MRI processing apparatus and method, and computer-readable recording medium storing program for executing method

Abstract

The invention discloses a magnetic resonance imaging (MRI) processing apparatus and method, and a computer-readable recording medium storing a program for executing the method. The present invention relates to a magnetic resonance imaging (MRI) processing apparatus and a magnetic resonance imaging (MRI) processing method, and a computer-readable recording medium storing a program for executing the method. An MRI processing apparatus according to an embodiment of the present invention is an MRI processing apparatus for generating LGE magnetic resonance imaging, and may comprise: a storage medium for storing an extracellular volume (ECV), a hematocrit value in blood, a T1 value of a myocardial before injection of a contrast agent, a T1 value of blood before injection of a contrast agent, and a T1 value of blood after injection of a contrast agent; and the processor is used for calculating the T1 value of the cardiac muscle after the injection of the contrast agent according to the ECV, the hematocrit value in the blood, the T1 value of the cardiac muscle before the injection of the contrast agent, the T1 value of the blood before the injection of the contrast agent and the T1 value of the blood after the injection of the contrast agent, and the optimal reversal time point of the MRI is calculated by using the calculated T1 value of the cardiac muscle after the contrast agent is injected.

Description

Technical Field

[0001] The present invention relates to an MRI processing apparatus and method, and a computer-readable recording medium storing a program for performing the method, and more specifically, to an MRI processing apparatus and method, and a computer-readable recording medium storing a program for performing the method, the MRI processing apparatus being used to generate late-gadolinium enhancement (LGE) MRI. Background Technology

[0002] Magnetic Resonance Imaging (MRI) is a diagnostic technique that uses radiofrequency (RF) waves emitted into the body of a patient when the patient is in a strong magnetic field.

[0003] MRI uses RF pulses and measures the reflected magnetic field to obtain images. The advantage of MRI is that, because it uses RF pulses and magnetic fields, it is harmless to the human body compared to X-ray imaging or CT scans, and it can obtain information about soft tissues in a variety of ways.

[0004] Among various MRI techniques, delayed contrast-enhanced MRI (LGE) is effective in diagnosing cardiomyopathy. LGE utilizes the tendency of contrast agent to remain in diseased myocardium for a longer time than in normal myocardium. More specifically, LGE can determine the presence or absence of a lesion based on the intensity difference of the imaging signal between normal and diseased myocardium. This intensity difference refers to the difference in imaging signal intensity between normal and diseased myocardium within the time frame after contrast agent injection, during which relatively more contrast agent is expelled from normal myocardium and relatively more is retained in diseased myocardium.

[0005] After the contrast agent is injected, a relatively large amount of the contrast agent is expelled from the normal myocardium, while a large amount of contrast agent remains in the diseased myocardium. Therefore, the contrast enhancement effect is only visible for a few seconds, which is extremely short. Furthermore, within this short period, the signal intensity of the normal and diseased myocardium on the MRI continuously changes.

[0006] To accurately diagnose lesions, an MRI image is needed that captures a specific time point on MRI where the grayscale difference between normal and diseased myocardium reaches a predetermined level during a short period when a relatively large amount of contrast agent is eliminated from normal myocardium while a significant amount remains in the diseased myocardium. However, to date, no technology has been able to accurately capture and image this time point on MRI during which the grayscale difference between normal and diseased myocardium reaches a predetermined level, while a relatively large amount of contrast agent is eliminated from normal myocardium and a significant amount remains in the diseased myocardium.

[0007] (Patent Document) Korean Patent Publication No. 10-2022-0030896, “Method for Correcting Errors in Magnetic Resonance Imaging Using the Intercardiac Period”, published on March 11, 2022. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The present invention aims to provide an MRI processing apparatus and method, as well as a computer-readable recording medium storing a program for performing the method. The MRI processing apparatus automatically calculates the time point in contrast-enhanced delayed-enhancement (LGE) MRI where the shadow difference between normal and diseased tissues appears above a predetermined level, and obtains the MRI image at that time point by using post-T1 map image post-processing.

[0010] The problems of this invention are not limited to those mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

[0011] means for solving problems

[0012] According to one aspect of the present invention, an MRI processing apparatus is provided for generating gadolinium-delayed enhancement (LGE) magnetic resonance imaging (MRI), comprising: a storage medium for storing extracellular volume (ECV), hematocrit values ​​in blood, T1 values ​​of myocardium before contrast agent injection, T1 values ​​of blood before contrast agent injection, and T1 values ​​of blood after contrast agent injection; and a processor for calculating the T1 value of myocardium after contrast agent injection based on the correlation between the ECV, the hematocrit values ​​in blood, the T1 value of myocardium before contrast agent injection, the T1 value of blood before contrast agent injection, and the T1 value of blood after contrast agent injection, and using the calculated T1 value of myocardium after contrast agent injection to calculate the optimal inversion time of the MRI.

