Method, device, terminal and medium for simultaneous quantitative magnetic resonance imaging of multi-parameters of a free-breathing heart

Abstract

The present application provides a method, apparatus, terminal, and medium for simultaneous quantitative magnetic resonance imaging of a free-breathing heart using multiple parameters. Based on an established corresponding simultaneous quantitative magnetic resonance sequence, the cardiac tissue of a subject under free breathing is scanned to obtain a magnetic resonance scan image, which is then processed to obtain a processed magnetic resonance scan image. The processed magnetic resonance scan image is matched with an established dictionary to obtain a parameter set map of the subject's cardiac tissue. The method of the present invention solves the problem in the prior art of being unable to simultaneously measure parameters such as T1, T2, and T1ρ of cardiac tissue under free breathing, as well as the problem of being unable to simultaneously correct the effect of an inhomogeneous B1 field on parameter measurement.

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] Quantitative cardiac magnetic resonance imaging (CMRI) can be used to measure the relaxation time of myocardial tissue. It is a non-invasive technique for assessing myocardial tissue characteristics and plays an important role in diagnosing diseases, assessing risks, and monitoring treatment efficacy. Relaxation times, such as longitudinal relaxation time (T1), transverse relaxation time (T2), and longitudinal relaxation time under spin-lock pulses (T1ρ), are inherent properties of myocardial tissue. In a clinical setting, simultaneous consideration of these relaxation time parameters allows for a comprehensive assessment of myocardial tissue, improving the diagnostic accuracy of difficult cardiomyopathies and reducing the likelihood of missed diagnoses.

[0003] Current quantitative cardiac magnetic resonance imaging techniques used in clinical diagnosis require a separate breath-hold scan for each parameter. However, this approach requires the patient to perform multiple breath-holds, which not only increases examination time but also the risk of scan failure. Furthermore, single breath-hold scans can lead to misregistration of the acquired parameter maps due to involuntary patient movement or variability in breath-holding status, hindering comparison of parameters in clinical diagnosis. These issues can be addressed using simultaneous multi-parameter quantitative sequences. This approach can save scan time and produce registered parameter maps. Current multi-parameter quantitative methods primarily measure longitudinal relaxation time (T1) and transverse relaxation time (T2) simultaneously and can be categorized into two types: one uses a sequence that simultaneously encodes T1, T2, or other parameters to acquire images and obtains parameter maps by fitting the acquired magnetic resonance signals to a sequence-dependent model; the other is based on magnetic resonance fingerprinting (MRF) and obtains parameter maps by finding the best match between the acquired multi-contrast magnetic resonance signals and a dictionary.

[0004] However, the above measurement method requires the subject to hold their breath during the acquisition process to eliminate the influence of respiratory motion on the acquisition. But for patients with heart disease, holding their 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 motion, 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 and the heart relatively still, 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 trajectory to generate stable and reliable myocardial multi-parameter quantitative results. The dictionary 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 of being unable to simultaneously measure more than three key parameters of the heart, such as T1, T2 and T1ρ, in a free breathing state, and being unable to simultaneously correct the influence of the inhomogeneous B1 field on parameter measurement.

[0007] To achieve the above-mentioned objectives and other related objectives, the first aspect of the present application provides a method for simultaneous quantitative magnetic resonance imaging of multiple parameters of a free-breathing heart, comprising: establishing a magnetic resonance sequence corresponding to simultaneous quantitative analysis of multiple cardiac parameters; scanning the cardiac 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 triggering signals corresponding to each cardiac cycle of each imaging level; simulating the evolution process of a magnetization vector based on the Bloch equation and the electrocardiographic triggering 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 cardiac 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 optimal pulse sequence combination involving each cardiac cycle; optimizing the pulse flip angle combination in the optimal pulse sequence combination by introducing a variable angle technology to obtain an optimal pulse flip angle combination; obtaining a magnetic resonance sequence corresponding to the simultaneous quantification 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.

