Prospective phase correction plane echo imaging technology

Abstract

The invention discloses a prospective phase correction planar echo imaging technology, which comprises a planar echo imaging phase encoding error measurement sequence, a phase encoding error calculation method, a phase encoding error compensation sequence and a phase encoding error compensation method in planar echo imaging. A phase encoding error is measured and calculated through a reference scanning sequence, and then a compensation gradient is added to phase encoding in a scanning sequence of planar echo imaging to compensate the influence of B0 field heterogeneity, an eddy current field,gradient channel asymmetry and the like, so that artifacts can be reduced, and the signal-to-noise ratio can be increased.

Description

technical field [0001] The invention relates to the technical field of nuclear magnetic resonance imaging, in particular to a forward-looking phase correction echo-planar imaging technology. Background technique [0002] Such as Figure 4 As shown, echo planar imaging (EPI) technology is currently the most widely used ultra-fast imaging technology. Its characteristic is that after the radio frequency pulse excitation, the frequency encoding gradient quickly switches in the positive and negative directions, and the signal readout is completed on both the positive and negative gradient platforms, and the entire K space is quickly filled, so it is called planar echo imaging. Echo-planar imaging technology can collect a complete image within 30ms or even less, can freeze various movements, and can also perform real-time dynamic imaging. It has been obtained in diffusion-weighted imaging, perfusion imaging, and brain function imaging. an extremely wide range of applications. ...

AI Technical Summary

Problems solved by technology

This type of technology can achieve good results, but its shortcomings are as follows: 1. The correction algorithm is complex and the amount of calculation is large

After measuring the EPI imaging trajectory, two-dimensional grid reconstruction or non-uniform sampling Fourier transform is often required for reconstruction, which takes a long time to reconstruct

Second, due to the long EPI echo chain, any small errors such as B0 field non-uniformity and eddy current field will accumulate and aggravate, causing the magnetization vector to lose phase and reduce the signal-to-noise ratio. Post-processing correction cannot restore this part of the signal-to-noise ratio loss.

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