Blood vessel state parameter calculation method and device, equipment and medium

Abstract

The invention provides a blood vessel state parameter calculation method and device, equipment and a medium, and can be applied to the field of life science, the field of fluid mechanics and the field of scientific calculation. The method comprises the following steps: processing a blood vessel inlet target pressure and a preset outlet pressure based on a first type boundary condition combination to obtain blood vessel inlet speed distribution; the blood vessel inlet velocity distribution is processed based on a second type of boundary condition combination to obtain blood vessel inlet pressure, and the second type of boundary condition combination is used for restraining the blood vessel inlet velocity distribution; determining steady-state outlet pressure according to the blood vessel inlet pressure and the blood vessel outlet resistance; the steady-state outlet pressure and the initial blood vessel lumped model parameters are processed based on an air bellow model, blood vessel state parameters are obtained, the blood vessel state parameters comprise the blood vessel outlet pressure at t moments and the blood vessel lumped model parameters, and fluid simulation is conducted according to the blood vessel state parameters and the blood vessel inlet flow speed at each moment to obtain the full-moment full-field fluid state.

Description

Technical Field

[0001] The present disclosure relates to the fields of life science, fluid mechanics and scientific computing, and more specifically, to a method, device, equipment, medium and program product for calculating vascular state parameters. Background Art

[0002] Although traditional angiography can show the degree of stenosis of diseased blood vessels, it cannot make functional predictions about the disease. To solve this problem, the blood flow reserve fraction was introduced as a functional assessment tool, which has become the gold standard to help doctors distinguish whether interventional treatment is needed in the case of coronary artery stenosis. The existing detection method in hospitals requires the use of an interventional pressure guidewire to measure the pressure before and after stenosis for calculation. The accuracy of the algorithm for calculating hemodynamic parameters using fluid mechanics simulation is affected by boundary conditions. In the case of an unknown absolute value of the vascular outlet pressure, the assumption that the outlet pressure is 0 or other numerical values ​​based on statistics ignores the impact of the rear-end blood vessels on the flow field caused by individual differences, and the blood flow reserve fraction cannot be accurately calculated. Summary of the invention

[0003] In view of the above problems, the present disclosure provides a method, device, equipment, medium and program product for calculating blood vessel status parameters.

[0004] According to a first aspect of the present disclosure, a method for calculating a vascular state parameter is provided, comprising:

[0005] Based on the first type of boundary condition combination, the target pressure of the blood vessel inlet and the preset outlet pressure are processed to obtain the blood vessel inlet velocity distribution, and the first type of boundary condition combination is used to constrain the target pressure of the blood vessel inlet and the preset outlet pressure; based on the second type of boundary condition combination, the blood vessel inlet velocity distribution is processed to obtain the blood vessel inlet pressure, and the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution; according to the blood vessel inlet pressure and the blood vessel outlet resistance, the steady-state outlet pressure is determined; based on the bellows model, the steady-state outlet pressure and the initial blood vessel lumped model parameters are processed to obtain the blood vessel state parameters, wherein the blood vessel state parameters include the blood vessel outlet pressure and the blood vessel lumped model parameters at t moments.

[0006] According to an embodiment of the present disclosure, determining the steady-state outlet resistance and pressure based on the vascular inlet pressure and flow includes: comparing the difference between the vascular inlet pressure and the vascular inlet target pressure with a preset threshold to obtain a comparison result; when the comparison result indicates that the difference is less than the preset threshold, updating the target outlet resistance based on the vascular inlet pressure and the vascular outlet resistance; and obtaining the steady-state outlet pressure based on the vascular inlet flow and the outlet resistance.

[0007] According to an embodiment of the present disclosure, a target outlet resistance and pressure are obtained according to the vascular inlet pressure and flow, including: subtracting the n-1-step vascular inlet pressure from the n-th step vascular inlet pressure to obtain the vascular inlet pressure difference, wherein n>1; subtracting the n-1-step vascular outlet resistance from the n-th step vascular outlet resistance to obtain the vascular outlet resistance difference; obtaining the Jacob ratio according to the vascular inlet pressure difference and the vascular outlet resistance difference; and updating the target outlet resistance according to the Jacob ratio and the difference between the vascular inlet target pressure and the current inlet pressure.

[0008] According to an embodiment of the present disclosure, determining the steady-state outlet resistance and pressure based on the blood vessel inlet pressure and flow includes: comparing the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold to obtain a comparison result; when the comparison result indicates that the difference is greater than the preset threshold, processing the steady-state outlet pressure and the blood vessel inlet target pressure based on a first type of boundary condition combination to obtain a first blood vessel inlet velocity distribution; processing the first blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a first blood vessel inlet pressure; and determining the first steady-state outlet pressure based on the first blood vessel inlet pressure and the first blood vessel outlet resistance.

[0009] According to an embodiment of the present disclosure, based on the bellows model and the steady-state outlet pressure, the initial vascular lumped model parameters are processed to obtain the vascular state parameters, including: determining the vascular outlet pressure at t moments based on the vascular inlet flow and the initial lumped parameters; determining the target gap based on the objective function and the outlet pressure; and updating the vascular lumped model parameters and the vascular outlet pressure at t moments based on the target gap.

[0010] According to an embodiment of the present disclosure, determining the blood vessel lumped model parameters according to the target result includes:

[0011] When the target result meets the preset conditions, the initial vascular lumped model parameters are determined as the vascular lumped model parameters; when the target result does not meet the preset conditions, the vascular lumped model parameters are updated according to the initial vascular lumped model parameters and the vascular inlet flow at time t.

[0012] According to an embodiment of the present disclosure, the vascular lumped model parameters are updated according to the initial vascular lumped model parameters and the vascular inlet flow at t moments, including: determining a derivative matrix according to the initial vascular lumped model parameters and the vascular inlet flow at t moments; processing the derivative matrix based on the derivative formula to determine a sensitivity matrix; updating the initial vascular lumped model parameters according to the sensitivity matrix, and updating the vascular lumped model parameters.

[0013] A second aspect of the present disclosure provides a device for calculating a blood vessel state parameter, comprising:

[0014] a velocity distribution module, used for processing the target pressure at the blood vessel inlet and the preset outlet pressure based on a first type of boundary condition combination to obtain a blood vessel inlet velocity distribution, wherein the first type of boundary condition combination is used to constrain the target pressure at the blood vessel inlet and the preset outlet pressure;

[0015] a blood vessel inlet pressure module, used for processing the blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a blood vessel inlet pressure, wherein the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution;

[0016] A steady-state outlet pressure module, used to determine a steady-state outlet pressure according to the blood vessel inlet pressure and the blood vessel outlet resistance;

[0017] The vascular state parameter module is used to process the steady-state outlet pressure and the initial vascular lumped model parameters based on the bellows model to obtain vascular state parameters, wherein the vascular state parameters include the vascular outlet pressures and vascular lumped model parameters at t moments.

