Free breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method and device, terminal and medium

Abstract

The invention provides a free breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method and device, a terminal and a medium, and the method comprises the steps: carrying out the scanning of the heart tissue of a detected object in a free breathing state based on an established corresponding heart multi-parameter simultaneous quantitative magnetic resonance sequence, and obtaining a magnetic resonance scanning image; and processing to obtain a processed magnetic resonance scanning image. And matching the processed magnetic resonance scanning image with the established dictionary to obtain a parameter chart of the heart tissue of the detected object. By means of the method, the problems that in the prior art, T1, T2, T1 rho and other parameters of the heart tissue cannot be measured at the same time in the free breathing state, and the influence of a non-uniform B1 field on parameter measurement cannot be corrected at the same time can be solved.

Description

Technical Field

[0001] The present application relates to the field of magnetic resonance imaging, and in particular to a method, device, terminal and medium for simultaneous quantitative magnetic resonance imaging of multiple parameters of a free-breathing heart. Background Art

[0002] Cardiac magnetic resonance quantitative imaging can be used to measure the relaxation time of myocardial tissue. It is a non-invasive technology for evaluating the characteristics of myocardial tissue and plays an important role in diagnosing diseases, assessing risks and monitoring treatment effects. Relaxation times such as longitudinal relaxation time (T1), transverse relaxation time (T2) and longitudinal relaxation time under spin-lock pulse (T1ρ) are inherent properties of myocardial tissue. In a clinical setting, considering the above relaxation time parameters at the same time can achieve a comprehensive assessment of myocardial tissue, improve the diagnostic accuracy of difficult cardiomyopathy, and reduce the possibility of missed diagnosis.

[0003] The cardiac magnetic resonance quantitative imaging technology currently used in clinical diagnosis requires a separate breath-hold scan when measuring each parameter, but this method requires the patient to hold his breath repeatedly multiple times, which not only increases the examination time but also increases the risk of scan failure. In addition, a single breath-hold scan will also cause misalignment between the parameter maps obtained by the scan due to the patient's involuntary movement or different breath-holding states, which is not conducive to the comparison of parameters in clinical diagnosis. The problems existing in the above methods can be solved by the method of simultaneous multi-parameter quantitative sequence. The simultaneous multi-parameter quantitative sequence can save scanning time and obtain the registered parameter group map. The current multi-parameter quantitative method is mainly for the simultaneous measurement of longitudinal relaxation time (T1) and transverse relaxation time (T2), which can be divided into two types: one is to obtain images using a sequence that can simultaneously encode T1, T2 or other parameters, and obtain the parameter map by fitting the acquired magnetic resonance signal to a model related to the sequence; the other is based on magnetic resonance fingerprint imaging (MRF), and obtains the parameter map by finding the best match between the acquired multi-contrast magnetic resonance signal and the dictionary library.

[0004] However, the above measurement method requires the subject to hold his breath during the acquisition process to eliminate the impact of respiratory movement on the acquisition. But for patients with heart disease, holding breath for up to 11 cardiac cycles and a series of repeated breath holds is a huge burden. In order to reduce the burden on patients, respiratory navigation can be used and images can be acquired only at the end of exhalation to effectively suppress respiratory movement, but this method of using respiratory navigation will also significantly increase the acquisition time. Real-time adjustment of the imaging layer position based on diaphragm navigation can also keep the imaging layer relatively still with the heart, thereby effectively suppressing the movement of the heart in the direction of the imaging layer. This method can use all cardiac cycles for imaging, thereby significantly improving acquisition efficiency.

[0005] In 2021, Guo et al. used diaphragm navigation and model fitting methods to successfully achieve simultaneous measurement of T1 and T2 of the entire left ventricle under free breathing. In 2022, Carlos et al. achieved simultaneous measurement of T1, T2 and T1ρ of myocardial tissue based on MRF. However, this method requires the subject to hold his breath for 16 cardiac cycles during acquisition, and does not consider the inhomogeneity of the B1 field. In the same year, Henningsson combined dictionary matching with the balanced steady state free precession (bSSFP) acquisition sequence of Cartesian sampling trajectories to generate stable and reliable myocardial multi-parameter quantitative results. The dictionary library matching method of Cartesian acquisition can simplify the reconstruction process and improve the signal-to-noise ratio. The above method can only measure T1 and T2 simultaneously under the assumption that the B1 field is uniform in the myocardial area and the subject is required to hold his breath. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for solving the problems in the prior art that more than three key parameters of the heart, such as T1, T2 and T1ρ, cannot be measured simultaneously in a free breathing state, and the influence of the uneven B1 field on parameter measurement cannot be corrected simultaneously.

[0007] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a method for simultaneous quantitative magnetic resonance imaging of a free-breathing heart with multiple parameters, comprising: establishing a magnetic resonance sequence corresponding to simultaneous quantitative analysis of multiple cardiac parameters; scanning the heart tissue of a subject in a free-breathing state at multiple imaging levels through the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic trigger signals for each cardiac cycle corresponding to each imaging level; simulating the evolution of a magnetization vector based on the Bloch equation and the electrocardiographic trigger signal, and establishing a dictionary; obtaining a processed magnetic resonance scan image by performing image processing on each magnetic resonance scan image; and obtaining a parameter group map of the heart tissue of the subject by matching the processed magnetic resonance scan image with the dictionary.

[0008] In some embodiments of the first aspect of the present application, the establishment of a magnetic resonance sequence corresponding to the simultaneous quantification of multiple cardiac parameters includes: determining an optimized best pulse sequence combination involving each cardiac cycle; optimizing the pulse flip angle combination in the best pulse sequence combination by introducing a variable angle technology to obtain an optimal pulse flip angle combination; based on the best pulse sequence combination and the best pulse flip angle combination, obtaining a magnetic resonance sequence corresponding to the simultaneous quantification of multiple cardiac parameters; wherein the magnetic resonance sequence includes: pulse data corresponding to each cardiac cycle.

