Methods, apparatuses, and storage media for assessing stroke risk associated with atrial fibrillation

Abstract

The application discloses a method and device for evaluating the risk of stroke related to atrial fibrillation and a storage medium, relates to the technical field of risk evaluation, and comprises the following steps: acquiring a cardiac image of a patient; acquiring a left atrial model according to the cardiac image, wherein the left atrial model comprises a left atrial body, a mitral annulus, a pulmonary vein atrium and a left atrial appendage; calculating blood flow parameters of the left atrium according to the left atrial model, wherein the blood flow parameters comprise at least one of particle residence time and blood shear rate; and evaluating a first risk index of stroke of the patient according to the blood flow parameters. The application solves the problem of weak prediction ability of risk evaluation in the prior art, achieves the effect of individualized prediction of the risk of stroke according to the cardiac image of the patient, and improves the prediction accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to a method, device and storage medium for evaluating stroke risk associated with atrial fibrillation, and belongs to the technical field of risk evaluation. BACKGROUND

[0002] Atrial fibrillation (AF) is the most common sustained arrhythmia. Its characteristic is rapid and irregular heartbeat. By 2010, the global AF patient was estimated to be about 33.5 million cases, and the incidence and prevalence were high. AF patients have a very high risk of ischemic stroke, which is 4-5 times higher than non-AF population. How to evaluate the stroke risk associated with AF has become an important topic.

[0003] In the prior art, CHA2DS2-VASc score is mainly used to evaluate the stroke risk associated with AF. However, the above method is based on very common clinical experience factors such as age, hypertension and diabetes, and does not evaluate the individual potential mechanism of thrombosis caused by heart structure and intracardiac blood flow, and has the problem of low prediction ability. SUMMARY

[0004] The purpose of the present application is to provide a method, device and storage medium for evaluating stroke risk associated with atrial fibrillation, to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] According to the first aspect, the present application provides a method for evaluating stroke risk associated with atrial fibrillation, comprising:

[0007] obtaining a heart image of a patient;

[0008] obtaining a left atrial model from the heart image, the left atrial model comprising a left atrial body, a mitral annulus, a pulmonary vein atrium and a left atrial appendage;

[0009] calculating blood flow parameters of the left atrium according to the left atrial model, the blood flow parameters comprising at least one of particle residence time and blood shear rate;

[0010] evaluating a first risk index of stroke of the patient according to the blood flow parameters.

[0011] Optionally, the left atrial model is obtained from the heart image, comprising:

[0012] segmenting the heart image to obtain a left atrial region in the heart image;

[0013] solidifying the segmented left atrial region to obtain the left atrial model.

[0014] Optionally, the solidification according to the left atrial region obtained by segmentation obtains the left atrial model, comprising:

[0015] solidification according to the left atrial region obtained by segmentation obtains the initial left atrial model;

[0016] The initial left atrial model is divided into a non-structured tetrahedral mesh to obtain the left atrial model after grid division.

[0017] Optionally, the blood flow parameter of the left atrium is calculated according to the left atrial model, comprising:

[0018] The left atrial model is calculated by a laminar flow model to obtain the unsteady flow field result of the left atrium;

[0019] The blood flow parameter is obtained by analyzing the unsteady flow field result.

[0020] Optionally, the first risk index of the patient suffering from stroke is evaluated according to the blood flow parameter, comprising:

[0021] For each blood flow parameter, a reference value corresponding to the blood flow parameter is obtained, the reference value comprising an average standard value and an average simulation calculation value of the blood flow parameter;

[0022] The first risk index is evaluated according to the calculated reference values.

[0023] Optionally, if the blood flow parameter comprises particle residence time and blood shear rate, the first risk index is evaluated according to the reference value, comprising:

[0024] A risk factor corresponding to each blood flow parameter is calculated according to the reference value corresponding to each blood flow parameter;

[0025] The first risk index is evaluated according to the calculated risk factors.