[0013] In an aspect of the MRI processing apparatus of the present invention, the processor can calculate the T1 value of the myocardium after the contrast agent injection according to the following mathematical formula 1.

[0014] (Mathematical Formula 1)

[0015]

[0016] (T1_Post_Myo: T1 value of myocardium after contrast agent injection, HCT: hematocrit value in blood, T1_Pre_Myo: T1 value of myocardium before contrast agent injection, T1_Pre_Blood: T1 value of blood before contrast agent injection, T1_Post_Blood: T1 value of blood after contrast agent injection).

[0017] In one aspect of the MRI processing apparatus of the present invention, the ECV may have a value selected in the range of 24% to 28%.

[0018] In one aspect of the MRI processing apparatus of the present invention, the hematocrit value of the blood may have a value selected in the range of 38% to 42%.

[0019] In one aspect of the MRI processing apparatus of the present invention, the processor can calculate the optimal reversal time point by substituting the T1 value of the myocardium after the contrast agent injection into the following mathematical formula 2.

[0020] (Mathematical Formula 2)

[0021] TI_optimal=0.69×T1_Post_Myo

[0022] (TI_optimal: optimal reversal time point, T1_Post_Myo: T1 value of myocardium after contrast agent injection).

[0023] In one aspect of the MRI processing apparatus of the present invention, the processor may use the following mathematical formula 3 to normalize the image signal included in the MRI data at the optimal reversal time point to generate a normalized image signal.

[0024] (Mathematical Formula 3)

[0025] S_normal = A × S_TI_optimal (S_normal: normalized image signal, S_TI_optimal: image signal included in the MRI data at the optimal inversion time point, A is a real number greater than or equal to 1).

[0026] In one aspect of the MRI processing apparatus of the present invention, the processor can identify lesions as the portion of the normalized MRI signal in the MRI at the optimal reversal time point that is higher than or equal to a reference value.

[0027] According to another aspect of the present invention, an MRI processing method is provided for generating gadolinium-delayed enhancement (LGE) magnetic resonance imaging (MRI), comprising the following steps: storing extracellular volume (ECV), hematocrit values ​​in blood, T1 values ​​of myocardium before contrast agent injection, T1 values ​​of blood before contrast agent injection, and T1 values ​​of blood after contrast agent injection in a storage medium; and a processor calculating the T1 value of myocardium after contrast agent injection based on the correlation between the ECV, the hematocrit values ​​in blood, the T1 value of myocardium before contrast agent injection, the T1 value of blood before contrast agent injection, and the T1 value of blood after contrast agent injection, and using the calculated T1 value of myocardium after contrast agent injection to calculate the optimal inversion time of MRI.

[0028] In another aspect of the MRI processing method of the present invention, in the step of calculating the optimal reversal time point, the processor may calculate the T1 value of the myocardium after the contrast agent injection according to the following mathematical formula 1.

[0029] (Mathematical Formula 1)

[0030]

[0031] (T1_Post_Myo: T1 value of myocardium after contrast agent injection, HCT: hematocrit value in blood, T1_Pre_Myo: T1 value of myocardium before contrast agent injection, T1_Pre_Blood: T1 value of blood before contrast agent injection, T1_Post_Blood: T1 value of blood after contrast agent injection).

[0032] In another aspect of the MRI processing method of the present invention, the ECV may have a value selected in the range of 24% to 28%.

[0033] In another aspect of the MRI processing method of the present invention, the hematocrit value of the blood may have a value selected in the range of 38% to 42%.

[0034] In another aspect of the MRI processing method of the present invention, in the step of calculating the optimal reversal time point, the processor can calculate the optimal reversal time point by substituting the T1 value of the myocardium after the contrast agent injection into the following mathematical formula 2.

[0035] (Mathematical Formula 2)

[0036] TI_optimal=0.69×T1_Post_Myo

[0037] (TI_optimal: the optimal inversion time point for MRI, T1_Post_Myo: the T1 value of the myocardium after contrast agent injection).

[0038] Another aspect of the MRI processing method of the present invention may further include the following step: the processor uses the following mathematical formula 3 to normalize the image signal included in the MRI data at the optimal reversal time point to generate a normalized image signal.

[0039] (Mathematical Formula 3)

[0040] S_normal = A × S_TI_optimal

[0041] (S_normal: normalized image signal, S_TI_optimal: image signal included in the MRI data at the optimal inversion time point, A is a real number greater than or equal to 1).

[0042] Another aspect of the MRI processing method of the present invention may further include the following step: the processor judges the portion of the normalized MRI signal presented in the MRI at the optimal inversion time point that is higher than or equal to a reference value as a lesion.

[0043] According to another aspect of the invention, a non-transitory computer-readable storage medium is provided, the program being used to perform the MRI processing method and including at least one instruction.

