Minimally invasive bypass surgery planning method based on multi-modal image fusion

Abstract

The invention relates to the technical field of surgery planning, in particular to a minimally invasive bypass surgery planning method based on multi-modal image fusion, which comprises the following steps: acquiring heart dynamic parameters; generating a dynamic three-dimensional model; calculating a blockage risk score, and determining an initial anastomosis angle of the bridge blood vessel and the target blood vessel according to the blockage risk score; determining the fluctuation range of the matching angle; acquiring the variation range of the eddy current intensity value, judging whether the matching angle meets the requirement or not, and correcting the matching angle in response to the inconformity of the requirement; and determining the anastomosis position of the bridge blood vessel and outputting an operation planning scheme. According to the method, the blockage risk of the bridge blood vessel is quantified by combining the past medical history and blood routine parameters in the medical record of the patient to obtain the blockage risk score, the corresponding anastomosis angle is determined according to the blockage risk score, and the anastomosis angle is corrected according to the vortex intensity value; therefore, the accuracy of the minimally invasive surgery is improved, and the risk of blockage of the bridge blood vessel after the surgery is reduced.

Description

Technical Field

[0001] This invention relates to the field of surgical planning technology, and in particular to a minimally invasive bypass surgery planning method based on multimodal image fusion. Background Technology

[0002] With the increasing aging of the global population and changes in dietary structure, the incidence of coronary heart disease is rising year by year. Coronary artery bypass grafting (CABG) is a core treatment for coronary heart disease, restoring myocardial blood supply and improving cardiac function. Minimally invasive CABG has become the preferred surgical method in clinical practice due to its advantages such as less trauma and faster postoperative recovery.

[0003] However, current planning for minimally invasive bypass surgery faces limitations in the application of medical imaging. A surgical plan requires the surgeon's experience to be combined with existing medical images, resulting in insufficient anatomical precision. Furthermore, in actual bypass surgery, the determination of anastomosis angles and graft length is often based on experience, without verifying whether the eddy current intensity during blood flow meets requirements. This carries the risk of premature graft blockage due to individual factors, significantly shortening the lifespan of the grafts.

[0004] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0005] The purpose of this invention is to provide a minimally invasive bypass surgery planning method based on multimodal image fusion to address the limitations of existing medical imaging applications. These methods require surgeons to combine existing medical images with their experience to arrive at a surgical plan, resulting in insufficient anatomical precision. Furthermore, in actual bypass surgery, the determination of anastomosis angles and graft lengths often relies on experience, without verifying whether the eddy current intensity during blood flow meets requirements. This leads to individual risks such as premature graft blockage, significantly shortening the lifespan of the grafts.

[0006] This invention provides a minimally invasive bypass surgery planning method based on multimodal image fusion, comprising: Acquire the patient's multimodal medical imaging data, and obtain the patient's dynamic cardiac parameters based on the multimodal medical imaging data; A dynamic three-dimensional model of the patient's chest region is generated based on the aforementioned cardiac dynamic parameters; Obtain the patient's past medical history and complete blood count data, calculate the blockage risk score based on the past medical history and complete blood count data, and determine the initial anastomosis angle between the bypass vessel and the target vessel based on the blockage risk score; The fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the entire cardiac cycle is determined based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel. The blood routine data and the fluctuation range are input into the blood flow model to obtain the variation range of the eddy current intensity value under the anastomosis angle. The anastomosis angle is determined to meet the requirements based on the variation range of the eddy current intensity value. If the eddy current intensity value does not meet the requirements, the anastomosis angle is corrected based on the variation range of the eddy current intensity value. Identify the anastomosis site of the bypass graft and generate a surgical plan.

[0007] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the step of generating a dynamic three-dimensional model of the patient's chest region based on the cardiac dynamic parameters includes: Within a single heartbeat cycle, N key time points are selected at preset time intervals, and their corresponding CT images are obtained. Using CT images as the basic coordinate system, for each key time point, the cardiac dynamic parameters in the corresponding angiography images are obtained, and the cardiac dynamic parameters are projected onto the three-dimensional anatomical structure to obtain the three-dimensional model corresponding to the key time point. The three-dimensional models corresponding to all key time nodes are sorted according to the time sequence of the heartbeat cycle. The spatial motion trajectories of the coronary artery trunk, target blood vessel, and cardiac surface feature points in each three-dimensional model are obtained. The spatial motion trajectories of the coronary artery trunk, target blood vessel, and cardiac surface feature points in each three-dimensional model are fitted to establish the dynamic three-dimensional model. The medical imaging data includes CT scans and contrast imaging. The cardiac dynamic parameters include: the coordinates of the center point of the stenotic segment of the coronary artery and the coordinates of the center point of the normal segment of the vessel.