[0018] A third aspect of the present disclosure provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors execute the above method.

[0019] The fourth aspect of the present disclosure also provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, causes the processor to execute the above method.

[0020] The fifth aspect of the present disclosure also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0021] According to the embodiments of the present disclosure, the target pressure at the blood vessel inlet and the preset outlet pressure are processed based on the first type of boundary condition combination to obtain the blood vessel inlet velocity distribution, the blood vessel inlet velocity distribution is processed based on the second type of boundary condition combination to obtain the blood vessel inlet pressure, and the steady-state outlet pressure is determined according to the blood vessel inlet pressure and the blood vessel outlet resistance. By alternately using the first type of boundary condition combination and the second type of boundary condition combination, the inlet velocity shape is continuously adjusted according to the current pressure difference to improve the overall calculation accuracy. The steady-state outlet pressure and the initial blood vessel lumped model parameters are processed based on the bellows model to obtain the blood vessel state parameters, thereby improving the accuracy of the outlet pressure boundary conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above contents and other purposes, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0023] Figure 1A diagram schematically shows an application scenario of a method for calculating blood vessel state parameters according to an embodiment of the present disclosure;

[0024] Figure 2 A flowchart schematically shows a method for calculating blood vessel state parameters according to an embodiment of the present disclosure;

[0025] Figure 3 A schematic diagram schematically shows a first type of boundary condition combination and a second type of boundary condition combination used according to an embodiment of the present disclosure;

[0026] Figure 4 A flow chart schematically illustrates a steady-state outlet pressure according to an embodiment of the present disclosure;

[0027] Figure 5 Schematically shows a flow chart of a bellows model iterative algorithm according to an embodiment of the present disclosure;

[0028] Figure 6 A schematic diagram schematically shows the pressure calculation result and parameter iteration change process obtained by the bellows model iteration algorithm according to an embodiment of the present disclosure;

[0029] Figure 7 Schematically shows a flow chart of blood vessel state parameter calculation according to an embodiment of the present disclosure;

[0030] Figure 8 A flowchart schematically shows a method for calculating blood vessel state parameters according to an embodiment of the present disclosure;

[0031] Fig. 9 A block diagram schematically shows a structure of a device for calculating blood vessel state parameters according to an embodiment of the present disclosure; and

[0032] Fig.10 A block diagram of an electronic device suitable for implementing a method for calculating blood vessel state parameters according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0034] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0035] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0036] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0037] Fractional Flow Reserve (FFR) is a method for quantitatively evaluating the effect of coronary artery stenosis on blood flow imaging. It refers to the ratio of the maximum blood flow that can be obtained in the myocardial area supplied by the blood vessel to the maximum blood flow that can be obtained in the same area under normal conditions in theory when there is a stenotic lesion in the coronary artery, that is, the ratio of the mean pressure in the coronary artery distal to the stenosis (Pd) under the state of maximum myocardial congestion to the mean pressure in the aorta at the coronary artery orifice (Pa). Although traditional angiography can show the degree of stenosis of the diseased blood vessels, it cannot make functional predictions about the disease. To solve this problem, the fractional flow reserve was introduced as a functional assessment tool, and it has become the gold standard for helping doctors distinguish whether interventional treatment is needed in terms of coronary artery stenosis. The existing detection method in hospitals requires the use of an invasive pressure guidewire to measure the pressure before and after stenosis for calculation.

[0038] The inventors found that the accuracy of the algorithm for calculating hemodynamic parameters using fluid mechanics simulation is affected by boundary conditions. When the absolute value of the outlet pressure is unknown, the assumption that the outlet pressure is 0 or other numerical values ​​obtained based on statistics ignores the impact of the rear-end blood vessels on the flow field caused by individual differences in the subjects, and the blood flow reserve fraction cannot be accurately calculated.

[0039] In view of this, the present disclosure provides a method, device, equipment and medium for calculating blood vessel state parameters, the method comprising: processing the target blood vessel inlet pressure and the preset outlet pressure based on a first type of boundary condition combination to obtain the blood vessel inlet velocity distribution, the first type of boundary condition combination is used to constrain the blood vessel inlet target pressure and the preset outlet pressure; processing the blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain the blood vessel inlet pressure, the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution; determining the steady-state outlet pressure based on the blood vessel inlet pressure and the blood vessel outlet resistance; processing the steady-state outlet pressure and the initial blood vessel lumped model parameters based on a bellows model to obtain the blood vessel state parameters, wherein the blood vessel state parameters include the blood vessel outlet pressures and the blood vessel lumped model parameters at t moments.

[0040] In the technical solution of the present disclosure, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0041] Figure 1 The application scenario diagram of the method for calculating blood vessel state parameters according to an embodiment of the present disclosure is schematically shown.

[0042] like Figure 1 As shown, the application scenario 100 according to this embodiment may include terminal devices 101, 102, 103, a network 104, and a server 105. The network 104 is used to provide a medium for a communication link between the terminal devices 101, 102, 103 and the server 105. The network 104 may include various connection types, such as wired, wireless communication links or optical fiber cables, etc.

[0043] Users can use terminal devices 101, 102, 103 to interact with server 105 through network 104 to receive or send messages, etc. Various communication client applications can be installed on terminal devices 101, 102, 103, such as shopping applications, web browser applications, search applications, instant messaging tools, email clients, social platform software, etc. (only examples).

[0044] The terminal devices 101 , 102 , and 103 may be various electronic devices having a display screen and supporting web browsing, including but not limited to smart phones, tablet computers, laptop computers, and desktop computers.

[0045] The server 105 may be a server that provides various services, such as a background management server (only as an example) that provides support for websites browsed by users using the terminal devices 101, 102, and 103. The background management server may analyze and process the received data such as user requests, and feed back the processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal device.

[0046] It should be noted that the method for calculating the vascular state parameters provided in the embodiment of the present disclosure can generally be executed by the server 105. Accordingly, the device for calculating the vascular state parameters provided in the embodiment of the present disclosure can generally be set in the server 105. The method for calculating the vascular state parameters provided in the embodiment of the present disclosure can also be executed by a server or server cluster that is different from the server 105 and can communicate with the terminal devices 101, 102, 103 and / or the server 105. Accordingly, the device for calculating the vascular state parameters provided in the embodiment of the present disclosure can also be set in a server or server cluster that is different from the server 105 and can communicate with the terminal devices 101, 102, 103 and / or the server 105.