[0009] In some embodiments of the first aspect of the present application, the scanning of the cardiac tissue of the subject in a free breathing state at multiple imaging levels through the magnetic resonance sequence to obtain a magnetic resonance scanning image and an electrocardiogram trigger signal for each cardiac cycle corresponding to each imaging level includes: based on the magnetic resonance sequence, performing magnetic resonance scanning operations on each imaging level in turn according to the acquired diastolic electrocardiogram images of each imaging level, to obtain a magnetic resonance scanning image and an electrocardiogram trigger signal for each cardiac cycle corresponding to each imaging level; wherein the magnetic resonance scanning operation includes: based on a pulse application rule, applying a corresponding pulse to each cardiac cycle according to the magnetic resonance sequence and the electrocardiogram trigger signal in the diastolic electrocardiogram images of each cardiac cycle of the acquired corresponding imaging level, to obtain a magnetic resonance scanning image and an electrocardiogram trigger signal for each cardiac cycle of the corresponding imaging level.

[0010] In some embodiments of the first aspect of the present application, the pulse application rule includes: an inversion pulse application rule, including: when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence to obtain a magnetic resonance scanning image of the corresponding inversion pulse cardiac cycle; a T2 preparation pulse application rule, including: when an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in the ECG image, a T2 preparation pulse is applied in the corresponding T2 preparation pulse cardiac cycle according to the magnetic resonance sequence to obtain a magnetic resonance scanning image of the corresponding T2 preparation pulse cardiac cycle; a T1ρ preparation pulse application rule, including: when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in the ECG image, a T1ρ preparation pulse is applied in the corresponding T1ρ preparation pulse cardiac cycle according to the magnetic resonance sequence to obtain a magnetic resonance scanning image of the corresponding T1ρ preparation pulse cardiac cycle.

[0011] In some embodiments of the first aspect of the present application, the inversion pulse application rule also includes: when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence; after applying the inversion recovery pulse, a diaphragm navigation operation is performed to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle; the T2 preparation pulse application rule also includes: when an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in the ECG image, a T2 preparation pulse is applied in the corresponding T2 preparation pulse cardiac cycle according to the magnetic resonance sequence; before applying the T2 preparation pulse, a diaphragm navigation operation is performed to obtain a magnetic resonance scanning image corresponding to the T2 preparation pulse cardiac cycle; the T1ρ preparation pulse application rule also includes: when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in the ECG image, a T1ρ preparation pulse is applied in the corresponding T1ρ preparation pulse cardiac cycle according to the magnetic resonance sequence; before applying the T1ρ preparation pulse, a diaphragm navigation operation is performed to obtain a magnetic resonance scanning image corresponding to the T1ρ preparation pulse cardiac cycle.

[0012] In some embodiments of the first aspect of the present application, the diaphragm navigation operation includes: correcting the imaging level of the subject's cardiac tissue based on the position of the diaphragm at the end of respiratory period determined by analyzing the diaphragm movement pattern in the cardiac tissue before scanning.

[0013] In some embodiments of the first aspect of the present application, the dictionary is established by simulating the evolution process of the magnetization vector based on the Bloch equation and the ECG trigger signal, including: obtaining multiple parameter combinations based on the numerical variation range and discretization step size of the set quantitative parameters; simulating the evolution process of the magnetization vector under each parameter combination based on the Bloch equation and the ECG trigger signal to obtain the transverse component intensity of the magnetization vector corresponding to the center line of the K space; obtaining the corresponding transverse component intensity curve of the magnetization vector based on the transverse component intensity of the magnetization vector corresponding to the center line of the K space; the parameter combination and the transverse component intensity curve of the magnetization vector constitute a dictionary.

[0014] In some embodiments of the first aspect of the present application, obtaining the parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scanning image with the dictionary includes: matching the transverse component intensity curve of the magnetization vector obtained based on each pixel point in the processed magnetic resonance scanning image with the dictionary to obtain the parameter value corresponding to each pixel point; and obtaining the parameter group map of the cardiac tissue of the subject based on the parameter value corresponding to each pixel point.

[0015] To achieve the above-mentioned purpose and other related purposes, the second aspect of the present application provides a free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance apparatus, characterized in that it includes: a sequence establishment module, used to establish a magnetic resonance sequence corresponding to the simultaneous quantitative measurement of cardiac multi-parameters; a scanning module, connected to the sequence establishment module, used to scan the cardiac tissue of the subject in a free-breathing state at multiple imaging levels through the magnetic resonance sequence, and obtain magnetic resonance scanning images and electrocardiographic trigger signals corresponding to each cardiac cycle of each imaging level; a dictionary establishment module, connected to the scanning module, used to simulate the evolution process of the magnetization vector based on the Bloch equation and the electrocardiographic trigger signal, and establish a dictionary; an image processing module, connected to the scanning module, used to obtain a processed magnetic resonance scanning image by performing image processing on each magnetic resonance scanning image; and a parameter group map generation module, respectively connected to the dictionary establishment module and the image processing module, used to obtain a parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scanning image with the dictionary.

[0016] To achieve the above-mentioned purpose and other related purposes, the third aspect of the present application provides an electronic terminal, including: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the free-breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method.

[0017] To achieve the above-mentioned purpose and other related purposes, the third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for simultaneous quantitative magnetic resonance imaging of multi-parameters of a free-breathing heart is implemented.

[0018] As described above, the method, device, terminal and medium for simultaneous quantitative magnetic resonance imaging of multi-parameters of a free-breathing heart of the present application have the following beneficial effects:

[0019] 1) The present invention can obtain quantitative cardiac images when the subject is breathing freely, which reduces the burden on the subject, and obtains multiple tissue parameters in one quick scan, greatly saving scanning time. In addition, the present invention can obtain magnetic resonance scanning image quality similar to that under breath-holding conditions.

[0020] 2) The present invention realizes pixel-by-pixel B1 correction and improves the quantitative accuracy of tissue parameters and B1 correction parameters by optimizing the pulse flip angle.

[0021] 3) The present invention can simultaneously obtain mutually registered T1, T2 and T1ρ parameter group images in a single scan. Compared with the conventional quantitative sequence requiring breath holding used in clinical practice, the present invention has the same image quality and quantitative accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a schematic flow chart of a method for simultaneous quantitative magnetic resonance imaging of a free-breathing heart with multiple parameters in one embodiment of the present application.

[0023] Figure 2 Shown is a flowchart of a method for establishing a magnetic resonance sequence corresponding to simultaneous quantification of multiple cardiac parameters in one embodiment of the present application.

[0024] Figure 3 Shown is a flowchart of a method for establishing a dictionary in one embodiment of the present application.