[0008] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the calculation of a blockage risk score based on past medical history and routine blood data includes: Each of the patient's medical history and routine blood parameters was assigned a corresponding weighting coefficient. Obtain the patient's past medical history and obtain the past medical history score based on the past medical history and the past medical history score database; Obtain the patient's complete blood count (CBC) parameters and determine the corresponding CBC parameter scores based on these parameters. The sum of the products of past medical history and routine blood parameters with their corresponding weighting coefficients is calculated and recorded as the blockage risk score. The past medical history includes: history of diabetes, history of hypertension, and history of bypass graft thrombosis; The blood routine data include: whole blood viscosity, fibrinogen, and hematocrit.

[0009] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the medical history score database has different scores set for different degrees or durations of diabetes, hypertension, and previous bypass vessel thrombosis, among which: The medical history scoring database has corresponding scores based on the duration of diabetes, with higher scores for longer durations. The medical history scoring database also has corresponding scores based on the systolic blood pressure of hypertension, with higher scores for higher systolic blood pressure. Furthermore, the medical history scoring database has different scores based on whether there is a history of bypass graft thrombosis; a score of zero is given for cases without a history of bypass graft thrombosis.

[0010] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the initial anastomosis angle between the bypass vessel and the target vessel is determined according to the occlusion risk score, wherein: Obtain surgical data from bypass surgeries that did not experience blockage within a preset period from historical surgical data; Obtain the anastomosis angle from the surgical data and calculate the corresponding blockage risk score. Establish the anastomosis angle range and the blockage risk score range respectively, and establish the mapping relationship between the blockage score and the anastomosis angle. The initial alignment angle is determined based on the mapping relationship and the calculated congestion risk score.

[0011] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the step of determining the fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the entire cardiac cycle based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel includes: Obtain the elastic modulus E of the bridging vessel; Two points are randomly selected within the candidate region as the anastomosis points of the graft vessel outlet and inlet. The distance between the anastomosis points of the graft vessel outlet and inlet during end-systole is defined as the systolic distance, and the distance between the anastomosis points of the graft vessel outlet and inlet during end-diastole is defined as the diastolic distance. The length of the bypass vessel is determined based on the contraction interval and the diastolic interval; Starting from the end of the heart's systole, the first anastomosis angle fluctuation range is calculated based on the systolic interval, diastolic interval, length of the bypass vessel, and elastic modulus E of the bypass vessel; starting from the end of the heart's diastole, the second anastomosis angle fluctuation range is calculated based on the systolic interval, diastolic interval, length of the bypass vessel, and elastic modulus E of the bypass vessel. Take the union of the first and second coincidence angle fluctuation ranges and denote it as the fluctuation range of the coincidence angle.

[0012] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the blood flow model is constructed based on fluid dynamics with the target vessel diameter and the bypass vessel diameter as the geometric basis. If the blood routine data and the anastomosis angle are input, the eddy current intensity value at the anastomosis angle is output.

[0013] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the step of determining whether the anastomosis angle meets the requirements based on the range of change in eddy current intensity includes: In response to the intensity threshold being within the range of eddy current intensity values, it is determined that the matching angle does not meet the requirements. The matching angle is then corrected based on the maximum value within the range of eddy current intensity values. The difference between the maximum value within the range of eddy current intensity values ​​and the intensity threshold is recorded as the intensity difference. The correction magnitude is positively correlated with the intensity difference; the larger the intensity difference, the larger the correction magnitude. If the intensity threshold is outside the range of variation of the eddy current intensity value, it is determined that the matching angle meets the requirements.

[0014] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, determining the anastomosis site of the bypass vessel includes: In the dynamic three-dimensional model, the narrow segment of the target blood vessel is located, and the blood vessels within a preset distance from the distal end of the narrow segment are selected as candidate anastomosis points at the exit end of the bypass vessel. The candidate region for anastomosis at the inlet end is determined based on the type of bypass vessel; within the candidate region, points that meet the corrected anastomosis angle or are deemed to meet the requirements are selected and used as the inlet and outlet anastomosis points of the bypass vessel. The length of the bypass vessel is determined based on the dynamic three-dimensional model, the inlet anastomosis point and the outlet anastomosis point of the bypass vessel, and the displacement difference of the heart during end-diastole and systole.

[0015] As a preferred technical solution for a minimally invasive bypass surgery planning method based on multimodal image fusion, the surgical planning scheme includes: The three-dimensional coordinates of the inlet and outlet anastomoses of the outgoing graft vessel; The location and number of surgical incisions are determined based on the operating radius of minimally invasive instruments.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: On the one hand, this invention collects surgical sample data from patients who have not experienced blockage within a preset period after surgery, thereby filtering out interference from factors such as anastomosis angle, blood routine parameters, or other factors, and obtaining sample data without blockage. Based on this sample data, training is performed to determine the relationship between the blockage risk assessment value and the anastomosis angle. On the other hand, this invention fuses multimodal images to obtain a dynamic three-dimensional model of the patient. Combining this with the patient's medical history and blood routine parameters, the blockage risk of the bypass graft is quantified to obtain a blockage risk score. The corresponding anastomosis angle is determined based on the blockage risk score, and the blood flow model is used to determine whether the anastomosis angle meets the requirements. If the determination result is not satisfactory, the anastomosis angle is corrected based on the eddy current intensity value. This constructs a multidimensional minimally invasive bypass surgery planning method based on "anatomical structure, individual factors leading to risk, and blood flow status." This allows for surgical planning schemes to vary according to individual patient conditions, providing surgeons with accurate surgical plans, improving the precision of minimally invasive surgery, and reducing the risk of postoperative bypass graft blockage. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the steps of a minimally invasive bypass surgery planning method based on multimodal image fusion, as described in an embodiment of the present invention. Detailed Implementation