[0047] It should be understood that Figure 1 The number of terminal devices, networks and servers in the embodiment is only for illustration. Any number of terminal devices, networks and servers may be provided according to implementation requirements.

[0048] The following will be based on Figure 1 The scene described by Figure 2~Figure 8 The calculation method of the blood vessel state parameter of the disclosed embodiment is described in detail.

[0049] Figure 2 The flowchart schematically shows a method for calculating blood vessel state parameters according to an embodiment of the present disclosure.

[0050] like Figure 2 As shown, the method for calculating the blood vessel state parameters of this embodiment includes operations S210 to S240.

[0051] In operation S210, based on the first type of boundary condition combination, the blood vessel inlet target pressure and the preset outlet pressure are used to obtain the blood vessel inlet velocity distribution.

[0052] In operation S220, the blood vessel inlet velocity distribution is processed based on the second type of boundary condition combination to obtain the blood vessel inlet pressure, and the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution.

[0053] In operation S230, a steady-state outlet pressure is determined based on the blood vessel inlet pressure and the blood vessel outlet resistance.

[0054] In operation S240, the steady-state outlet pressure and the initial vascular lumped model parameters are processed based on the bellows model to obtain vascular state parameters, wherein the vascular state parameters include vascular outlet pressures and vascular lumped model parameters at t moments.

[0055] According to the embodiment of the present disclosure, the first type of boundary condition combination can obtain the inlet velocity distribution under a specific blood vessel morphology. The second type of boundary condition combination can iteratively obtain the steady-state outlet pressure under the blood vessel inlet pressure and flow constraints.

[0056] According to an embodiment of the present disclosure, the distribution shape of the inlet velocity of the blood vessel under this pressure difference condition can be obtained based on the first type of boundary condition combination according to the target pressure at the inlet of the blood vessel and the preset outlet pressure.

[0057] According to an embodiment of the present disclosure, based on the second type of boundary conditions combined with a fixed inlet velocity distribution shape, when the vascular inlet flow is also known, the vascular inlet pressure at the moment can be obtained through the outlet pressure model.

[0058] According to the embodiments of the present disclosure, the target pressure at the vascular inlet can be used as the optimization target, and an iterative optimization calculation process can be constructed to determine the vascular outlet resistance and steady-state outlet pressure using the vascular inlet velocity distribution, vascular inlet flow, and outlet pressure model.

[0059] According to the embodiments of the present disclosure, the outlet pressure model may adopt any model related to flow rate, and the specific type of the outlet pressure model is not limited herein.

[0060] According to an embodiment of the present disclosure, the steady-state outlet pressure can be determined based on the vascular inlet flow rate and the vascular inlet target pressure. The vascular outlet resistance can assume the initial value of the outlet resistance, and the resistance fluctuation coefficient can be set to 0.99, but is not limited to this. The embodiment of the present disclosure does not limit the specific value of the resistance fluctuation coefficient. The first outlet resistance value can be calculated based on the resistance fluctuation coefficient and the initial value of the outlet resistance. The steady-state outlet pressure can be determined based on the vascular inlet pressure, the initial value of the outlet resistance and the first outlet resistance value. The vascular outlet resistance initially needs to calculate the initial value of the outlet resistance and the first outlet resistance value, and the steady-state outlet pressure can be determined based on iteration later.

[0061] According to an embodiment of the present disclosure, the bellows model may use a commonly used transient distal vascular lumped model, such as a three-element bellows model, but is not limited thereto. The embodiment of the present disclosure does not limit the specific type of the bellows model. The initial vascular lumped model parameters may be limited by empirical values. The steady-state outlet pressure and the initial vascular lumped model parameters may be processed based on the bellows model to obtain vascular state parameters, which may include vascular outlet pressures and vascular lumped model parameters at t moments.

[0062] According to an embodiment of the present disclosure, the vascular state parameters include the vascular outlet pressure at t moments and the vascular lumped model parameters, and a more accurate blood flow reserve fraction can be obtained based on the vascular outlet pressure at t moments and the vascular lumped model parameters.

[0063] Figure 3 The diagram schematically shows a first type of boundary condition combination and a second type of boundary condition combination used according to an embodiment of the present disclosure.

[0064] like Figure 3 As shown, the first type of boundary condition combination (i.e., boundary condition combination 1) can realize the adjustment of the inlet velocity shape, and the second type of boundary condition combination (i.e., boundary condition combination 2) can realize the fluid calculation of the flow inlet pressure outlet boundary under a specific outlet velocity shape. The velocity inlet and pressure outlet of the second type of boundary condition combination are programmed by themselves. In the first type of boundary condition combination, the target pressure of the blood vessel inlet and the preset outlet pressure can be constrained, and the inlet velocity distribution of the blood vessel under this pressure difference can be obtained on this basis. Based on this inlet velocity distribution, the velocity in the second type of boundary condition combination can be determined, and the blood vessel inlet pressure can be calculated based on the known outlet pressure model. Among them, the blood vessel wall is zero gradient pressure and no slip velocity.

[0065] According to the embodiments of the present disclosure, in the steady-state iterative calculation process, for blood vessels with stenosis, especially eccentric stenosis, the inlet velocity shape has a greater impact on the calculation of the pressure difference. In the algorithm proposed in this embodiment, by alternating between different boundary conditions, the inlet velocity shape is continuously adjusted according to the current pressure difference situation to improve the overall calculation accuracy. By comparing the invasive measurement of the subject's blood pressure with the inlet velocity shape obtained by using the standard parabolic inlet velocity and the inlet velocity shape obtained by alternating calculations, the pressure calculation error is reduced from more than 10% to less than 1% in individual cases.

[0066] According to the embodiments of the present disclosure, the target pressure at the blood vessel inlet and the preset outlet pressure are processed based on the first type of boundary condition combination to obtain the blood vessel inlet velocity distribution, the blood vessel inlet velocity distribution is processed based on the second type of boundary condition combination to obtain the blood vessel inlet pressure, and the steady-state outlet pressure is determined according to the blood vessel inlet pressure and the blood vessel outlet resistance. By alternately using the first type of boundary condition combination and the second type of boundary condition combination, the inlet velocity shape is continuously adjusted according to the current pressure difference to improve the overall calculation accuracy. The steady-state outlet pressure and the initial blood vessel lumped model parameters are processed based on the bellows model to obtain the blood vessel state parameters, thereby improving the accuracy of the outlet pressure boundary conditions.