[0026] Optionally, the first risk index is evaluated according to the calculated risk factors, comprising:

[0027]

[0028] Wherein, A is the first risk index, a is a preset value, b1 is a risk factor corresponding to the calculated particle residence time, b2 is a risk factor corresponding to the calculated blood shear rate, RT0 is a standard value of the average particle residence time of the patient; RT s is the simulation calculation value of the average particle residence time of the patient, SSR0 is the standard value of the average blood shear rate of the patient; SSRs an average blood shear rate simulation value for the patient.

[0029] Optionally, after the first risk index of the patient suffering from stroke is evaluated according to the blood flow parameter, the method further comprises:

[0030] obtaining a second risk index of the patient suffering from stroke evaluated according to an empirical factor, the empirical factor including at least one of age, hypertension, diabetes, height, weight and gender;

[0031] comprehensively evaluating a final risk index according to the first risk index and the second risk index.

[0032] In a second aspect, a device for evaluating a risk of stroke related to atrial fibrillation is provided, the device comprising a memory and a processor, the memory storing at least one program instruction, and the processor loading and executing the at least one program instruction to implement the method of the first aspect.

[0033] In a third aspect, a computer storage medium is provided, the computer storage medium storing at least one program instruction, and the at least one program instruction being loaded and executed by a processor to implement the method of the first aspect.

[0034] By obtaining a cardiac image of a patient, obtaining a left atrial model from the cardiac image, the left atrial model including a left atrial body, a mitral annulus, a pulmonary vein atrium and a left atrial appendage, calculating a blood flow parameter of the left atrium according to the left atrial model, the blood flow parameter including at least one of particle residence time and blood shear rate, and evaluating a first risk index of the patient suffering from stroke according to the blood flow parameter, the problem of weak prediction ability of risk evaluation in the prior art is solved, and the effect of individualized prediction of stroke risk according to the cardiac image of the patient and improved prediction accuracy is achieved.

[0035] In addition, after the first risk index is obtained, a second risk index calculated according to an existing method can also be obtained, and then a final risk index is determined according to the first risk index and the second risk index, further improving the accuracy of stroke evaluation.

[0036] By simulating the blood flow in the left atrium of a specific patient through the left atrial model of the patient, the formation and risk of thrombus in the left atrium of the patient can be predicted, and the prediction time length is long.

[0037] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application and to implement the content of the description, the following will be described in detail with the preferred embodiments of the present application and with the aid of the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A method flow chart of a method for assessing stroke risk associated with atrial fibrillation is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0040] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0043] Reference should be made to Figure 1 which shows a method flow chart of a method for assessing stroke risk associated with atrial fibrillation provided by an embodiment of the present application, as shown in Figure 1 The method comprises:

[0044] Step 101, acquiring a cardiac image of a patient;

[0045] Among them, the cardiac image in the present embodiment can be a CT image, or an ultrasound image, of course, in actual implementation, it can also be other types of medical images, which are not limited. And, except for special description below, the cardiac image is taken as a CT cardiac image for example.

[0046] Step 102, obtaining a left atrium model according to the cardiac image;

[0047] This step includes:

[0048] (1) performing image segmentation on the cardiac image to obtain a left atrium region in the cardiac image;

[0049] Perform image segmentation on the obtained CT cardiac image to obtain the part of the left atrium of the patient. Optionally, the segmented part can be exported as an STL (stereolithography) file.

[0050] (2) solidifying the left atrium region obtained by segmentation to obtain the left atrium model, which includes a left atrium body, a mitral annulus, a pulmonary vein vestibule, and a left atrial appendage model.

[0051] Solidify the left atrium model according to the exported STL file to obtain the left atrium model.

[0052] Optionally, in actual implementation, after obtaining the left atrium model by solidification, the solidified left atrium model can also be divided into a non-structure tetrahedral mesh to obtain the left atrium model after mesh division. The left atrium model after mesh division is used for subsequent use.

