Ultra-short time of echo magnetic resonance fingerprint relaxation time measuring method

Abstract

The invention discloses an ultra-short time of echo magnetic resonance fingerprint relaxation time measuring method. According to the method, semi-pulse excitation and semi-projection readout are adopted to shorten TE to achieve acquisition of an ultra-short T2 time signal; and image acquisition and reconstruction are based on a magnetic resonance fingerprint imaging technology. A TE change mode of sinusoidal fluctuation is introduced, so that the distinguishing capability of a magnetic resonance fingerprint signal to short T2 and ultra-short T2 tissues is improved, and simultaneous multi-parameter quantitative imaging of the short T2 and ultra-short T2 tissues and long T2 tissues is realized. The non-uniformity of a magnetic field is modulated into phase information of the fingerprint signal through the TE of the sinusoidal fluctuation; a B0 graph is directly reconstructed according to an amplitude modulation signal demodulation principle; and the phase change caused by a B0 field iscompensated in the fingerprint signal, so that the accuracy of signal recognition is improved. In magnetic resonance skeletal muscle system imaging, simultaneous quantitative measurement of T1, T2, PDand B0 of the bone (ultra-short T2) and muscle (long T2) tissues can be realized; and the method can also be used for imaging the brain and measuring the grey / white matter relaxation time and the skull structure.

Description

technical field [0001] The invention relates to the technical field of information processing, in particular to a method for measuring the relaxation time of an ultrashort echo time magnetic resonance fingerprint. Background technique [0002] Magnetic resonance techniques provide rich soft tissue imaging contrast. However, traditional MRI techniques are basically unable to detect bone, Achilles tendon, meniscus, and myelin sheath wall with short T2 or even ultra-short T2 (about 1-10ms). Ultra-short echo technology and zero-echo imaging technology have been widely used in the imaging of the above-mentioned tissues by shortening the echo time. Due to the long scanning time of single-point technology and multi-point technology, they are rarely used in the research of the subjects. In order to improve the sampling efficiency of k-space, the center-out readout trajectory is used for signal acquisition, including: semi-projected radial trajectory and spiral trajectory. The half...

AI Technical Summary

Problems solved by technology

However, there are still challenges in the quantification of ultrashort T2 tissues by existing MRF techniques

[0006] First, because the shortest echo time of traditional MRF technology is several milliseconds, it is difficult for MRF to detect ultra-short T2 tissue signals

[0007] Secondly, tissues with ultra-short T2 usually have low proton density, resulting in low overall signal intensity, which reduces the accuracy of MRF dictionary identification

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