[0025] Figure 4 Shown is a schematic diagram of simultaneous quantitative magnetic resonance imaging of multiple parameters of a free-breathing heart in one embodiment of the present application.

[0026] Figure 5A Shown is a schematic diagram of a parameter group diagram obtained from a phantom experiment in a specific embodiment of the present application.

[0027] Figure 5B Shown is a scatter diagram of quantitative results at different heart rates in a phantom experiment in a specific embodiment of the present application.

[0028] Figure 5C Shown is a scatter diagram of the quantitative results and reference values ​​obtained from a phantom experiment in a specific embodiment of the present application.

[0029] Figure 5D Shown is a Bland-Altman statistical diagram of a phantom experiment in a specific embodiment of the present application.

[0030] Fig. 6A Shown is a schematic diagram of the correlation analysis between the quantitative results in a specific embodiment of the present application and the quantitative results of traditional clinical sequences.

[0031] Figure 6B Shown is a statistical diagram of the consistency analysis between the quantitative results in a specific embodiment of the present application and the quantitative results of traditional clinical sequences.

[0032] Figure 7 Shown is a schematic diagram of a free-breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging device in one embodiment of the present application.

[0033] Figure 8 Shown is a schematic diagram of the structure of a terminal in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] It should be noted that in the following description, with reference to the accompanying drawings, several embodiments of the present application are described in the accompanying drawings. It should be understood that other embodiments may also be used, and mechanical composition, structure, electrical and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is limited only by the claims of the published patents. The terms used here are only for describing specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0036] In this application, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix", "hold" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described here can be implemented in an order other than that illustrated or described here. In addition, the terms "comprising" and "including" indicate the presence of the described features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. It should be further understood that the terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition occur only when a combination of elements, functions, or operations are inherently mutually exclusive in some manner.

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution in the embodiments of the present invention is further described in detail through the following embodiments and in combination with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0039] The present invention provides a method for simultaneous quantitative magnetic resonance imaging of multiple parameters of a free-breathing heart, such as Figure 1 As shown, the method includes:

[0040] Step S101: establishing a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters;

[0041] Optionally, the establishment of a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters is as follows: Figure 2 As shown, including:

[0042] Step S201: determining an optimized best pulse sequence combination involving each cardiac cycle;

[0043] Optionally, the optimal pulse sequence combination includes: the number of cardiac cycles to which the pulse is applied, the type of pulse applied corresponding to each cardiac cycle, the number of pulses corresponding to each pulse type, and the pulse parameters of each pulse. The optimal pulse sequence is optimized through digital simulation experiments, phantom experiments, and in vivo experiments to determine the pulse sequence combination with the smallest error. Among them, the pulse sequence combination with the smallest error is the optimal pulse sequence combination.

[0044] It should be noted that the pulse sequence combination with the smallest error is the pulse sequence combination with the smallest quantitative error for multiple cardiac parameters.

[0045] Step S202: Optimize the pulse flip angle combination in the optimal pulse sequence combination by introducing the variable angle technology to obtain the optimal pulse flip angle combination; optionally, optimize the pulse flip angle in the pulse parameters in the optimal pulse sequence combination by introducing the variable angle technology through digital simulation experiments, phantom experiments and in vivo experiments to determine the pulse flip angle combination with the smallest error. Wherein, the pulse flip angle combination includes: the pulse flip angle corresponding to each cardiac cycle group; the cardiac cycle to which the pulse is applied is divided into multiple groups, each group being a cardiac cycle group. The pulse flip angle combination with the smallest error is the pulse flip angle combination with the smallest quantitative error for multiple cardiac parameters.

[0046] Optionally, a readout excitation pulse is applied corresponding to each cardiac cycle; all cardiac cycles are divided into multiple cardiac cycle groups; the pulse flip angles of the readout excitation pulses applied corresponding to each cardiac cycle in each cardiac cycle group are the same; and the best pulse flip angle combination is optimized to optimize the pulse flip angle corresponding to each cardiac cycle group.

[0047] Step S203: obtaining a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters based on the optimal pulse sequence combination and the optimal pulse flip angle combination; wherein the magnetic resonance sequence includes pulse data corresponding to each cardiac cycle.

[0048] Optionally, the pulse data corresponding to each cardiac cycle includes: the number of cardiac cycles to which the pulse is applied, the type of pulse applied corresponding to each cardiac cycle, the number of pulses corresponding to each pulse type, and the pulse parameters of each pulse; wherein the pulse parameters of each pulse include: the pulse flip angle in the optimal flip angle combination.

[0049] Step S102: scanning the cardiac tissue of the subject in a free breathing state at multiple imaging levels through the magnetic resonance sequence to obtain magnetic resonance scanning images and electrocardiographic triggering signals corresponding to each cardiac cycle of each imaging level;

[0050] Optionally, the scanning of the cardiac tissue of the subject in a free-breathing state at multiple imaging levels by the magnetic resonance sequence to obtain a magnetic resonance scan image and an electrocardiogram triggering signal corresponding to each cardiac cycle of each imaging level includes: based on the magnetic resonance sequence, performing magnetic resonance scanning operations at each imaging level in turn according to the acquired electrocardiogram images of each imaging level to obtain a magnetic resonance scan image and an electrocardiogram triggering signal corresponding to each cardiac cycle of each imaging level;

[0051] Among them, the magnetic resonance scanning operation includes: based on the pulse application rule, applying corresponding pulses to each cardiac cycle according to the magnetic resonance sequence and the electrocardiographic trigger signal in the electrocardiographic image of each cardiac cycle at the corresponding imaging level, so as to obtain the magnetic resonance scanning image and electrocardiographic trigger signal of each cardiac cycle at the corresponding imaging level.

[0052] Optionally, the magnetic resonance scanning image of each cardiac cycle is a magnetic resonance scanning image of the heart's diastole.

