A method and device for determining coronary blood flow reserve fraction

Abstract

The embodiments of the present application disclose a method, an apparatus and a computer-readable storage medium for determining a coronary artery blood flow reserve fraction. The method comprises: acquiring image information of the coronary artery, acquiring characteristic parameters of coronary artery lesions from the image information of the coronary artery; determining correction parameters of the coronary artery lesions based on the characteristic parameters of the coronary artery lesions; correcting a flow control equation based on the correction parameters to obtain a corrected flow control equation; solving the corrected flow control equation to obtain a blood pressure value inside the coronary artery; and obtaining a blood flow reserve fraction FFR of the coronary artery based on the blood pressure value inside the coronary artery and a first blood pressure value.

Description

Technical Field

[0001] The present application relates to biomedical engineering technology, and in particular to a method, device and computer storable medium for determining coronary blood flow reserve fraction. Background Art

[0002] According to the data of the 2018 "China Cardiovascular Disease Report", there are 290 million cardiovascular disease patients in my country, including 13 million coronary heart disease patients, and the incidence rate is still on the rise. The medical expenses of coronary heart disease patients have become a major public health burden in my country. Coronary heart disease mainly refers to the narrowing or obstruction of the vascular lumen caused by coronary atherosclerosis, which leads to myocardial ischemia, hypoxia, and necrosis, and then causes angina pectoris, myocardial infarction and even sudden death. It is a high-incidence disease that plagues people all over the world. Therefore, how to effectively and accurately assess coronary ischemia and intervene in effective treatment in a timely manner has been a long-term research focus of the medical community.

[0003] At present, coronary artery computer tomography angiography (CTA) and invasive coronary angiography (ICA) are routine methods for diagnosing coronary heart disease, but myocardial ischemia is a physiological function state that is closely related to vascular stenosis, myocardial supply size, microcirculatory status, etc. Vascular stenosis alone cannot fully reflect the state of myocardial ischemia. Studies have shown that judging myocardial ischemia based on coronary artery stenosis has 28% false positives and 13% false negatives in the diagnosis of coronary heart disease.

[0004] Nowadays, the "gold standard" for clinically evaluating myocardial ischemia caused by vascular stenosis is the coronary artery blood flow reserve fraction (FFR). FFR refers to the ratio of the maximum blood flow that can be obtained by the blood vessels when there are stenotic lesions under the state of maximum congestion of the coronary microcirculation to the maximum blood flow that can be obtained by the blood vessels under normal conditions. The resistance under the state of congestion of the coronary microcirculation is negligible. According to the theory of fluid mechanics, the blood flow of myocardial tissue is proportional to the perfusion pressure. Therefore, FFR can be calculated by the ratio of the pressure at the distal downstream end of the stenotic lesion to the pressure upstream of the stenosis. However, the FFR examination requires the use of expensive surgical consumables pressure guide wires, and the operation time is long. There is a risk of damaging the diseased blood vessels during the operation. The microcirculation dilation drugs that need to be injected also have certain side effects. Many reasons limit its clinical application.

[0005] So coronary artery FFR CTA Technology came into being, coronary artery FFR CTAThe technology is based on the patient's CT angiography images to achieve three-dimensional model reconstruction of the coronary artery, and then uses numerical simulation methods to achieve fluid mechanics simulation of the coronary artery. Through simulation calculation, the proximal and distal pressure values ​​of the coronary artery lesions are obtained, thereby non-invasively obtaining the FFR value of the patient's coronary artery. CTA In the technology, the quality of coronary artery three-dimensional model reconstruction and the setting of fluid dynamics calculation boundary conditions are two main factors affecting the accuracy of calculation results.

[0006] In the interventional treatment of coronary heart disease, diffuse lesions account for about 20%, and there is a trend of increasing year by year. Diffuse lesions are usually more complex and have their own unique characteristics: they are often accompanied by angulation, calcification, distortion, eccentricity, irregular flow path, etc. Calcification, eccentricity and irregular flow path are difficult to reproduce through three-dimensional reconstruction. The lack of this information will limit the applicability of general computational fluid dynamics (CFD) methods. At the same time, these complex characteristics also increase the difficulty of clinical diagnosis. Therefore, more conservative interventional treatment methods are often used directly in clinical practice. The reason is that there is currently no efficient and targeted diagnostic method for diffuse lesions. Summary of the invention

[0007] To solve the above technical problems, the embodiments of the present application hope to provide a method, device and computer-readable storage medium for determining the coronary blood flow reserve fraction, which can especially perform personalized and accurate FFR calculation for complex lesions such as diffuse lesions.

[0008] The technical solution of this application is implemented as follows:

[0009] In a first aspect, a method for determining coronary flow reserve fraction is provided, the method comprising:

[0010] Acquiring image information of the coronary arteries, and acquiring characteristic parameters of coronary artery lesions from the image information of the coronary arteries;

[0011] Determining correction parameters of the coronary artery lesions based on the characteristic parameters of the coronary artery lesions;

[0012] Correcting the flow control equation based on the correction parameter to obtain a corrected flow control equation;

[0013] Solving the modified flow control equation to obtain the blood pressure value inside the coronary artery;

[0014] Based on the blood pressure value inside the coronary artery and the first blood pressure value, a blood flow reserve fraction FFR of the coronary artery is obtained.

[0015] In a second aspect, an embodiment of the present application further provides a device for determining a coronary blood flow reserve fraction, the device comprising:

[0016] An image processing module, used for acquiring image information of the coronary arteries, and acquiring characteristic parameters of coronary artery lesions from the image information of the coronary arteries;

[0017] A correction module, used to determine correction parameters of the coronary artery lesions based on the characteristic parameters of the coronary artery lesions; and to correct the flow control equation based on the correction parameters to obtain a corrected flow control equation;

[0018] The calculation module is used to solve the modified flow control equation to obtain the blood pressure value inside the coronary artery; based on the blood pressure value inside the coronary artery and the first blood pressure value, obtain the blood flow reserve fraction FFR of the coronary artery.