[0044] Invention Effects

[0045] Based on the above configuration, the MRI processing apparatus and method of the present invention, as well as the computer-readable recording medium storing a program for performing the method, are capable of accurately calculating the time point in contrast agent delayed enhancement (LGE) MRI where the shadow difference between normal tissue and diseased tissue is greatest, and effectively obtaining the MRI at that time point.

[0046] It should be understood that the effects of the present invention are not limited to those described above, but include all effects that can be inferred from the detailed description of the invention or the composition of the invention as set forth in the claims. Attached Figure Description

[0047] Figure 1 This is a structural diagram of an MRI processing apparatus according to an embodiment of the present invention.

[0048] Figure 2 It is a diagram that briefly shows the heart of the patient with myocardial lesions on a horizontal plane.

[0049] Figure 3 This is a graph showing the changes in MRI signal intensity of normal and diseased tissues over time after contrast agent injection, where more contrast agent is retained in the diseased tissue compared to normal tissue.

[0050] Figure 4 This is a flowchart of an embodiment of the MRI processing method of the present invention. Detailed Implementation

[0051] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings to facilitate implementation by those skilled in the art. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. For clarity of illustration, parts of the drawings not related to the description have been omitted, and throughout the specification, the same or similar reference numerals are used to refer to the same or similar constituent elements.

[0052] The words and terms used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, but should be interpreted in accordance with the principle that inventors define terms and concepts in order to best illustrate their invention, and should be interpreted as meanings and concepts consistent with the technical ideas of the invention.

[0053] In this specification, it should be understood that terms such as "comprising" or "having" are intended to describe the presence of features, figures, steps, operations, constituent elements, components or combinations thereof described in the specification, and should not be construed as pre-excluding the presence or additional possibilities of one or more other features, figures, steps, operations, constituent elements, components or combinations thereof.

[0054] Figure 1 This is a structural diagram of an MRI processing apparatus according to an embodiment of the present invention.

[0055] An embodiment of the magnetic resonance imaging (MRI) processing apparatus 100 of the present invention is used for late-enhanced gadolinium magnetic resonance imaging (LGE MRI). In other words, an embodiment of the MRI processing apparatus 100 of the present invention is used to obtain late-enhanced (LGE) MRI using a gadolinium-based contrast agent. Hereinafter, the contrast agent may refer to a contrast agent containing gadolinium.

[0056] Furthermore, an MRI processing apparatus 100 according to an embodiment of the present invention can generate T1-weighted MRI for diagnosing intramyocardial lesions. More specifically, an MRI processing apparatus 100 according to an embodiment of the present invention can generate synthetic lategadolinium enhancement (synLGE) images by utilizing a post-T1 map of MRI after contrast agent injection.

[0057] In this context, a post-contrast T1 map is a collection of MRI data showing the cumulative signal intensity changes over a predetermined time period, categorized by each pixel of the MRI image after the contrast agent has been injected into the subject. More specifically, a post-contrast T1 map can be defined as the collection of T1 values ​​for each pixel of the MRI image.

[0058] The T1 value refers to the time required for the magnetic field, in which rotating protons are aligned by a magnetic field generated within an MRI device, to be reversed by an RF pulse, and for the magnetic field to be rearranged. More specifically, the T1 value can be defined as the time required for the longitudinal (Z-axis) component of magnetization to reach 63% of the maximum magnetization value of the protons in their initial alignment state after the protons are reversed by an RF pulse injection while they are aligned in the magnetic field.

[0059] In one embodiment of the present invention, the post-contrast T1 map can also be defined as a set of signal intensity data of each MRI pixel at any time point within a predetermined time interval after contrast agent injection. In other words, the post-contrast T1 map can include signal intensity data of each MRI pixel at any time point within a predetermined time interval after contrast agent injection.

[0060] Reference Figure 1 An embodiment of the present invention provides an MRI processing apparatus 100 that is associated with the generation of T1-weighted MRI, which may include a storage medium 110 and a processor 120.

[0061] Storage medium 110 is used to store extracellular volume (ECV), hematocrit values ​​in blood, T1 values ​​of myocardium before contrast agent injection, T1 values ​​of blood before contrast agent injection, and T1 values ​​of blood after contrast agent injection.

[0062] Storage medium 110 can be magnetic media such as hard disks, floppy disks, and magnetic tapes; optical media such as compact disk read-only memory (CD-ROM) and digital video disks (DVD); magneto-optical media such as floppy disks; ROM; RAM; flash memory; etc.

[0063] The ECV refers to the tissue space or volume in the subject's body that is not occupied by cells. In the case of the subject's myocardium, the ECV reflects the collagen content within the myocardium.

