Left atrial appendage occlusion simulation method and system based on CT image

Abstract

The invention discloses a left atrial appendage occlusion simulation method and system based on a CT image, and the method comprises the steps: reading CT image data of a patient, segmenting a left atrium and a left atrial appendage from the CT image data, and obtaining corresponding binary three-dimensional image data; reading a left auricle opening mark point set by a user, and calculating geometric parameters of the left auricle opening in combination with the binary three-dimensional image data; reading the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava, calculating the optimal atrial septum puncture site and the rotation angle of the left auricle occluder conveying sheath after entering the left atrium, calculating the corresponding conveying sheath movement track curve, and outputting or visualizing the calculation result. By utilizing the embodiment of the invention, more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under the three-dimensional condition can be realized, and a doctor is helped to evaluate the surgical process before the surgery.

Description

Technical Field

[0001] The present invention belongs to the technical field of computer-assisted surgery, and in particular to a left atrial appendage occlusion simulation method and system based on CT images. Background Art

[0002] Atrial fibrillation is a supraventricular tachycardia characterized by rapid, disordered atrial electrical activity. It is the most common arrhythmia in clinical practice. Stroke is a serious complication of atrial fibrillation, with a very high disability and mortality rate. The mechanism of atrial fibrillation causing stroke is that when atrial fibrillation occurs, the left atrial appendage's ability to pump blood is weakened, causing blood to accumulate in the left atrial appendage and form a thrombus. The thrombus will fall out of the left atrial appendage and enter the arterial system, eventually blocking the blood vessels in the brain and causing a stroke.

[0003] To reduce the risk of thrombosis in the left atrial appendage and stroke, patients can undergo left atrial appendage occlusion. Left atrial appendage occlusion is a minimally invasive surgery. During left atrial appendage occlusion, the doctor uses the left atrial appendage occluder delivery sheath to deliver the left atrial appendage occluder to the inferior vena cava via the femoral vein, and then delivers it to the left atrial appendage through atrial septal puncture and blocks it to prevent blood from entering the area, thereby significantly reducing the risk of thrombosis in the heart.

[0004] The left atrial appendage occlusion of current standard uses two-dimensional transesophageal echocardiography and X-ray fluoroscopy to obtain the three-dimensional morphological parameters (including opening position, diameter, axial direction, left atrial appendage depth etc.) of the left atrial appendage. These parameters will play an important guiding role in the left atrial appendage occlusion process. However, due to the large variation in the form of the left atrial appendage and the relationship with its surrounding structures in three-dimensional space, simply using two-dimensional imaging technology will lose a large amount of spatial information, and it is likely to misjudge the three-dimensional morphological parameters of the left atrial appendage.

[0005] Multi-slice spiral CT can obtain three-dimensional images of the heart with high spatial resolution. The patient's preoperative CT images can more accurately reflect the true anatomical relationship and can more accurately guide the left atrial appendage occlusion operation. In recent years, the value of multi-slice spiral CT in guiding the left atrial appendage occlusion operation has been recognized by many studies. At present, there are few applications of computer-assisted systems in preoperative planning and simulation of left atrial appendage occlusion, which is an urgent problem to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a left atrial appendage occlusion simulation method and system based on CT images to address the deficiencies in the prior art, and to achieve more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, thereby helping doctors to evaluate the surgical process before the operation.

[0007] An embodiment of the present application provides a left atrial appendage occlusion simulation method based on CT images, the method comprising:

[0008] Reading CT image data of the patient, segmenting the left atrium and left atrial appendage from the CT image data, and obtaining corresponding binary and three-dimensional image data;

[0009] Reading the left atrial appendage opening marking point set by the user, and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0010] Read the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculate the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculate the corresponding delivery sheath motion trajectory curve, and output or visualize the calculation results.

[0011] Optionally, the reading of CT image data of the patient, segmenting the left atrium and the left atrial appendage from the CT image data, and obtaining corresponding binary and three-dimensional image data includes:

[0012] Reading CT image data of a patient, and performing mean filtering on the CT image data using a three-dimensional mean filter;

[0013] Draw a distribution map for the pixel distribution on a straight line passing through the left atrium in the current CT image data, and read the segmentation threshold determined by the user using the distribution map;

[0014] Use the segmentation threshold to perform binary segmentation on the current CT image data, and retain the maximum connected domain in the binary segmentation result;

[0015] The holes are filled using the closing operation to obtain the segmentation results of the left atrium and left atrial appendage.