[0019] In a third aspect, an embodiment of the present application further provides another device for determining a coronary blood flow reserve fraction, the device comprising: a processor and a memory configured to store a computer program that can be run on the processor,

[0020] Wherein, the processor is configured to execute the steps of any of the aforementioned methods when running the computer program.

[0021] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, wherein the computer program implements the steps of the aforementioned method when executed by a processor.

[0022] By adopting the above technical solution, after coronary artery lesions are diagnosed, there is no need for invasive surgical examination. Instead, the characteristic parameters of the individual's coronary artery lesions are used to obtain personalized correction parameters, and then the correction parameters are used to correct the flow control equations, so that the influence of the complexity of coronary artery lesions on blood flow can be reflected in the fluid dynamics calculation, thereby compensating for the inevitable information loss when calculating the FFR of complex coronary artery lesions using general CFD methods and reducing the calculation error of FFR. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the method for determining the coronary blood flow reserve fraction in the embodiment of the present application Figure 1 ;

[0024] Figure 2 This is a schematic diagram of a CTA image of a heart in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of a three-dimensional image of a heart image in an embodiment of the present application;

[0026] Figure 4A schematic diagram of a three-dimensional image of the aorta and coronary arteries in an embodiment of the present application;

[0027] Figure 5 Schematic diagram of a CPR image of a coronary artery in an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of a grid image of the left coronary artery in an embodiment of the present application;

[0029] Figure 7 Based on the general FFR in the embodiment of this application CTA Schematic diagram of FFR distribution in the left coronary artery obtained by the method;

[0030] Figure 8 A schematic diagram of the modified FFR distribution in the left coronary artery in the embodiment of the present application;

[0031] Fig. 9 The process diagram of the FFR determination method in the embodiment of the present application is as follows: Figure 2 ;

[0032] Fig.10 The schematic diagram of the structure of the device for determining the coronary blood flow reserve fraction in the embodiment of the present application is as follows Figure 1 ;

[0033] Fig.11 The schematic diagram of the structure of the device for determining the coronary blood flow reserve fraction in the embodiment of the present application is as follows Figure 2 . DETAILED DESCRIPTION

[0034] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0035] Embodiment 1

[0036] like Figure 1 As shown, the method for determining the coronary blood flow reserve fraction specifically includes:

[0037] Step 101: obtaining image information of the coronary arteries, and obtaining characteristic parameters of coronary artery lesions from the image information of the coronary arteries;

[0038] Step 102: determining correction parameters of the coronary artery lesions based on characteristic parameters of the coronary artery lesions;

[0039] Step 103: Correcting the flow control equation based on the correction parameter to obtain a corrected flow control equation;

[0040] Step 104: Solve the modified flow control equation to obtain the blood pressure value inside the coronary artery;

[0041] Step 105: Obtaining the fractional flow reserve FFR of the coronary artery based on the blood pressure value inside the coronary artery and the first blood pressure value.

[0042] Here, the execution body of steps 101 to 105 may be a processor of the device for determining the coronary blood flow reserve fraction.

[0043] Here, FFR refers to the ratio of the maximum blood flow that can be obtained by the blood vessel when there is a stenotic lesion under the state of maximum coronary hyperemia to the maximum blood flow that can be obtained by the blood vessel under normal conditions. In clinical medical applications, it can be equivalent to the mean pressure (P) in the distal coronary artery of the stenosis under the state of maximum hyperemia. d ) and the mean aortic pressure at the coronary artery ostium (P a ) ratio.

[0044] Here, the image information of the coronary artery is a two-dimensional image, a three-dimensional image or other forms of images that conform to the Digital Imaging and Communications in Medicine (DICOM) specification and can represent the characteristics of coronary artery lesions, such as a CTA image.

[0045] In practical applications, step 101 may also include: obtaining a three-dimensional image of the coronary artery according to the image information of the coronary artery; the three-dimensional image of the coronary artery may be used to further generate a CFD model for calculation. Here, the CFD model is used to solve the modified flow control equation, and the CFD model may be a three-dimensional model, a dimensionality reduction model (such as a one-dimensional or POD dimensionality reduction model, etc.), and an approximate simplified model.

[0046] Here, the flow control equation may be the Navier-Stokes equation (NS equation) in conventional computational fluid dynamics calculations, or may be a simplified or deformed fluid flow control equation used in calculating a dimensionality reduction model or an approximate simplified model.

[0047] Here, the method of acquiring image information of the coronary arteries may specifically include: acquiring image information of the heart, and acquiring image information of the coronary arteries from the image information of the heart.

[0048] Exemplarily, computed tomography angiography (CTA) image information of the heart is acquired; a three-dimensional image of the heart is reconstructed based on the CTA image information of the heart to obtain a three-dimensional image of the heart; a three-dimensional image of the myocardium and a three-dimensional image of the coronary arteries are separated from the three-dimensional image of the heart; based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary arteries, the outlet impedance of the coronary arteries is calculated; wherein the outlet impedance of the coronary arteries is used to solve a modified flow control equation.

[0049] CTA images of the heart Figure 2 As shown, a three-dimensional image of the heart is reconstructed based on the CTA image information of the heart, which is to process the second-order grayscale image data of the CTA image of the heart using a three-dimensional image reconstruction algorithm to obtain the three-dimensional structure data of the heart and display it as a realistic three-dimensional image, such as Figure 3 shown.

[0050] The three-dimensional image of the myocardium and the three-dimensional image of the coronary artery are separated from the three-dimensional image of the heart. The three-dimensional image data corresponding to each part of the myocardium, the aorta, and each branch of the coronary artery are separated by using an image recognition method on the reconstructed three-dimensional image of the heart. Figure 4 As shown, this is the three-dimensional image data of the coronary arteries obtained through image recognition, cutting, and region growing-based methods, in which the thicker blood vessels in the upper part are the aorta, and the thinner branch blood vessels in the lower part are the coronary arteries.

[0051] Accordingly, step 101 may specifically include: acquiring curved surface reconstructed CPR image information of the coronary arteries from the CTA image information of the heart; and acquiring characteristic parameters of coronary artery lesions from the CPR image information of the coronary arteries.

