.