[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 magnetic resonance scanning images and electrocardiographic triggering signals 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 electrocardiographic images of each imaging level to obtain magnetic resonance scanning images and electrocardiographic triggering signals for each cardiac cycle corresponding to each imaging level; wherein the magnetic resonance scanning operation includes: based on a pulse application rule, applying corresponding pulses to each cardiac cycle according to the magnetic resonance sequence and the acquired electrocardiographic triggering signals in the diastolic electrocardiographic images of each cardiac cycle of the corresponding imaging level to obtain magnetic resonance scanning images and electrocardiographic triggering signals for each cardiac cycle of the corresponding imaging level.

[0010] In some embodiments of the first aspect of the present application, the pulse application rules include: an inversion pulse application rule, including: 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; a T2 preparation pulse application rule, including: 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 to obtain a magnetic resonance scanning image corresponding to the 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 an ECG image, a T1ρ preparation pulse is applied in the corresponding T1ρ preparation pulse cardiac cycle according to a magnetic resonance sequence to obtain a magnetic resonance scanning image corresponding to the 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, applying an inversion recovery pulse in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence; performing a diaphragm navigation operation after applying the inversion recovery pulse to obtain a magnetic resonance scan 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, applying a T2 preparation pulse in the corresponding T2 preparation pulse cardiac cycle according to the magnetic resonance sequence; performing a diaphragm navigation operation before applying the T2 preparation pulse to obtain a magnetic resonance scan 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, applying a T1ρ preparation pulse in the corresponding T1ρ preparation pulse cardiac cycle according to the magnetic resonance sequence; performing a diaphragm navigation operation before applying the T1ρ preparation pulse to obtain a magnetic resonance scan 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 cardiac tissue of the subject 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 K-space center line; obtaining the corresponding transverse component intensity curve of the magnetization vector based on the transverse component intensity of the magnetization vector corresponding to the K-space center line; 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 scan 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 scan 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 objectives and other related objectives, the second aspect of the present application provides a free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance imaging apparatus, characterized in that it includes: a sequence establishment module, configured to establish a magnetic resonance sequence corresponding to the simultaneous quantitative analysis of multiple cardiac parameters; a scanning module, connected to the sequence establishment module, configured 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 triggering signals corresponding to each cardiac cycle of each imaging level; a dictionary establishment module, connected to the scanning module, configured to simulate the evolution of the magnetization vector based on the Bloch equation and the electrocardiographic triggering signal, and establish a dictionary; an image processing module, connected to the scanning module, configured 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, connected to the dictionary establishment module and the image processing module, respectively, and configured 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, comprising: 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 performs 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, which, when executed by a processor, implements the free-breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method.

[0018] As described above, the present invention provides a method, device, terminal, and medium for simultaneous quantitative magnetic resonance imaging of a free-breathing heart with multiple parameters, which has the following beneficial effects:

[0019] 1) The present invention can acquire quantitative cardiac images while the subject is breathing freely, reducing the burden on the subject. Multiple tissue parameters can be obtained in a single rapid scan, significantly reducing scanning time. Furthermore, the present invention can achieve image quality similar to that of MRI scans performed 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 maps in a single scan. Compared with the traditional clinical quantitative sequence that requires breath holding, the present invention has the same image quality and quantitative accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a 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 flow chart 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] Figure 6A Shown is a schematic diagram of the correlation analysis between the quantitative results of 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 of 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 cardiac multi-parameter simultaneous quantitative magnetic resonance imaging apparatus according to 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. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed 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 unless they conflict.

[0035] It should be noted that in the following description, reference is made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may also be used, and that mechanical, structural, 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 herein 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 one element or feature shown in the figure and another element or feature.