[0053] In order to better illustrate the scanning of the cardiac tissue of the subject in the free breathing state by the magnetic resonance sequence in this embodiment, the following will be described in detail as follows:

[0054] The cardiac tissue of the subject in a free-breathing state is divided into multiple imaging planes, and the multiple imaging planes are scanned in sequence. For example, the short-axis plane of the cardiac tissue can be divided into three layers, namely, the apical layer, the middle layer, and the basal layer. The scanning of each imaging plane includes: scanning in multiple cardiac cycles, and obtaining a magnetic resonance scanning image corresponding to each cardiac cycle. The acquired electrocardiogram is the acquired electrocardiogram (ECG) of the subject. Among them, the electrocardiogram (ECG) is a graph of various forms of point changes in the heart, which are excited successively by the pacemaker, atrium, and ventricle in each cardiac cycle, accompanied by changes in the electrocardiogram bioelectricity, and is drawn from the body surface through an electrocardiograph; the electrocardiogram includes: P wave, Q wave, R wave, S wave, and T wave. The ECG trigger signal is generated by the R wave. The corresponding ECG trigger signal will be acquired for each cardiac cycle.

[0055] Taking an imaging layer as an example, when an ECG trigger signal corresponding to a cardiac cycle is collected, a corresponding pulse is applied to the cardiac cycle based on the magnetic resonance sequence to obtain a magnetic resonance scan image corresponding to the cardiac cycle. After the corresponding pulses are applied to the cardiac cycles corresponding to the imaging layer based on the magnetic resonance sequence, magnetic resonance scan images of all cardiac cycles corresponding to the imaging layer are obtained.

[0056] It should be noted that the cardiac cycle refers to the time required for the heart to complete one contraction and relaxation from the start of one heartbeat to the start of the next heartbeat. In the present invention, the ECG trigger signal represents the start of a cardiac cycle, and the current ECG trigger signal to the next trigger signal represents a cardiac cycle.

[0057] Optionally, a readout excitation pulse is applied corresponding to each cardiac cycle, and the readout excitation pulse is used for magnetic resonance imaging.

[0058] Optionally, the magnetic resonance sequence includes: an inversion recovery pulse, a T2 preparation pulse, a T1ρ preparation pulse, and a readout excitation pulse. The pulse application rules corresponding to the magnetic resonance sequence include:

[0059] The inversion pulse application rule includes: when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in an ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to a magnetic resonance sequence to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle; wherein the inversion pulse cardiac cycle is a cardiac cycle in which an inversion pulse is applied; and the magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle is a magnetic resonance scanning image with T1 weight introduced.

[0060] Specifically, when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence. After applying the inversion recovery pulse, a readout excitation pulse is applied to obtain a magnetic resonance scan image corresponding to the inversion pulse cardiac cycle.

[0061] The T2 preparation pulse application rule includes: when an electrocardiographic trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in an electrocardiographic image, a T2 preparation pulse is applied in the corresponding T2 preparation pulse cardiac cycle according to a magnetic resonance sequence to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle; wherein the T2 preparation pulse cardiac cycle is a cardiac cycle in which the T2 preparation pulse is applied; and the magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle is a magnetic resonance scan image in which a T2 weight is introduced.

[0062] Specifically, when an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in an ECG image, a T2 preparation pulse is applied in the corresponding T2 preparation pulse cardiac cycle according to a magnetic resonance sequence. After applying the T2 preparation pulse, a readout excitation pulse is applied to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle.

[0063] The T1ρ preparation pulse application rule includes: when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an ECG image, a T1ρ preparation pulse is applied in the cardiac cycle corresponding to the T1ρ preparation pulse according to a magnetic resonance sequence to obtain a magnetic resonance scan image corresponding to the T1ρ preparation pulse cardiac cycle; wherein the T1ρ preparation pulse cardiac cycle is a cardiac cycle in which the T1ρ preparation pulse is applied; and the magnetic resonance scan image corresponding to the T1ρ preparation pulse cardiac cycle is a magnetic resonance scan image into which a T1ρ weight is introduced.

[0064] Specifically, when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an ECG image, a T1ρ preparation pulse is applied in the cardiac cycle corresponding to the T1ρ preparation pulse according to a magnetic resonance sequence. After applying the T1ρ preparation pulse, a readout excitation pulse is applied to obtain a magnetic resonance scan image corresponding to the T1ρ preparation pulse cardiac cycle.

[0065] It should be noted that the application period of the above-mentioned pulses is determined by Figure 2 The various steps in the method shown are obtained.

[0066] Based on the magnetic resonance scan image with T1 weight, the magnetic resonance scan image with T2 weight, and the

[0067] T1ρ-weighted magnetic resonance scan images can obtain T1 parameters, T2 parameters and T1ρ parameters.

[0068] Optionally, in order to obtain a more accurate magnetic resonance image, a diaphragm navigation operation needs to be performed to keep the imaging plane and the heart relatively still. Corresponding to the pulse application rule in the above embodiment, the pulse application rule including the diaphragm navigation operation is:

[0069] Inversion pulse application rule: when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence; after applying the inversion recovery pulse, a diaphragm navigation operation is performed to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle; wherein the inversion pulse cardiac cycle is a cardiac cycle in which an inversion pulse is applied; and the magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle is a magnetic resonance scanning image with T1 weight introduced.

[0070] Specifically, when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence. After applying the inversion recovery pulse, a diaphragm navigation operation is performed. After performing the diaphragm navigation operation, a readout excitation pulse is applied to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle.

[0071] T2 preparation pulse application rule: when an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in a diastolic ECG image, a T2 preparation pulse is applied in the cardiac cycle corresponding to the T2 preparation pulse according to a magnetic resonance sequence; before applying the T2 preparation pulse, a diaphragm navigation operation is performed to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle; wherein the T2 preparation pulse cardiac cycle is a cardiac cycle in which the T2 preparation pulse is applied; and the magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle is a magnetic resonance scan image in which a T2 weight is introduced.

[0072] Specifically, when an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in an ECG image, a T2 preparation pulse is applied in the cardiac cycle corresponding to the T2 preparation pulse according to a magnetic resonance sequence. Before applying the T2 preparation pulse, a diaphragm navigation operation is performed. After applying the T2 preparation pulse, a readout excitation pulse is applied to obtain a magnetic resonance scan image corresponding to the cardiac cycle in which the T2 preparation pulse is applied.