[0018] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0019] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0020] Please see Figure 1 The diagram shows a flowchart of the steps in the minimally invasive bypass surgery planning method based on multimodal image fusion according to an embodiment of the present invention, including: Step S1: Obtain the patient's multimodal medical imaging data, and obtain the patient's cardiac dynamic parameters based on the multimodal medical imaging data; Step S2: Generate a dynamic three-dimensional model of the patient's chest region based on cardiac dynamic parameters; Step S3: Obtain the patient's past medical history and blood routine data, calculate the blockage risk score based on the past medical history and blood routine data, and determine the initial anastomosis angle between the bypass vessel and the target vessel based on the blockage risk score. Step S4: Determine the fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the entire cardiac cycle based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel. Step S5: Input the blood routine data and fluctuation range into the blood flow model to obtain the variation range of the eddy current intensity value under the anastomosis angle. Determine whether the anastomosis angle meets the requirements based on the variation range of the eddy current intensity value. If the eddy current intensity value does not meet the requirements, correct the anastomosis angle based on the maximum value in the variation range of the eddy current intensity value. Step S6: Determine the anastomosis site of the bypass vessel and output the surgical plan.

[0021] In practice, coronary CT images (0.5mm slice thickness) and coronary angiography images from multiple projection angles were acquired from the patient. An iterative nearest-point algorithm based on the vessel center point was used to fuse the vascular stenosis data from the angiography images with the anatomical structures from the CT scan, generating a dynamic 3D model including the heart, coronary arteries, and thoracic cavity. Key anatomical structures included: cardiac surface nerve fibers, pericardial reflection, and branches of the thoracic aorta.

[0022] Specifically, this invention fuses multimodal images to obtain a dynamic three-dimensional model of the patient, combines the patient's medical history and routine blood parameters to quantify the occlusion risk of the bypass graft and obtain an occlusion risk score, determines the corresponding anastomosis angle based on the occlusion risk score, and judges whether the anastomosis angle meets the requirements based on the blood flow model. In response to the judgment result not meeting the requirements, the anastomosis angle is corrected based on the eddy current intensity value, thereby improving the precision of minimally invasive surgery, reducing the postoperative occlusion risk of the bypass graft, and increasing the service life of the bypass graft.

[0023] Furthermore, a dynamic three-dimensional model of the patient's chest region is generated based on multimodal medical imaging data, including: Within a single heartbeat cycle, N key time points are selected at preset time intervals, and their corresponding CT images are obtained. Using CT images as the basic coordinate system, for each key time point, the corresponding cardiac dynamic parameters in the angiography images are obtained, and the cardiac dynamic parameters are projected onto the three-dimensional anatomical structure to obtain the three-dimensional model corresponding to the key time point. Based on the time sequence of the heartbeat cycle, sort the three-dimensional models corresponding to all key time nodes, obtain the spatial motion trajectory of the coronary artery trunk, target blood vessel and heart surface feature points in each three-dimensional model, and fit the spatial motion trajectory of the coronary artery trunk, target blood vessel and heart surface feature points in each three-dimensional model to establish a dynamic three-dimensional model. Among them: medical imaging data includes: CT scans and contrast imaging; Cardiac dynamic parameters include: the coordinates of the center point of the stenotic segment of the coronary artery and the coordinates of the center point of the normal segment of the vessel.

[0024] In implementation, the preset time interval is determined based on the actual computing power of the computer and the accuracy of the model. In this embodiment of the invention, the preset time interval is 0.1s. Since the cardiac cycle is 0.8s, the value of N is 8. Using CT images as the basic coordinate system, for each key time node, the corresponding cardiac dynamic parameters in the angiography image are obtained. The cardiac dynamic parameters are projected onto the three-dimensional anatomical structure to obtain the three-dimensional model corresponding to the key time node. The specific steps include: A three-dimensional rectangular coordinate system is constructed by selecting the vertex of the sternum as the origin, where: the left and right directions of the origin are the X-axis, the front and back directions are the Y-axis, and the up and down directions are the Z-axis; Convert CT image sequences into three-dimensional coordinates; Extract the centerline coordinates of the stenotic and normal segments of the left anterior descending artery from the angiographic images (the centerline coordinates of the normal segment were taken at 0.5mm intervals). Three pairs of coplanar points (such as the aortic root and the left ventricular fixed point) are selected to calculate the transformation matrix. The centerline coordinates of the stenotic and normal segments of the left anterior descending artery are mapped to a three-dimensional rectangular coordinate system to obtain a three-dimensional model.

