Image fusion method and application of nuclear medicine PET multi-mode myocardial metabolism imaging

Abstract

The application discloses a kind of nuclear medicine PET multimode myocardial metabolism imaging image fusion method and application, it is related to nuclear medicine image processing technical field.The method is sequentially through coordinate system conversion, 3D myocardial surface generation, image registration, myocardial residual correction, image standardization, image superposition and image analysis step, for one day method imaging correction myocardial residual interference, realize multimode image interactive normalization by standardization processing, again according to myocardial exercise load or resting state completes corresponding image superposition, finally generates total myocardial metabolism image and obtains each metabolism mode proportion.The present application solves the problem that the prior art cannot completely evaluate total myocardial metabolism level, can qualitatively evaluate metabolic defect site, quantitatively analyze metabolic defect degree, and provides accurate support for myocardial metabolism related disease diagnosis.

Description

Technical Field

[0001] This invention relates to the field of nuclear medicine image processing technology, and in particular to an image fusion method and application for nuclear medicine PET multimodal myocardial metabolic imaging. Background Technology

[0002] The main energy metabolic pathways in the myocardium include myocardial glucose metabolism, myocardial fatty acid metabolism, and myocardial lactate metabolism. Under stress (e.g., exercise load or physiological stress) and at rest, these three metabolic levels must be assessed simultaneously to comprehensively and effectively reflect the overall myocardial metabolic status. Nuclear medicine cardiac PET molecular imaging, as a commonly used medical imaging method for assessing myocardial metabolic levels, can qualitatively assess myocardial metabolic levels in a single metabolic mode through image intensity. However, it has significant technical limitations in multimodal imaging applications.

[0003] 1. When using the one-day method for multimodal PET myocardial imaging, the first myocardial metabolic imaging agent may remain in the myocardium, interfering with the detection results of the second imaging agent;

[0004] 2. There is a lack of effective cross-normalization methods among multiple sets of PET myocardial metabolic images, which cannot eliminate the quantitative differences between different modes;

[0005] 3. Existing technologies cannot generate unified PET myocardial metabolic images that can represent the total myocardial metabolic level, nor can they accurately obtain the proportion of each myocardial metabolic mode in the total metabolism.

[0006] The aforementioned problems make it impossible to accurately assess and quantitatively analyze the total metabolic level of the myocardium, thus making it impossible to identify the location and extent of metabolic defects, which seriously hinders the practical application of multimodal myocardial metabolic imaging in clinical diagnosis.

[0007] Therefore, the field of nuclear medicine cardiology urgently needs an innovative technical approach that can solve the above-mentioned technical challenges. Summary of the Invention

[0008] The purpose of this invention is to provide an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging, which solves the technical problems of residual myocardial interference, inability to interactively normalize images, and difficulty in assessing the total myocardial metabolic level in existing multimodal PET myocardial metabolic imaging, thereby achieving accurate calculation of the proportion of each metabolic mode and qualitative and quantitative assessment of the location and degree of metabolic defects.

[0009] To achieve the above objectives, this invention provides an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging, comprising the following steps:

[0010] S1. Coordinate system transformation: The rotation axis of the PET myocardial metabolism image acquired in the body coordinate system is translated to a position close to the center of the myocardium. Then, the PET myocardial metabolism image is rotated from the body coordinate system to the heart coordinate system through two rotation angles (θ, φ) to generate a short-axis PET myocardial metabolism image that fully displays multiple layers from the apex to the base of the heart.

[0011] S2 and 3D myocardial surface generation: with the heart chamber as the origin, the short-axis PET myocardial metabolic image is transformed from a rectangular coordinate system to a spherical coordinate system to generate a polar diagram. In the polar diagram, the myocardial midline of each slice is found by radial sampling of coordinates (r, θ, φ). The myocardial midlines of each slice are connected and local discontinuous pixels are corrected to obtain a continuous 3D myocardial midline surface.