[0073] The T1ρ preparation pulse application rule includes: when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an ECG image, applying a T1ρ preparation pulse in the cardiac cycle corresponding to the T1ρ preparation pulse according to a magnetic resonance sequence; performing a diaphragm navigation operation before applying the T1ρ preparation pulse to obtain a magnetic resonance scanning image corresponding to the T1ρ preparation pulse cardiac cycle; wherein the T1ρ preparation pulse cardiac cycle is a cardiac cycle in which the T1ρ preparation pulse is applied; and the magnetic resonance scanning image corresponding to the T1ρ preparation pulse cardiac cycle is a magnetic resonance scanning image in which a T1ρ weight is introduced.

[0074] Specifically, when an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an ECG image, a T1ρ preparation pulse is applied in the cardiac cycle corresponding to the T1ρ preparation pulse according to a magnetic resonance sequence. Before applying the T1ρ preparation pulse, a diaphragm navigation operation is performed. After applying the T1ρ preparation pulse, a readout excitation pulse is applied to obtain a magnetic resonance scan image corresponding to the cardiac cycle in which the T1ρ preparation pulse is applied.

[0075] It should be noted that the diaphragm navigation operation is performed before the T2 preparation pulse or the T1ρ preparation pulse to prevent the T2 preparation pulse and the T1ρ preparation pulse from interfering with the signal corresponding to the diaphragm navigation operation. The diaphragm navigation operation is performed after the inversion recovery pulse to shorten the time interval between the navigation operation corresponding to each cardiac cycle and the readout excitation pulse.

[0076] Optionally, the inversion recovery pulse includes: a layer-selective flip pulse, which is used to eliminate the interference of the inversion recovery pulse on the signal corresponding to the diaphragm navigation operation.

[0077] Optionally, the diaphragm navigation operation includes: correcting the imaging level of the subject's cardiac tissue based on the position of the diaphragm at the end of respiratory period determined by analyzing the diaphragm movement pattern in the cardiac tissue before scanning.

[0078] Specifically, before scanning, the diaphragm movement pattern of the subject is learned and analyzed based on the set diaphragm navigation repetition time (TR) to determine the position of the diaphragm at the end of breathing. According to experience, the displacement of the heart in the head-foot direction is 60% of the diaphragm displacement. Based on the above experience, the position of the imaging plane can be corrected by the displacement of the diaphragm. Correcting the position of the imaging plane can significantly eliminate the trans-plane movement of the heart caused by the breathing of the subject, so as to achieve relative stillness between the imaging plane and the heart.

[0079] It should be noted that the diaphragm is a muscle-fiber structure located between the chest and abdomen and is an important respiratory muscle of the body. The diaphragm navigation repetition time is the same as the average heartbeat interval of the subject; the time between one heart beat and the next is the heartbeat interval.

[0080] Optionally, the diaphragm position is detected by a cross-excited navigation bar. The liver top position is found on the transverse image, and the cross portion of the diaphragm navigation bar is set on the liver top position; the highest position of the liver is found on the coronal image, and the center of the cross-excited navigation bar is placed at the junction of the liver and lung.

[0081] It should be noted that the transverse plane represents the long axis of the heart, and the coronal plane represents the short axis of the heart.

[0082] Step S103: simulating the evolution of the magnetization vector based on the Bloch equation and the ECG trigger signal, and establishing a dictionary;

[0083] Optionally, the evolution process of the magnetization vector is simulated based on the Bloch equation and the ECG trigger signal, and a dictionary is established, such as Figure 3 As shown, including:

[0084] Step S301: Obtain multiple parameter combinations based on the set numerical variation range of the quantitative parameters and the discretization step size; wherein the quantitative parameters include: T1 (longitudinal relaxation time), T2 (transverse relaxation time), T1ρ (longitudinal relaxation time under the spin-lock pulse) and B1 parameters; the parameter combinations include: discrete T1, T2, T1ρ and B1 parameters.

[0085] Optionally, the B1 parameter is obtained based on the flip angle of the readout excitation pulse applied to each cardiac cycle. Specifically, the flip angle determined when establishing the magnetic resonance sequence corresponding to the simultaneous quantitative measurement of multiple cardiac parameters in step S101 is the designed flip angle, and in the actual scanning process, the actual flip angle of the readout excitation pulse applied to each cardiac cycle is different from the designed flip angle due to the limitations of actual conditions. The B1 parameter is the ratio of the actual flip angle of the readout excitation pulse applied to each cardiac cycle to the designed flip angle.

[0086] Optionally, the variable angle technique in step S202 refers to using different readout flip angles in different cardiac cycles. The inversion recovery process is affected by both T1 relaxation and the readout excitation pulse. Therefore, only by obtaining the magnetization vector evolution process under different flip angles can the influence of tissue T1 value and flip efficiency on magnetization vector evolution be accurately distinguished. The quantitative accuracy of B1 parameters can be further improved by optimizing the pulse flip angle combination.

[0087] It should be noted that the numerical variation range and discretization step size of the quantitative parameters are set based on the results of traditional clinical quantification.

[0088] It should be noted that the above quantitative parameters can be used for a comprehensive assessment of cardiac tissue. For example, in the case of edema, inflammation, and fibrosis, increased free water or increased fibrous tissue in the cardiac tissue will lead to an increase in the T1 value; in the case of iron deposition or increased fat content (such as glycosphingolipid accumulation in Fabry disease), the T1 value will decrease. An increase in the T2 value reflects an increase in the free water content in the tissue and can be used to diagnose myocardial edema and inflammation; acute or chronic myocardial infarction and other non-ischemic myocardial diseases, such as dilated cardiomyopathy and hypertrophic cardiomyopathy, will lead to an increase in the T1ρ value. The T1ρ value can detect focal and diffuse myocardial fibrosis without the injection of contrast agents.

[0089] Step S302: Based on the Bloch equation and the ECG trigger signal, the evolution process of the magnetization vector under each parameter combination is simulated to obtain the transverse component intensity of the magnetization vector corresponding to the center line of the K space; specifically, taking the simulation process of one parameter combination as an example: based on the Bloch equation and the ECG trigger signal, the evolution process of the magnetization vector under the parameter combination is simulated to obtain the transverse component intensity of the magnetization vector corresponding to the center line of the K space corresponding to each cardiac cycle.

[0090] It should be noted that by setting the B1 parameters for simulation, the influence of the inhomogeneity of the B1 field can be corrected. The inhomogeneity of the B1 field will affect the quantitative accuracy of the T1, T2 and T1ρ parameters.