[0052] The CPR image information of the coronary artery is obtained from the CTA image information of the heart. Based on the second-order grayscale image data of CTA, the projection images of different angles of view corresponding to the coronary artery are obtained by using the surface reconstruction algorithm. Figure 5 As shown, Figure 5 Also shown are the coordinates, index information, and pixels [R, G, B] of the two points, where the first point's [X, Y] is [317, 105], the index is 1455, and [R, G, B] is [0.502, 0.502, 0.502]; the second point's [X, Y] is [254, 271], the index is 1449, and [R, G, B] is [0.498, 0.498, 0.498].

[0053] The characteristic parameters of coronary artery lesions are obtained from the CPR image information of the coronary arteries. In order to quantify the CPR image information of the coronary arteries, a series of parameters such as lesion length, blood vessel diameter, plaque cross-sectional area, etc. are measured by software and converted and calculated to obtain the corresponding characteristic parameters.

[0054] Here, the outlet impedance of the coronary arteries is calculated based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary arteries, including: calculating the total blood flow of the coronary arteries based on the three-dimensional image of the myocardium; calculating the blood flow of at least one branch of the coronary arteries based on the three-dimensional image of the coronary arteries and the total blood flow of the coronary arteries; calculating the outlet impedance of at least one branch of the coronary artery based on the blood flow of at least one branch of the coronary artery and a third blood pressure value.

[0055] Exemplarily, the total blood flow in the coronary arteries is calculated based on the three-dimensional image of the myocardium, including: determining the myocardial volume of the left ventricle based on the three-dimensional image of the myocardium; obtaining the myocardial mass of the left ventricle based on the myocardial volume and myocardial density of the left ventricle; and obtaining the total blood flow in the coronary arteries based on the myocardial mass of the left ventricle and the blood flow coefficient.

[0056] The blood flow of at least one branch of the coronary artery is calculated based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery, including: obtaining entrance information of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery; and allocating the total blood flow of the coronary artery based on the entrance information of at least one branch of the coronary artery to obtain the blood flow entering at least one branch of the coronary artery.

[0057] In practical applications, step 102 may specifically include: determining correction parameters of coronary artery lesions based on characteristic parameters of coronary artery lesions and at least one constant. Exemplarily, the characteristic parameters of coronary artery lesions include at least: coronary artery diameter stenosis rate, lesion length, minimum diameter of coronary artery lesions, and volume loss rate.

[0058] In practical applications, step 103 may specifically include: obtaining a source term of the flow control equation based on the correction parameter and the hemodynamic viscosity of the coronary artery; and adding the source term to the flow control equation to obtain a corrected flow control equation.

[0059] Blood is generally considered to be an incompressible fluid in medicine, so its flow control equation (here is the NS equation) can be expressed as:

[0060]

[0061] in is the blood flow velocity, t is time, ▽ is divergence, ρ is blood density, p is pressure, μ is blood dynamic viscosity, is the kinematic viscosity, S i is the source term, S i It can be regarded as an additional constraint when solving the flow control equation.

[0062] For example, when a coronary artery has a lesion, such as a diffuse lesion, some features of the diffuse lesion are difficult to reproduce through the three-dimensional reconstruction of the coronary artery. In order to compensate for the lack of these features that affect FFR, an additional source term is introduced into the flow control equation as a correction and added to the CFD calculation:

[0063]

[0064] Where v is the blood flow velocity, and C1 and C2 are constants.

[0065] In vascular laminar flow, the constant C2 in the above formula can be regarded as 0, so the correction model (which can be understood as the source term) obtained based on the correction parameters can be simplified as follows:

[0066]

[0067] Therefore, in CFD calculation, the pressure loss components of blood flow in each direction are:

[0068]

[0069]

[0070]

[0071] Among them, v j are the velocity components in the x, y, and z directions, Δn x , Δn y and Δn z is the length of the diffuse lesion in the x, y, and z directions, and the relationship between the correction parameter C1 and the characteristic parameter of the diffuse lesion is:

[0072] C1=A(DS a ·L b ·MLD c ·VL d ) e +B(DS a ·L b ·MLD c ·VL d )+C

[0073] Among them, A, B, C and a, b, c, d, e are constants obtained by regression through mathematical methods, that is, at least one constant in the embodiment of the present application, DS is the coronary artery diameter stenosis rate, L is the diffuse lesion length, MLD is the minimum diameter of the coronary artery lesion, and VL is the volume loss rate. Here, the corrected model is obtained by correcting the parameter C1, and the corrected model is added to the flow control equation as a source term.

[0074] Here, the flow control equations may be the Navier-Stokes equations (NS equations) in conventional computational fluid dynamics calculations, or simplified or deformed fluid flow control equations used in calculating dimensionality reduction models or approximate simplified models. When the modified model is added as a source term to these flow control equations, its expression may be slightly different depending on the expression of the specific control equations.

[0075] Here, the diameter stenosis rate, length, minimum diameter, and volume loss rate of diffuse lesions are effective characteristic parameters screened out by statistical methods, which are used to comprehensively characterize the severity of diffuse lesions. According to these characteristic parameters, personalized correction parameters can be obtained, and then the correction parameters can be used to obtain a correction model. The correction model can be used to reflect the impact of the complexity of diffuse lesions on blood flow in fluid mechanics calculations.

[0076] In practical applications, step 104 may specifically include: dividing the three-dimensional image of the coronary artery into regions to obtain grid data of the coronary artery; setting boundary conditions using the outlet impedance of the coronary artery and the second blood pressure value; solving the modified flow control equation based on the grid data and boundary conditions of the coronary artery to obtain the blood pressure value inside the coronary artery. Here, the second blood pressure value may be the same as the first blood pressure value, for example, the first blood pressure value and the second blood pressure value are both average blood pressure values ​​at the entrance of the coronary artery.