[0064] For normal individuals, the ECV is a constant value, unaffected by MRI and imaging conditions. Based on the facts described above, the ECV can be preset. In other words, the ECV can be determined by a preset value, rather than a measured value. For example, the ECV can have a value selected within the range of 24% to 28%. More specifically, the ECV can be determined to be 26%.

[0065] The hematocrit value in blood is expressed as a percentage, representing the volume of red blood cells in the blood of the person being examined. Blood consists of plasma and serum, and serum contains red blood cells, white blood cells, and platelets. The hematocrit value in blood refers to the proportion of red blood cells in the total blood volume.

[0066] In one embodiment of the invention, the hematocrit value in the blood can be a value measured for a subject undergoing an MRI examination.

[0067] On the other hand, given that the measured hematocrit value in the blood generally does not vary from person to person, the hematocrit value can be determined using a preset value. For example, the hematocrit value in the blood can be selected within the range of 38% to 42%. More specifically, the hematocrit value in the blood can be determined to be 40%.

[0068] Regarding the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection, the T1 value can be defined as the time required for the magnetic field to be rearranged after the rotating protons, which are aligned by the magnetic field formed within the MRI device, are reversed by an RF pulse. As described above, after the RF pulse injection reverses the proton alignment in the magnetic field, the time required for the longitudinal axis (Z-axis) component of magnetization to reach 63% of the maximum magnetization value in the initial proton alignment state.

[0069] On the other hand, the T1 value of the myocardium before contrast agent injection refers to the T1 value of the myocardium as observed during MRI imaging without contrast agent injection. Additionally, the T1 value of the blood before contrast agent injection refers to the T1 value of the blood before contrast agent injection. Furthermore, the T1 value of the blood after contrast agent injection refers to the T1 value of the blood when the contrast agent remains in the patient's bloodstream.

[0070] In one embodiment of the present invention, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection can be pre-measured values. That is, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection can be determined by measuring the subject.

[0071] The processor 120 calculates the T1 value of the myocardium after contrast agent injection based on the correlation between the ECV, the hematocrit value of the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection, and uses the calculated T1 value of the myocardium after contrast agent injection to calculate the optimal inversion time of MRI.

[0072] Figure 2 It is a diagram that briefly shows the heart of the patient with myocardial lesions on a horizontal plane.

[0073] Reference Figure 2 The heart 10 includes myocardium 11 and ventricles 12 formed within the myocardium 11. Blood can be stored in the ventricles 12. At this time, diseased myocardium 13 may be present in the myocardium 11.

[0074] As described above, an MRI processing apparatus 100 according to an embodiment of the present invention can be used to perform delayed contrast-enhanced (LGE) MRI. LGE MRI utilizes the tendency of gadolinium-based contrast agents to remain in diseased myocardium 13 for a longer time than in normal myocardium 11.

[0075] Contrast-delayed enhancement MRI can determine the presence or absence of a lesion based on the intensity difference of the imaging signals between normal myocardium 11 and diseased myocardium 13. The intensity difference is the difference in the intensity of the imaging signals between normal myocardium 11 and diseased myocardium 13 as shown in the MRI data obtained within the time range after contrast agent injection, when most of the contrast agent in normal myocardium 11 is expelled while a large amount of contrast agent remains in diseased myocardium 13.

[0076] Synthetic contrast-enhanced delayed-enhancement (synLGE) MRI can determine the presence or absence of a lesion based on the intensity difference of the imaging signals between normal myocardium 11 and diseased myocardium 13. This intensity difference refers to the difference in imaging signal intensity between normal myocardium 11 and diseased myocardium 13 within one or more MRI datasets obtained after contrast agent injection, when a relatively large amount of contrast agent remains in the diseased myocardium 13 compared to normal myocardium 11. In this case, the MRI data may be obtained from the aforementioned post-enhancement T1-weighted images. That is, synthetic contrast-enhanced delayed-enhancement MRI can be derived from the post-enhancement T1-weighted images.

[0077] Figure 3 This is a graph showing the changes in MRI signal intensity over time in normal and diseased tissues after contrast agent injection, where more contrast agent remains in the diseased tissue compared to normal tissue. More detailed... Figure 3 This is a graph showing the changes in MRI signal intensity over time in normal and diseased tissues after contrast agent injection, where most of the contrast agent is expelled from normal tissues, while a relatively large amount remains in diseased tissues. Figure 3 In the diagram, the negative signal intensity is inverted into a positive signal.

[0078] Reference Figure 3 During the time T when contrast agent is injected into normal myocardium 11 and a large amount of contrast agent remains in diseased myocardium 13, the intensity of the image signal of normal myocardium and the image signal of the lesion included in the MRI data continuously changes. When attempting to determine the presence or absence of a lesion by normalizing (or amplifying) the image signal of MRI data obtained at a specific time point, it is preferable to obtain the MRI data at the time point (TI_optimal) when the absolute value of the image signal intensity of normal myocardium is the smallest (e.g., the image signal intensity is 0), or to obtain the T1 image at that time point.