[0036] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," "holding," and the like should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on 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," and so on (if any) in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "comprising" and "including" indicate the presence of the stated features, operations, elements, components, items, types, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, operations, elements, components, items, types, and / or groups. It should be further understood that the terms "or" and "and / or" used herein are to be interpreted as inclusive, or to mean any one or any combination. Thus, "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 solutions and advantages of the present invention more clearly understood, the following embodiments and the accompanying drawings are used to further describe the technical solutions in the embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present 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 imaging 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 for pulse application, the type of pulse applied for 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 minimum error. The pulse sequence combination with the minimum error is considered 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 using the introduced variable angle technology to obtain the optimal pulse flip angle combination; optionally, optimize the pulse flip angle in the pulse parameters of the optimal pulse sequence combination through digital simulation experiments, phantom experiments, and in vivo experiments using the introduced variable angle technology to determine the pulse flip angle combination with the smallest error. 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 to each cardiac cycle; all cardiac cycles are divided into multiple cardiac cycle groups; the pulse flip angles of the readout excitation pulses applied to each cardiac cycle in each cardiac cycle group are the same; and the optimal pulse flip angle combination is optimized to optimize the pulse flip angles 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 using the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle at 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 magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle of each imaging level includes: based on the magnetic resonance sequence, sequentially performing magnetic resonance scanning operations at each imaging level according to the acquired electrocardiographic images of each imaging level to obtain magnetic resonance scan images and electrocardiographic triggering signals 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 of the corresponding imaging level, so as to obtain the magnetic resonance scanning image and electrocardiographic trigger signal of each cardiac cycle of 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] 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 is a detailed description:

[0054] The cardiac tissue of the subject in a free-breathing state is divided into multiple imaging slices, and scans of these slices are performed sequentially. For example, the short-axis slice of the cardiac tissue can be divided into three layers: the apical layer, the middle layer, and the basal layer. Scanning each imaging slice includes scanning during multiple cardiac cycles, with one magnetic resonance imaging image corresponding to each cardiac cycle. The acquired electrocardiogram (ECG) is the electrocardiogram (ECG) of the subject. An ECG is a graph of various point changes in the body surface, as the pacemaker, atria, and ventricles are sequentially excited during each cardiac cycle, accompanied by changes in the ECG bioelectricity. The ECG includes the following: P wave, Q wave, R wave, S wave, and T wave. The ECG trigger signal is generated by the R wave. A corresponding ECG trigger signal is acquired for each cardiac cycle.

[0055] Taking a single imaging slice as an example, when an ECG trigger signal corresponding to a cardiac cycle is acquired, a pulse corresponding to that cardiac cycle is applied based on the MRI sequence to obtain an MRI scan image corresponding to that cardiac cycle. After sequentially applying pulses corresponding to the cardiac cycle corresponding to the imaging slice based on the MRI sequence, MRI scan images for all cardiac cycles corresponding to that imaging slice 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 time from 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, applying an inversion recovery pulse in the corresponding inversion pulse cardiac cycle according to a magnetic resonance sequence to obtain a magnetic resonance scan image corresponding to the inversion pulse cardiac cycle; wherein the inversion pulse cardiac cycle is a cardiac cycle in which the inversion pulse is applied; and the magnetic resonance scan image corresponding to the inversion pulse cardiac cycle is a magnetic resonance scan image with T1 weighting 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 during the corresponding inversion pulse cardiac cycle according to the MRI sequence. After the inversion recovery pulse is applied, a readout excitation pulse is applied to obtain an MRI 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, applying a T2 preparation pulse 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 the ECG image, a T2 preparation pulse is applied in the cardiac cycle corresponding to the T2 preparation pulse according to the MRI sequence. After applying the T2 preparation pulse, a readout excitation pulse is applied to obtain an MRI scan image corresponding to the T2 preparation pulse cardiac cycle.

[0063] The T1ρ preparation pulse application rule includes: when an electrocardiographic trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an electrocardiographic image, applying a T1ρ preparation pulse in the corresponding T1ρ preparation pulse cardiac cycle 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 the ECG image, a T1ρ preparation pulse is applied in the cardiac cycle corresponding to the T1ρ preparation pulse according to the MRI sequence. After applying the T1ρ preparation pulse, a readout excitation pulse is applied to obtain an MRI scan image corresponding to the T1ρ preparation pulse cardiac cycle.