[0091] Step S303: obtaining a corresponding magnetization vector transverse component intensity curve based on the magnetization vector transverse component intensity corresponding to the K-space center line; specifically, taking a parameter combination as an example, when the magnetization vector transverse component intensity corresponding to the K-space center line of each cardiac cycle of the parameter combination is obtained, the magnetization vector transverse component intensity corresponding to the K-space center line of all cardiac cycles of the parameter combination constitutes a corresponding magnetization vector transverse component intensity curve.

[0092] It should be noted that K space is: the Fourier space of rectangular coordinate space, that is, the frequency space of Fourier change, also known as Fourier space. The projection curve of MR signal in K space is called K trajectory, also known as Fourier line. The magnetization vector is used to describe the intensity of magnetism.

[0093] Step S304: The parameter combination and the magnetization vector transverse component intensity curve form a dictionary.

[0094] Step S104: performing image processing on each magnetic resonance scan image to obtain a processed magnetic resonance scan image;

[0095] Optionally, the image processing includes: performing noise reduction on the magnetic resonance scan image and performing a registration operation on the magnetic resonance scan image; wherein the registration operation includes: performing registration between the magnetic resonance scan images of each cardiac cycle corresponding to each imaging layer.

[0096] Optionally, the registration operation adopts a group registration algorithm based on principal component analysis.

[0097] Step S105: Obtaining a parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scan image with the dictionary.

[0098] Specifically, the transverse component intensity curve of the magnetization vector obtained based on each pixel point in the processed magnetic resonance scan image is matched with each transverse component intensity curve of the magnetization vector in the dictionary to determine the best matching curve, so as to obtain the parameter value corresponding to the best matching curve according to the best matching curve. The parameter value corresponding to the best matching curve is the parameter value corresponding to each pixel point; based on the parameter value corresponding to each pixel point, a parameter group map of the cardiac tissue of the subject is obtained.

[0099] In order to better explain the free-breathing heart multi-parameter simultaneous quantitative magnetic resonance method of the present invention, a specific example is provided below.

[0100] Embodiment 1: A multi-parameter simultaneous quantitative magnetic resonance imaging method for a free-breathing heart.

[0101] The cardiac tissue is divided into three imaging layers in the short axis direction of the heart, namely the apical layer, the middle layer and the basal layer. Figure 4 As shown in the middle A area, the number of corresponding scanned cardiac cycles is 16.

[0102] The established magnetic resonance sequence includes: inversion recovery pulse (SSIR, IR), T2 preparation pulse (T2-Prep), T1ρ preparation pulse (T1ρ-Prep) and readout excitation pulse (Acq). The inversion recovery pulse includes: a non-slice-selective 180° adiabatic pulse and a slice-selective 180° adiabatic pulse. The T2 preparation pulse includes: two adiabatic refocusing pulses and two 90 ° Hard excitation pulse. T1ρ preparation pulse includes: one refocusing pulse, two 90° hard excitation pulses and four spin lock pulses. Divide the 16 cardiac cycles into 4 groups, such as Figure 4As shown in the middle A area, the first cardiac cycle group is from the 1st cardiac cycle to the 4th cardiac cycle, the 5th cardiac cycle to the 8th cardiac cycle is the 2nd cardiac cycle group, the 9th cardiac cycle to the 12th cardiac cycle is the 3rd cardiac cycle group, and the 13th cardiac cycle to the 16th cardiac cycle is the 4th cardiac cycle group. The optimization range of the pulse flip angle corresponding to each cardiac cycle group is 35 degrees to 70 degrees, with a step size of 5 degrees.

[0103] According to the pulse application rules, the corresponding pulses are applied to each cardiac cycle: according to the inversion pulse application rules in the pulse application rules, the inversion recovery pulse is applied to the 1st and 9th cardiac cycles, and the diaphragm navigation operation (dNAV) is performed after the inversion recovery pulse is applied, and then the readout excitation pulse is applied; wherein, the inversion time of each inversion recovery pulse is 255ms; the inversion time is the time interval between the inversion recovery pulse and the readout excitation pulse; according to the T2 preparation pulse application rules in the pulse application rules, the T2 preparation pulse is applied to the 5th to 8th cardiac cycles in sequence. Before applying the T2 preparation pulse to each cardiac cycle, the diaphragm navigation operation is performed. After applying the T2 preparation pulse to each cardiac cycle, the readout excitation pulse is applied. The preparation times corresponding to the 5th to 8th cardiac cycles are: 35, 45, 55, 65ms, respectively. Among them, two adiabatic refocusing pulses and two 90° hard excitation pulses are applied to each cardiac cycle; according to the T1ρ preparation pulse application rule in the pulse application rule, T1ρ preparation pulses are applied to the 13th to 16th cardiac cycles in sequence. Before applying the T1ρ preparation pulse in each cardiac cycle, the diaphragm navigation operation is performed. After applying the T1ρ preparation pulse to each cardiac cycle, the readout excitation pulse is applied. The T1ρ preparation pulse applied to each cardiac cycle has the same 350Hz spin lock frequency, and the spin lock time is: 16, 30, 40, 50ms in sequence. Among them, one refocusing pulse, two 90° hard excitation pulses and four spin lock pulses are applied to each cardiac cycle.

[0104] After applying the pulses corresponding to each cardiac cycle in sequence according to the above scheme for 16 cardiac cycles, the following is obtained: Figure 4 16 pairs of magnetic resonance scan images corresponding to each cardiac cycle are shown in area B in FIG. Noise reduction and registration operations are performed on the 16 pairs of magnetic resonance scan images corresponding to each cardiac cycle to obtain processed magnetic resonance scan images. The processed magnetic resonance images are compared with the Figure 4 The dictionary established in area B is matched to obtain Figure 5A Parameter group diagram of the cardiac tissue of the subject shown.

[0105] The results of the actual application of the method in this embodiment are as follows:

[0106] The phantom experiment was carried out at different heart rates to obtain the parameter values ​​of each parameter and generate the corresponding scatter plot. Figure 5B It can be seen that there is no obvious difference between the parameter values ​​measured at different heart rates, indicating that the method in this embodiment is not sensitive to heart rate and has good accuracy and robustness.

[0107] pass Figure 5C As can be seen from the scatter diagram, there is a strong correlation between the quantitative results obtained in the phantom experiment using the method in this embodiment and the reference value.