[0079] like Figure 3As shown, at the time point (TI_optimal) when the absolute value of the imaging signal intensity of normal myocardium in LGE reaches its minimum value S1, the absolute value (S2) of the imaging signal intensity of diseased myocardium is greater than that of normal myocardium. When the imaging signal of the MRI data acquired at this time point (TI_optimal) is normalized (or amplified), normal myocardium appears dark on MRI, while diseased myocardium appears bright. Therefore, the presence of lesions can be accurately identified using the MRI data at this time point, and further, when lesions are present, their location can be accurately identified.

[0080] Therefore, in one embodiment of the present invention, the optimal reversal time point (TI_optimal) can be defined as: the time point during which the image signal intensity of the normal myocardium included in the MRI data is at its minimum during the time T during which a relatively large amount of contrast agent remains in the diseased myocardium 13 compared to the normal myocardium 11, after contrast agent injection. In other words, the optimal reversal time point (TI_optimal) can be the time point at which the absolute value of the image signal intensity of the normal myocardium included in the MRI data reaches its minimum (e.g., 0).

[0081] Theoretically, the minimum value is preferably 0. However, considering normalization (or amplification), the minimum value can also be arbitrarily determined within a predetermined range. In other words, the optimal reversal time point (TI_optimal) can also be defined as any time point selected within the time interval during which the imaging signal intensity of normal myocardium appears within the predetermined range.

[0082] For example, regarding the minimum value, the predetermined range can be set to a value below 70-80 when the image signal intensity of normal myocardium is normalized (or amplified). Furthermore, the optimal reversal time point can be arbitrarily selected within the time interval where the image signal intensity of normal myocardium appears within the predetermined range.

[0083] Regarding the calculation of the optimal reversal time point, the processor 120 can calculate the T1 value of the myocardium after the contrast agent injection according to the following mathematical formula 1.

[0084] (Mathematical Formula 1)

[0085]

[0086] (T1_Post_Myo: T1 value of myocardium after contrast agent injection, HCT: hematocrit value in blood, T1_Pre_Myo: T1 value of myocardium before contrast agent injection, T1_Pre_Blood: T1 value of blood before contrast agent injection, T1_Post_Blood: T1 value of blood after contrast agent injection).

[0087] As described below, in order to calculate the optimal reversal time point, the T1 value of the myocardium after contrast agent injection is required. Here, myocardium refers to normal tissue, and the T1 value of the myocardium after contrast agent injection refers to the T1 value of the myocardium as it appears after the contrast agent is injected and remains within the myocardium. As mentioned above, the T1 value can be defined as the time it takes for 63% of the average magnetization of the initial state to return to the longitudinal direction after the proton alignment is reversed by the injected RF pulse.

[0088] After contrast agent injection, the contrast agent remains in the myocardium for a very short time, only a few seconds. Therefore, it is practically difficult to measure the T1 value of the myocardium after contrast agent injection.

[0089] In one embodiment of the present invention, the processor 120 calculates the T1 value of the myocardium after contrast agent injection using the aforementioned mathematical formula 1. Thus, in the present invention, the T1 value of the myocardium after contrast agent injection, which is practically difficult to measure, can be accurately calculated through computation, as described below, to accurately calculate the optimal reversal time point.

[0090] The processor 120 can calculate the optimal reversal time point by substituting the T1 value of the myocardium after the contrast agent injection into the following mathematical formula 2.

[0091] (Mathematical Formula 2)

[0092] TI_optimal=0.69×T1_Post_Myo

[0093] (TI_optimal: optimal reversal time point, T1_Post_Myo: T1 value of myocardium after contrast agent injection).

[0094] Furthermore, the processor 120 uses the following mathematical formula 3 to normalize the image signals included in the MRI data at the optimal inversion time point (TI_optimal) to generate a normalized image signal. More specifically, the processor 120 can select the MRI data at the optimal inversion time point (TI_optimal) from the MRI data included in the enhanced T1 image, and use mathematical formula 3 to normalize the image signal of each pixel of the MRI data separately.

[0095] (Mathematical Formula 3)

[0096] S_normal = A × S_TI_optimal

[0097] (S_normal: normalized image signal, S_TI_optimal: image signal included in the MRI data at the optimal inversion time point, A is a real number greater than or equal to 1).

[0098] At this point, in the mathematical formula 3, A can be determined based on the desired normalization level of the signal. For example, A can be 1000. Of course, this is just an example, and A can be increased or decreased arbitrarily according to the desired normalization (or amplification) level.

[0099] When protons are aligned in a magnetic field, an RF pulse injection reverses the proton alignment. During the process of proton alignment restoration, the absolute value of the MRI image signal of normal myocardium follows the following mathematical formula 4.