[0067] According to an embodiment of the present disclosure, determining a steady-state outlet pressure based on the vascular inlet pressure and the vascular inlet flow rate includes: comparing the difference between the vascular inlet pressure and the vascular inlet target pressure with a preset threshold value to obtain a comparison result; when the comparison result indicates that the difference is less than the preset threshold value, updating the outlet resistance based on the vascular inlet pressure and the vascular outlet resistance; and obtaining a steady-state outlet pressure based on the vascular inlet flow rate and the outlet resistance.

[0068] According to an embodiment of the present disclosure, a target outlet resistance and pressure are obtained according to the blood vessel inlet pressure and flow, including: subtracting the n-1-step blood vessel inlet pressure from the n-th step blood vessel inlet pressure to obtain the blood vessel inlet pressure difference, wherein n>1; subtracting the n-1-step blood vessel outlet resistance from the n-th step blood vessel outlet resistance to obtain the blood vessel outlet resistance difference; obtaining the Jacob ratio according to the blood vessel inlet pressure difference and the blood vessel outlet resistance difference; and updating the outlet resistance according to the Jacob ratio and the blood vessel inlet target pressure difference.

[0069] According to an embodiment of the present disclosure, the n-th step vascular inlet pressure can be subtracted from the n-1-th step vascular inlet pressure to obtain the vascular inlet pressure difference, where n>1; the n-th step vascular outlet resistance can be subtracted from the n-1-th step vascular outlet resistance to obtain the vascular outlet resistance difference; based on the vascular inlet pressure difference and the vascular outlet resistance difference, the Jacob's ratio can be obtained, as shown in formula (1).

[0070] (1)

[0071] in, represents Jacob's ratio, P represents vascular pressure, subscript in represents vascular inlet, superscript n represents the number of steps, R represents resistance, and subscript n represents the number of steps.

[0072] According to an embodiment of the present disclosure, the target outlet resistance can be determined according to the Jacob's ratio and the target blood vessel inlet pressure, as shown in formula (2).

[0073] (2)

[0074] Where R represents resistance, subscript n represents the number of steps, and target represents the target blood vessel pressure. Represents the Jacob's ratio.

[0075] According to the embodiment of the present disclosure, two resistance values ​​of different steps are required in formula (1), so an empirical value is required to determine the initial value of the outlet resistance at the beginning, and then the first outlet resistance value is determined according to the resistance fluctuation coefficient. Therefore, the target outlet resistance can be calculated using formula (1) and formula (2).

[0076] According to an embodiment of the present disclosure, determining the steady-state outlet resistance and pressure based on the blood vessel inlet pressure and flow includes: comparing the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold to obtain a comparison result; when the comparison result indicates that the difference is greater than the preset threshold, processing the steady-state outlet pressure and the blood vessel inlet target pressure based on a first type of boundary condition combination to obtain a first blood vessel inlet velocity distribution; processing the first blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a first blood vessel inlet pressure; and determining the first steady-state outlet pressure based on the first blood vessel inlet pressure and the first blood vessel outlet resistance.

[0077] According to an embodiment of the present disclosure, the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure can be compared with a preset threshold to obtain a comparison result. The blood vessel inlet target pressure is a constant value. When the comparison result indicates that the difference is greater than the preset threshold, the steady-state outlet pressure and the blood vessel inlet target pressure can be processed based on the first type of boundary conditions to obtain the first blood vessel inlet velocity distribution. The first blood vessel inlet pressure can be obtained by processing the first blood vessel inlet velocity distribution based on the second type of boundary conditions. The first steady-state outlet pressure can be finally determined based on the first blood vessel inlet pressure and the first blood vessel outlet resistance.

[0078] Figure 4 A flow chart of steady-state outlet pressure according to an embodiment of the present disclosure is schematically shown.

[0079] like Figure 4 As shown, first, the target blood vessel inlet pressure P can be obtained. target , inlet flow measurement value Q in , assuming the initial value of the outlet resistance is R0 (i.e. S410). Based on the first type of boundary condition combination, the target pressure P of the blood vessel inlet is processed target and preset outlet pressure Q in , and obtain the vascular inlet velocity distribution (i.e., S420). Based on the combination of the second type of boundary conditions, the vascular inlet velocity distribution is processed to obtain the vascular inlet pressure (i.e., S430). Since two iterative steps of resistance are required when calculating the Jacob ratio, a resistance fluctuation coefficient needs to be set to calculate R1 (i.e., S440). Based on the combination of the second type of boundary conditions, the vascular inlet velocity distribution is processed to obtain the vascular inlet pressure (i.e., S450). The difference between the vascular inlet pressure and the vascular inlet target pressure is compared with a preset threshold to obtain a comparison result (i.e., S460). The vascular inlet target pressure is a constant value. When the comparison result indicates that the difference is less than the preset threshold (i.e., S460), the Jacob ratio is calculated using formula (1) (i.e., S470), and then the outlet resistance is updated using formula (2) Newton-Raphson iteration method (i.e., S480). Finally, the vascular outlet pressure is updated using the flow rate and the updated outlet resistance (i.e., S490).

[0080] According to the embodiment of the present disclosure, when the difference in the comparison result is greater than the preset threshold, the current iteration number needs to be increased by 1 (i.e., S4100). When the iteration number is greater than the set value, the iteration step is terminated. When the iteration number is less than the set value, the updated blood vessel inlet pressure and the blood vessel inlet target pressure need to be reprocessed according to the first type of boundary condition combination to obtain a new inlet velocity distribution. Figure 4 The flowchart is iterated.

[0081] According to the embodiments of the present disclosure, a pure resistance outlet boundary model is used in this embodiment, and the blood vessel outlet pressure is specified to be proportional to the first power of the flow rate. The initial value of the resistance is assumed to make the calculated value of the blood vessel outlet pressure close to 70% of the inlet pressure. Thereafter, the resistance is manually reduced to 99% of the initial estimate to obtain pressure fluctuations, and the inlet pressure and resistance values ​​at two moments are obtained to meet the calculation needs of the subsequent iterative process. Finally, the outlet pressure value is updated according to a given iterative method. When performing fluid calculations, blood adopts a non-Newtonian fluid laminar flow model. The iterative process is implemented by adding calculation, update and control codes to the outer layer of the SIMPLE algorithm under the OpenFoam architecture.