[0108] pass Figure 5D As shown in the Bland-Altman statistical diagram, the quantitative results obtained in the phantom experiment using the method in this embodiment are within the consistency range with the reference value.

[0109] Fig. 6A This is a violin plot comparing the quantitative results of the currently widely used quantitative technology in clinical practice with the method in this embodiment on the myocardial tissue of 15 healthy subjects. As shown in the figure, it shows that there is a strong correlation between the measured quantitative results and the reference values. Figure 6B The Bland-Altman statistical graph drawn for consistency analysis of the in vivo experimental results shows that the multi-parameter quantitative results of the method in this embodiment and the quantitative results of the technology currently widely used in clinical practice are within the consistency range.

[0110] The present invention also provides a free-breathing heart multi-parameter simultaneous quantitative magnetic resonance device, such as Figure 7 As shown, the device 7 comprises:

[0111] A sequence establishment module 71 is used to establish a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters;

[0112] A scanning module 72, connected to the sequence establishing module 71, is used to scan the cardiac tissue of the subject in a free breathing state at multiple imaging levels through the magnetic resonance sequence to obtain magnetic resonance scanning images and electrocardiographic triggering signals corresponding to each cardiac cycle of each imaging level;

[0113] A dictionary building module 73, connected to the scanning module 72, is used to simulate the evolution process of the magnetization vector based on the Bloch equation and the ECG trigger signal, and to build a dictionary;

[0114] An image processing module 74, connected to the scanning module 72, for obtaining a processed magnetic resonance scanning image by performing image processing on each magnetic resonance scanning image;

[0115] The parameter group map generating module 75 is connected to the dictionary building module 73 and the image processing module 74 respectively, and is used to obtain the parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scan image with the dictionary.

[0116] It should be noted that the modules provided in this embodiment are similar to the free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance method provided above, and thus will not be described in detail. It should also be noted that it should be understood that the division of the modules of the above device is only a division of logical functions, and can be fully or partially integrated into a physical entity or physically separated in actual implementation. And these modules can all be implemented in the form of software called by a processing element; they can also be implemented in the form of hardware; some modules can also be implemented in the form of software called by a processing element, and some modules can be implemented in the form of hardware. For example, the image processing module 74 can be a separately established processing element, or it can be integrated in a chip of the above device, and in addition, it can also be stored in the memory of the above device in the form of program code, and called and executed by a processing element of the above device. The implementation of other modules is similar. In addition, all or part of these modules can be integrated together, or they can be implemented independently. The processing element described here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above modules can be completed by an integrated logic circuit of hardware in a processor element or instructions in the form of software.

[0117] For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs). For another example, when a module is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processors that can call program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0118] The present invention also provides a terminal 8, such as Figure 8As shown, the terminal 8 comprises: a processor 82 and a memory 81; the memory 81 is used to store a computer program; the processor 82 is used to execute the computer program stored in the memory, so that the terminal 8 performs the following Figure 1 The method for simultaneous quantitative magnetic resonance imaging of multiple parameters of a free-breathing heart.

[0119] Optionally, the number of the memory 81 can be one or more, the number of the processor 82 can be one or more, and Figure 8 Take one as an example.

[0120] Optionally, the processor 82 in the control device will Figure 1 In the above steps, one or more instructions corresponding to the process of the application are loaded into the memory 81, and the processor 82 runs the application stored in the first memory, thereby achieving the following Figure 1 The described free-breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method has various functions.

[0121] Optionally, the memory 81 may include but is not limited to high-speed random access memory and non-volatile memory. For example, one or more disk storage devices, flash memory devices or other non-volatile solid-state storage devices; the processor 82 may include but is not limited to a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0122] Optionally, the processor 82 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0123] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program is executed as follows: Figure 1 The method for simultaneous quantitative magnetic resonance imaging of free-breathing heart multi-parameters. The computer-readable storage medium may include, but is not limited to, a floppy disk, an optical disk, a CD-ROM (Compact Disc Read Only Memory), a magneto-optical disk, a ROM (Read Only Memory), a RAM (Random Access Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), a magnetic card or an optical card, a flash memory, or other types of media / machine-readable media suitable for storing machine-executable instructions. The computer-readable storage medium may be a product that is not connected to a computer device, or may be a component that is connected to a computer device for use.

[0124] In some embodiments of the present invention, the computer readable and writable storage medium may include a read-only memory, a random access memory, an EEPROM, a CD-ROM or other optical disk storage device, a magnetic disk storage device or other magnetic storage device, a flash memory, a USB flash drive, a mobile hard disk, or any other medium that can be used to store the desired program code in the form of an instruction or data structure and can be accessed by a computer. In addition, any connection can be appropriately referred to as a computer-readable medium. For example, if the instruction is sent from a website, server or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwaves are included in the definition of the medium. However, it should be understood that computer readable and writable storage media and data storage media do not include connections, carriers, signals or other temporary media, but are intended to be non-temporary, tangible storage media. Disk and disc, as used in this application, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

[0125] In summary, the present application provides a method, device, terminal and medium for simultaneous quantitative magnetic resonance imaging of a free-breathing heart with multiple parameters, wherein the heart tissue of the subject under free-breathing state is scanned based on the established corresponding cardiac multiple-parameter simultaneous quantitative magnetic resonance sequence to obtain a magnetic resonance scan image, and then processed to obtain a processed magnetic resonance scan image. The processed magnetic resonance scan image is matched with the established dictionary to obtain a parameter group map of the heart tissue of the subject. The method of the present invention can solve the problem in the prior art that parameters such as T1, T2 and T1ρ of the heart tissue cannot be measured simultaneously under free-breathing state, and the problem that the influence of the uneven B1 field on the parameter measurement cannot be corrected simultaneously. Therefore, the present application effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0126] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A method for simultaneous quantitative magnetic resonance imaging of a free-breathing heart with multiple parameters, characterized in that: include: Establish a magnetic resonance imaging sequence corresponding to simultaneous quantification of multiple cardiac parameters; Scanning the cardiac tissue of the subject in a free breathing state at multiple imaging levels through the magnetic resonance sequence to obtain magnetic resonance scanning images and electrocardiographic triggering signals corresponding to each cardiac cycle at each imaging level; The evolution of magnetization vector is simulated based on Bloch equation and ECG trigger signal, and a dictionary is established; By performing image processing on each magnetic resonance scan image, a processed magnetic resonance scan image is obtained; By matching the processed magnetic resonance scan image with the dictionary, a parameter group map of the cardiac tissue of the subject is obtained.