[0025] In detail, CT images can display the anatomical structure of the heart (such as the myocardium, the course of blood vessels, or surrounding tissues), while angiography can show the location of vascular stenosis. However, in minimally invasive bypass surgery, it is necessary to combine the information displayed by both. This invention, through the construction of a dynamic three-dimensional model, can overcome the shortcomings of using CT and angiography alone, intuitively displaying the relationship between blood vessels and surrounding tissues, and reducing errors caused by manually fusing CT and angiography information.

[0026] In detail, a blockage risk score is calculated based on past medical history and complete blood count data, including: Each of the patient's medical history and routine blood parameters was assigned a corresponding weighting coefficient. Obtain the patient's past medical history and obtain the past medical history score based on the past medical history and the past medical history score database; Obtain the patient's complete blood count (CBC) parameters and determine the corresponding CBC parameter scores based on these parameters. The sum of the products of past medical history and routine blood parameters with their corresponding weighting coefficients is calculated and recorded as the blockage risk score. Past medical history includes: history of diabetes, history of hypertension, and history of bypass graft thrombosis; Complete blood count data include: whole blood viscosity, fibrinogen, and hematocrit.

[0027] In practice, the weighting coefficients were determined through multivariate regression analysis. Clinical data from at least 300 patients undergoing minimally invasive bypass surgery were collected, including past medical history, routine blood parameters, and bypass patency rate at 6 months post-surgery. Regression analysis was performed with patency rate as the dependent variable and past medical history and routine blood parameters as independent variables to calculate the influence coefficient of each variable on the patency rate. The weighting coefficients were obtained by normalizing the influence coefficients. In this embodiment of the invention, the weighting coefficient for past medical history ranged from 0.4, and the weighting coefficient for routine blood parameters ranged from 0.6.

[0028] Furthermore, the medical history scoring database includes different scores for varying degrees or durations of diabetes, hypertension, and a history of bypass graft thrombosis. In the past medical history scoring database, a corresponding score is set according to the number of years of diabetes, and the longer the number of years of diabetes, the higher the score; in the past medical history scoring database, a corresponding score is determined according to the systolic blood pressure of hypertension, and the higher the systolic blood pressure, the higher the score; in the past medical history scoring database, different scores are set according to whether there is a history of bypass graft thrombosis, and the score is zero if there is no history of bypass graft thrombosis.

[0029] Understandably, the scores for past medical history and blood routine parameters are both set by the system.

[0030] In detail, in this embodiment of the invention, the scores in the past medical history score database are as follows: Diabetes: 0 points for non-existent diabetes; 2 points for disease duration less than 5 years; 4 points for disease duration greater than or equal to 5 years and less than 10 years; 5 points for disease duration greater than or equal to 10 years.

[0031] Hypertension: Normal blood pressure score is 0; systolic blood pressure less than or equal to 179 mmHg is scored as 2 points; systolic blood pressure greater than 180 mmHg is scored as 3 points.

[0032] Previous history of bypass graft thrombosis: 5 points are awarded for thrombosis; 0 points are awarded for no thrombosis.

[0033] Obtain the patient's past medical history and match it with the past medical history score database to obtain the patient's past medical history score.

[0034] Furthermore, a corresponding blood routine score database is determined for each blood routine parameter, and the blood routine parameters are compared with the blood routine database to obtain the corresponding score. In this embodiment of the invention, the scores in the blood routine score database are as follows: Whole blood viscosity: less than or equal to 5.0 mPa∙s, score 2 points; greater than 5.0 mPa∙s and less than 5.5 mPa∙s, score 3 points; greater than or equal to 5.5 mPa∙s, score 5 points. Fibrinogen: ≤5.0g / L, score 2 points; ≥5.0g / L and ≤6.0g / L, score 3 points; ≥6.0g / L, score 4 points.

[0035] Hematocrit: less than or equal to 60%, score 3 points; greater than 60%, score 5 points.

[0036] Obtain the patient's complete blood count (CBC) parameters and compare them with a CBC score database to obtain the patient's CBC score.

[0037] The blockage risk score α is calculated based on the determined past medical history score and blood routine parameter scores. The past medical history score is the sum of the scores for diabetes, hypertension, and previous history of bypass graft thrombosis; the blood routine parameter scores are the sum of the scores for whole blood viscosity, fibrinogen, and hematocrit. The calculation method for the blockage risk score α is defined as follows: ; Where: T is the diabetes score, G is the hypertension score, J is the history of bypass graft thrombosis score, α is the weighting coefficient of past medical history, Q is the whole blood viscosity score, X is the fibrinogen score, H is the hematocrit score, and β is the weighting coefficient of blood routine parameters.