[0012] S3. Image registration: Using the 3D myocardial midline surface of the first-mode PET myocardial metabolism image as a reference, calculate the difference gradient of the corresponding surface of the second-mode PET myocardial metabolism image in the radial direction. Based on the difference gradient, the second-mode PET myocardial metabolism image is radially moved to achieve registration in the spherical coordinate system. Then, the registered image is converted to the rectangular coordinate system. For the third-mode PET myocardial metabolism image, the same method is used, using the 3D myocardial midline surface of the first-mode PET myocardial metabolism image as a reference, to sequentially perform the operations of radial difference gradient calculation, radial movement registration, and rectangular coordinate system conversion.

[0013] S4. Myocardial residual correction: Whether to perform residual correction depends on the imaging method.

[0014] If a one-day method is used for multimodal myocardial metabolic imaging, multiple PET myocardial metabolic imaging agents are injected sequentially and PET myocardial metabolic images are acquired. The residual amount of the previous imaging agent in the myocardium is estimated based on the start time, imaging duration, radionuclide half-life, and time interval between two PET imaging starts of the previous mode PET myocardial metabolic image. The residual amount of the previous imaging agent in the myocardium is removed in the PET myocardial metabolic image of the next mode.

[0015] The formula for calculating residual myocardial mass is:

[0016]

[0017] in, The radiation concentration of a pixel in a PET myocardial metabolic image of the former mode is expressed in Bq / ml. For the latter mode of PET imaging startup time, This refers to the PET imaging start-up time in the previous mode. The half-life of the radionuclide used in the PET imaging agent for the former mode;

[0018] If a multi-day method is used for multimodal myocardial metabolic imaging, different types of PET myocardial metabolic imaging agents are injected sequentially over multiple days and PET myocardial metabolic images are acquired, without the need for myocardial residual correction.

[0019] S5. Image Standardization: The PET myocardial metabolic images processed by S1 to S4 are converted to radiation concentration based on the relationship between pixel values ​​and radiation concentration. Then, using myocardial radiation concentration, injection activity, and body weight, a PET myocardial metabolic image with standardized myocardial uptake values ​​is generated. The calculation formula is as follows:

[0020]

[0021] in, This represents the standardized myocardial uptake value, expressed in g / ml. This refers to the concentration of radiation to the myocardium, expressed in Bq / ml; D 注射 Injection activity is expressed in Bq; W represents body weight in g.

[0022] S6. Image overlay: When the myocardium is under exercise load, the standardized uptake values ​​of PET myocardial metabolism images corresponding to the three modes of myocardial glucose metabolism, myocardial fatty acid metabolism and myocardial lactate metabolism are overlaid at the pixel level to generate an overlaid image representing total myocardial metabolism; when the myocardium is in a resting state, the standardized uptake values ​​of PET myocardial metabolism images corresponding to the two modes of myocardial glucose metabolism and myocardial fatty acid metabolism are overlaid at the pixel level to generate an overlaid image representing total myocardial metabolism.

[0023] S7. Image analysis: For PET myocardial metabolic images of a single mode and the superimposed standardized uptake value, 3D sampling is performed using the 3D myocardial surface generation method described in S2. Then, the myocardial metabolic target image is converted into a single mode and the superimposed myocardial metabolic target image through the geometric correspondence matrix between the myocardium and the target image. The average myocardial metabolic standardized uptake value of the single mode and the superimposed one is calculated, and then the proportion of the average uptake value of the single mode in the average uptake value of the superimposed one is obtained.

[0024] Preferably, in S4, the myocardial metabolism imaging agent is a PET myocardial metabolism imaging agent, specifically including a PET myocardial glucose metabolism imaging agent, a PET myocardial fatty acid metabolism imaging agent, and a PET myocardial lactate metabolism imaging agent.

