Gradient echo sequence setting method, magnetic resonance imaging system scanning method, equipment and medium

Abstract

The embodiment of the present invention discloses a sequence setting method, a magnetic resonance imaging system scanning method, equipment and media. The sequence setting method includes: acquiring pre-set layer selection gradient basic parameters, phase encoding gradient basic parameters and frequency encoding gradient basic parameters parameters; according to the layer selection gradient basic parameters, phase encoding gradient basic parameters, frequency encoding gradient basic parameters and parameters to be determined, the optimization objective function is generated; according to the optimization objective function and preset constraints, the parameter values ​​​​of the parameters to be determined are calculated, and based on the parameters Value sets the gradient echo sequence. The parameter values ​​of the sequence are calculated by optimizing the objective function and constraint conditions, so that the setting of the sequence makes full use of the falling time of the layer selection gradient and the rising time of the readout gradient, shortens the echo time in the sequence, and improves the display effect of the image .

Description

technical field [0001] Embodiments of the present invention relate to the technical field of medical imaging, and in particular to a gradient echo sequence setting method, a magnetic resonance imaging system scanning method, equipment and media. Background technique [0002] Gradient echo is an echo signal of MRI. Conventional gradient echo (GRE) sequence is composed of radio frequency pulse, slice selection gradient, phase encoding gradient, readout gradient and NMR signal. Conventional GRE sequence has two characteristics: (1) The excitation angle of radio frequency pulse is less than 90° °; (2) The generation of echo depends on the switching of the readout gradient field (that is, the frequency encoding gradient field). Generally, the time interval between the small-angle pulse midpoint and the echo midpoint is defined as echo time (TE), and the time interval between two adjacent small-angle pulse repetitions is defined as repetition time (TR). [0003] The GRE sequence...

AI Technical Summary

Problems solved by technology

[0004] Taking the Balanced Steady-State Free Processing (BSSFP) sequence as an example, the measures adopted to reduce TE and TR are ramp sampling (Ramp Sampling), which is carried out by making full use of the ramp-up period of the readout gradient. The reading of the signal, but the signal collected by the RampSampling measure is nonlinear, and linear sampling data needs to be obtained by interpolation. Therefore, the image reconstruction of the sampled data collected by the RampSampling measure requires a better interpolation function, and the interpolation operation There is a risk of affecting image quality

In addition, the RampSampling measure has limited space to shorten TE and TR

Images