2. The method according to claim 1, characterized in that The establishment of a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters comprises: Determining an optimized best pulse sequence combination involving each cardiac cycle; The pulse flip angle combination in the optimal pulse sequence combination is optimized by introducing a variable angle technology to obtain an optimal pulse flip angle combination; Based on the optimal pulse sequence combination and the optimal pulse flip angle combination, a magnetic resonance sequence corresponding to simultaneous quantitative measurement of multiple cardiac parameters is obtained; wherein the magnetic resonance sequence includes: pulse data corresponding to each cardiac cycle.

3. The method according to claim 2, characterized in that The scanning of the cardiac tissue of the subject in a free breathing state at multiple imaging levels by the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic trigger signals corresponding to each cardiac cycle of each imaging level includes: Based on the magnetic resonance sequence, magnetic resonance scanning operations are performed in sequence at each imaging level according to the acquired electrocardiogram images at each imaging level, so as to obtain magnetic resonance scanning images and electrocardiogram trigger signals corresponding to each cardiac cycle at each imaging level; Wherein, the magnetic resonance scanning operation includes: Based on the pulse application rule, a corresponding pulse is applied to each cardiac cycle according to the magnetic resonance sequence and the ECG trigger signal in the acquired ECG image of each cardiac cycle at the corresponding imaging level to obtain the magnetic resonance scanning image and ECG trigger signal of each cardiac cycle at the corresponding imaging level.

4. The method according to claim 3, characterized in that: The pulse application rules include: The inversion pulse application rule includes: when an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, applying an inversion recovery pulse in the corresponding inversion pulse cardiac cycle according to a magnetic resonance sequence to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle; The T2 preparation pulse application rule includes: when an electrocardiographic trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in an electrocardiographic image, applying a T2 preparation pulse in a cardiac cycle corresponding to the T2 preparation pulse according to a magnetic resonance sequence to obtain a magnetic resonance scanning image corresponding to the T2 preparation pulse cardiac cycle; The T1ρ preparation pulse application rule includes: when an ECG trigger signal corresponding to the T1ρ preparation pulse cardiac cycle is detected in the ECG image, a T1ρ preparation pulse is applied in the corresponding T1ρ preparation pulse cardiac cycle according to the magnetic resonance sequence to obtain a magnetic resonance scanning image corresponding to the T1ρ preparation pulse cardiac cycle.

5. The method according to claim 4, characterized in that The inversion pulse application rule also includes: When an ECG trigger signal corresponding to an inversion pulse cardiac cycle is detected in the ECG image, an inversion recovery pulse is applied in the corresponding inversion pulse cardiac cycle according to a magnetic resonance sequence; performing a diaphragm navigation operation after applying the inversion recovery pulse to obtain a magnetic resonance scanning image corresponding to the inversion pulse cardiac cycle; The T2 preparation pulse application rule also includes: When an ECG trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in the ECG image, a T2 preparation pulse is applied in the corresponding T2 preparation pulse cardiac cycle according to a magnetic resonance sequence; performing a diaphragm navigation operation before applying the T2 preparation pulse to obtain a magnetic resonance scanning image corresponding to the cardiac cycle of the T2 preparation pulse; The T1ρ preparation pulse application rule also includes: When an ECG trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in the ECG image, a T1ρ preparation pulse is applied in the corresponding T1ρ preparation pulse cardiac cycle according to a magnetic resonance sequence; A diaphragm navigation operation is performed before applying the T1ρ preparation pulse to obtain a magnetic resonance scanning image corresponding to the cardiac cycle of the T1ρ preparation pulse.

6. The method according to claim 5, characterized in that The diaphragm navigation operation includes: The imaging plane of the cardiac tissue of the subject is corrected based on the position of the diaphragm at the end of breathing determined by analyzing the diaphragm movement pattern in the cardiac tissue before scanning.

7. The method according to claim 1, characterized in that The dictionary is established based on the Bloch equation and the ECG trigger signal by simulating the evolution process of the magnetization vector, including: A plurality of parameter combinations are obtained based on the numerical variation range and discretization step size of the set quantitative parameters; Based on the Bloch equation and ECG trigger signal, the evolution process of the magnetization vector under each parameter combination is simulated to obtain the transverse component intensity of the magnetization vector corresponding to the center line of the K space; Obtaining a corresponding magnetization vector transverse component intensity curve based on the magnetization vector transverse component intensity corresponding to the K-space center line; The parameter combination and the magnetization vector transverse component intensity curve form a dictionary.

8. The method according to claim 1, characterized in that The obtaining of the parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scan image with the dictionary comprises: Matching a transverse component intensity curve of a magnetization vector obtained based on each pixel point in the processed magnetic resonance scan image with the dictionary to obtain a parameter value corresponding to each pixel point; Based on the parameter values ​​corresponding to the pixel points, a parameter group map of the cardiac tissue of the subject is obtained.

9. A free-breathing heart multi-parameter simultaneous quantitative magnetic resonance device, characterized in that: include: A sequence establishment module is used to establish a magnetic resonance sequence corresponding to simultaneous quantitative analysis of multiple cardiac parameters; A scanning module, connected to the sequence establishing module, for scanning the cardiac tissue of the subject in a free breathing state at multiple imaging levels through the magnetic resonance sequence, and obtaining magnetic resonance scanning images and electrocardiographic triggering signals corresponding to each cardiac cycle of each imaging level; A dictionary building module, connected to the scanning module, for simulating the evolution process of the magnetization vector based on the Bloch equation and the ECG trigger signal, and building a dictionary; An image processing module, connected to the scanning module, for obtaining a processed magnetic resonance scanning image by performing image processing on each magnetic resonance scanning image; The parameter group map generating module is connected to the dictionary building module and the image processing module respectively, and is used to obtain the parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scanning image with the dictionary.

10. A terminal, characterized in that: include: Processor and memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so as to enable the terminal to perform the method according to any one of claims 1 to 8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method described in any one of claims 1 to 8 is implemented.

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