[0025] Preferably, the PET myocardial glucose metabolism imaging agent is a PET imaging agent with glucose characteristics, including: 18 F-FDG, 11 C-FDG, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled glucose or similar substances.

[0026] Preferably, the PET myocardial fatty acid metabolism imaging agent is a PET imaging agent with fatty acid characteristics, including... 11 C-Palmitate, 18 F-FTHA, 18 F-FTP, 18 F-FCPHA, 18 F-FTO, 18 F-F7, 18 F-F3, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled fatty acids or similar substances.

[0027] Preferably, the PET myocardial lactate metabolism imaging agent is a PET imaging agent with lactate characteristics, including... 11 C-Lactate, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled lactic acid or similar substances.

[0028] Preferably, in S4, when using a one-day multimodal myocardial metabolic imaging method, the PET myocardial metabolic imaging agent in the first mode is any one of the PET myocardial glucose metabolism imaging agent, the PET myocardial fatty acid metabolism imaging agent, and the PET myocardial lactate metabolism imaging agent; the second mode is any one of the remaining two modes; and the third mode is the last remaining one.

[0029] An application of an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging includes:

[0030] Qualitative assessment: The maximum myocardial metabolic uptake value corresponding to the superimposed target image in various modes is used to adjust the display intensity of the target image by intensity normalization. The area with intensity below the set threshold in the target image is regarded as the area with low metabolic level, so as to identify the metabolic defect site.

[0031] Quantitative assessment: The proportion of each myocardial metabolic pattern represents the myocardial metabolic level of the corresponding pattern. The standardized myocardial metabolic uptake values ​​of each pattern and the superimposed pattern in the metabolically deficient area and normal area are quantitatively measured, and the ratio of the two is calculated to represent the degree of metabolic deficiency.

[0032] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0033] This invention precisely solves the problem of residual interference from preceding myocardial metabolic imaging agents in one-day multimodal imaging through a myocardial residual correction step. Combined with image standardization processing, it achieves interactive normalization of multimodal PET myocardial metabolic images, effectively eliminating the metrological differences between different modes of images and laying a data foundation for subsequent accurate analysis.

[0034] By relying on pre-processes such as coordinate system transformation, 3D myocardial surface generation and image registration to ensure spatial consistency of multi-mode images, and then using three or two sets of pixel-level superposition according to myocardial exercise load or resting state, a fusion image that can completely represent the total myocardial metabolic level is successfully generated. At the same time, the proportion of each metabolic mode in the total metabolism is obtained through image analysis, clearly presenting the activity level of a single metabolic pathway.

[0035] This method supports both qualitative assessment, which can accurately identify the defect sites of each mode and total metabolism through intensity normalization adjustment, and quantitative analysis, which can quantify the degree of defect through standardized uptake values ​​of the defect site. It completely solves the technical pain points of existing technologies that cannot fully assess the total metabolic level of myocardium, are difficult to locate metabolic abnormalities and quantify the degree of defect, and significantly improves the clinical application value of multimodal myocardial metabolic imaging.

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic flowchart of an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to Embodiment 1 of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the principle of the S1 coordinate system transformation step in Embodiment 1 of the present invention;

[0040] Figure 3 This is a schematic diagram illustrating the principle of the 3D myocardial surface generation step in S2 of Embodiment 1 of the present invention;

[0041] Figure 4 This is a schematic diagram illustrating the principle of the S3 image registration step in Embodiment 1 of the present invention;

[0042] Figure 5 This is a comparison chart of radiation concentration-time curves for the S4 myocardial residue correction step in Embodiment 1 of the present invention;

[0043] Figure 6 This is a comparison chart of the effects of the S4 myocardial residue correction step in Embodiment 1 of the present invention;

[0044] Figure 7 This is a schematic diagram illustrating the principle of the S5 image overlay step in Embodiment 1 of the present invention;

[0045] Figure 8 The target images for the S7 image analysis step in Embodiment 1 of the present invention are as follows: (a) is the target image for the normalized myocardial uptake value of the first mode, (b) is the target image for the normalized myocardial uptake value of the second mode, (c) is the target image for the normalized myocardial uptake value of the third mode, and (d) is the target image for the normalized myocardial uptake value after superposition.