[0038] Specifically, known clinical data shows that long-term hypertension can directly damage the endothelium of bypass grafts through mechanical shearing forces, accelerating the migration and regeneration of smooth muscle cells, thereby exacerbating vascular stenosis. Patients with diabetes also have a significantly higher probability of bypass graft occlusion than those without diabetes. Based on this, this invention uses differentiated scores for different degrees or durations of diabetes, hypertension, history of bypass graft thrombosis, whole blood viscosity, fibrinogen, and hematocrit. This allows the occlusion score to more accurately reflect the patient's actual condition, providing a precise basis for determining the subsequent anastomosis angle.

[0039] Furthermore, the initial anastomosis angle between the bypass graft and the target vessel is determined based on the occlusion risk score, wherein: Obtain surgical data from bypass surgeries that did not experience blockage within a preset period from historical surgical data; Obtain the anastomosis angle from the surgical data and calculate the corresponding blockage risk score. Establish the anastomosis angle range and the blockage risk score range respectively, and establish the mapping relationship between the blockage score and the anastomosis angle. The initial alignment angle is determined based on the mapping relationship and the calculated congestion risk score.

[0040] It should be noted that the mapping relationship is between the anastomosis angle range and the occlusion score range, requiring that a higher occlusion risk score corresponds to a smaller anastomosis angle. The anastomosis angle range is determined according to relevant regulations for coronary artery revascularization surgery, such as the "Guidelines for Coronary Artery Revascularization." In this embodiment of the invention, the safe range for the anastomosis angle is determined to be between 10° and 45° according to the guidelines for coronary artery revascularization. The occlusion score range is determined based on historical surgical data. Based on the established mapping relationship of the anastomosis angle range and the occlusion score range, a clear mapping rule is established using these two known ranges, which is existing technology and will not be elaborated upon here.

[0041] Furthermore, the purpose of the preset period is to filter out bypass surgery sample data that did not experience blockage within the set time limit, providing accurate data for the subsequent mapping relationship between blockage score and anastomosis angle. In this embodiment of the invention, the preset period is set to 3 years.

[0042] In detail, this invention collects surgical data on grafts that did not become blocked after surgery, and establishes a mapping relationship based on the anastomosis angle and blockage risk score in the surgical data. This avoids the postoperative uncertainty of graft surgery caused by relying on experience to select the anastomosis angle in traditional surgery, and reduces the risk of graft blockage caused by improper selection of the anastomosis angle.

[0043] Furthermore, based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel, the fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the cardiac cycle is determined, including: Obtain the elastic modulus E of the bridging vessel; Two points are randomly selected within the candidate region as the anastomosis points of the graft vessel outlet and inlet. The distance between the anastomosis points of the graft vessel outlet and inlet during end-systole is defined as the systolic distance, and the distance between the anastomosis points of the graft vessel outlet and inlet during end-diastole is defined as the diastolic distance. The length of the bypass graft is determined based on the systolic and diastolic intervals. Starting from the end of the heart's systole, the fluctuation range of the first anastomosis angle is calculated based on the systolic interval, diastolic interval, length of the graft vessel, and elastic modulus E of the graft vessel; starting from the end of the heart's diastole, the fluctuation range of the second anastomosis angle is calculated based on the systolic interval, diastolic interval, length of the graft vessel, and elastic modulus E of the graft vessel. Take the union of the fluctuation range of the first coincidence angle and the fluctuation range of the second coincidence angle, and denote it as the fluctuation range of the coincidence angle.

[0044] In practice, the diameter and wall thickness of the bypass graft are obtained, and the elastic modulus E of the bypass graft is obtained by combining relevant clinical literature data. The length of the bypass graft is k times the spacing (the spacing is the maximum value between the anastomosis points at the outlet and inlet ends of the bypass graft throughout the entire cardiac cycle), and the value of k is selected according to the actual situation. Based on the length of the bypass graft and the initial anastomosis angle, two points are randomly selected from the candidate region as the anastomosis points at the outlet and inlet ends of the bypass graft. When selecting, it is only necessary to ensure that the anastomosis angle between the bypass graft and the target vessel is the initial anastomosis angle. Starting at either the end of systole or end of diastole, the fluctuation range of the anastomosis angle during cardiac cycle is calculated as the heart contracts and relaxes. Due to the supporting effect of blood pressure on blood vessels, the bridging vessel can be regarded as an "elastic rod" with a fixed length L. Since the length of the bridging vessel, the systolic distance between anastomoses, the diastolic distance, and the elastic modulus E of the bridging vessel are all known quantities, the fluctuation range of the anastomosis angle is calculated by combining the cosine theorem and bending strength or other physical laws in mechanics of materials. The calculation process of the angle between the endpoint and the contact position when the distance between the two endpoints is different, given the length and elastic modulus of the "elastic rod", is a prior art and will not be elaborated here.