[0100] (Mathematical Expression 4)

[0101]

[0102] (TI: at any time, T1_Post_Myo: T1 value of the myocardium after contrast agent injection).

[0103] If the optimal inversion time point (TI_optimal) is substituted into TI in the aforementioned mathematical formula 4, the signal intensity is 0. Therefore, when the processor 120 normalizes (or amplifies) the image signal (absolute value of image signal intensity) included in the MRI data at the optimal inversion time point, the signal intensity of the normal myocardium is not actually amplified, while the signal intensity of the lesion appears relatively high. Therefore, in the MRI data obtained from the enhanced T1 map, the normal myocardium may appear dark, while the lesion may appear bright.

[0104] Furthermore, the processor 120 can identify lesions based on the portion of the normalized MRI signal at the optimal inversion time point (TI_optimal) that is higher than or equal to a reference value. If the subject's heart is free of lesions, even if the MRI data at the optimal inversion time point (TI_optimal) in the enhanced T1-weighted image is normalized, areas where the image signal is significantly amplified may not be present. Considering this, the processor 120 can identify lesions based on the portion of the normalized MRI signal at the MRI data that is higher than or equal to a reference value.

[0105] At this point, the reference value can be appropriately determined based on the MRI device and imaging environment. For example, the reference value can be selected from 150 to 250. More specifically, the reference value can be 200.

[0106] On the other hand, the reference value can be stored in the storage medium 110. In other words, the reference value can be preset and stored in the storage medium 110.

[0107] The processor 120 may be a hardware unit that performs calculations and control within a computer. For example, the processor 120 may include at least one arithmetic logic unit (ALU) and a processing register.

[0108] The following describes an embodiment of the MRI processing method of the present invention.

[0109] Figure 4 This is a flowchart of an embodiment of the MRI processing method of the present invention.

[0110] Reference Figure 4 An embodiment of the MRI processing method S100 of the present invention is used to generate gadolinium-delayed enhancement (LGE) magnetic resonance imaging (MRI), and can be performed according to the following steps. An embodiment of the MRI processing method of the present invention can be performed by an embodiment of the MRI processing apparatus of the present invention.

[0111] First, in step S110, the storage medium 110 stores the extracellular volume (ECV), the hematocrit value of the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection.

[0112] In one embodiment of the invention, the ECV may be determined using a preset value rather than a measured value. For example, the ECV may have a value selected within the range of 24% to 28%. More specifically, the ECV may be determined to be 26%.

[0113] Furthermore, the hematocrit value in the blood can be determined using a preset value. For example, the hematocrit value in the blood can be selected within the range of 38% to 42%. More specifically, the hematocrit value in the blood can be determined to be 40%.

[0114] On the other hand, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection can be measured values. That is, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection can be determined by measuring the subject.

[0115] The details regarding the ECV value, the hematocrit value in the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection are as described above.

[0116] Then, in step S120, the processor 120 calculates the T1 value of the myocardium after contrast agent injection based on the correlation between the ECV, the hematocrit value of the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection, and uses the calculated T1 value of the myocardium after contrast agent injection to calculate the optimal inversion time of MRI.

[0117] Regarding the calculation of the optimal reversal time point, the processor 120 can calculate the T1 value of the myocardium after the contrast agent injection according to the following mathematical formula 1.

[0118] (Mathematical Formula 1)

[0119]

[0120] (T1_Post_Myo: T1 value of myocardium after contrast agent injection, HCT: hematocrit value in blood, T1_Pre_Myo: T1 value of myocardium before contrast agent injection, T1_Pre_Blood: T1 value of blood before contrast agent injection, T1_Post_Blood: T1 value of blood after contrast agent injection).

[0121] As described above, in order to calculate the optimal reversal time point, the T1 value of the myocardium after contrast agent injection is required. Here, myocardium refers to normal tissue, and the T1 value of the myocardium after contrast agent injection refers to the T1 value of the myocardium as it appears after the contrast agent is injected and remains within the myocardium.

[0122] The T1 value of the myocardium after contrast agent injection is actually difficult to measure. However, in this invention, the processor 120 can accurately calculate the T1 value of the myocardium after contrast agent injection using the aforementioned mathematical formula 1.

[0123] The optimal reversal time point can be accurately calculated using the T1 value of the myocardium after contrast agent injection, as calculated above. Specifically, the processor 120 can calculate the optimal reversal time point by substituting the T1 value of the myocardium after contrast agent injection into the following mathematical formula 2.

[0124] (Mathematical Formula 2)

[0125] TI_optimal=0.69×T1_Post_Myo

[0126] (TI_optimal: the optimal inversion time point for MRI, T1_Post_Myo: the T1 value of the myocardium after contrast agent injection).