[0046] Figure 9 This is a schematic diagram of the clinical application effect of an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to Embodiment 2 of the present invention; (a) is the target image of the myocardial standardized uptake value in the first mode; (b) is the target image of the myocardial standardized uptake value in the second mode; (c) is the target image of the myocardial standardized uptake value in the third mode; (d) is the target image of the myocardial standardized uptake value after superposition. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] An image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging, such as Figure 1 As shown, the steps are as follows:

[0051] S1. Coordinate system transformation for data acquisition, such as... Figure 2 As shown.

[0052] 1) Rotation center translation: The rotation axis is translated from the PET myocardial metabolic images acquired from the body coordinate system to a position close to the center of the myocardium;

[0053] 2) Image rotation: The PET myocardial metabolism image is rotated from the body coordinate system to the heart coordinate system by two rotation angles (θ, φ) to generate a short-axis PET myocardial metabolism image. The short-axis PET myocardial metabolism image is characterized by being able to fully display multi-slice images from the apex to the base of the heart.

[0054] S2 and 3D myocardial curvature are generated, such as Figure 3 As shown.

[0055] 1) Spherical coordinate system transformation: Using the heart chamber as the origin, the short-axis PET myocardial metabolic image is transformed from a rectangular coordinate system to a spherical coordinate system to generate a polarogram.

[0056] 2) Radial sampling: In the polar plot, the myocardial midline of each slice is found by radial sampling with coordinates (r, θ, φ);

[0057] 3) Generate a 3D myocardial midline surface: Connect the myocardial midlines of each slice and correct the local discontinuities based on the discontinuities to generate a 3D myocardial midline surface with continuous features.

[0058] S3, Image registration, such as Figure 4 As shown.

[0059] 1) Registration of the myocardial midline surface: Using the 3D myocardial midline surface of the first mode PET myocardial metabolic image as a reference, the difference gradient between the two modes of the 3D myocardial midline surface of the second mode PET myocardial metabolic image is calculated in the radial direction.

[0060] 2) Radial translation: Using the differential gradient of the 3D myocardial midline surface as a reference, the second-mode PET myocardial metabolic image is radially translated, and a second-mode PET myocardial metabolic image registered with the first-mode PET myocardial metabolic image is generated in the spherical coordinate system.

[0061] 3) Rectangular coordinate system transformation: The registered second-mode PET myocardial metabolism image is transformed from the spherical coordinate system to the rectangular coordinate system, and the registered second-mode PET myocardial metabolism image is generated in the rectangular coordinate system.

[0062] S4. Correct residual myocardial tissue.

[0063] 1) When performing multimodal myocardial metabolic imaging within one day (one-day method), in the case of multiple myocardial metabolic imaging agent injections, the first mode of myocardial metabolic imaging agent (e.g., myocardial glucose imaging agent) is injected and PET myocardial metabolic imaging is performed first to obtain the first mode of myocardial metabolic PET myocardial metabolic image. Before the injection of the second mode of myocardial metabolic imaging agent (e.g., myocardial fatty acid imaging agent or myocardial lactate imaging agent), the myocardial residue of the first mode of myocardial metabolic imaging agent before the injection of the second mode of myocardial metabolic imaging agent is estimated by using the first mode of myocardial metabolic PET myocardial metabolic image, the time interval between the injection of the second mode of myocardial metabolic imaging agent and the injection of the first mode of myocardial metabolic imaging agent. Then, the myocardial residue of the first mode of myocardial metabolic imaging agent is removed from the second mode of myocardial metabolic image generated by the second mode of PET myocardial metabolic imaging to obtain an accurate second mode of PET myocardial metabolic image. This process is repeated to obtain an accurate third mode of PET myocardial metabolic image.