[0016] Optionally, the geometric parameters of the left atrial appendage opening include: shape, center coordinates, maximum and minimum diameters, equation of the left atrial appendage opening plane and normal vector parameters;

[0017] The reading of the left atrial appendage opening mark point set by the user and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data include:

[0018] Read the coordinates of several left atrial appendage opening marking points set by the user on the left atrium three-dimensional model;

[0019] The equation of the left atrial appendage opening plane is obtained by fitting the least square method, and the normal vector of the left atrial appendage opening plane and a group of basis vectors in the left atrial appendage opening plane are calculated according to the equation;

[0020] Performing region growing in the plane determined by the basis vectors to obtain the shape and boundary of the left atrial appendage opening, and calculating the center of the left atrial appendage opening;

[0021] All line segments passing through the center of the left atrial appendage opening and with endpoints on the opening boundary are traversed, and the maximum and minimum values ​​of all line segments are calculated as the maximum and minimum diameters of the left atrial appendage opening.

[0022] Optionally, the method of reading the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculating the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, and calculating the corresponding delivery sheath motion trajectory curve includes:

[0023] Reading the inferior vena cava opening mark point and another mark point on the inferior vena cava specified by the user in the CT image;

[0024] Based on the CT image data, all points located on the left atrium boundary and whose distance from the initial atrial septal puncture site is less than a preset threshold are calculated as candidate atrial septal puncture sites, and all candidate atrial septal puncture sites are traversed to calculate the corresponding motion trajectory curve of the left atrial appendage occluder delivery sheath before entering the left atrium;

[0025] For each atrial septal puncture site, the possible rotation angles of the delivery sheath after atrial septal puncture are traversed with a preset step length, and the corresponding motion trajectory curve of the delivery sheath after entering the left atrium is calculated;

[0026] For the obtained motion trajectory curve, the angle between the tangent vector at the intersection of the motion trajectory curve with the left atrial appendage opening plane and the normal vector of the left atrial appendage opening plane, the shortest distance between the motion trajectory curve and the left atrial appendage opening boundary, and the length of the motion trajectory curve in the inner part of the left atrial appendage are calculated, and the combination of the candidate atrial septal puncture site and the rotation angle after puncture is scored according to the angle, the shortest distance and the length;

[0027] The combination with the highest score is selected, the data in the selected combination is determined as the optimal atrial septum puncture site and the rotation angle after puncture, and the delivery sheath motion trajectory curve corresponding to the selected combination is determined as the optimal delivery sheath motion trajectory curve.

[0028] Another embodiment of the present application provides a left atrial appendage occlusion simulation system based on CT images, the system comprising:

[0029] A left atrium segmentation module is used to read the patient's CT image data, segment the left atrium and left atrial appendage from the CT image data, and obtain corresponding binary and three-dimensional image data;

[0030] A left atrial appendage parameter calculation module is used to read the left atrial appendage opening mark point set by the user, and calculate the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0031] The surgical path calculation module is used to read the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculate the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculate the corresponding delivery sheath motion trajectory curve, and output or visualize the calculation results.

[0032] Yet another embodiment of the present application provides a storage medium, wherein the storage medium stores a computer program, wherein the computer program is configured to execute any of the above methods when running.

[0033] Yet another embodiment of the present application provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute any of the methods described above.

[0034] Compared with the prior art, the present invention provides a left atrial appendage occlusion simulation method based on CT images, which reads the patient's CT image data, segments the left atrium and left atrial appendage from the CT image data, and obtains corresponding binary three-dimensional image data; reads the left atrial appendage opening mark point set by the user, and calculates the geometric parameters of the left atrial appendage opening in combination with the binary three-dimensional image data; reads the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava, calculates the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculates the corresponding delivery sheath motion trajectory curve, and outputs or visualizes the calculation results, thereby realizing more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, and helping doctors to evaluate the surgical process before the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A hardware structure block diagram of a computer terminal for a left atrial appendage occlusion simulation method based on CT images provided in an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a flow chart of a left atrial appendage occlusion simulation method based on CT images provided in an embodiment of the present invention;