[0053] Step 103, calculating blood flow parameters of the left atrium according to the left atrium model, the blood flow parameters including at least one of particle residence time and blood shear rate;

[0054] This step can include:

[0055] (1) calculating the left atrium model by a laminar flow model to obtain the unsteady flow field result of the left atrium;

[0056] In actual implementation, the heart cycle of the patient and the mitral orifice blood flow velocity under the atrial fibrillation state can be obtained according to clinical data, and the obtained parameters can be implanted into the laminar flow model for simulation calculation to obtain the unsteady flow field result of the left atrium.

[0057] Optionally, an additional variable RT can be added, and its calculation equation is shown in Equation 1, which is used to calculate the distribution of the left atrium blood residence time. After setting the calculation conditions, the calculation is performed.

[0058]

[0059] Where: t is time, v is velocity, and DRT is the self-diffusion rate of blood.

[0060] (2) obtaining the blood flow parameters according to the non-steady flow field results.

[0061] Step 104, evaluating a first risk index of stroke of the patient according to the blood flow parameters.

[0062] Optionally, the step includes:

[0063] First, for each blood flow parameter, obtaining a reference value corresponding to the blood flow parameter, the reference value including an average standard value and an average simulation value of the blood flow parameter;

[0064] For the particle residence time, obtaining RT0 and RT s , wherein RT0 is a standard value of average particle residence time of the patient; RT s is a simulation value of average particle residence time of the patient. For the blood shear rate, obtaining SSR0 and SSR s , SSR0 is a standard value of average blood shear rate of the patient; SSR s is a simulation value of average blood shear rate of the patient.

[0065] Second, evaluating the first risk index according to the calculated reference values.

[0066] When the blood flow parameters include both the particle residence time and the blood shear rate, the step includes:

[0067] (1) calculating a risk factor corresponding to each blood flow parameter according to the reference value corresponding to the blood flow parameter;

[0068] For the particle residence time, the corresponding risk factor is calculated according to the following formula (2); for the blood shear rate, the corresponding risk factor is calculated according to the following formula (3).

[0069]

[0070]

[0071] wherein X is a personalized risk assessment coefficient, which is a constant.

[0072] (2) evaluating the first risk index according to the calculated risk factors.

[0073]

[0074] Wherein, A is the first risk index, a is a preset value, b1 is a risk factor corresponding to the calculated particle residence time, b2 is a risk factor corresponding to the calculated blood shear rate, RT0 is a standard value of the average particle residence time of the patient; RT s is a simulated calculation value of the average particle residence time of the patient, SSR0 is a standard value of the average blood shear rate of the patient; SSR s is a simulated calculation value of the average blood shear rate of the patient.

[0075] After the first risk index is calculated, the risk of the patient suffering from stroke can be evaluated according to the first risk index. Optionally, the first risk index is compared with a high risk threshold and a medium risk threshold, and the risk is evaluated according to the comparison structure. Specifically, if the first risk index is greater than or equal to the high risk threshold, it means that the patient has a high risk of suffering from stroke; if the high risk threshold is greater than the first risk index and the first risk index is greater than or equal to the medium risk threshold, it means that the patient has a medium risk of suffering from stroke; and if the first risk threshold is less than the medium risk threshold, it means that the patient has a low risk of suffering from stroke.

[0076] In actual implementation, after the first risk threshold is obtained, the following steps can be further included:

[0077] First, a second risk index of the patient suffering from stroke is obtained according to an evaluation of clinical experience factors, wherein the experience factors include at least one of age, hypertension, diabetes, height, weight and gender;

[0078] In actual implementation, the second risk index B of suffering from stroke can be evaluated according to the experience factors through the existing CHA2DS2-VASc scoring standard.

[0079] Second, a final risk index is comprehensively evaluated according to the first risk index and the second risk index.