[0064] 2) The specific type of myocardial metabolic imaging agent injected in the first mode is not fixed and can be one of myocardial glucose metabolism, myocardial fatty acid metabolism, or myocardial lactate metabolism. The second mode uses one of the remaining types, and the third mode uses the last remaining type. Among these, the myocardial glucose imaging agent can be selected from... 18 F-FDG, 11 C-FDG; myocardial fatty acid imaging agent optional 11 C-Palmitate, 18 F-FTHA, 18 F-FTP, 18 F-FCPHA, 18 F-FTO, 18 F-F7, 18 F-F3, a myocardial lactate imaging agent, is used. 11 C-Lactate.

[0065] 3) All PET myocardial metabolism images need to be processed through coordinate system transformation, 3D myocardial surface generation, and image registration steps to generate second-mode and third-mode PET myocardial metabolism images that are registered with the first-mode PET myocardial metabolism images.

[0066] Figure 5 This demonstrates a comparison of residual radiation concentration-time curves with and without correction when using the one-day method. Figure 6 The comparison of PET myocardial metabolic images with and without correction demonstrates that by estimating and removing the residual amount of the former imaging agent, interference between different modes is effectively eliminated, making the distribution of radioactivity concentration in each mode more consistent with the actual uptake and metabolism of the imaging agent.

[0067] 4) When performing multimodal myocardial metabolic imaging over multiple days (multi-day method), different types of PET myocardial metabolic imaging agents are injected sequentially over multiple days and PET myocardial metabolic images are acquired. Since the interval between two adjacent imaging sessions exceeds several times the half-life of the radionuclide, the previous imaging agent has naturally decayed, and there is no need to correct for the myocardial residue of the previous day.

[0068] S5, Image Standardization

[0069] 1) PET myocardial metabolic images processed by coordinate system transformation, 3D myocardial surface generation, image registration, and correction of residual myocardium.

[0070] 2) Radiation concentration conversion: From the processed PET myocardial metabolic images, the pixel values ​​are converted into radiation concentration (unit: Bq / ml) based on the relationship between pixel values ​​and radiation concentration;

[0071] 3) Standardized Uptake Value Conversion: Using myocardial radiation concentration, injection activity (mCi or MBq), and body weight (g), all processed PET myocardial metabolic images were converted into PET myocardial metabolic images with standardized uptake values ​​(SUV) (g / ml). The calculation formula is as follows:

[0072]

[0073] in Standardized myocardial uptake values; D represents the myocardial radiation concentration (unit: Bq / ml). 注射 The value is the injection activity (unit: Bq), and W is the body weight (unit: g).

[0074] S6, Image overlay, such as Figure 7 As shown.

[0075] 1) Triple overlay: The PET myocardial metabolic images of the first, second and third modes of myocardial uptake are overlaid at the pixel level to produce a set of overlaid standardized uptake PET myocardial metabolic images to represent total myocardial metabolism. The triple overlay mode is suitable for stress conditions (e.g., exercise load, physiological load) when the myocardium uses myocardial glucose metabolism, myocardial fatty acid metabolism and myocardial lactate metabolism simultaneously.

[0076] 2) Two-group superposition: PET images of myocardial metabolism with myocardial standardized uptake representing the first mode and the second mode are superimposed at the pixel level to produce a set of superimposed PET images of myocardial metabolism with myocardial standardized uptake, which are used to represent total myocardial metabolism. Two-group superposition is suitable for resting conditions, when there is no lactate supply, and the myocardium only uses myocardial glucose metabolism and myocardial fatty acid metabolism at the same time.