[0037] Figure 3 A schematic structural diagram of a left atrial appendage occlusion simulation system based on CT images provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0039] At present, there are few applications of computer-aided systems in the preoperative planning and simulation of left atrial appendage occlusion. The patent with the publication number "CN103646135A" and the name "Computer-aided Ultrasound Diagnosis Method of Left Atrial / Left Atrial Appendage Thrombus" proposes a method for automatically detecting left atrial and left atrial appendage thrombi from grayscale video and real-time three-dimensional dynamic video. The common point between this invention and the present invention is that three-dimensional imaging technology is used to guide diagnosis. However, the processes of left atrial appendage occlusion and left atrial appendage thrombus detection are very different, and the imaging modalities used in this invention and the present invention are not the same, and the technical routes of the two are also quite different; the patent with the publication number "CN108876769 A" and the name "A Left Atrial Appendage CT Image Segmentation Method" proposes a method for segmenting the left atrial appendage in CT images. This invention has a certain reference value for the present invention, because left atrial / left atrial appendage segmentation is a link in the workflow of the present invention. In comparison, the left atrial appendage segmentation method in the present invention is simpler and easier to implement, and the segmentation effect can meet the requirements of subsequent processes.

[0040] The embodiment of the present invention firstly provides a left atrial appendage occlusion simulation method based on CT images, which can be applied to electronic devices, such as computer terminals, specifically ordinary computers, etc.

[0041] The following describes it in detail by taking running on a computer terminal as an example. Figure 1 The hardware structure block diagram of a computer terminal for simulating a left atrial appendage occlusion method based on CT images provided in an embodiment of the present invention. Figure 1 As shown, the computer device includes a processor, a memory, and a network interface connected via a system bus, wherein the memory may include a non-volatile storage medium and an internal memory.

[0042] The non-volatile storage medium can store an operating system and a computer program. The computer program includes program instructions, and when the program instructions are executed, the processor can execute any left atrial appendage occlusion simulation method based on CT images.

[0043] The processor is used to provide computing and control capabilities and support the operation of the entire computer equipment.

[0044] The internal memory provides an environment for the operation of the computer program in the non-volatile storage medium. When the computer program is executed by the processor, the processor can execute any left atrial appendage occlusion simulation method based on CT images.

[0045] The network interface is used for network communication, such as sending assigned tasks, etc. Those skilled in the art will understand that Figure 1The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0046] It should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0047] See also Figure 2 The embodiment of the present invention provides a left atrial appendage occlusion simulation method based on CT images, which may include the following steps:

[0048] S201, reading CT image data of a patient, segmenting the left atrium and left atrial appendage from the CT image data, and obtaining corresponding binary three-dimensional image data;

[0049] Specifically, the patient's CT image data can be read, and the CT image data can be mean filtered using a three-dimensional mean filter; a distribution map is drawn for the pixel distribution on a straight line passing through the left atrium in the current CT image data, and the segmentation threshold determined by the user using the distribution map is read; the current CT image data is binary segmented using the segmentation threshold, and the maximum connected domain is retained in the binary segmentation result; the holes are filled using a closing operation to obtain the segmentation results of the left atrium and left atrial appendage.

[0050] S202, reading the left atrial appendage opening marking point set by the user, and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0051] The geometric parameters of the left atrial appendage opening include but are not limited to: the shape of the left atrial appendage opening, the center coordinates, the maximum and minimum diameters, the equation of the left atrial appendage opening plane and the normal vector parameters.

[0052] Specifically, the coordinates of several left atrial appendage opening marking points set by the user on the left atrium three-dimensional model can be read; the equation of the left atrial appendage opening plane is obtained by fitting the least squares method, and the normal vector of the left atrial appendage opening plane and a set of basis vectors in the left atrial appendage opening plane are calculated according to the equation; regional growth is performed in the plane determined by the basis vectors to obtain the shape and boundary of the left atrial appendage opening, and the center of the left atrial appendage opening is calculated; all line segments passing through the center of the left atrial appendage opening and with endpoints on the opening boundary are traversed, and the maximum and minimum values ​​of all line segments are calculated as the maximum and minimum diameters of the left atrial appendage opening.

[0053] S203, reads the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava, calculates the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculates the corresponding delivery sheath motion trajectory curve, and outputs or visualizes the calculation results.