[0045] Understandably, during cardiac systole, the distance between anastomoses shortens, and the anastomosis angle increases. During cardiac diastole, the distance between anastomoses increases, and the anastomosis angle decreases. Therefore, even if the same anastomosis angle is used during cardiac diastole and systole, differences will still exist in the actual surgical outcome. Based on the above theory, this invention uses the anastomosis angle between the bypass vessel and the target vessel at the end of cardiac diastole and the end of cardiac systole as the initial anastomosis angle, respectively. It calculates the fluctuation range of the first anastomosis angle and the fluctuation range of the second anastomosis angle, and takes their union to obtain the fluctuation range of the anastomosis angle during the actual surgical process.

[0046] Furthermore, the blood flow model is constructed based on fluid dynamics, using the target vessel diameter and the bridge vessel diameter as the geometric basis. If blood routine data and anastomosis angle are input, the output is the eddy current intensity value at the anastomosis angle.

[0047] In the implementation, the diameter of the target blood vessel and the diameter of the bridging blood vessel are first obtained. A dynamic three-dimensional model of the blood vessel is established based on the anastomosis angle, the diameter of the target blood vessel, and the diameter of the bridging blood vessel. The eddy current intensity value is calculated using the finite volume method and fluid mechanics. The theoretical formulas and calculation processes of fluid mechanics and the finite volume method are existing technologies and will not be elaborated here.

[0048] It is understandable that, due to individual differences in physical condition, the resistance encountered by blood flowing in the same blood vessels varies. If the same anastomosis angle is used for bypass surgery, some patients have a higher risk of postoperative blockage. Therefore, it is necessary to determine different anastomosis angles based on the patient's specific situation. This invention establishes a blood flow model using the patient's actual blood vessel diameter and blood parameters as input and eddy current intensity as output. This model simulates the eddy current intensity at the anastomosis site, providing a basis for subsequent judgment on whether the anastomosis angle meets requirements based on the simulation results. This reduces the likelihood of unsatisfactory surgical outcomes and blockage caused by eddy currents resulting from mismatched anastomosis angles.

[0049] Furthermore, the matching angle is determined based on the range of variation of the eddy current intensity value. In response to the intensity threshold being within the range of variation of the eddy current intensity value, it is determined that there is a situation where the eddy current intensity is greater than the intensity threshold during the cardiac cycle, and the matching angle does not meet the requirements. The matching angle is corrected based on the maximum value in the range of variation of the eddy current intensity value. The difference between the maximum value in the range of variation of the eddy current intensity value and the intensity threshold is recorded as the intensity difference. The correction magnitude is positively correlated with the intensity difference. The larger the intensity difference, the larger the correction magnitude. Since the intensity threshold is outside the range of eddy current intensity values, it is determined that the eddy current intensity is less than the intensity threshold during the cardiac cycle, and the matching angle meets the requirements.

[0050] Specifically, the intensity threshold is determined based on relevant medical standards, the actual condition of the patient's blood vessels, and other factors. In this embodiment of the invention, the intensity threshold is set to 1000 s. -1If the intensity threshold falls within the range of eddy current intensity variation, it indicates that there are values ​​greater than the intensity threshold within the range of eddy current intensity variation, and it cannot be guaranteed that the eddy current intensity value will be less than the intensity threshold throughout the cardiac cycle. If the intensity threshold is outside the range of eddy current intensity variation, it indicates that the eddy current intensity values ​​within the range of eddy current intensity variation are all greater than or less than the intensity threshold. However, in actual surgical procedures, relevant medical guidelines for coronary artery bypass grafting have specified a reference range for the selection of anastomosis angles. Therefore, within this range, there is no situation where the values ​​within the range of eddy current intensity variation are all greater than the intensity threshold throughout the cardiac cycle. Thus, there is only a situation where the eddy current intensity values ​​within the range of eddy current intensity variation are all less than the intensity threshold. This situation constitutes a situation where the eddy current intensity is less than the intensity threshold throughout the cardiac cycle, and therefore should be considered compliant. It is understandable that the smaller the anastomosis angle, the smaller the eddy current generated at the anastomosis site, and the corrected value of the anastomosis angle should be smaller than the original value. However, the larger the area to be anastomosed, the greater the surgical difficulty. Therefore, a smaller anastomosis angle is not always better. Corrections to the matching angle can be made using correction coefficients, interval mapping, or other correction methods, as long as the actual situation and the positive correlation between the larger the intensity difference and the larger the correction magnitude are satisfied.

[0051] This invention provides a method for correcting the anastomosis angle, comprising: determining the feasible range of the anastomosis angle based on the actual situation; where there are no special requirements, the anastomosis angle is between 10° and 45°, and the specific range is narrowed according to the patient's actual situation. In this embodiment of the invention, the range of the anastomosis angle is 10° to 42°, and the angle is increased by 200s for every 200s increase in intensity difference. -1 The anastomosis angle decreases by 5°.

[0052] In detail, when the anastomosis angle is determined to be unsuitable, the present invention calculates the strength difference and corrects the anastomosis angle based on the strength difference, thereby ensuring that the final anastomosis angle not only meets the patient's actual situation but also reduces the difficulty of the surgery.