[0065] It should be noted that the application period of each of the above pulses is determined by Figure 2 The 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 rules in the above embodiment, the pulse application rules including the diaphragm navigation operation are:

[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 scan image corresponding to the inversion pulse cardiac cycle; wherein, the inversion pulse cardiac cycle is a cardiac cycle in which the inversion pulse is applied; and the magnetic resonance scan image corresponding to the inversion pulse cardiac cycle is a magnetic resonance scan image with T1 weighting 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 during the corresponding inversion pulse cardiac cycle according to the MRI sequence. After applying the inversion recovery pulse, a diaphragm navigation procedure is performed. After the diaphragm navigation procedure is performed, a readout excitation pulse is applied to obtain an MRI scan 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 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 scan image corresponding to the T2 preparation pulse cardiac cycle; wherein, the T2 preparation pulse cardiac cycle is the 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 with T2 weighting 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 the MRI 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 an MRI scan image corresponding to the cardiac cycle in which the T2 preparation pulse was applied.

[0073] The T1ρ preparation pulse application rule includes: when an electrocardiographic trigger signal corresponding to a T1ρ preparation pulse cardiac cycle is detected in an electrocardiographic 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 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 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 the MRI sequence. Before applying the T1ρ preparation pulse, a diaphragm navigation procedure is performed. After applying the T1ρ preparation pulse, a readout excitation pulse is applied to obtain an MRI scan image corresponding to the cardiac cycle in which the T1ρ preparation pulse was 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 interference with the signal corresponding to the diaphragm navigation operation. The diaphragm navigation operation is performed after the inversion recovery pulse to shorten the interval between the navigation operation and the readout of the excitation pulse for each cardiac cycle.

[0076] Optionally, the inversion recovery pulse includes a slice-selective flip pulse, which is used to eliminate 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 plane of the cardiac tissue of the subject 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 subject's breathing, so as to achieve relative stillness between the imaging plane and the heart.

[0079] The diaphragm, a muscular structure located between the thoracic and abdominal cavities, is a crucial respiratory muscle. The repetition time for diaphragm navigation is equal to the subject's average heartbeat interval, defined as the time between one heartbeat and the next.

[0080] Optionally, the diaphragm position can be detected using a cross-excitation navigation bar. On the transverse image, the liver dome is located, and the cross section of the diaphragm navigation bar is positioned at the liver dome. On the coronal image, the highest point of the liver is located, and the center of the cross-excitation navigation bar is placed at the liver-lung junction.

[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 spin-lock pulse) and B1 parameter; the parameter combination includes: 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 during each cardiac cycle. Specifically, the flip angle determined when establishing the magnetic resonance sequence corresponding to simultaneous quantification of multiple cardiac parameters in step S101 is the design flip angle. However, during the actual scanning process, due to practical limitations, the actual flip angle of the readout excitation pulse applied during each cardiac cycle may differ from the design flip angle. The B1 parameter is the ratio of the actual flip angle of the readout excitation pulse applied during each cardiac cycle to the design flip angle.

[0086] Optionally, the variable-angle technique in step S202 uses different readout flip angles during different cardiac cycles. The inversion recovery process is influenced by both T1 relaxation and the readout excitation pulse. Therefore, only by analyzing the magnetization vector evolution at different flip angles can we accurately distinguish the effects of tissue T1 values ​​and flip efficiency on magnetization vector evolution. Optimizing the pulse flip angle combination can further improve the quantitative accuracy of the B1 parameter.

[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 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 agent.

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

[0090] It should be noted that by setting the B1 parameters for simulation, the influence of B1 field inhomogeneity can be corrected. B1 field inhomogeneity can affect the quantitative accuracy of 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 curve is constructed based on the magnetization vector transverse component intensity corresponding to the K-space center line of all cardiac cycles of the parameter combination.

[0092] It should be noted that K-space is the Fourier space of rectangular coordinates, that is, the frequency space of Fourier transforms, also known as Fourier space. The projection curve of the MR signal in K-space is called the K-trajectory, also known as the Fourier line. The magnetization vector is used to describe the strength of the 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 processing 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, a transverse component intensity curve of a magnetization vector obtained based on each pixel point in the processed magnetic resonance scan image is matched with each transverse component intensity curve of a magnetization vector in the dictionary to determine an optimal matching curve, thereby obtaining parameter values ​​corresponding to the optimal matching curve based on the optimal matching curve. The parameter values ​​corresponding to the optimal matching curve are the parameter values ​​corresponding to each pixel point; and based on the parameter values ​​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 cardiac multi-parameter simultaneous quantitative magnetic resonance method of the present invention, a specific example is provided below.