[0077] Figure 7 In the first mode of the three-group overlay, PET / CT equipment is used under stress conditions. 18 For F-FDG myocardial glucose metabolism PET imaging, the intravenous injection dose is 5.3 mCi, followed by a 10-minute PET imaging session one hour after injection. The second mode involves immediately injecting 15.1 mCi of F-FDG while maintaining a stress state after completing the first mode of PET imaging. 11 C-Palmitate, wait 5 minutes, then perform PET imaging for 20 minutes; the third mode is to wait 10 minutes after completing the second mode of PET imaging, then inject 20.3 mCi while maintaining a stress state. 11 C-Lactate was administered, followed by PET imaging for 20 minutes after a 5-minute wait. All PET imaging data underwent PET myocardial metabolic image reconstruction, and were then processed through steps S1-S6 to generate superimposed PET myocardial metabolic images based on normalized myocardial uptake. The images were displayed in short-axis format. The first superimposed mode represented 15.8 mCi at rest. 11 C-Palmitate, wait 5 minutes, then perform PET imaging for 20 minutes. The second mode involves immediately injecting 6.1 mCi after completing the first mode of PET imaging. 18 F-FDG was injected, followed by a 10-minute PET scan 1 hour later. All PET scan data were then reconstructed into PET myocardial metabolic images and processed through steps S1-S6 to finally generate a superimposed PET myocardial metabolic image with standardized myocardial uptake. The image was displayed in a horizontal long axis format.

[0078] S7, Image Analysis

[0079] 1) Target image conversion: The PET myocardial metabolic images of a single mode and the superimposed myocardial normalized uptake values ​​are converted into a single mode myocardial metabolic target image and a superimposed myocardial metabolic target image by a 3D myocardial surface generation step. The myocardial uptake values ​​measured at the 3D sampling points are converted into a single mode myocardial metabolic target image and a superimposed myocardial metabolic target image by a geometric correspondence matrix between the myocardium and the target image.

[0080] 2) Calculate the proportion of myocardial metabolic patterns: Find the maximum myocardial metabolic standardized uptake value by using a single pattern and the superimposed target map, and calculate the average myocardial metabolic standardized uptake value of the single pattern and the superimposed average myocardial metabolic standardized uptake value respectively, and calculate the proportion of the single average myocardial metabolic standardized uptake value in the superimposed average myocardial metabolic standardized uptake value.

[0081] The output results of image analysis are as follows Figure 8As shown in Table 1, (a) is the bullseye map of the myocardial standardized uptake value for the first mode, (b) is the bullseye map of the myocardial standardized uptake value for the second mode, (c) is the bullseye map of the myocardial standardized uptake value for the third mode, and (d) is the bullseye map of the myocardial standardized uptake value after superposition. Key quantitative indicators for the three individual modes (myocardial glucose metabolism, fatty acid metabolism, and lactate metabolism) and the superimposed total metabolic mode are shown in Table 1. The maximum myocardial metabolic standardized uptake value reflects the peak metabolic activity of local myocardial regions in each mode; a higher value indicates more vigorous metabolism in that region. The average myocardial metabolic standardized uptake value reflects the overall metabolic level of the myocardium in each mode, avoiding interference from local peak values ​​in the overall judgment. The percentage is the ratio of the average uptake value of a single mode to the average uptake value of the superimposed total metabolic mode, intuitively quantifying the contribution weight of each mode in total myocardial metabolism.

[0082] Table 1. Quantitative Analysis of Multimodal Myocardial Metabolic Imaging

[0083]

[0084] Example 2

[0085] An application of an image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging includes:

[0086] 1) Qualitative assessment: such as Figure 9 As shown, the maximum myocardial metabolic uptake value corresponding to the target image of each mode and the superimposed target image is used to readjust the intensity of the target image display of each mode by intensity normalization. If the intensity is lower than the set threshold, the metabolic defect sites of each mode and the superimposed target image can be further identified. Figure 9 In the diagram, (a) is the target image of the myocardial standardized uptake value in the first mode; (b) is the target image of the myocardial standardized uptake value in the second mode; (c) is the target image of the myocardial standardized uptake value in the third mode; and (d) is the target image of the myocardial standardized uptake value after superposition.