[0053] Specifically, determining the anastomosis site of the bypass vessels includes: In the dynamic 3D model, the narrow segment of the target blood vessel is located, and the blood vessels within a preset distance from the distal end of the narrow segment are selected as candidate anastomosis points at the exit end of the bypass vessel. The candidate region for the anastomosis point at the inlet end is determined according to the type of graft vessel. In practice, the graft vessel types are divided into internal mammary artery and great saphenous vein. The candidate region for the inlet end of the internal mammary artery is the origin of the subclavian artery, and the candidate region for the great saphenous vein is the non-calcified region of the ascending aorta. Within the candidate region, points that meet the corrected anastomosis angle or are deemed to meet the requirements are selected and used as the inlet and outlet anastomosis points of the bypass graft. The length of the bypass vessel is determined based on a dynamic three-dimensional model, the inlet anastomosis point and the outlet anastomosis point of the bypass vessel, and the displacement difference of the heart during end-diastole and systole.

[0054] In implementation, the preset distance range is 1-2 cm. Areas with a diameter greater than or equal to 1.8 mm and without calcification are designated as candidate anastomosis points at the graft vessel exit end. Candidate anastomosis points at the inlet end are determined based on the graft vessel type, including: if the graft vessel type is the internal mammary artery, the candidate anastomosis point at the inlet end is within 12 cm of the free segment starting 2 cm below the origin of the subclavian artery; if the vessel type is the great saphenous vein, two 5 mm diameter areas are marked on the anterior wall of the ascending aorta as candidate anastomosis points at the inlet end. Points conforming to the anastomosis angle are selected as the anastomosis points at both the graft vessel exit and inlet ends. The straight-line distance between the anastomosis points at the graft vessel exit and inlet ends is measured, and the graft vessel length is determined by combining this with the difference in cardiac displacement during end-diastole and systole. It is understood that those skilled in the art can accurately calculate the length of the graft vessel once the selection of anastomosis points and the construction of the dynamic three-dimensional model are completed.

[0055] Furthermore, the generated surgical planning scheme includes: The three-dimensional coordinates of the inlet and outlet anastomoses of the outgoing graft vessel; The location and number of surgical incisions are determined based on the operating radius of minimally invasive instruments.

[0056] It should be noted that determining the location and number of surgical incisions based on the operating radius of minimally invasive instruments is a routine procedure in coronary artery bypass surgery. This mainly includes the following steps: Based on the operating radius of the minimally invasive instruments, the anastomosis points in the dynamic three-dimensional model are projected onto the chest wall to determine the operating range that the instruments can cover; the number of incisions follows the principle of minimization, and the location is selected in the intersection area that covers all anastomosis points, avoiding ribs and chest wall blood vessels; the three-dimensional coordinates, intercostal location, and functional positioning of the incisions are output.

[0057] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A minimally invasive bypass surgery planning method based on multimodal image fusion, characterized in that, include: Acquire the patient's multimodal medical imaging data, and obtain the patient's dynamic cardiac parameters based on the multimodal medical imaging data; A dynamic three-dimensional model of the patient's chest region is generated based on the aforementioned cardiac dynamic parameters; Obtain the patient's past medical history and complete blood count data, calculate the blockage risk score based on the past medical history and complete blood count data, and determine the initial anastomosis angle between the bypass vessel and the target vessel based on the blockage risk score; The fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the entire cardiac cycle is determined based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel. The blood routine data and the fluctuation range are input into the blood flow model to obtain the variation range of the eddy current intensity value under the anastomosis angle. The anastomosis angle is determined to meet the requirements based on the variation range of the eddy current intensity value. If the eddy current intensity value does not meet the requirements, the anastomosis angle is corrected based on the variation range of the eddy current intensity value. Identify the anastomosis site of the bypass graft and generate a surgical plan.

2. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 1, characterized in that, The process of generating a dynamic three-dimensional model of the patient's chest region based on the cardiac dynamic parameters includes: Within a single heartbeat cycle, N key time points are selected at preset time intervals, and their corresponding CT images are obtained. Using CT images as the basic coordinate system, for each key time point, the cardiac dynamic parameters in the corresponding angiography images are obtained, and the cardiac dynamic parameters are projected onto the three-dimensional anatomical structure to obtain the three-dimensional model corresponding to the key time point. The three-dimensional models corresponding to all key time nodes are sorted according to the time sequence of the heartbeat cycle. The spatial motion trajectories of the coronary artery trunk, target blood vessel, and cardiac surface feature points in each three-dimensional model are obtained. The spatial motion trajectories of the coronary artery trunk, target blood vessel, and cardiac surface feature points in each three-dimensional model are fitted to establish the dynamic three-dimensional model. The medical imaging data includes CT scans and contrast imaging. The cardiac dynamic parameters include: the coordinates of the center point of the stenotic segment of the coronary artery and the coordinates of the center point of the normal segment of the vessel.

3. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 1, characterized in that, The calculation of the blockage risk score based on past medical history and blood routine data includes: Each of the patient's medical history and routine blood parameters was assigned a corresponding weighting coefficient. Obtain the patient's past medical history and obtain the past medical history score based on the past medical history and the past medical history score database; Obtain the patient's complete blood count (CBC) parameters and determine the corresponding CBC parameter scores based on these parameters. The sum of the products of past medical history and routine blood parameters with their corresponding weighting coefficients is calculated and recorded as the blockage risk score. The past medical history includes: history of diabetes, history of hypertension, and history of bypass graft thrombosis; The blood routine data include: whole blood viscosity, fibrinogen, and hematocrit.

4. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 3, characterized in that, The medical history scoring database includes different scores for varying degrees or durations of diabetes, hypertension, and a history of bypass graft thrombosis. The medical history scoring database has corresponding scores based on the duration of diabetes, with higher scores for longer durations. The medical history scoring database also has corresponding scores based on the systolic blood pressure of hypertension, with higher scores for higher systolic blood pressure. Furthermore, the medical history scoring database has different scores based on whether there is a history of bypass graft thrombosis; a score of zero is given for cases without a history of bypass graft thrombosis.

5. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 4, characterized in that, The initial anastomosis angle between the bypass graft and the target vessel is determined based on the occlusion risk score, wherein: Obtain surgical data from bypass surgeries that did not experience blockage within a preset period from historical surgical data; Obtain the anastomosis angle from the surgical data and calculate the corresponding blockage risk score. Establish the anastomosis angle range and the blockage risk score range respectively, and establish the mapping relationship between the blockage score and the anastomosis angle. The initial alignment angle is determined based on the mapping relationship and the calculated congestion risk score.

6. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 1, characterized in that, The step of determining the fluctuation range of the anastomosis angle between the bypass vessel and the target vessel throughout the entire cardiac cycle based on the dynamic three-dimensional model, the initial anastomosis angle, and the candidate region of the anastomosis point between the bypass vessel and the target vessel includes: Obtain the elastic modulus E of the bridging vessel; Two points are randomly selected within the candidate region as the anastomosis points of the graft vessel outlet and inlet. The distance between the anastomosis points of the graft vessel outlet and inlet during end-systole is defined as the systolic distance, and the distance between the anastomosis points of the graft vessel outlet and inlet during end-diastole is defined as the diastolic distance. The length of the bypass vessel is determined based on the contraction interval and the diastolic interval; Starting from the end of the heart's systole, the first anastomosis angle fluctuation range is calculated based on the systolic interval, diastolic interval, length of the bypass vessel, and elastic modulus E of the bypass vessel; starting from the end of the heart's diastole, the second anastomosis angle fluctuation range is calculated based on the systolic interval, diastolic interval, length of the bypass vessel, and elastic modulus E of the bypass vessel. Take the union of the first and second coincidence angle fluctuation ranges and denote it as the fluctuation range of the coincidence angle.

7. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 6, characterized in that, The blood flow model is constructed based on fluid dynamics, using the target blood vessel diameter and the bridge blood vessel diameter as the geometric basis. If the blood routine data and the anastomosis angle are input, the eddy current intensity value at the anastomosis angle will be output.

8. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 7, characterized in that, The step of determining whether the matching angle meets the requirements based on the range of variation of the eddy current intensity value includes: In response to the intensity threshold being within the range of eddy current intensity values, it is determined that the matching angle does not meet the requirements. The matching angle is then corrected based on the maximum value within the range of eddy current intensity values. The difference between the maximum value within the range of eddy current intensity values ​​and the intensity threshold is recorded as the intensity difference. The correction magnitude is positively correlated with the intensity difference; the larger the intensity difference, the larger the correction magnitude. If the intensity threshold is outside the range of variation of the eddy current intensity value, it is determined that the matching angle meets the requirements.

9. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 1, characterized in that, The determination of the anastomosis site of the bypass vessel includes: In the dynamic three-dimensional model, the narrow segment of the target blood vessel is located, and the blood vessels within a preset distance from the distal end of the narrow segment are selected as candidate anastomosis points at the exit end of the bypass vessel. The candidate region for anastomosis at the inlet end is determined based on the type of bypass vessel; within the candidate region, points that meet the corrected anastomosis angle or are deemed to meet the requirements are selected and used as the inlet and outlet anastomosis points of the bypass vessel. The length of the bypass vessel is determined based on the dynamic three-dimensional model, the inlet anastomosis point and the outlet anastomosis point of the bypass vessel, and the displacement difference of the heart during end-diastole and systole.

10. The minimally invasive bypass surgery planning method based on multimodal image fusion according to claim 9, characterized in that, The surgical planning scheme includes: The three-dimensional coordinates of the inlet and outlet anastomoses of the outgoing graft vessel; The location and number of surgical incisions are determined based on the operating radius of minimally invasive instruments.

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