[0077] That is to say, a CFD model that can be used for calculation is generated at least based on the grid data and boundary conditions, and the modified flow control equation is solved on the CFD model. Here, the CFD model can be a three-dimensional model, a dimensionality reduction model (such as a one-dimensional or POD dimensionality reduction model, etc.) and an approximate simplified model. For example, when the grid data is three-dimensional, a corresponding three-dimensional CFD model is established, and the modified flow control equation is solved on the three-dimensional CFD model; when a dimensionality reduction model such as a one-dimensional model is used, a corresponding one-dimensional CFD model is established, and the modified flow control equation is solved on the one-dimensional CFD model. Which model is used for solving depends on the requirements of the actual situation for CFD calculations.

[0078] Exemplarily, the three-dimensional image of the coronary artery is regionally discretized to obtain grid data of the coronary artery, which is used to solve the flow control equation on each grid using a numerical method, and finally obtain the blood flow field information of each grid area of ​​the coronary artery. Here, the blood flow field information at least includes the blood pressure value of each grid area inside the coronary artery.

[0079] Due to the complexity of the coronary artery structure, tetrahedral meshes are usually used, and prismatic meshes are used for the boundary layer. After meshing, the three-dimensional image of the left coronary artery is as follows Figure 6 shown.

[0080] Here, the second blood pressure value is the mean arterial blood pressure at the coronary artery inlet, which is used as the boundary condition of the coronary artery inlet. The impedance of each coronary artery outlet R i To serve as the outlet boundary condition, the diffuse lesion correction model is added as a source term into the flow control equation:

[0081]

[0082]

[0083] By solving the flow control equations using numerical methods, we can obtain the flow field parameter information at various locations in the coronary artery. Here we are concerned with the blood pressure value P at various locations in the coronary artery. CAi .

[0084] In practical applications, the FFR value is approximately equal to the distal pressure P of the coronary artery stenosis. d Proximal coronary artery pressure P a (i.e. the first blood pressure value), therefore, the FFR value of the coronary artery is:

[0085]

[0086] When P CAi Take it far from the lesion, which is equivalent to P d , the FFR value obtained at this time is the FFR value in the general medical sense. CAi The blood pressure value inside the coronary artery is taken at a position 2-3 cm away from the lesion.

[0087] Due to the presence of complex diffuse lesions in the coronary arteries, general FFR is used CTA The grayscale image of the calculated left coronary artery FFR value is shown in Figure 2. Figure 7 As shown in Figure 2, the grayscale image of the left coronary artery FFR value obtained by adding the diffuse lesion correction model is shown in Figure 2. Figure 8 As shown, Figure 7 and Figure 8 The left side of the middle is a scale for determining the FFR value. The depth of color at different positions of the left coronary artery represents the size of the FFR value. The darker the color, the smaller the FFR value and the more serious the lesion damage; the lighter the color, the larger the FFR value and the less serious the lesion damage. The method for determining FFR provided in the embodiment of the present application can obtain personalized correction parameters based on the specific characteristic parameters of coronary artery lesions to correct the flow control equation, thereby improving the calculation accuracy of the blood flow field, reducing errors caused by individual differences and the complexity of diffuse lesions, and further improving the calculation accuracy of FFR. Comparison Figure 7 and Figure 8It can be seen that the FFR value obtained by using the diffuse lesion correction model is smaller than that obtained without the diffuse lesion correction model, and is closer to the true value. The introduction of the diffuse lesion correction model can more accurately obtain the FFR value of the coronary artery with diffuse lesions, thereby providing powerful assistance for clinical diagnosis.

[0088] By adopting the above technical solution, after coronary artery lesions are diagnosed, there is no need for invasive surgical examination. Instead, the characteristic parameters of the individual's coronary artery lesions are used to obtain personalized correction parameters, and then the correction parameters are used to correct the flow control equations, so that the influence of the complexity of coronary artery lesions on blood flow can be reflected in the fluid dynamics calculation, thereby compensating for the inevitable information loss when calculating the FFR of complex coronary artery lesions using general CFD methods and reducing the calculation error of FFR.

[0089] Embodiment 2

[0090] In order to further embody the technical solution of the present application, further examples are given based on the first embodiment of the present application. Fig. 9 As shown, the method for determining the coronary blood flow reserve fraction specifically includes:

[0091] Step 901: Acquire cardiac computed tomography angiography (CTA) image information;

[0092] Step 902: reconstructing a three-dimensional image of the heart based on the CTA image information of the heart to obtain a three-dimensional image of the heart; and separating a three-dimensional image of the myocardium and a three-dimensional image of the coronary arteries from the three-dimensional image of the heart;

[0093] Specifically, the second-order grayscale image data of the CTA image of the heart is processed using a three-dimensional image reconstruction algorithm to obtain the three-dimensional structure data of the heart and display it as a realistic three-dimensional image, such as Figure 4 As shown; the three-dimensional image data corresponding to each part of the myocardium, the aorta, and each branch of the coronary artery are separated from the three-dimensional image of the heart by an image recognition method.

[0094] Step 903: Calculating the exit impedance of the coronary arteries based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary arteries;

[0095] Specifically, based on the three-dimensional image of the myocardium, the total blood flow of the coronary artery is calculated; based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery, the blood flow of at least one branch of the coronary artery is calculated; based on the blood flow of at least one branch of the coronary artery and the third blood pressure value, the outlet impedance of at least one branch of the coronary artery is calculated. Here, the third blood pressure value is the average blood pressure value at the coronary artery outlet when it is assumed that there is no lesion in the coronary artery.

[0096] Among them, the myocardial volume of the left ventricle is determined based on the three-dimensional image of the myocardium; the myocardial mass of the left ventricle is obtained based on the myocardial volume and myocardial density of the left ventricle; and the total blood flow of the coronary artery is obtained based on the myocardial mass of the left ventricle and the blood flow coefficient.

[0097] Calculating the blood flow of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery includes: obtaining the entrance information of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery; allocating the total blood flow of the coronary artery based on the entrance information of at least one branch of the coronary artery to obtain the blood flow entering at least one branch of the coronary artery. Here, the branch entrance information may be the entrance diameter of the branch, and the entrance diameter of each branch of the coronary artery is specifically defined by the hydraulic diameter.