[0100] Example 1: A free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance method.

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

[0102] The established MRI 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 area A, the first cardiac cycle group consists of the first to fourth cardiac cycles, the second cardiac cycle group consists of the fifth to eighth cardiac cycles, the third cardiac cycle group consists of the ninth to twelfth cardiac cycles, and the fourth cardiac cycle group consists of the thirteenth to sixteenth cardiac cycles. The optimized pulse flip angle for each cardiac cycle group ranges from 35 degrees to 70 degrees, with a step size of 5 degrees.

[0103] According to the pulse application rules, the corresponding pulses were applied to each cardiac cycle: According to the inversion pulse application rule in the pulse application rules, an inversion recovery pulse was applied to the first and ninth cardiac cycles. After the inversion recovery pulse was applied, a diaphragm navigation maneuver (dNAV) was performed, and then the readout excitation pulse was applied. The inversion time of each inversion recovery pulse was 255 ms; the inversion time was the interval between the inversion recovery pulse and the readout excitation pulse. According to the T2 preparation pulse application rule in the pulse application rules, T2 preparation pulses were applied sequentially from the fifth to the eighth cardiac cycle. Before applying the T2 preparation pulse in each cardiac cycle, a diaphragm navigation maneuver was performed. After applying the T2 preparation pulse in each cardiac cycle, the readout excitation pulse was applied. The preparation times for the fifth to eighth cardiac cycles were 35, 45, 55, and 65 ms, respectively. Two adiabatic refocusing pulses and two 90° hard excitation pulses were applied in each cardiac cycle. T1ρ preparation pulses were applied sequentially from the 13th to the 16th cardiac cycle according to the T1ρ preparation pulse application rule in the pulse application rule. Diaphragm navigation was performed before applying the T1ρ preparation pulse in each cardiac cycle. After applying the T1ρ preparation pulse in each cardiac cycle, a readout excitation pulse was applied. The T1ρ preparation pulses applied in each cardiac cycle had the same 350 Hz spinlock frequency, with spinlock times of 16, 30, 40, and 50 ms, respectively. One refocusing pulse, two 90° hard excitation pulses, and four spinlock pulses were applied in 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 Figure 4 The 16 magnetic resonance scan images corresponding to each cardiac cycle are shown in area B. The 16 magnetic resonance scan images corresponding to each cardiac cycle are subjected to noise reduction and registration operations to obtain processed magnetic resonance scan images. The processed magnetic resonance images are compared with the images shown in FIG. Figure 4 The dictionary shown 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 insensitive to heart rate and has good accuracy and robustness.

[0107] pass Figure 5C As can be seen from the scatter diagram shown, 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] Figure 6A This is a violin plot comparing the quantitative results of the currently widely used quantitative technology in clinical practice with the method of 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 are within the consistency range with the quantitative results of the technology currently widely used in clinical practice.

[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 includes:

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

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

[0113] a dictionary building module 73 connected to the scanning module 72, for simulating the evolution of the magnetization vector based on the Bloch equation and the ECG trigger signal, and building a dictionary;

[0114] An image processing module 74 is connected to the scanning module 72 and is used to obtain 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 in implementation to the free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance method provided above, and therefore will not be described in detail here. It should also be understood that the division of the modules of the above apparatus is merely a division of logical functions. In actual implementation, they may be fully or partially integrated into a single physical entity, or physically separated. Furthermore, these modules may be implemented entirely as software invoked by a processing element, or entirely as hardware. Alternatively, some modules may be implemented as software invoked by a processing element, while others may be implemented as hardware. For example, image processing module 74 may be a separate processing element, or integrated into a chip of the above apparatus. Furthermore, it may be stored in the form of program code in the memory of the above apparatus, invoked by a processing element of the apparatus, and perform the functions of the image processing module 74. The implementation of the other modules is similar. Furthermore, these modules may be fully or partially integrated or implemented independently. The processing element described herein may be an integrated circuit with signal processing capabilities. During implementation, the steps of the above method or the above modules may be performed by hardware integrated logic circuits within the processor element, or by software instructions.