[0127] The optimal reversal time point can be defined as: the time point during which the image signal intensity of the normal myocardium included in the MRI data reaches its minimum within a time period T after contrast agent injection, when a relatively large amount of contrast agent remains in the diseased myocardium 13 compared to the normal myocardium 11. In other words, the optimal reversal time point can be the time point at which the absolute value of the image signal intensity of the normal myocardium included in the MRI data reaches its minimum (e.g., 0).

[0128] As mentioned above, theoretically, the minimum value is preferably 0. However, considering normalization (or amplification), the minimum value can also be arbitrarily determined within a predetermined range. In other words, the optimal reversal time point (TI_optimal) can also be defined as any time point selected within the time interval during which the imaging signal intensity of normal myocardium appears within the predetermined range.

[0129] Then, in step S130, the processor 120 normalizes the image signals included in the MRI data at the optimal reversal time point using the following mathematical formula 3 to generate a normalized image signal. More specifically, the processor 120 may use mathematical formula 3 to normalize the signal of each pixel in the MRI data at the optimal reversal time point (TI_optimal) included in the enhanced T1 image.

[0130] (Mathematical Formula 3)

[0131] S_normal = A × S_TI_optimal (S_normal: normalized image signal, S_TI_optimal: image signal included in the MRI data at the optimal inversion time point, A is a real number greater than or equal to 1).

[0132] At this point, in the mathematical formula 3, A can be determined based on the desired normalization level of the signal. For example, A can be 1000. Of course, this is just an example, and A can be increased or decreased arbitrarily according to the desired normalization (or amplification) level.

[0133] When the processor 120 normalizes (or amplifies) the image signals (absolute values ​​of image signal intensity) included in the MRI data at the optimal reversal time point, the signal intensity of the normal myocardium is not actually amplified, while the signal intensity of the lesion appears relatively high. Therefore, on the MRI image, the normal myocardium may appear dark, and the lesion may appear bright.

[0134] Finally, in step S140, the processor 120 can identify lesions as the portion of the normalized MRI signal in the MRI at the optimal reversal time point that is higher than or equal to a reference value. As described above, when the processor 120 normalizes (or amplifies) the image signals (absolute values ​​of image signal intensity) included in the MRI data at the optimal reversal time point, the signal intensity of normal myocardial regions is very low, while the signal intensity of fibroblasts in lesion regions is relatively high. Based on this fact, the processor 120 can identify lesions as the portion of the normalized MRI signal in the MRI data that is higher than or equal to a reference value.

[0135] The present invention also provides a non-transitory computer-readable storage medium storing a program, said program including at least one instruction for performing the MRI processing method of the above embodiments. In this case, the instructions include not only machine code generated by a compiler, but also computer-executable high-level language code.

[0136] The storage medium may include a hardware device for storing and executing program instructions such as magnetic media (hard disk, floppy disk, magnetic tape), optical media (compact disk read only memory, CD-ROM), magnetic recording media (digital video disk, DVD), magneto-optical media (magnetic-optical media) (floptical disk), ROM, RAM, flash memory, etc.

[0137] A non-transitory computer-readable storage medium according to an embodiment of the present invention can be configured for use in an MRI apparatus.

[0138] According to the existing synLGE method, after contrast agent injection, a post-T1 map of MRI is generated. This post-T1 map is a collection of signal intensity data for each MRI pixel at any time point within a predetermined time period. From the post-T1 map, the examiner (doctor) needs to select MRI data from appropriate time points for diagnosis. In other words, in the existing synLGE method, the selection of MRI data from appropriate time points where the grayscale difference between normal and diseased tissue is above a specified level is manually performed within the post-T1 map. This can lead to problems such as selecting MRI data at inappropriate time points or taking a long time to select MRI data.

[0139] However, in this invention, after contrast agent injection, the optimal inversion time point is automatically calculated during the period when a relatively large amount of contrast agent remains in the lesion compared to normal myocardium. In other words, the optimal inversion time point is the time point when the image signal intensity of normal myocardium included in the MRI data is minimized on the enhanced T1-weighted image. Furthermore, by selecting the MRI data from the optimal inversion time point on the enhanced T1-weighted image and normalizing it, lesion identification can be achieved quickly, accurately, and automatically.

[0140] Embodiments of the present invention have been described, but the spirit of the invention is not limited to the embodiments presented in this specification. Those skilled in the art who understand the spirit of the invention can easily propose other embodiments by adding, modifying, deleting, or adding constituent elements within the same scope of the concept, but these also fall within the scope of the present invention.