[0098] Specifically, the left ventricular myocardial volume V can be calculated based on the three-dimensional image data of the myocardium, and then the left ventricular myocardial average density ρ can be taken to calculate the left ventricular myocardial mass according to the formula m=ρV; and the relationship between the total blood flow entering the coronary artery and the myocardial mass is:

[0099] Q=Q0m 3 / 4

[0100] Among them, Q is the total blood flow entering the coronary artery, and Q0=5.4mL / g·min is the blood flow coefficient.

[0101] According to the three-dimensional image of the coronary artery, the entrance information of each branch of the coronary artery is calculated, and the blood flow entering each branch of the coronary artery is distributed according to the entrance information of each branch.

[0102] First, the flow of the left and right coronary arteries is allocated according to the empirical ratio based on the dominant type of the individual coronary artery. For example, when the coronary artery is left dominant, the empirical ratio of the flow of the left and right coronary arteries is 7:3, when it is right dominant, the empirical ratio of the flow of the left and right coronary arteries is 3:7, and when it is balanced, the empirical ratio of the flow of the left and right coronary arteries is 5:5.

[0103] Then, the blood flow into each branch of the coronary artery is calculated step by step according to the ratio of the entrance diameters of each branch of the coronary artery. For example, the ratio of the entrance diameters of the left coronary artery and the right coronary artery in the first level of the coronary artery is 7:3, and the ratio of the entrance diameters of the left anterior descending branch and the left circumflex branch in the second level of the left coronary artery is 4:6.

[0104] It should be noted that since the cross section of the coronary artery is not strictly circular, in practical applications, the cross-sectional area S and the circumference C are mainly obtained based on the three-dimensional image data of the coronary artery, and the hydraulic diameter D = 4S / C is used to define the inlet diameter of the coronary artery;

[0105] Since the blood flow of each branch is proportional to the cube of the diameter of the blood vessel entrance, the blood flow entering each branch of the coronary artery is distributed according to the proportion of the diameter of each branch entrance. Here, the descending branch and the circumflex branch are taken as examples, and the blood flow at the entrance of the left coronary artery is set to Q L The diameter of the inlet of the anterior descending branch is D LAD The diameter of the cyclotron inlet is D LCX , then the blood flow into the left anterior descending branch is Q LAD for:

[0106] Theorem of representation

[0107] Correspondingly, the blood flow into the circumflex artery is Q LCX for:

[0108] Q LCX =Q L -Q LAD

[0109] The other levels are also distributed step by step in this way until all branch flows are obtained. Here, LAD (left anterior descending artery) refers to the left anterior descending artery, and LCX (left circumflex artery) refers to the left circumflex artery.

[0110] In one embodiment, based on the patient's myocardial three-dimensional image data, the left ventricular myocardial volume V=165.25 mL is obtained, and then the empirical average density of the left ventricular myocardium ρ=1050 kg / m 3 , the calculated left ventricular myocardial mass is m=ρV=173.51g.

[0111] The total blood flow of the corresponding coronary artery is:

[0112] Q=Q0m 3 / 4 =5.4×173.51 0.75 =4.30×10 -6 m 3 / s

[0113] When the coronary artery is determined to be left dominant based on the three-dimensional image data of the coronary artery, 70% is taken as the inlet flow rate of the left coronary artery and 30% is taken as the inlet flow rate of the right coronary artery according to experience.

[0114] Among them, the flow rate at the inlet of the left coronary artery is: Q L =Q×70%=3.01×10 -6 m 3 / s;

[0115] The flow rate at the right coronary artery inlet is: Q R =Q×30%=1.29×10-6 m 3 / s.

[0116] When the coronary artery lesion occurs in the left coronary artery, according to the three-dimensional image data of the left coronary artery, the hydraulic diameter of the anterior descending branch entrance is measured to be 5.393mm, and the hydraulic diameter of the circumflex branch entrance is 5.729mm. Then, the blood flow entering the anterior descending branch is:

[0117]

[0118] The blood flow into the circumflex artery is:

[0119] Q LCX =Q L -Q LAD =1.64×10 -6 m 3 / s.

[0120] The traffic distribution of other secondary branches is similar.

[0121] Furthermore, the impedance of each coronary artery outlet is calculated based on the blood flow of each branch of the coronary artery and the third blood pressure value. Here, the third blood pressure value is the average blood pressure value at the coronary artery outlet when it is assumed that there is no lesion in the coronary artery.

[0122] The formula for calculating the coronary artery branch outlet impedance is: P3 = Q OUTi ×R i , here, R i is the outlet impedance of the i-th branch, Q OUTi is the outlet blood flow of the i-th branch, and P3 is the third blood pressure value. Therefore, according to the outlet blood flow of each branch, the outlet impedance R of each branch is determined. i =P3 / Q OUTi .

[0123] Step 904: obtaining curved surface reconstructed CPR image information of the coronary artery from the CTA image information of the heart; obtaining characteristic parameters of the coronary artery lesions from the CPR image information of the coronary artery;

[0124] Specifically, the CPR image information of the coronary artery is quantified, and a series of parameters such as lesion length, blood vessel diameter, plaque cross-sectional area, etc. are measured by software, and the corresponding characteristic parameters are converted and calculated.

[0125] The CTA image of the heart in the embodiment of the present application is as follows Figure 2 As shown in FIG. 1 , the surface reconstruction CPR image information of the coronary artery is obtained from the CTA image information of the heart. Based on the second-order grayscale image data of CTA, the projection images of different viewing angles of the coronary artery are obtained by using the surface reconstruction algorithm. Figure 3 shown.

[0126] Step 905: obtaining a source term of the flow control equation based on the correction parameter and the hemodynamic viscosity of the coronary artery; adding the source term to the flow control equation to obtain a corrected flow control equation;

[0127] Blood is generally considered to be an incompressible fluid in medicine, so its flow control equation can be expressed as:

[0128]

[0129] in is the blood flow velocity, t is time, ▽ is divergence, ρ is blood density, p is pressure, μ is blood dynamic viscosity, is the kinematic viscosity, S i is the source term, S i It can be regarded as a constraint condition of the flow control equation.