[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), one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs). For another example, when a module is implemented by scheduling program code through a processing element, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor 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, it includes: a processor 82 and a memory 81; the memory 81 is used to store computer programs; the processor 82 is used to execute the computer programs stored in the memory, so that the terminal 8 performs the following Figure 1 The free-breathing heart multi-parameter simultaneous quantitative magnetic resonance imaging method.

[0119] Optionally, the number of the memories 81 can be one or more, the number of the processors 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 present invention relates to a method for simultaneous quantitative magnetic resonance imaging of the free-breathing heart with multi-parameters.

[0121] Optionally, the memory 81 may include, but is not limited to, high-speed random access memory and non-volatile memory, such as 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 gate or transistor logic devices, or 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 gate or transistor logic devices, discrete hardware components.

[0123] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed, implements the following Figure 1 The method for simultaneous quantitative multi-parameter magnetic resonance imaging of a free-breathing heart. 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 not connected to a computer device, or a component 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 desired program code in the form of instructions or data structures 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 instructions are sent from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, 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. Based on an established corresponding simultaneous quantitative magnetic resonance sequence of multiple parameters of the heart, the cardiac tissue of the subject in a free-breathing state is scanned to obtain a magnetic resonance scan image, and the image is processed to obtain a processed magnetic resonance scan image. The processed magnetic resonance scan image is matched with an established dictionary to obtain a parameter group map of the cardiac 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 cardiac tissue cannot be measured simultaneously in a 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 this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this 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 the simultaneous quantification of multiple cardiac parameters; Scanning the cardiac tissue of the subject in a free-breathing state at multiple imaging levels using the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle at each imaging level; The method of scanning the cardiac tissue of the subject in a free-breathing state at multiple imaging levels using the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle at each imaging level includes: Based on the magnetic resonance sequence, performing magnetic resonance scanning operations at each imaging level in sequence according to the acquired electrocardiogram images at each imaging level, to obtain magnetic resonance scanning images and electrocardiogram triggering signals corresponding to each cardiac cycle at each imaging level; And wherein, the magnetic resonance scanning operation includes: Based on the pulse application rule, applying a corresponding pulse to each cardiac cycle according to the magnetic resonance sequence and the electrocardiographic trigger signal in the acquired electrocardiographic image of each cardiac cycle at the corresponding imaging level, so as to obtain the magnetic resonance scan image and the electrocardiographic trigger signal for each cardiac cycle at the corresponding imaging level; The pulse application rules include: reversal pulse application rule, T2 preparation pulse application rule and T1ρ preparation pulse application rule; Performing a diaphragm navigation operation after applying an inversion recovery pulse to obtain a magnetic resonance scan image corresponding to the inversion pulse cardiac cycle; performing a diaphragm navigation operation before applying a T2 preparation pulse to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle; performing a diaphragm navigation operation before applying a T1ρ preparation pulse to obtain a magnetic resonance scan image corresponding to the T1ρ preparation pulse cardiac cycle; Diaphragm navigation procedures include: Correcting the imaging plane of the subject's cardiac tissue based on a position of the diaphragm at end-of-respiration determined by analyzing a diaphragm movement pattern in the cardiac tissue before scanning; The evolution of the magnetization vector is simulated based on the Bloch equation and ECG trigger signals, 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 quantification of multiple cardiac parameters includes: Determining the optimized best pulse sequence combination involving each cardiac cycle; The optimal pulse flip angle combination is obtained by optimizing the pulse flip angle combination in the optimal pulse sequence combination by introducing a variable angle technology; A magnetic resonance sequence corresponding to simultaneous quantification of multiple cardiac parameters is obtained 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.

3. The method according to claim 1, characterized in that The pulse application rules include: The inversion pulse application rule includes: when an electrocardiographic trigger signal corresponding to an inversion pulse cardiac cycle is detected in the electrocardiographic image, applying an inversion recovery pulse in the corresponding inversion pulse cardiac cycle according to the magnetic resonance sequence to obtain a magnetic resonance scan 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 the electrocardiographic image, applying the T2 preparation pulse in the cardiac cycle corresponding to the T2 preparation pulse according to the magnetic resonance sequence to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle; The T1ρ preparation pulse application rule includes: when an electrocardiographic trigger signal corresponding to the T1ρ preparation pulse cardiac cycle is detected in the electrocardiographic image, applying the T1ρ preparation pulse 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.