[0054] Specifically, the inferior vena cava opening marking point and another marking point on the inferior vena cava specified by the user in the CT image can be read; based on the CT image data, all points located on the left atrium boundary and whose distance from the initial atrial septal puncture site is less than a preset threshold are calculated as candidate atrial septal puncture sites, all candidate atrial septal puncture sites are traversed, and the motion trajectory curve of the corresponding left atrial appendage occluder delivery sheath before entering the left atrium is calculated; for each atrial septal puncture site, the possible rotation angles of the delivery sheath after atrial septal puncture are traversed with a preset step size, and the motion trajectory curve of the corresponding delivery sheath after entering the left atrium is calculated. motion trajectory curve; for the obtained motion trajectory curve, calculate the angle between the tangent vector at the intersection with the left atrial appendage opening plane and the normal vector of the left atrial appendage opening plane, the shortest distance between the tangent vector and the left atrial appendage opening boundary, and the length of the inner part of the left atrial appendage, and score the combination of candidate atrial septal puncture site and the rotation angle after puncture according to the angle, the shortest distance and the length; select the combination with the highest score, determine the data in the selected combination as the optimal atrial septal puncture site and the rotation angle after puncture, and determine the delivery sheath motion trajectory curve corresponding to the selected combination as the optimal delivery sheath motion trajectory curve.

[0055] The present invention belongs to the field of computer-assisted surgery, and provides a left atrial appendage occlusion planning and simulation system based on preoperative CT image data of a patient. The system segments the left atrium from the CT image data of the patient through a left atrial segmentation module; calculates the shape, center coordinates, maximum and minimum diameters, equation and normal vector of the left atrial appendage opening plane and other parameters through a left atrial appendage parameter calculation module; calculates the optimal atrial septum puncture site, the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium and the corresponding delivery sheath motion trajectory curve through a surgical path calculation module, and outputs or visualizes the calculation results through a user interaction module.

[0056] A user interaction module may also be provided to allow the user to set marker points on the CT image or three-dimensional model and to output or visualize the calculation results.

[0057] Left atrium segmentation module, this module reads the patient's preoperative CT image data and uses a three-dimensional mean filter to perform mean filtering on the CT image. A distribution map is drawn for the pixel distribution on a straight line passing through the left atrium in the CT image, which facilitates the user to determine the appropriate segmentation threshold. The threshold is then used to perform binary segmentation on the CT image, and the maximum connected domain is retained in the segmentation result. Finally, a closing operation is used to fill the holes to obtain the segmentation results of the left atrium and left atrial appendage.

[0058] Left atrial appendage parameter calculation module, this module requires the user to provide several left atrial appendage opening markers. The program will use the marker coordinates to fit the left atrial appendage opening plane equation through the least squares method, and calculate the plane normal vector based on the plane equation. After obtaining the left atrial appendage opening plane equation, it is easy to obtain a set of basis vectors for the plane. Similar to the region growing algorithm of general images, the mean of the left atrial appendage opening marker points is used as the seed point, and region growth is performed in the plane determined by the basis vector to obtain the shape and boundary of the left atrial appendage opening, and calculate the center of mass of the left atrial appendage opening. The program will traverse all line segments that pass through the center of mass and whose endpoints are on the boundary of the opening area, and find the maximum and minimum values ​​of these line segments as the maximum and minimum diameters of the left atrial appendage opening.

[0059] The surgical path calculation module requires the user to provide the opening mark point of the inferior vena cava and another mark point on the inferior vena cava. Subsequently, the CT image data is traversed and all points (these points are candidate atrial septal puncture sites) located on the left atrium boundary and the distance between the preset initial atrial septal puncture site is less than a certain threshold value, and the motion trajectory of the left atrial appendage occluder delivery sheath moving to this point is calculated. After that, for the above-mentioned candidate atrial septal puncture site, the rotation angle of the delivery sheath after entering the left atrium through the puncture site is traversed with a certain step length, and the motion trajectory of the delivery sheath after entering the left atrium is obtained. In other words, for each candidate atrial septal puncture site and the combination of the rotation angle of the delivery sheath after entering the left atrium through the site, a complete left atrial appendage occluder delivery sheath motion trajectory curve can be determined. For each delivery sheath motion trajectory curve, the angle between the tangent vector at the intersection of the left atrial appendage opening plane and the normal vector of the left atrial appendage opening plane, the shortest distance between the left atrial appendage opening boundary, and the length of the inner part of the left atrial appendage can be calculated. The sheath motion trajectory curve is scored based on these three parameters. Finally, we select the sheath motion trajectory curve with the highest score, obtain its corresponding atrial septal puncture site and the rotation angle of the sheath after entering the left atrium through the site, which is the optimal atrial septal puncture site and rotation angle. This sheath motion trajectory curve is the optimal sheath motion trajectory curve.