[0080] Optionally, the final risk index C can be calculated according to the first risk index A, the second risk index B and respective corresponding weights.

[0081] Specifically, C = A × a + B × b.

[0082] Wherein: a, b are weighting numbers.

[0083] After the final risk index is obtained, the risk can be evaluated according to the risk index, and the specific evaluation method is similar to the above, which will not be described here.

[0084] In summary, by acquiring a cardiac image of a patient, a left atrium model (including a left atrium body, a mitral annulus, a pulmonary vein atrium and a left atrial appendage) is acquired according to the cardiac image, blood flow parameters of the left atrium are calculated according to the left atrium model, the blood flow parameters include at least one of particle residence time and blood shear rate, and a first risk index of the patient suffering from stroke is evaluated according to the blood flow parameters. The problem of weak prediction ability of risk assessment in the prior art is solved, and the effect of individualized risk assessment of left atrial thrombosis and stroke risk according to the cardiac image of the patient is achieved, and the prediction accuracy is improved.

[0085] In addition, after acquiring the first risk index, a second risk index calculated according to an existing method can also be acquired, and then a final risk index is determined according to the first risk index and the second risk index, further improving the accuracy of stroke evaluation.

[0086] By simulating the blood flow in the left atrium of a specific patient, the formation and risk of thrombosis in the left atrium of the patient can be predicted, and the prediction time length is long.

[0087] The application also provides an atrial fibrillation related stroke risk assessment device, the device comprising a memory and a processor, the memory storing at least one program instruction, and the processor loading and executing the at least one program instruction to realize the method as described above.

[0088] The application also provides a computer storage medium, characterized in that the computer storage medium stores at least one program instruction, and the at least one program instruction is loaded and executed by a processor to realize the method as described above.

[0089] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present disclosure.

[0090] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A method of assessing stroke risk associated with atrial fibrillation, the method comprising: The method comprises: obtaining a cardiac image of a patient; performing image segmentation on the cardiac image to obtain a left atrium region in the cardiac image; performing solidification according to the segmented left atrium region to obtain an initial left atrium model; performing non-structure tetrahedral mesh division on the initial left atrium model to obtain the left atrium model after mesh division, the left atrium model comprising a left atrium body, a mitral annulus, a pulmonary vein atrium, and a left atrial appendage; performing calculation on the left atrium model through a laminar flow model to obtain a non-steady flow field result of the left atrium; analyzing the non-steady flow field result to obtain blood flow parameters, the blood flow parameters comprising particle residence time and blood shear rate; for each blood flow parameter, obtaining a reference value corresponding to the blood flow parameter, the reference value comprising an average standard value and an average simulation calculation value of the blood flow parameter; calculating a risk factor corresponding to each blood flow parameter according to the reference value corresponding to the blood flow parameter; evaluating a first risk index according to the calculated risk factors; the evaluating the first risk index according to the calculated risk factors comprises: wherein A is the first risk index, a is a preset value, b1 is the risk factor corresponding to the calculated particle residence time, b2 is the risk factor corresponding to the calculated blood shear rate, RT0 is a standard value of the average particle residence time of the patient; RTs is a simulation calculation value of the average particle residence time of the patient, SSR0 is a standard value of the average blood shear rate of the patient; and SSRs is a simulation calculation value of the average blood shear rate of the patient; obtaining a second risk index of stroke of the patient evaluated according to an experience factor, the experience factor comprising at least one of age, hypertension, diabetes, height, weight, and gender; comprehensively evaluating a final risk index according to the first risk index and the second risk index.

2. An atrial fibrillation related stroke risk assessment device, characterized by, The device comprises a memory and a processor, at least one program instruction is stored in the memory, and the processor loads and executes the at least one program instruction to realize the method in claim 1.

3. A computer storage medium, characterized in that, The computer storage medium stores at least one program instruction, and the at least one program instruction is loaded and executed by the processor to realize the method in claim 1.

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