4. The method according to claim 3, characterized in that The inversion pulse application rule also includes: When an electrocardiographic trigger signal corresponding to an inversion pulse cardiac cycle is detected in the electrocardiographic 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 scan image corresponding to the inversion pulse cardiac cycle; The T2 preparation pulse application rules also include: When an electrocardiographic trigger signal corresponding to a T2 preparation pulse cardiac cycle is detected in the electrocardiographic image, a T2 preparation pulse is applied in the cardiac cycle corresponding to the T2 preparation pulse according to the magnetic resonance sequence; performing a diaphragm navigation operation before applying a T2 preparation pulse to obtain a magnetic resonance scan image corresponding to a cardiac cycle of the T2 preparation pulse; The T1ρ preparation pulse application rule also includes: When an electrocardiographic trigger signal corresponding to a cardiac cycle of a T1ρ preparation pulse is detected in the electrocardiographic image, a T1ρ preparation pulse is applied in the cardiac cycle corresponding to the T1ρ preparation pulse according to the magnetic resonance sequence; A diaphragm navigation operation is performed before applying the T1ρ preparation pulse to obtain a magnetic resonance scan image corresponding to the cardiac cycle of the T1ρ preparation pulse.

5. The method according to claim 1, wherein 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; The magnetization vector evolution process under various parameter combinations is simulated based on the Bloch equation and ECG trigger signals to obtain the transverse component intensity of the magnetization vector corresponding to the center line of 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.

6. The method according to claim 1, characterized in that The obtaining of a parameter group map of the cardiac tissue of the subject by matching the processed magnetic resonance scan image with the dictionary comprises: matching a magnetization vector transverse component intensity curve 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.

7. A free-breathing cardiac multi-parameter simultaneous quantitative magnetic resonance imaging device, characterized in that: include: A sequence establishment module is used to establish a magnetic resonance sequence corresponding to simultaneous quantification 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 using the magnetic resonance sequence, and obtaining magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle at each imaging level; The method of scanning the cardiac tissue of the subject in a free-breathing state at multiple imaging levels using the magnetic resonance sequence to obtain magnetic resonance scan images and electrocardiographic triggering signals corresponding to each cardiac cycle at each imaging level includes: Based on the magnetic resonance sequence, performing magnetic resonance scanning operations at each imaging level in sequence according to the acquired electrocardiogram images at each imaging level, to obtain magnetic resonance scanning images and electrocardiogram triggering signals corresponding to each cardiac cycle at each imaging level; And wherein, the magnetic resonance scanning operation includes: Based on the pulse application rule, applying a corresponding pulse to each cardiac cycle according to the magnetic resonance sequence and the electrocardiographic trigger signal in the acquired electrocardiographic image of each cardiac cycle at the corresponding imaging level, so as to obtain the magnetic resonance scan image and the electrocardiographic trigger signal for each cardiac cycle at the corresponding imaging level; The pulse application rules include: reversal pulse application rule, T2 preparation pulse application rule and T1ρ preparation pulse application rule; Performing a diaphragm navigation operation after applying an inversion recovery pulse to obtain a magnetic resonance scan image corresponding to the inversion pulse cardiac cycle; performing a diaphragm navigation operation before applying a T2 preparation pulse to obtain a magnetic resonance scan image corresponding to the T2 preparation pulse cardiac cycle; performing a diaphragm navigation operation before applying a T1ρ preparation pulse to obtain a magnetic resonance scan image corresponding to the T1ρ preparation pulse cardiac cycle; Diaphragm navigation procedures include: Correcting the imaging plane of the subject's cardiac tissue based on a position of the diaphragm at end-of-respiration determined by analyzing a diaphragm movement pattern in the cardiac tissue before scanning; a dictionary building module, connected to the scanning module, for simulating the evolution 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, and configured to obtain 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 scan image with the dictionary.

8. 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 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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