[0060] A user interaction module includes the following functions: performing three-dimensional reconstruction of the left atrium and left atrial appendage according to the segmentation results output by the left atrial segmentation module, and displaying them together with the CT image; allowing the user to set marker points in the left atrial three-dimensional model and CT image for use by the left atrial appendage parameter calculation module and the surgical path calculation module; after obtaining the results of the left atrial appendage parameter calculation module, highlighting the left atrial appendage opening boundary, center, maximum and minimum diameters on the left atrial three-dimensional model and in the CT image; after obtaining the results of the surgical path calculation module, highlighting the atrial septal puncture site on the left atrial appendage three-dimensional model, and generating a motion simulation animation of the left atrial appendage occluder delivery sheath.

[0061] In the specific implementation, Python language can be used to write a plug-in under the Slicer software platform to implement the system. First, write the left atrium segmentation module of the plug-in:

[0062] Use the Dicom file reading interface provided by Slicer to read the preoperative CT data of a patient undergoing left atrial appendage occlusion.

[0063] Read the segmentation threshold provided by the user (described later), and call the Threshold function (threshold-based segmentation), Is lands function (retain the maximum connected domain), and Smoothing function (morphological closing operation, filling holes) in the Segment Editor plug-in provided by Sl icer in turn to obtain the segmentation results of the left atrium and left atrial appendage, and call the three-dimensional model generation interface in the Segmentation plug-in to generate a three-dimensional model of the left atrium and left atrial appendage.

[0064] Write the left atrial appendage parameter calculation module of the plug-in:

[0065] The coordinates of the left atrial appendage opening marker points provided by the user (described later) are read, and the least squares function in the Numpy package is called to fit the coefficients of the plane equation where these marker points are located, and the normal vector of the plane is calculated accordingly. This is the equation and axial vector of the left atrial appendage opening plane.

[0066] By averaging the coordinates of the LAA opening marker points, a point located inside the LAA opening can be obtained. At the same time, according to the plane equation, a set of basis vectors of the plane can be easily obtained. By linearly combining the basis vectors, a displacement vector in the LAA opening plane can be obtained.

[0067] Applying this displacement vector to a point inside the obtained left atrial appendage opening can obtain another point in the left atrial appendage plane. Limit the coefficient of the basis vector to an integer, set the growth seed point to the inside point of the left atrial appendage opening obtained by the above-mentioned averaging, and set the growth condition to that the point after displacement must be located inside the left atrial appendage obtained by segmentation, so as to easily implement the regional growing algorithm in the left atrial appendage opening. In the process of regional growth, for each point grown to, it can also be judged whether its adjacent points can be grown to. If not, it can be judged that the point is a point on the boundary of the left atrial appendage opening. In this way, a series of points covering the inside of the left atrial appendage opening and distributed in a grid shape can be obtained, and it is known which points are located on the boundary of the left atrial appendage.

[0068] After obtaining a series of grid-shaped points covering the entire left atrial appendage opening, their coordinates can be averaged, thereby obtaining the coordinates of the center point of the left atrial appendage opening.

[0069] After obtaining the center point of the left atrial appendage opening and a series of points on the opening boundary, all line segments passing through the center of the left atrial appendage opening and with endpoints on the left atrial appendage boundary can be traversed to find the maximum and minimum values ​​as the maximum and minimum diameters of the left atrial appendage opening area.

[0070] Write a plug-in for the surgical path calculation module:

[0071] The module pre-sets an initial atrial septal puncture point. Regarding the setting of the initial atrial septal puncture point, it is only necessary to ensure that the position of the point is approximately located on the front of the left atrium.

[0072] From the left atrium segmentation results, all points whose distance from the point is less than a certain threshold, whose coordinate values ​​are integers, and located on the left atrium boundary are obtained, and these points are used as candidate atrial septum puncture sites.

[0073] For each candidate transatrial septal puncture site, take the inferior vena cava opening as the starting point and the inferior vena cava axis as the direction (the method of obtaining the inferior vena cava opening and the axis will be introduced later), set a certain step size, and traverse the points on the axis. Take this point as the starting point and the candidate transatrial septal puncture site as the end point to determine whether a circular arc with a radius equal to the radius of the curved section of the single-bend delivery sheath can be made. If so, we can determine the trajectory curve of the delivery sheath moving from the inferior vena cava to a candidate transatrial septal puncture site. We define these candidate transatrial septal puncture sites that can obtain the trajectory curve according to the above method as reachable transatrial septal puncture sites.