[0082] According to the embodiments of the present disclosure, the steady-state iterative algorithm can be used to calculate the absolute value of the outlet pressure of the responsible blood vessel segment in a non-invasive manner when the flow rate, inlet pressure and outlet pressure model are known. The existing commonly used human vascular hemodynamics calculation methods use zero outlet pressure or fixed outlet pressure methods, which cannot obtain the patient's own personalized absolute pressure value, cannot make an effective estimate of the solid force on the blood vessel wall, and cannot accurately calculate the blood flow reserve fraction. The algorithm proposed in the present disclosure provides a way to accurately calculate the blood flow reserve fraction, and also provides a basis for fluid-solid coupling calculations and blood vessel wall stress analysis.

[0083] According to an embodiment of the present disclosure, the steady-state outlet pressure and the initial vascular lumped model parameters are processed based on a bellows model to obtain vascular state parameters, including: determining the vascular outlet pressure at t moments based on the vascular inlet flow; processing the steady-state outlet pressure value based on an objective function to determine a target result, wherein the objective function is determined based on the bellows model; determining the vascular lumped model parameters based on the target result, wherein the vascular state parameters include the vascular outlet pressure at t moments and the vascular lumped model parameters.

[0084] According to an embodiment of the present disclosure, the blood vessel outlet pressure at time t can be determined based on the blood vessel inlet flow and the steady-state outlet pressure, as shown in formula (3).

[0085] (3)

[0086] in, represents the vascular outlet pressure at time t, represents the blood vessel inlet flow, Rs and Rd represent the resistance in the bellows model, and C represents the capacitance in the bellows model.

[0087] According to an embodiment of the present disclosure, the objective function is determined based on a bellows model. For example, the bellows model is a three-element bellows model. This model takes a model in which a resistor is connected in series with a resistor and a capacitor are connected in parallel as an example, and can simultaneously simulate the influence of the end resistance of the vascular network and the elasticity of the rear end blood vessels on the hemodynamic state. The differential equation describing this circuit system (i.e., the control equation N) is shown in formula (4).

[0088] (4)

[0089] in, represents pressure, Rs and Rd represent resistance in the bellows model, C represents capacitance in the bellows model, represents the blood vessel inlet flow, represents the tth moment.

[0090] In order to obtain the values ​​of the circuit parameters C, Rd, and Rs in formula (4), an optimization problem for the above differential equation is constructed, as shown in formula (5).

[0091] (5)

[0092] in, To minimize, L is the objective function, u represents the state variable, that is, the pressure at each moment, express .

[0093] According to an embodiment of the present disclosure, the steady-state outlet pressure value may be processed based on the objective function to determine the target result, as shown in formula (6).

[0094] |L ref -L | = | P out_sys , P out_dia , P out_mid |-|P max , P min , P mid | T (6)

[0095] Among them, L ref represents the objective function of the circuit system, P out_sys , P out_dia , P out_mid They represent the maximum pressure, minimum pressure, and average pressure calculated from the current state of the circuit system, respectively. max , P min , P midThey respectively represent the maximum pressure, minimum pressure and average pressure obtained during the calculation of the steady-state outlet pressure.

[0096] According to an embodiment of the present disclosure, the blood vessel lumped model parameters may be determined according to the target result.

[0097] Figure 5 The flowchart of the bellows model iterative algorithm according to the embodiment of the present disclosure is schematically shown.

[0098] like Figure 5 As shown, Figure A shows the standard elliptical inlet velocity distribution; Figure B shows the change process of the three values ​​under the elliptical inlet velocity; Figure C shows the flow field streamline diagram when the inlet pressure meets the conditions in this case; Figure D shows the inlet velocity distribution obtained based on the first type of boundary condition combination; Figure E shows the parameter value change process during the iteration process based on the second type of boundary condition combination; Figure F shows the flow field streamline diagram when the blood vessel inlet meets the pressure conditions in this case. By correcting the inlet shape, the error of the pressure calculation result compared with the measured value is reduced from 3.2481% to 0.3008%.

[0099] Figure 6 The diagram schematically shows the pressure calculation results and parameter iterative change process obtained by the iterative algorithm of the bellows model according to the embodiment of the present disclosure.

[0100] like Figure 6 As shown, Figure A is the calculation result of the responsible blood vessel pressure field at the diastolic pressure moment; Figure B is the calculation result of the responsible blood vessel pressure field at the systolic pressure moment; Figure C is the change process of the three lumped parameters during the iteration process; Figure D is the outlet pressure waveform obtained after the bellows model iteration is completed and the pressure relationship between the three control points.

[0101] According to an embodiment of the present disclosure, determining the blood vessel lumped model parameters according to the target result includes:

[0102] When the target result meets the preset conditions, the initial vascular lumped model parameters are determined as the vascular lumped model parameters; when the target result does not meet the preset conditions, the vascular lumped model parameters are determined based on the initial vascular lumped model parameters and the vascular outlet pressure at time t.

[0103] According to an embodiment of the present disclosure, in the target result (i.e., L ref –L value) satisfies a preset condition, for example, when the target result is less than a certain value, the initial vascular lumped model parameters may be determined as the vascular lumped model parameters.

[0104] According to an embodiment of the present disclosure, when the target result does not meet the preset conditions, for example, when the target result is greater than a certain value, the vascular lumped model parameters can be updated according to the initial vascular lumped model parameters and the vascular inlet flow at t moments.

[0105] According to an embodiment of the present disclosure, the vascular lumped model parameters are updated according to the initial vascular lumped model parameters and the vascular inlet flow at t moments, including: determining the derivative matrix according to the initial vascular lumped model parameters and the differential format of the vascular flow and the bellows model at t moments; processing the derivative matrix based on the derivative formula to determine the sensitivity matrix; updating the initial vascular lumped model parameters according to the sensitivity matrix to determine the vascular lumped model parameters.

[0106] According to an embodiment of the present disclosure, the derivative matrix can be determined according to the initial vascular lumped model parameters and the differential format of the vascular inlet flow and the bellows model at t moments. The vascular inlet flow can be detected in real time. The partial differential of the objective function L to the state variable u (i.e., the pressure at each moment) is shown in formula (7).

[0107] (7)

[0108] The matrix size is m×3, where m is the number of blood pressure points recorded in a cardiac cycle. Each row has only one item that is 1. The position of the item with a size of 1 in the first row corresponds to the time point of the maximum blood pressure, the position of the item in the second row corresponds to the time point of the minimum blood pressure, and the third row is the position point of the mean.

[0109] According to an embodiment of the present disclosure, the derivative of the partial derivative of the state variable u with respect to the control equation N is shown in formula (8).

[0110] (8)

[0111] Among them, the matrix size is m×m, , , Rd represents the resistance in the bellows model, C represents the capacitance in the bellows model, represents the tth moment.

