Zhejiang University

Huihui Ye

Huafeng Liu

Qing Li

Jinmin Xu

Hongjian He

Xiaozhi Cao

Qiuping Ding

Jianhui Zhong

Zijing Zhang

Dakun Hu

The present invention is a high-resolution magnetic resonance fingerprinting method based on radio frequency encoding, a device and storage medium, where radio frequency encoding is introduced into MRF, n time evolution signals can be collected by designing and respectively scanning a set of n radio frequency pulse signals, separate time evolution signals representing n sub-slices can be obtained after decoding and calculating according to a encoding process, and then separate quantitative images of the n sub-slices can be obtained through dictionary matching. Compared with conventional MRF, a slice resolution of the quantitative images obtained in the imaging method of the present invention is increased by n times and a signal-to-noise ratio is not reduced. Through a phantom experiment and a human experiment, accuracy of quantitative effect and an effective improvement of the resolution of the present invention are proved, and the present invention can provide higher-resolution quantitative imaging results.

High-resolution magnetic resonance fingerprinting method and device based on radio frequency encoding

The present invention discloses a magnetic resonance fingerprinting imaging method with variable number of echoes, in addition to conventional MRF coding such as changing the excitation pulse angle, the method also introduces the change of the number of echoes, so that quantitative maps of B, B+, Tand T* can be obtained in a single scan. Further, if the echo time corresponding to the in-phase, opposed-phase and in-phase of water and fat is set for three consecutive echoes, the present invention can also image water and fat, and achieve the accurate quantification of B, B+, T, T, [T*]and [T*]. Through in vivo experiments and simulations, the effectiveness of the present invention has been proved. Therefore, the present invention can provide multiple information representations for common brain diseases (glioma) and fatty diseases (such as lipoma, fatty liver, etc.), which is conducive to clinical diagnosis and treatment.

Magnetic resonance fingerprinting imaging method with variable number of echoes

The disclosure provides a modified EPI sequence for acquiring multi-shot and multi-echo images with interleaved blip-up and blip-down phase encoding; the blip-up and blip-down images are processed by topup in FSL to estimate the inhomogeneous main magnetic field Bmap that causes image distortions; the Bmap is then incorporated into the encoding matrix with a low rank constraint to form a joint reconstruction model; the joint reconstruction model is solved to obtain multiple distortion-free images; and the multiple distortion-free images are matched to dictionary to simultaneous acquire the quantitative T(=1/R) and T*(=1/R*) maps. In the phantom and in-vivo measurements, the disclosed method rapidly acquires the comparable quantitative images within one hold-breath (for 20 s) to the conventional mapping method, thus providing important practical application value for evaluation of liver damage, iron level and cancer lesion.

Method for simultaneous multiple magnetic resonance parameter mapping of liver

The present disclosure discloses a method for measuring relaxation time of ultrashort echo time magnetic resonance fingerprinting. In the method, semi-pulse excitation and semi-projection readout are adopted to shorten echo time (TE) to achieve acquisition of an ultrashort T2 time signal; and image acquisition and reconstruction are based on magnetic resonance fingerprint imaging technology. A TE change mode of sinusoidal fluctuation is introduced, so that distinguishing capability of a magnetic resonance fingerprint signal to short T2 and ultrashort T2 tissues is improved, and multi-parameter quantitative imaging of the short T2 and ultrashort T2 tissues and long T2 tissues is realized. 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-modulated signal demodulation principle; and the phase change caused by a B0 field is compensated in the fingerprint signal.

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Hangzhou, China

Huihui Ye