[0087] 2) Quantitative Analysis: The proportion of each pattern and the superimposed myocardial metabolic pattern represents the myocardial metabolic level of each pattern. Further quantitative analysis was conducted on the standardized uptake values ​​of myocardial metabolism at the metabolic defect sites of each pattern and the superimposed pattern to represent the degree of metabolic deficiency. The core results of its clinical application are shown in Table 2. The standardized uptake value of the metabolic defect site reflects the actual metabolic activity level of the defect area; the value is lower than the mean of the normal area, and the larger the difference, the more severe the defect. The degree of metabolic deficiency is calculated by (average uptake value of the normal area - uptake value of the defect site) / average uptake value of the normal area, quantifying the metabolic difference between the defect area and the normal area in decimal form; the higher the value, the more severe the defect.

[0088] Table 2 Clinical Application Assessment Table for Myocardial Metabolic Deficiency

[0089]

[0090] The remaining technical features in the above embodiments can be flexibly selected by those skilled in the art to meet different specific practical needs according to actual circumstances. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims. In the above description, numerous specific details have been set forth to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention. In other instances, to avoid obscuring the present invention, well-known techniques, such as specific construction details, operating conditions, and other technical conditions, have not been specifically described.

[0091] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging, characterized in that, The steps are as follows: S1. Coordinate system transformation: The rotation axis of the PET myocardial metabolism image acquired in the body coordinate system is translated to a position close to the center of the myocardium. The PET myocardial metabolism image is rotated from the body coordinate system to the heart coordinate system through two rotation angles (θ, φ) to generate a short-axis PET myocardial metabolism image that fully displays multiple layers from the apex to the base of the heart. S2 and 3D myocardial surface generation: with the heart chamber as the origin, the short-axis PET myocardial metabolic image is transformed from a rectangular coordinate system to a spherical coordinate system to generate a polar diagram. In the polar diagram, the myocardial midline of each slice is found by radial sampling of coordinates (r, θ, φ). The myocardial midlines of each slice are connected and local discontinuous pixels are corrected to obtain a continuous 3D myocardial midline surface. S3. Image registration: Using the 3D myocardial midline surface of the first-mode PET myocardial metabolism image as a reference, calculate the difference gradient of the corresponding surface of the second-mode PET myocardial metabolism image in the radial direction. Based on the difference gradient, the second-mode PET myocardial metabolism image is radially moved to achieve registration in the spherical coordinate system. Then, the registered image is converted to the rectangular coordinate system. For the third-mode PET myocardial metabolism image, the same method is used, using the 3D myocardial midline surface of the first-mode PET myocardial metabolism image as a reference, to sequentially perform the operations of radial difference gradient calculation, radial movement registration, and rectangular coordinate system conversion. S4. Myocardial residual correction: Whether to perform residual correction depends on the imaging method. If a one-day method is used for multimodal myocardial metabolic imaging, multiple PET myocardial metabolic imaging agents are injected sequentially and PET myocardial metabolic images are acquired. The residual amount of the previous imaging agent in the myocardium is estimated based on the start time, imaging duration, radionuclide half-life, and time interval between two PET imaging starts of the previous mode PET myocardial metabolic image. The residual amount of the previous imaging agent in the myocardium is removed in the PET myocardial metabolic image of the next mode. The formula for calculating residual myocardial mass is: in, The radiation concentration of a pixel in a PET myocardial metabolic image of the former mode is expressed in Bq / ml. For the latter mode of PET imaging startup time, This refers to the PET imaging start-up time in the previous mode. The half-life of the radionuclide used in the PET imaging agent for the former mode; If a multi-day method is used for multimodal myocardial metabolic imaging, different types of PET myocardial metabolic imaging agents are injected sequentially over multiple days and PET myocardial metabolic images are acquired, without the need for myocardial residual correction. S5. Image Standardization: The PET myocardial metabolic images processed by S1 to S4 are converted to radiation concentration based on the relationship between pixel values ​​and radiation concentration. Then, using myocardial radiation concentration, injection activity, and body weight, a PET myocardial metabolic image with standardized myocardial uptake values ​​is generated. The calculation formula is as follows: in, This represents the standardized myocardial uptake value, expressed in g / ml. This refers to the concentration of radiation to the myocardium, expressed in Bq / ml; D 注射 Injection activity is expressed in Bq; W represents body weight in g. S6. Image overlay: When the myocardium is under exercise load, the standardized uptake values ​​of PET myocardial metabolism images corresponding to the three modes of myocardial glucose metabolism, myocardial fatty acid metabolism and myocardial lactate metabolism are overlaid at the pixel level to generate an overlaid image representing total myocardial metabolism; when the myocardium is in a resting state, the standardized uptake values ​​of PET myocardial metabolism images corresponding to the two modes of myocardial glucose metabolism and myocardial fatty acid metabolism are overlaid at the pixel level to generate an overlaid image representing total myocardial metabolism. S7. Image analysis: For PET myocardial metabolic images of a single mode and the superimposed standardized uptake value, 3D sampling is performed using the 3D myocardial surface generation method described in S2. Then, the myocardial metabolic target image is converted into a single mode and the superimposed myocardial metabolic target image through the geometric correspondence matrix between the myocardium and the target image. The average myocardial metabolic standardized uptake value of the single mode and the superimposed one is calculated, and then the proportion of the average uptake value of the single mode in the average uptake value of the superimposed one is obtained.

