Abstract: 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 B0, B1+, T1 and T2* 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 B0, B1+, T1w, T1F, [T2*]w and [T2*]F. 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.

Abstract: 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 B0 map that causes image distortions; the B0 map 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 T2 (=1/R2) and T2* (=1/R2*) 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.

Abstract: 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.

Abstract: 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.

Abstract: Methods for reducing scan time in magnetic resonance imaging (“MRI”), particularly when imaging three-dimensional image volumes, using a simultaneous time-interleaved multislice (“STIMS”) acquisition are described. The unused time in each repetition time (“TR”) period is exploited to provide an additional reduction in encoding time for a three-dimensional acquisition (e.g., a 3D whole brain coverage). Groups of spatially interleaved slices are excited in a single TR, with the excitation and acquisition of the groups of slices being interleaved in time.

Abstract: Magnetic resonance fingerprinting (MRF) with simultaneous multivolume acquisition (SMVA) is described. One example nuclear magnetic resonance (NMR) apparatus includes an NMR logic that repetitively and variably samples (k, t, E) spaces associated with different volumes (e.g., slices) in an object to simultaneously acquire sets of NMR signals that are associated with different points in the (k, t, E) spaces. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and compares the NMR signal evolution to reference signal evolutions. Since different volumes are excited differently, resulting signal evolutions can be acquired simultaneously from the different volumes and NMR parameters may be simultaneously determined for the multiple volumes, which reduces acquisition time and parameter map creation time.

Abstract: Methods for reducing scan time in magnetic resonance imaging (“MRI”), particularly when imaging three-dimensional image volumes, using a simultaneous time-interleaved multislice (“STIMS”) acquisition are described. The unused time in each repetition time (“TR”) period is exploited to provide an additional reduction in encoding time for a three-dimensional acquisition (e.g., a 3D whole brain coverage). Groups of spatially interleaved slices are excited in a single TR, with the excitation and acquisition of the groups of slices being interleaved in time.

Abstract: Magnetic resonance fingerprinting (MRF) with simultaneous multivolume acquisition (SMVA) is described. One example nuclear magnetic resonance (NMR) apparatus includes an NMR logic that repetitively and variably samples (k, t, E) spaces associated with different volumes (e.g., slices) in an object to simultaneously acquire sets of NMR signals that are associated with different points in the (k, t, E) spaces. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and compares the NMR signal evolution to reference signal evolutions. Since different volumes are excited differently, resulting signal evolutions can be acquired simultaneously from the different volumes and NMR parameters may be simultaneously determined for the multiple volumes, which reduces acquisition time and parameter map creation time.