[0130] For example, when a coronary artery has a lesion, such as a diffuse lesion, some features of the diffuse lesion are difficult to reproduce through the three-dimensional reconstruction of the coronary artery. In order to compensate for the lack of these features that affect FFR, an additional source term is introduced into the flow control equation as a correction and added to the CFD calculation:

[0131]

[0132] Where v is the blood flow velocity, and C1 and C2 are constants.

[0133] In vascular laminar flow, the constant C2 in the above formula can be regarded as 0, so the correction model (which can be understood as the source term) obtained based on the correction parameters can be simplified as follows:

[0134]

[0135] Therefore, in CFD calculation, the pressure loss of blood flow in each direction is decomposed into:

[0136]

[0137]

[0138]

[0139] Among them, v j are the velocity components in the x, y, and z directions, Δn x , Δn y and Δn zis the length of the diffuse lesion in the x, y, and z directions, and the relationship between the correction parameter C1 and the characteristic parameter of the diffuse lesion is:

[0140] C1=A(DS a ·L b ·MLD c ·VL d ) e +B(DS a ·L b ·MLD c ·VL d )+C

[0141] Among them, A, B, C and a, b, c, d, e are constants obtained by mathematical regression, DS is the coronary artery diameter stenosis rate, L is the diffuse lesion length, MLD is the minimum diameter of coronary artery lesions, and VL is the volume loss rate. Here, the corrected model is obtained by correcting the parameter C1, and the corrected model is added to the source term of the flow control equation.

[0142] Here, the flow control equations may be the Navier-Stokes equations (NS equations) in conventional computational fluid dynamics calculations, or simplified or deformed fluid flow control equations used in calculating dimensionality reduction models or approximate simplified models. When the modified model is added as a source term to these flow control equations, its expression may be slightly different depending on the expression of the specific control equations.

[0143] Exemplarily, based on the extracted diffuse lesion characteristic parameters, the correction parameters can be calculated as:

[0144] C1=232133×(DS·L·MLD 1.8 ·VL) 2 -3×10 6 ×(DS·L·MLD 1.8 ·VL)+2×10 7 =2.98×10 7

[0145] Then the modified model is added as a source term of the flow control equation to obtain the modified flow control equation, and the modified flow control equation is solved.

[0146] Step 906: Generate a CFD model that can be used for calculation based on the mesh data and boundary conditions of the coronary artery, solve the modified flow control equation on the CFD model, and obtain the blood pressure value inside the coronary artery;

[0147] Here, the CFD model can be a three-dimensional model, a dimensionality reduction model (such as a one-dimensional or POD dimensionality reduction model, etc.) and an approximate simplified model. For example, when the grid data is three-dimensional, a corresponding three-dimensional CFD model is established, and the modified flow control equation is solved in the three-dimensional CFD model; when a dimensionality reduction model such as a one-dimensional model is used, a corresponding one-dimensional CFD model is established, and the modified flow control equation is solved on the one-dimensional CFD model. Which model to use depends on the actual situation's requirements for CFD calculations.

[0148] Specifically, the three-dimensional image of the coronary artery is divided into regions to obtain the grid data of the coronary artery, which is further converted into a CFD model for calculation; the boundary conditions are set using the outlet impedance of the coronary artery and the second blood pressure value. Here, the second blood pressure value is the mean arterial blood pressure at the entrance of the coronary artery. It is used as the boundary condition of the entrance of the coronary artery. The flow control equations are solved by numerical methods to obtain the flow field parameter information at various locations of the coronary artery. Here, we are concerned with the blood pressure value P at various locations of the coronary artery. CAi .

[0149] Step 907: Obtaining the fractional flow reserve FFR of the coronary artery based on the blood pressure value inside the coronary artery and the first blood pressure value.

[0150] In practical applications, the FFR value is approximately equal to the distal pressure P of the coronary artery stenosis. d Proximal coronary artery pressure P a Therefore, the FFR value of the coronary artery is:

[0151]

[0152] When P CAi Take it far from the lesion, which is equivalent to P d , the FFR value obtained at this time is the FFR value in the general medical sense. CAi The blood pressure value inside the coronary artery is taken at a position 2-3 cm away from the lesion.

[0153] Here, the diameter stenosis rate, length, minimum diameter, and volume loss rate of diffuse lesions are effective characteristic parameters selected by statistical methods to comprehensively characterize the severity of diffuse lesions. According to these characteristic parameters, personalized correction parameters can be obtained, and then the correction parameters are used to obtain a correction model. The correction model can reflect the influence of the complexity of diffuse lesions on blood flow in fluid mechanics calculations. In this way, the method for determining FFR provided by the present application can make up for the inevitable information loss when using general CFD methods to calculate complex lesions such as diffuse lesions, and greatly reduce the calculation error of FFR.

[0154] Embodiment 3

[0155] Based on the same inventive concept, the present application also provides a device for determining the coronary blood flow reserve fraction. Fig.10 As shown, the device comprises:

[0156] An image processing module 1001 is used to obtain image information of the coronary arteries, and obtain characteristic parameters of coronary artery lesions from the image information of the coronary arteries;

[0157] A correction module 1002 is used to determine correction parameters of the coronary artery lesions based on the characteristic parameters of the coronary artery lesions; and to correct the flow control equation based on the correction parameters to obtain a corrected flow control equation;

[0158] The calculation module 1003 is used to solve the modified flow control equation to obtain the blood pressure value inside the coronary artery; based on the blood pressure value inside the coronary artery and the first blood pressure value, obtain the blood flow reserve fraction FFR of the coronary artery.

[0159] In some embodiments, the correction module 1002 is specifically used to determine the correction parameters of the coronary artery lesions based on the characteristic parameters of the coronary artery lesions and at least one constant. Exemplarily, the characteristic parameters at least include: coronary artery diameter stenosis rate, lesion length, minimum diameter of coronary artery lesions and volume loss rate.