2. The image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to claim 1, characterized in that: In S4, the myocardial metabolism imaging agent is a PET myocardial metabolism imaging agent, specifically including PET myocardial glucose metabolism imaging agent, PET myocardial fatty acid metabolism imaging agent, and PET myocardial lactate metabolism imaging agent.

3. The image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to claim 2, characterized in that: PET myocardial glucose metabolism imaging agents are PET imaging agents with glucose characteristics, including: 18 F-FDG, 11 C-FDG, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled glucose.

4. The image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to claim 2, characterized in that: PET myocardial fatty acid metabolism imaging agents are PET imaging agents with fatty acid characteristics, including... 11 C-Palmitate, 18 F-FTHA, 18 F-FTP, 18 F-FCPHA, 18 F-FTO, 18 F-F7, 18 F-F3, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled fatty acids.

5. The image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to claim 2, characterized in that: PET myocardial lactate metabolism imaging agents are PET imaging agents with lactate characteristics, including... 11 C-Lactate, and 11 C 18 F, 64 Cu、 124 I, 68 Ga-labeled lactic acid.

6. The image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging according to claim 2, characterized in that: In S4, when using a one-day multimodal myocardial metabolic imaging method, the PET myocardial metabolic imaging agent in the first mode is any one of the PET myocardial glucose metabolism imaging agent, the PET myocardial fatty acid metabolism imaging agent, and the PET myocardial lactate metabolism imaging agent; the second mode is any one of the remaining two modes; and the third mode is the last remaining one.

7. The application method of the image fusion method for nuclear medicine PET multimodal myocardial metabolic imaging as described in any one of claims 1-6, characterized in that, include: Qualitative assessment: The maximum myocardial metabolic uptake value corresponding to various modes and the superimposed target image is used to adjust the display intensity of the target image by intensity normalization. The area with intensity below the set threshold in the target image is regarded as the area with low metabolic level, so as to identify the metabolic defect site. Quantitative assessment: The proportion of each myocardial metabolic pattern represents the myocardial metabolic level of the corresponding pattern. The standardized myocardial metabolic uptake values ​​of each pattern and the superimposed pattern in the metabolically deficient area and normal area are quantitatively measured, and the ratio between the two is calculated to represent the degree of metabolic deficiency.

Images