[0112] According to an embodiment of the present disclosure, the partial derivative matrix form of the control equation N with respect to the design variable φ is shown in formula (9).

[0113] (9)

[0114] in,

[0115] (10)

[0116] (11)

[0117] (12)

[0118] in, represents pressure, Rs and Rd represent resistance in the bellows model, C represents capacitance in the bellows model, represents the blood vessel inlet flow, represents the tth moment.

[0119] According to an embodiment of the present disclosure, the derivative matrix can be processed based on the derivative formula to determine the sensitivity matrix, as shown in formula (13).

[0120] (13)

[0121] in, represents the sensitivity matrix, represents the objective function, represents the state variable, N represents the control equation, and φ represents the design variable.

[0122] According to the embodiments of the present disclosure, the initial vascular lumped model parameters can be updated according to the sensitivity matrix to determine the vascular lumped model parameters. The second term after the equal sign in formula (10) is set to zero in the first and second steps, and after the third step, this term is directly calculated according to the state of the previous two time points. The calculation process of this optimization problem calculates the pressure value at each time point in a cardiac cycle. The required input is the flow rate and the pressure at three moments (i.e., the maximum pressure moment, the minimum pressure moment, and the average pressure moment) in the cardiac cycle as control variables. In the calculation process, the periodic assumption of flow rate and pressure can be used, and formula (3) can be used to perform multiple cycle calculations, and the calculation cycle result with stable results within a cycle is taken as the result of the forward calculation.

[0123] According to the embodiment of the present disclosure, the outlet pressure sequence is completed and the vessel lumped model parameters After iterative calculation, the pressure sequence can be used as the outlet pressure boundary condition of the responsible vascular segment to perform transient fluid dynamics calculations, obtain the pressure and velocity conditions of the entire flow field at all time points in a cardiac cycle, and perform post-processing parameter calculations as needed.

[0124] According to the embodiments of the present disclosure, in the existing human vascular hemodynamics simulation calculation, the parameters in the lumped parameter model that considers the influence of downstream blood vessels on the outlet pressure are mostly based on statistical average values, which cannot consider the specificity of the patient's own vascular system. The vascular state parameter iteration method proposed in the present disclosure provides an optimization algorithm based on the target pressure of the inlet of the object blood vessel as a reference, and obtains three parameters of specific downstream blood vessel characteristics (i.e. ), improves the accuracy of the outlet pressure boundary conditions, and provides a quantitative judgment basis for clinical diagnosis and prognosis prediction. Through the three inlet control pressures and non-invasively measured blood flow, the pressure field and velocity field of the blood vessels throughout the cardiac cycle are obtained, providing a basis for the calculation of parameters such as average wall shear force and oscillation shear coefficient based on a cardiac cycle.

[0125] Figure 7 The flowchart of blood vessel state parameter calculation according to an embodiment of the present disclosure is schematically shown.

[0126] like Figure 7 As shown, first give the initial value of the state variable matrix φ0 (i.e. The initial value of the pressure is calculated at each time point in a cardiac cycle (i.e., formula (3)). The objective function L is calculated, and then the steady-state outlet pressure value is processed based on the objective function to determine the target result (i.e., S740). When the target result is less than the set value, the calculated vascular lumped model parameters and the vascular outlet pressure at time t can be used to determine the vascular lumped model parameters (i.e., S780). When the target result is greater than the set value, the derivative matrix can be calculated using formulas (5)-(10), and then the sensitivity matrix can be calculated using formula (11). Finally, the state variable matrix is ​​updated to obtain the conditional (ie S770).

[0127] Figure 8 The flowchart schematically shows a method for calculating blood vessel state parameters according to an embodiment of the present disclosure.

[0128] like Figure 8 As shown, firstly, the object vascular image, blood flow measurement value and vascular inlet target pressure are obtained (i.e. S810), and then pre-processing is performed, which includes vascular image segmentation, gridding, etc. (i.e. S820). The Hessian matrix enhancement plus wavefront collision plus baseline measurement algorithm can be used to complete the vascular image segmentation, and the open source tool Gmsh can be used to complete the gridding algorithm. Then, the steady-state pressure iteration algorithm (i.e. Figure 4 ) calculates the outlet pressure (i.e. S830), and finally uses the bellows model iteration algorithm (i.e. Figure 7 ) calculates the periodic outlet pressure sequence (i.e., the vascular outlet pressure at t moments) and performs transient fluid dynamics calculations of the responsible vascular segment (i.e., S840). Figure 4 and Figure 7 Two fluid solving algorithms including iterative algorithms were developed and implemented in the OpenFoam framework.

[0129] According to the embodiments of the present disclosure, by Figure 4 and Figure 7The combination of two iterative optimization algorithms improves the accuracy of flow field calculation in stenotic blood vessels. At the same time, through the optimization algorithm in this calculation process, three parameters that can reflect the vascular status at the rear end of the subject's own responsible blood vessel are obtained, providing a new scientific basis for clinical diagnosis and prognosis prediction.

[0130] Based on the above-mentioned method for calculating blood vessel state parameters, the present disclosure also provides a device for calculating blood vessel state parameters. Fig. 9 The device is described in detail.

[0131] Fig. 9 The structure block diagram of the device for calculating blood vessel state parameters according to an embodiment of the present disclosure is schematically shown.

[0132] like Fig. 9 As shown, the blood vessel state parameter calculation device 900 of this embodiment includes a velocity distribution module 910 , a blood vessel inlet pressure module 920 , a steady-state outlet pressure module 930 and a blood vessel state parameter module 940 .

[0133] a velocity distribution module, used for processing the target pressure at the blood vessel inlet and the preset outlet pressure based on a first type of boundary condition combination to obtain a blood vessel inlet velocity distribution, wherein the first type of boundary condition combination is used to constrain the target pressure at the blood vessel inlet and the preset outlet pressure;

[0134] a blood vessel inlet pressure module, used for processing the blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a blood vessel inlet pressure, wherein the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution;

[0135] A steady-state outlet pressure module, used to determine a steady-state outlet pressure according to the blood vessel inlet pressure and the blood vessel outlet resistance;

[0136] The vascular state parameter module is used to process the steady-state outlet pressure and the initial vascular lumped model parameters based on the bellows model to obtain vascular state parameters, wherein the vascular state parameters include the vascular outlet pressures and vascular lumped model parameters at t moments.

