System and method for designing multi-channel RF pulses for MR imaging
AssigneesGeneral Electric Company, The Board of Trustees of the University of Illinois
InventorsDan Xu, Kevin F. King, Zhi-Pei Liang
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Abstract
A system and method are provided for designing RF pulses for multi-channel and/or multi-dimensional spatially-selective applications using a linear approximation. Embodiments of the system and method may use a generalized linear-class large tip angle approximation to design RF pulses for multi-channel and parallel transmission. Further, some of these approximations allow for the design of arbitrarily large flip angles, irregularly-shaped flip angle profiles, or arbitrary initial magnetization values. Embodiments of the system and method may also provide for the design of k-space trajectories which aid in maintaining assumptions of the various linear class approximations.
Claims20
A magnetic resonance (MR) imaging apparatus comprising:
- a plurality of gradient coils positioned about a bore of a magnet;
- an RF transceiver system and switch controlled by a pulse module to transmit RF signals to a multi-channel RF coil assembly to acquire MR images;
- and
- a system control operatively connected to the pulse module and programmed to:
- receive user parameters describing a desired RF pulse;
- create a linear class large tip angle (LCLTA) waveform representing the desired RF pulse for the multi-channel RF coil assembly;
- cause the pulse module to transmit the waveform via the multi-channel RF coil assembly to acquire MR image data;
- and
- at least temporarily store the MR image data in memory.
A method for MR imaging comprising:
- designing at least one multi-channel, multi-dimensional spatially-selective RF pulse using a linear approximation for an arbitrary initial magnetization;
- defining a k-space trajectory to maintain at least one assumption of the linear approximation;
- transmitting the at least one multi-channel, multi-dimensional spatially-selective RF pulse to acquire MR data according to the k-space trajectory;
- and
- reconstructing an MR image from the MR image data and displaying the image to a user.
A computer-readable storage medium having a set of instructions stored thereon which, when executed by a computer, cause the computer to:
- characterize a waveform for a multi-channel, multi-dimensional spatially-selective RF pulse using a linear equation;
- determine a refocusing k-space trajectory for the waveform;
- instruct an MR apparatus to transmit an RF pulse according to the waveform and k-space trajectory;
- and
- acquire MR data resulting from transmission of the RF pulse.
Dependencies are inferred from the claim text.