[0074] For each accessible atrial septal puncture site, the interval from 0° to 360° is traversed with a certain step size. This angle is the angle at which the portion of the delivery sheath located in the left atrium rotates around the tangent vector of the motion trajectory at the atrial septal puncture site after the delivery sheath passes through the atrial septum puncture and enters the left atrium.

[0075] For each rotation angle, under the above conditions and the radius of the curved section of the delivery sheath, a unique motion trajectory can be determined, and the portion inside the left atrium is taken as the motion trajectory after the delivery sheath enters the left atrium.

[0076] In this way, for each combination of accessible atrial septal puncture site and rotation angle, we can obtain a complete sheath motion trajectory, which is composed of the motion trajectory of the delivery sheath axially moving from the inferior vena cava to the atrial septal puncture site and the motion trajectory of the delivery sheath after passing through the atrial septal puncture site and entering the left atrium.

[0077] For the above motion trajectory, calculate its intersection with the left atrial appendage opening area. If there is no intersection, then discard this motion trajectory.

[0078] For the intersection point obtained above, the tangent vector of the motion trajectory curve at the intersection point is calculated, and the angle between the tangent vector and the normal vector of the left atrial appendage opening plane is calculated (recorded as parameter a), and the shortest distance from the intersection point to the left atrial appendage opening boundary is calculated (recorded as parameter b). We hope that parameter a is as small as possible to maintain the coaxiality between the left atrial appendage occluder and the left atrial appendage main axis, and we hope that parameter b is as large as possible. If the delivery sheath is too close to the left atrial appendage opening boundary, the occluder may not be released normally.

[0079] In addition, the length of the motion trajectory in the left atrial appendage (recorded as parameter c) needs to be calculated. We hope that parameter c is as large as possible. In principle, the length of the delivery sheath in the left atrial appendage needs to be greater than the diameter of the left atrial appendage occluder so that the occluder can be deployed normally.

[0080] After obtaining the above three parameters, a scoring function can be implemented to score the delivery sheath motion trajectory. In this example, the cosine value of parameter 1 multiplied by the square root of parameter 2 and parameter 3 are used as the scoring function. We select the atrial septal puncture site and rotation angle corresponding to the motion trajectory with the highest score as the optimal atrial septal puncture site and rotation angle, and record this motion trajectory with the highest score.

[0081] Write the user interaction module of the plug-in:

[0082] The Markups plug-in provided in Slicer is called and prompt information is output to prompt the user to specify two marking points of the left atrium on the two-dimensional CT image interface.

[0083] Call the Line Profile plug-in provided in Slicer to draw the pixel value distribution map on the line passing through the left atrium, and output a prompt message to prompt the user to determine the appropriate segmentation threshold based on the distribution map. Then read the segmentation threshold provided by the user and use it as the input of the left atrium segmentation module.

[0084] The left atrium 3D model output by the left atrium segmentation module is displayed in the 3D interface. The Markups plug-in provided in Slicer is called, and prompt information is output to prompt the user to specify the marking points of the left atrial appendage opening on the left atrium 3D model in the 3D interface (the number must be no less than three, as the input of the left atrial appendage parameter calculation module), and specify the marking points of the opening of the inferior vena cava and the marking points of the axial direction of the inferior vena cava in the 2D CT image interface (as the input of the surgical path calculation module). The left atrial appendage opening center coordinates, normal vector, left atrial appendage opening boundary points, maximum and minimum diameters output by the left atrial appendage parameter calculation module are read. The left atrial appendage opening center coordinates and normal vector are output in the command line for the user to view, and the Markups plug-in provided in Slicer is called to draw the left atrial appendage opening boundary points, maximum and minimum diameters in the 3D interface. For example, the maximum diameter of the left atrial appendage opening is 29.4mm, and the minimum diameter of the left atrial appendage opening is 18.7mm.

[0085] The delivery sheath motion trajectory output by the surgical path calculation module is read and divided into a series of arcs with smaller curvatures. The VTK package is called to draw these arcs in sequence on the 3D interface at certain time intervals to simulate the delivery sheath motion.