[0137] According to the embodiments of the present disclosure, the target pressure at the blood vessel inlet and the preset outlet pressure are processed based on the first type of boundary condition combination to obtain the blood vessel inlet velocity distribution, the blood vessel inlet velocity distribution is processed based on the second type of boundary condition combination to obtain the blood vessel inlet pressure, and the steady-state outlet pressure is determined according to the blood vessel inlet pressure and the blood vessel outlet resistance. By alternately using the first type of boundary condition combination and the second type of boundary condition combination, the inlet velocity shape is continuously adjusted according to the current pressure difference to improve the overall calculation accuracy. The steady-state outlet pressure and the initial blood vessel lumped model parameters are processed based on the bellows model to obtain the blood vessel state parameters, thereby improving the accuracy of the outlet pressure boundary conditions.

[0138] According to an embodiment of the present disclosure, the steady-state outlet pressure module includes: a comparison result unit, a target outlet resistance unit and a steady-state outlet pressure unit.

[0139] The comparison result unit is used to compare the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold value to obtain a comparison result.

[0140] The target outlet resistance unit is used to obtain the target outlet resistance according to the blood vessel inlet pressure and the blood vessel outlet resistance when the difference represented by the comparison result is less than a preset threshold.

[0141] The steady-state outlet pressure unit is used to obtain the steady-state outlet pressure according to the blood vessel inlet flow and the target outlet resistance.

[0142] According to an embodiment of the present disclosure, the target outlet resistance unit includes: an inlet pressure difference subunit, an outlet resistance difference subunit, a Jacobi value obtaining subunit and a target outlet resistance subunit.

[0143] The inlet pressure difference subunit is used to subtract the inlet pressure of the n-1th blood vessel from the inlet pressure of the nth blood vessel to obtain the blood vessel inlet pressure difference, where n>1.

[0144] The outlet resistance difference subunit is used to subtract the outlet resistance of the nth blood vessel from the outlet resistance of the n-1th blood vessel to obtain the blood vessel outlet resistance difference.

[0145] The Jacobi value obtaining subunit is used to obtain the Jacobi value according to the blood vessel inlet pressure difference and the blood vessel outlet resistance difference.

[0146] The target outlet resistance subunit is used to determine the target outlet resistance according to the Jacob ratio value and the target pressure at the blood vessel inlet.

[0147] According to an embodiment of the present disclosure, the steady-state outlet pressure module includes: a first comparison result unit, a first velocity distribution unit, a first blood vessel inlet pressure unit and a first steady-state outlet pressure unit.

[0148] The first comparison result unit is used to compare the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold value to obtain a comparison result.

[0149] The first velocity distribution unit is used to process the steady-state outlet pressure and the blood vessel inlet target pressure based on the first type of boundary conditions to obtain a first blood vessel inlet velocity distribution when the difference in the comparison result is greater than a preset threshold.

[0150] The first blood vessel inlet pressure unit is used to process the first blood vessel inlet velocity distribution based on the second type boundary condition combination to obtain the first blood vessel inlet pressure.

[0151] The first steady-state outlet pressure unit is used to determine the first steady-state outlet pressure according to the first blood vessel inlet pressure and the first blood vessel outlet resistance.

[0152] According to an embodiment of the present disclosure, the blood vessel state parameter module includes: a blood vessel outlet pressure submodule, a target result submodule and a blood vessel lumped model parameter submodule.

[0153] The vascular outlet pressure submodule is used to determine the vascular outlet pressure at time t based on the vascular inlet flow and the steady-state outlet pressure.

[0154] The target result submodule is used to process the steady-state outlet pressure value based on the target function to determine the target result, wherein the target function is determined based on the bellows model.

[0155] The vascular lumped model parameter submodule is used to determine the vascular lumped model parameters according to the target results, wherein the vascular state parameters include the vascular outlet pressure at t moments and the vascular lumped model parameters.

[0156] According to an embodiment of the present disclosure, the blood vessel lumped model parameter submodule includes: a first determination unit and a second determination unit.

[0157] A first determining unit, configured to determine the initial vascular lumped model parameters as the vascular lumped model parameters when the target result meets a preset condition;

[0158] The second determination unit is used to update the blood vessel lumped model parameters according to the initial blood vessel lumped model parameters and the blood vessel inlet flow rates at t moments when the target result does not meet the preset conditions.

[0159] According to an embodiment of the present disclosure, the second determination unit includes: a derivative matrix determination subunit, a sensitivity matrix determination subunit and a blood vessel lumped model parameter determination subunit.

[0160] The derivative matrix determination subunit is used to determine the derivative matrix according to the initial blood vessel lumped model parameters and the blood vessel inlet flow at t moments.

[0161] The sensitivity matrix determination subunit is used to process the derivative matrix based on the derivative formula and determine the sensitivity matrix.

[0162] The vascular lumped model parameter determination subunit is used to update the initial vascular lumped model parameters according to the sensitivity matrix and update the vascular lumped model parameters.

[0163] According to an embodiment of the present disclosure, any multiple modules of the velocity distribution module 910, the vascular inlet pressure module 920, the steady-state outlet pressure module 930, and the vascular state parameter module 940 can be combined in one module, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the velocity distribution module 910, the vascular inlet pressure module 920, the steady-state outlet pressure module 930, and the vascular state parameter module 940 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware, and firmware, or in any appropriate combination of any of them. Alternatively, at least one of the velocity distribution module 910, the blood vessel inlet pressure module 920, the steady-state outlet pressure module 930 and the blood vessel state parameter module 940 may be at least partially implemented as a computer program module, which may perform corresponding functions when executed.

[0164] Fig.10 A block diagram of an electronic device suitable for implementing a method for calculating blood vessel state parameters according to an embodiment of the present disclosure is schematically shown.

[0165] like Fig.10 As shown, the electronic device 1000 according to an embodiment of the present disclosure includes a processor 1001, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage part 1008 to a random access memory (RAM) 1003. The processor 1001 may include, for example, a general-purpose microprocessor (such as a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (for example, an application-specific integrated circuit (ASIC)), etc. The processor 1001 may also include an onboard memory for caching purposes. The processor 1001 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0166] In RAM 1003, various programs and data required for the operation of electronic device 1000 are stored. Processor 1001, ROM 1002 and RAM 1003 are connected to each other via bus 1004. Processor 1001 performs various operations of the method flow according to the embodiment of the present disclosure by executing the program in ROM 1002 and / or RAM 1003. It should be noted that the program can also be stored in one or more memories other than ROM 1002 and RAM 1003. Processor 1001 can also perform various operations of the method flow according to the embodiment of the present disclosure by executing the program stored in the one or more memories.

