A Sequence Design Method for Three-Dimensional Spatially Selective Excitation for Magnetic Resonance Imaging

Abstract

The invention discloses a selective excitation sequential design method for magnetic resonance imaging in a three-dimensional space. According to the sequential design method disclosed by the invention, a proper excitation K space track is optimally determined according to space sensitive conditions of an excitation target and a plurality of transmitting channels of a radio-frequency coil, thereby a gradient pulse waveform and a radio frequency pulse envelope waveform corresponding to each transmitting channel are determined. A gradient driving unit and a radio-frequency driving unit in a magnetic resonance system can be used for generating gradient pulse and radio frequency pulse according to the radio frequency pulse envelope waveform and the gradient pulse waveform and driving a gradient coil and the radio frequency coil to apply the gradient pulse and radio frequency pulse in a scanning space, thereby the expected selective excitation target in the three-dimensional space is realized.

Description

technical field [0001] The invention relates to a sequence design method for three-dimensional space selective excitation for magnetic resonance imaging. Background technique [0002] When substances such as human tissue are placed in a uniform static magnetic field (B 0 field, that is, the main magnetic field), the direction of the proton magnetic moment in the tissue will tend to be in line with the B 0 The field is consistent and precesses along this direction at the Larmor frequency, so that the direction of the magnetization vector at this time is the positive direction of the z-axis, and the amplitude is M 0 , which means that the protons in the tissue are in equilibrium. If the direction and B are applied at this time 0 The field is vertical (that is, in the xy plane), and the radio frequency field close to the Larmor frequency (B 1 field), the magnetization vector inside the tissue will rotate to the xy plane, and its trajectory is in the same position as B 1 In...

AI Technical Summary

Problems solved by technology

First of all, in the imaging of a small-scale field of view (or small-scale FOV, FOV is the field of view), although the imaging time is shortened due to the undersampling of the imaging K-space, it also brings artifacts containing information of other parts; Through the selective excitation of the three-dimensional body, the protons in the small range of FOV are selectively excited, and there will be no artifacts from the interference of excited protons in other parts of the imaging results.

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