[0086] Compared with the prior art, the present invention has the following advantages:

[0087] First, the present invention performs relevant calculations based on the patient's preoperative CT images, and can obtain the three-dimensional structural information of the left atrium and left atrial appendage with higher resolution. Compared with the current method using two-dimensional imaging technology, the relevant parameters of the left atrial appendage can be obtained more accurately;

[0088] Second, the present invention can not only calculate the relevant parameters of the left atrial appendage, but also plan and simulate the surgical path based on the patient's preoperative CT imaging data, which is convenient for users to evaluate the difficulty of the operation; the optimal atrial septal puncture site and the motion trajectory curve of the left atrial appendage occluder delivery sheath obtained by the system have certain guiding significance for the operation;

[0089] Third, the present invention can visualize the left atrial appendage opening boundary, center, maximum and minimum diameters, atrial septal puncture site, and movement trajectory of the left atrial appendage occluder delivery sheath in two-dimensional and three-dimensional planes, allowing users to have a more intuitive understanding of left atrial appendage related parameters and surgical procedures;

[0090] Fourth, the present invention is easy to use, most of the processes can be completed automatically, and it is less dependent on user input, which can reduce the workload of users.

[0091] It can be seen that the patient's CT image data is read, the left atrium and left atrial appendage are segmented from the CT image data, and the corresponding binary three-dimensional image data are obtained; the left atrial appendage opening mark point set by the user is read, and the geometric parameters of the left atrial appendage opening are calculated in combination with the binary three-dimensional image data; the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava are read, the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium are calculated, and the corresponding delivery sheath motion trajectory curve is calculated, and the calculation results are output or visualized, so as to achieve more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, and help doctors evaluate the surgical process before surgery.

[0092] Another embodiment of the present invention provides a left atrial appendage occlusion simulation system based on CT images, see Figure 3 , the system may include:

[0093] The left atrium segmentation module 301 is used to read the CT image data of the patient, segment the left atrium and the left atrial appendage from the CT image data, and obtain the corresponding binary and three-dimensional image data;

[0094] The left atrial appendage parameter calculation module 302 is used to read the left atrial appendage opening mark point set by the user, and calculate the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0095] The surgical path calculation module 303 is used to read the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculate the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculate the corresponding delivery sheath motion trajectory curve, and output or visualize the calculation results.

[0096] It can be seen that the patient's CT image data is read, the left atrium and left atrial appendage are segmented from the CT image data, and the corresponding binary three-dimensional image data are obtained; the left atrial appendage opening mark point set by the user is read, and the geometric parameters of the left atrial appendage opening are calculated in combination with the binary three-dimensional image data; the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava are read, the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium are calculated, and the corresponding delivery sheath motion trajectory curve is calculated, and the calculation results are output or visualized, so as to achieve more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, and help doctors evaluate the surgical process before surgery.

[0097] An embodiment of the present invention further provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0098] Specifically, in this embodiment, the above storage medium may be configured to store a computer program for performing the following steps:

[0099] S201, reading CT image data of a patient, segmenting the left atrium and left atrial appendage from the CT image data, and obtaining corresponding binary three-dimensional image data;

[0100] S202, reading the left atrial appendage opening marking point set by the user, and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0101] S203, reads the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava, calculates the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculates the corresponding delivery sheath motion trajectory curve, and outputs or visualizes the calculation results.

[0102] It can be seen that the patient's CT image data is read, the left atrium and left atrial appendage are segmented from the CT image data, and the corresponding binary three-dimensional image data are obtained; the left atrial appendage opening mark point set by the user is read, and the geometric parameters of the left atrial appendage opening are calculated in combination with the binary three-dimensional image data; the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava are read, the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium are calculated, and the corresponding delivery sheath motion trajectory curve is calculated, and the calculation results are output or visualized, so as to achieve more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, and help doctors evaluate the surgical process before surgery.

[0103] An embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0104] Specifically, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0105] Specifically, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0106] S201, reading CT image data of a patient, segmenting the left atrium and left atrial appendage from the CT image data, and obtaining corresponding binary three-dimensional image data;

[0107] S202, reading the left atrial appendage opening marking point set by the user, and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data;

[0108] S203, reads the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava, calculates the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculates the corresponding delivery sheath motion trajectory curve, and outputs or visualizes the calculation results.

[0109] It can be seen that the patient's CT image data is read, the left atrium and left atrial appendage are segmented from the CT image data, and the corresponding binary three-dimensional image data are obtained; the left atrial appendage opening mark point set by the user is read, and the geometric parameters of the left atrial appendage opening are calculated in combination with the binary three-dimensional image data; the opening of the inferior vena cava set by the user and another arbitrary point on the inferior vena cava are read, the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium are calculated, and the corresponding delivery sheath motion trajectory curve is calculated, and the calculation results are output or visualized, so as to achieve more accurate left atrial appendage parameter acquisition, surgical path planning and three-dimensional simulation of the surgical process under three-dimensional conditions, and help doctors evaluate the surgical process before surgery.