[0160] In some embodiments, the correction module 1002 is specifically used to obtain the source term of the flow control equation based on the correction parameter and the hemodynamic viscosity of the coronary artery; and add the source term to the flow control equation to obtain a corrected flow control equation.

[0161] In some embodiments, the image processing module 1001 is specifically used to obtain computed tomography angiography (CTA) image information of the heart;

[0162] reconstructing a three-dimensional image of the heart based on the CTA image information of the heart to obtain a three-dimensional image of the heart;

[0163] separating a three-dimensional image of the myocardium and a three-dimensional image of the coronary arteries from the three-dimensional image of the heart;

[0164] Based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary artery, the outlet impedance of the coronary artery is calculated; wherein the outlet impedance of the coronary artery is used to solve the modified flow control equation;

[0165] Acquire curved surface reconstructed CPR image information of the coronary artery from the CTA image information of the heart;

[0166] The characteristic parameters of the coronary artery lesions are obtained from the CPR image information of the coronary arteries.

[0167] In some embodiments, the image processing module 1001 is further used to repair the inlet and outlet surfaces of the coronary arteries in a plane perpendicular to the blood flow direction as the boundaries of the corresponding coronary arteries.

[0168] In some embodiments, the calculation module 1003 is specifically used to divide the three-dimensional image of the coronary artery into regions to obtain grid data of the coronary artery;

[0169] Setting boundary conditions using the outlet impedance of the coronary artery and the second blood pressure value;

[0170] Based on the grid data and boundary conditions of the coronary artery, the modified flow control equation is solved to obtain the blood pressure value inside the coronary artery.

[0171] In some embodiments, the image processing module 1001 is specifically used to calculate the total blood flow of the coronary artery based on the three-dimensional image of the myocardium; calculate the blood flow of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery; calculate the outlet impedance of at least one branch of the coronary artery based on the blood flow of at least one branch of the coronary artery and a third blood pressure value.

[0172] In some embodiments, the image processing module 1001 is specifically used to determine the myocardial volume of the left ventricle according to the three-dimensional image of the myocardium; obtain the myocardial mass of the left ventricle according to the myocardial volume and myocardial density of the left ventricle; and obtain the total blood flow of the coronary artery based on the myocardial mass of the left ventricle and the blood flow coefficient;

[0173] The image processing module 1001 is specifically used to obtain the entrance information of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery; allocate the total blood flow of the coronary artery based on the entrance information of at least one branch of the coronary artery to obtain the blood flow entering at least one branch of the coronary artery.

[0174] In practical applications, the above-mentioned memory can be a volatile memory (volatile memory), such as a random access memory (RAM); or a non-volatile memory (non-volatile memory), such as a read-only memory (ROM), a flash memory, a hard disk (HDD, Hard Disk Drive) or a solid-state drive (SSD, Solid-State Drive); or a combination of the above types of memory, and provide instructions and data to the processor.

[0175] The processor may be at least one of an application-specific integrated circuit (ASIC), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a controller, a microcontroller, and a microprocessor. It is understandable that for different devices, the electronic device used to implement the functions of the processor may also be other, and the embodiments of the present application do not specifically limit this.

[0176] By adopting the above technical solution, after coronary artery lesions are diagnosed, there is no need for invasive surgical examination. Instead, the characteristic parameters of the individual's coronary artery lesions are used to obtain personalized correction parameters, and then the correction parameters are used to correct the flow control equations, so that the influence of the complexity of coronary artery lesions on blood flow can be reflected in the fluid dynamics calculation, thereby compensating for the inevitable information loss when calculating the FFR of complex coronary artery lesions using general CFD methods and reducing the calculation error of FFR.

[0177] Based on the hardware implementation of each unit in the above device, the embodiment of the present application also provides another device for determining the coronary blood flow reserve fraction, such as Fig.11 As shown, the apparatus 110 includes: a processor 1101 and a memory 1102 configured to store a computer program that can be run on the processor;

[0178] The processor 1101 is configured to execute the method steps in the aforementioned embodiment when running a computer program.

[0179] Of course, in practical applications, Fig.11As shown, the various components in the device 110 are coupled together via a bus system 1103. It is understood that the bus system 1103 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 1103 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Fig.11 Various buses are labeled as bus system 1103.

[0180] In practical applications, the processor may be at least one of an application-specific integrated circuit (ASIC), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a controller, a microcontroller, and a microprocessor. It is understandable that for different devices, the electronic device used to implement the functions of the processor may also be other, and the embodiments of the present application do not specifically limit this.

[0181] The above-mentioned memory can be a volatile memory (volatile memory), such as a random access memory (RAM); or a non-volatile memory (non-volatile memory), such as a read-only memory (ROM), a flash memory, a hard disk (HDD) or a solid-state drive (SSD); or a combination of the above-mentioned types of memory, and provide instructions and data to the processor.

[0182] In an exemplary embodiment, the embodiment of the present application further provides a computer-readable storage medium, such as a memory 1102 including a computer program, and the above-mentioned computer program can be executed by the processor 1101 of the device 110 to complete the aforementioned method steps.

[0183] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of hardware embodiments, software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0184] The present application is described with reference to the flowcharts and / or block diagrams of the methods, apparatuses, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0185] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the instructions in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0186] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0187] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application.

Claims

1. A method for determining coronary artery blood flow reserve fraction, characterized in that: The method comprises: Acquiring image information of the coronary arteries, and acquiring characteristic parameters of coronary artery lesions from the image information of the coronary arteries; Determining correction parameters of the coronary artery lesions for correcting the flow control equation based on the characteristic parameters of the coronary artery lesions; wherein the characteristic parameters of the coronary artery lesions include at least: coronary artery diameter stenosis rate, lesion length, minimum diameter of coronary artery lesions and volume loss rate; Obtaining a source term of the flow control equation based on the correction parameter, the hemodynamic viscosity of the coronary artery, and the blood flow velocity of the coronary artery; Adding the source term to the flow control equation to obtain a modified flow control equation; Solving the modified flow control equation to obtain the blood pressure value inside the coronary artery; Based on the blood pressure value inside the coronary artery and the first blood pressure value, the blood flow reserve fraction FFR of the coronary artery is obtained; wherein the first blood pressure value is the average blood pressure value at the entrance of the coronary artery.