Claims

1. An MRI processing apparatus for generating gadolinium-delayed-contrast magnetic resonance images, characterized in that, include: Storage medium for storing extracellular volume, hematocrit values ​​in blood, T1 values ​​of myocardium before contrast agent injection, T1 values ​​of blood before contrast agent injection, and T1 values ​​of blood after contrast agent injection; and The processor calculates the T1 value of the myocardium after contrast agent injection based on the correlation between the extracellular volume, the hematocrit value of the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection, and uses the calculated T1 value of the myocardium after contrast agent injection to calculate the optimal inversion time point for MRI.

2. The MRI processing device according to claim 1, characterized in that, The processor calculates the T1 value of the myocardium after contrast agent injection according to the following mathematical formula 1 (Mathematical Formula 1). Wherein, T1_Post_Myo is the T1 value of the myocardium after contrast agent injection, HCT is the hematocrit value in the blood, T1_Pre_Myo is the T1 value of the myocardium before contrast agent injection, T1_Pre_Blood is the T1 value of the blood before contrast agent injection, and T1_Post_Blood is the T1 value of the blood after contrast agent injection.

3. The MRI processing device according to claim 1, characterized in that, The extracellular volume has a value selected within the range of 24% to 28%.

4. The MRI processing device according to claim 1, characterized in that, The hematocrit value in the blood is selected from a range of 38% to 42%.

5. The MRI processing apparatus according to claim 1, characterized in that, The processor calculates the optimal reversal time point by substituting the T1 value of the myocardium after the contrast agent injection into the following mathematical formula 2. (Mathematical Formula 2) TI_optimal=0.69×T1_Post_Myo Wherein, TI_otimal is the optimal reversal time point, and T1_Post_Myo is the T1 value of the myocardium after contrast agent injection.

6. The MRI processing apparatus according to claim 1, characterized in that, The processor uses the following mathematical formula 3 to normalize the image signals included in the MRI data at the optimal reversal time point to generate normalized image signals. (Mathematical Formula 3) S_normal = A × S_TI_optimal Where S_normal is the normalized image signal, S_TI_optimal is the image signal included in the MRI data at the optimal inversion time point, and A is a real number greater than or equal to 1.

7. The MRI processing apparatus according to claim 6, characterized in that, The processor identifies lesions as the portion of the normalized MRI signal at the optimal reversal time point that is above a baseline value.

8. An MRI processing method for generating gadolinium-delayed-contrast magnetic resonance imaging, characterized in that, The steps include the following: The storage medium stores extracellular volume, hematocrit values ​​in blood, T1 values ​​of myocardium before contrast agent injection, T1 values ​​of blood before contrast agent injection, and T1 values ​​of blood after contrast agent injection. as well as The processor calculates the T1 value of the myocardium after contrast agent injection based on the correlation between the extracellular volume, the hematocrit value of the blood, the T1 value of the myocardium before contrast agent injection, the T1 value of the blood before contrast agent injection, and the T1 value of the blood after contrast agent injection, and uses the calculated T1 value of the myocardium after contrast agent injection to calculate the optimal inversion time point of MRI.

9. The MRI processing method according to claim 8, characterized in that, In the step of calculating the optimal reversal time point, the processor calculates the T1 value of the myocardium after contrast agent injection according to the following mathematical formula 1. (Mathematical Formula 1) Wherein, T1_Post_Myo is the T1 value of the myocardium after contrast agent injection, HCT is the hematocrit value in the blood, T1_Pre_Myo is the T1 value of the myocardium before contrast agent injection, T1_Pre_Blood is the T1 value of the blood before contrast agent injection, and T1_Post_Blood is the T1 value of the blood after contrast agent injection.

10. The MRI processing method according to claim 8, characterized in that, The extracellular volume has a value selected within the range of 24% to 28%.

11. The MRI processing method according to claim 8, characterized in that, The hematocrit value in the blood is selected from a range of 38% to 42%.

12. The MRI processing method according to claim 8, characterized in that, In the step of calculating the optimal reversal time point, the processor calculates the optimal reversal time point by substituting the T1 value of the myocardium after the contrast agent injection into the following mathematical formula 2. (Mathematical Formula 2) TI_optimal=0.69×T1_Post_Myo Wherein, TI_optimal is the optimal inversion time point for MRI, and T1_Post_Myo is the T1 value of the myocardium after contrast agent injection.

13. The MRI processing method according to claim 8, characterized in that, It also includes the following steps: The processor uses the following mathematical formula 3 to normalize the image signals included in the MRI data at the optimal reversal time point to generate normalized image signals. (Mathematical Formula 3) S_normal = A × S_TI_optimal Where S_normal is the normalized image signal, S_TI_optimal is the image signal included in the MRI data at the optimal inversion time point, and A is a real number greater than or equal to 1.

14. The MRI processing method according to claim 13, characterized in that, It also includes the following steps: The processor identifies lesions as the portion of the normalized MRI signal at the optimal reversal time point that is above a baseline value.

15. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores a program for executing the MRI processing method according to claim 8 and includes at least one instruction.

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