[0167] According to an embodiment of the present disclosure, the electronic device 1000 may further include an input / output (I / O) interface 1005, which is also connected to the bus 1004. The electronic device 1000 may further include one or more of the following components connected to the I / O interface 1005: an input portion 1006 including a keyboard, a mouse, etc.; an output portion 1007 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 1008 including a hard disk, etc.; and a communication portion 1009 including a network interface card such as a LAN card, a modem, etc. The communication portion 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as needed, so that a computer program read therefrom is installed into the storage portion 1008 as needed.

[0168] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present disclosure is implemented.

[0169] According to an embodiment of the present disclosure, a computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device. For example, according to an embodiment of the present disclosure, a computer-readable storage medium may include the ROM 1002 and / or RAM 1003 described above and / or one or more memories other than ROM 1002 and RAM 1003.

[0170] The embodiment of the present disclosure also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the method for calculating the vascular state parameter provided by the embodiment of the present disclosure.

[0171] The above functions defined in the system / device of the embodiment of the present disclosure are performed when the computer program is executed by the processor 1001. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0172] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 1009, and / or installed from the removable medium 1011. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0173] In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1009, and / or installed from the removable medium 1011. When the computer program is executed by the processor 1001, the above functions defined in the system of the embodiment of the present disclosure are performed. According to the embodiment of the present disclosure, the system, device, means, module, unit, etc. described above can be implemented by a computer program module.

[0174] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect through the Internet).

[0175] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0176] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0177] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for calculating blood vessel status parameters, characterized in that: The method comprises: Processing the target blood vessel inlet pressure and the preset outlet pressure based on a first type of boundary condition combination to obtain a blood vessel inlet velocity distribution, wherein the first type of boundary condition combination is used to constrain the target blood vessel inlet pressure and the preset outlet pressure; Processing the blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a blood vessel inlet pressure, wherein the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution; The steady-state inlet and outlet pressures are determined based on the vascular inlet velocity distribution, vascular inlet flow rate, and vascular outlet resistance; Steady-state inlet and outlet pressures, inlet flow sequence and initial vascular lumped model parameters are processed based on the bellows model to obtain vascular state parameters, wherein the vascular state parameters include vascular outlet pressures and vascular lumped model parameters at t moments.

2. The method according to claim 1, characterized in that According to the vascular inlet velocity distribution and vascular inlet flow rate, the target outlet resistance and steady-state outlet pressure are determined including: Comparing the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold value to obtain a comparison result; When the comparison result indicates that the difference is less than the preset threshold, obtaining a target outlet resistance according to the blood vessel inlet pressure and the blood vessel outlet resistance; The steady-state outlet pressure is obtained according to the blood vessel inlet flow and the target outlet resistance.

3. The method according to claim 2, characterized in that The updating of the target outlet resistance according to the blood vessel inlet pressure and the blood vessel outlet resistance comprises: Subtract the blood vessel inlet pressure at step n-1 from the blood vessel inlet pressure at step n to obtain the blood vessel inlet pressure difference, where n>1; Subtract the vascular outlet resistance at step n from the vascular outlet resistance at step n-1 to obtain the vascular outlet resistance difference; Obtaining a Jacob's ratio value according to the blood vessel inlet pressure difference and the blood vessel outlet resistance difference; The target outlet resistance is updated according to the Jacob ratio value, the target blood vessel inlet pressure and the current inlet pressure.

4. The method according to claim 1, characterized in that: Determining the steady-state outlet pressure according to the blood vessel inlet pressure and the blood vessel outlet resistance comprises: Comparing the difference between the blood vessel inlet pressure and the blood vessel inlet target pressure with a preset threshold value to obtain a comparison result; When the comparison result indicates that the difference is greater than the preset threshold, the steady-state outlet pressure and the blood vessel inlet target pressure are processed based on the first type of boundary conditions to obtain a first blood vessel inlet velocity distribution; Processing the first blood vessel inlet velocity distribution based on the second type of boundary conditions to obtain the first blood vessel inlet pressure; A first steady-state outlet pressure is determined according to the first blood vessel inlet pressure and the first blood vessel outlet resistance.

5. The method according to claim 1, characterized in that The steady-state outlet pressure and the initial blood vessel lumped model parameters are processed based on the bellows model to obtain blood vessel state parameters, including: Determining the blood vessel outlet pressure at the time t according to the blood vessel inlet flow and the target pressure; Processing the outlet pressure value at a specific moment in a steady state based on the objective function to determine a target result, wherein the outlet pressure at the specific moment is determined based on the bellows model parameters and the blood vessel inlet flow rate; According to the target result, the blood vessel lumped model parameters and the blood vessel outlet pressure at time t are determined.

6. The method according to claim 5, characterized in that Determining the blood vessel lumped model parameters according to the target result includes: In the case where the target result meets the preset conditions, the blood vessel lumped model parameters are determined as the target blood vessel lumped model parameters; When the target result does not meet the preset conditions, the vascular lumped model parameters are updated according to the initial vascular lumped model parameters and the vascular inlet flow rates at t moments.

7. The method according to claim 6, characterized in that The updating of the blood vessel lumped model parameters according to the initial blood vessel lumped model parameters and the blood vessel inlet flow at time t includes: Determining a derivative matrix according to the initial blood vessel lumped model parameters and the blood vessel inlet flow rates at the t moments; Processing the derivative matrix based on a derivative formula to determine a sensitivity matrix; The initial blood vessel lumped model parameters are updated according to the sensitivity matrix, and the blood vessel lumped model parameters are updated.

8. A device for calculating blood vessel state parameters, characterized in that: The device comprises: a velocity distribution module, used for processing the target pressure at the blood vessel inlet and the preset outlet pressure based on a first type of boundary condition combination to obtain a blood vessel inlet velocity distribution, wherein the first type of boundary condition combination is used to constrain the target pressure at the blood vessel inlet and the preset outlet pressure; a blood vessel inlet pressure module, used for processing the blood vessel inlet velocity distribution based on a second type of boundary condition combination to obtain a blood vessel inlet pressure, wherein the second type of boundary condition combination is used to constrain the blood vessel inlet velocity distribution; A steady-state outlet pressure module, used to determine a steady-state outlet pressure according to the blood vessel inlet pressure and the blood vessel outlet resistance; The vascular state parameter module is used to process the steady-state outlet pressure and the initial vascular lumped model parameters based on the bellows model to obtain vascular state parameters, wherein the vascular state parameters include the vascular outlet pressures and vascular lumped model parameters at t moments.

9. An electronic device, comprising: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, causes the processor to execute the method according to any one of claims 1 to 7.

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