2. The method according to claim 1, characterized in that: The step of determining correction parameters of the coronary artery lesions for correcting the flow control equation based on the characteristic parameters of the coronary artery lesions comprises: Based on the characteristic parameter of the coronary artery lesion and at least one constant, a correction parameter of the coronary artery lesion for correcting the flow control equation is determined.

3. The method according to claim 1, characterized in that The method further comprises: Acquire computed tomography angiography (CTA) image information of the heart; reconstructing a three-dimensional image of the heart based on the CTA image information of the heart to obtain a three-dimensional image of the heart; separating a three-dimensional image of the myocardium and a three-dimensional image of the coronary arteries from the three-dimensional image of the heart; Based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary artery, the outlet impedance of the coronary artery is calculated; wherein the outlet impedance of the coronary artery is used to solve the modified flow control equation; The step of acquiring image information of the coronary arteries and acquiring characteristic parameters of coronary artery lesions from the image information of the coronary arteries includes: Acquire curved surface reconstructed CPR image information of the coronary artery from the CTA image information of the heart; The characteristic parameters of the coronary artery lesions are obtained from the CPR image information of the coronary arteries.

4. The method according to claim 3, characterized in that The step of solving the modified flow control equation to obtain the blood pressure value inside the coronary artery includes: Dividing the three-dimensional image of the coronary artery into regions to obtain grid data of the coronary artery; The boundary condition is set by using the outlet impedance of the coronary artery and the second blood pressure value; wherein the second blood pressure value is the average blood pressure value of the inlet of the coronary artery; Based on the grid data and boundary conditions of the coronary artery, the modified flow control equation is solved to obtain the blood pressure value inside the coronary artery.

5. The method according to claim 3, characterized in that: The step of calculating the outlet impedance of the coronary artery based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary artery comprises: Calculating the total blood flow of the coronary artery based on the three-dimensional image of the myocardium; Calculating the blood flow of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery; The outlet impedance of at least one branch of the coronary artery is calculated based on the blood flow of at least one branch of the coronary artery and a third blood pressure value; wherein the third blood pressure value is an average blood pressure value at the outlet of the coronary artery when no lesions exist in the coronary artery.

6. The method according to claim 5, characterized in that The calculating the total blood flow of the coronary artery based on the three-dimensional image of the myocardium comprises: determining the myocardial volume of the left ventricle based on the three-dimensional image of the myocardium; Obtaining the myocardial mass of the left ventricle according to the myocardial volume and myocardial density of the left ventricle; Based on the myocardial mass and blood flow coefficient of the left ventricle, the total blood flow of the coronary artery is obtained; The calculating the blood flow of at least one branch of the coronary artery based on the three-dimensional image of the coronary artery and the total blood flow of the coronary artery comprises: Based on the three-dimensional image of the coronary artery, obtaining at least one branch entrance information of the coronary artery; The total blood flow of the coronary artery is distributed based on the entrance information of at least one branch of the coronary artery to obtain the blood flow entering at least one branch of the coronary artery.

7. A device for determining coronary blood flow reserve fraction, characterized in that The device comprises: An image processing module, used to obtain image information of the coronary arteries, and obtain characteristic parameters of coronary artery lesions from the image information of the coronary arteries; A correction module, for determining correction parameters of the coronary artery lesions for correcting the flow control equation based on the characteristic parameters of the coronary artery lesions; obtaining source terms of the flow control equation based on the correction parameters, the hemodynamic viscosity of the coronary arteries and the blood flow velocity of the coronary arteries; adding the source terms to the flow control equation to obtain a corrected flow control equation; wherein the characteristic parameters of the coronary artery lesions include at least: coronary artery diameter stenosis rate, lesion length, minimum diameter of coronary artery lesions and volume loss rate; A calculation module is used to solve the modified flow control equation to obtain the blood pressure value inside the coronary artery; based on the blood pressure value inside the coronary artery and a first blood pressure value, obtain the blood flow reserve fraction FFR of the coronary artery; wherein the first blood pressure value is the average blood pressure value at the entrance of the coronary artery.

8. The device according to claim 7, characterized in that The correction module is specifically used to determine the correction parameters of the coronary artery lesions for correcting the flow control equation based on the characteristic parameters of the coronary artery lesions and at least one constant.

9. The device according to claim 7, characterized in that The image processing module is specifically used to obtain computed tomography angiography (CTA) image information of the heart; reconstructing a three-dimensional image of the heart based on the CTA image information of the heart to obtain a three-dimensional image of the heart; separating a three-dimensional image of the myocardium and a three-dimensional image of the coronary arteries from the three-dimensional image of the heart; Based on the three-dimensional image of the myocardium and the three-dimensional image of the coronary artery, the outlet impedance of the coronary artery is calculated; wherein the outlet impedance of the coronary artery is used to solve the modified flow control equation; Acquire curved surface reconstructed CPR image information of the coronary artery from the CTA image information of the heart; The characteristic parameters of the coronary artery lesions are obtained from the CPR image information of the coronary arteries.

10. The device according to claim 9, characterized in that The calculation module is specifically used to divide the three-dimensional image of the coronary artery into regions to obtain grid data of the coronary artery; The boundary condition is set by using the outlet impedance of the coronary artery and the second blood pressure value; wherein the second blood pressure value is the average blood pressure value of the inlet of the coronary artery; Based on the grid data and boundary conditions of the coronary artery, the modified flow control equation is solved to obtain the blood pressure value inside the coronary artery.

11. A device for determining coronary artery blood flow reserve fraction, the device comprising: a processor and a memory configured to store a computer program capable of being executed on the processor, Wherein, the processor is configured to execute the steps of the method according to any one of claims 1 to 6 when running the computer program.

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

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