[0110] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A left atrial appendage occlusion simulation method based on CT images, characterized in that: The method comprises: Reading CT image data of the patient, segmenting the left atrium and left atrial appendage from the CT image data, and obtaining corresponding binary and three-dimensional image data; Reading the left atrial appendage opening marking point set by the user, and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data; Read the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculate the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculate the corresponding delivery sheath motion trajectory curve, and output or visualize the calculation results.

2. The method according to claim 1, characterized in that The step of reading the CT image data of the patient, segmenting the left atrium and the left atrial appendage from the CT image data, and obtaining corresponding binary and three-dimensional image data includes: Reading CT image data of a patient, and performing mean filtering on the CT image data using a three-dimensional mean filter; Draw a distribution map for the pixel distribution on a straight line passing through the left atrium in the current CT image data, and read the segmentation threshold determined by the user using the distribution map; Use the segmentation threshold to perform binary segmentation on the current CT image data, and retain the maximum connected domain in the binary segmentation result; The holes are filled using the closing operation to obtain the segmentation results of the left atrium and left atrial appendage.

3. The method according to claim 2, characterized in that The geometric parameters of the left atrial appendage opening include: the shape of the left atrial appendage opening, the center coordinates, the maximum and minimum diameters, the equation of the left atrial appendage opening plane and the normal vector parameters; The reading of the left atrial appendage opening mark point set by the user and calculating the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data include: Read the coordinates of several left atrial appendage opening marking points set by the user on the left atrium three-dimensional model; The equation of the left atrial appendage opening plane is obtained by fitting the least square method, and the normal vector of the left atrial appendage opening plane and a group of basis vectors in the left atrial appendage opening plane are calculated according to the equation; Performing region growing in the plane determined by the basis vectors to obtain the shape and boundary of the left atrial appendage opening, and calculating the center of the left atrial appendage opening; All line segments passing through the center of the left atrial appendage opening and with endpoints on the opening boundary are traversed, and the maximum and minimum values ​​of all line segments are calculated as the maximum and minimum diameters of the left atrial appendage opening.

4. The method according to claim 3, characterized in that The method of reading the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculating the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, and calculating the corresponding delivery sheath motion trajectory curve includes: Reading the inferior vena cava opening mark point and another mark point on the inferior vena cava specified by the user in the CT image; Based on the CT image data, all points located on the left atrium boundary and whose distance from the initial atrial septal puncture site is less than a preset threshold are calculated as candidate atrial septal puncture sites, and all candidate atrial septal puncture sites are traversed to calculate the corresponding motion trajectory curve of the left atrial appendage occluder delivery sheath before entering the left atrium; For each atrial septal puncture site, the possible rotation angles of the delivery sheath after atrial septal puncture are traversed with a preset step length, and the corresponding motion trajectory curve of the delivery sheath after entering the left atrium is calculated; For the obtained motion trajectory curve, the angle between the tangent vector at the intersection of the motion trajectory curve with the left atrial appendage opening plane and the normal vector of the left atrial appendage opening plane, the shortest distance between the motion trajectory curve and the left atrial appendage opening boundary, and the length of the motion trajectory curve in the inner part of the left atrial appendage are calculated, and the combination of the candidate atrial septal puncture site and the rotation angle after puncture is scored according to the angle, the shortest distance and the length; The combination with the highest score is selected, the data in the selected combination is determined as the optimal atrial septum puncture site and the rotation angle after puncture, and the delivery sheath motion trajectory curve corresponding to the selected combination is determined as the optimal delivery sheath motion trajectory curve.

5. A left atrial appendage occlusion simulation system based on CT images, characterized in that: The system comprises: A left atrium segmentation module is used to read the patient's CT image data, segment the left atrium and left atrial appendage from the CT image data, and obtain corresponding binary and three-dimensional image data; A left atrial appendage parameter calculation module is used to read the left atrial appendage opening mark point set by the user, and calculate the geometric parameters of the left atrial appendage opening in combination with the binary and three-dimensional image data; The surgical path calculation module is used to read the opening of the inferior vena cava and another arbitrary point on the inferior vena cava set by the user, calculate the optimal atrial septum puncture site and the rotation angle of the left atrial appendage occluder delivery sheath after entering the left atrium, calculate the corresponding delivery sheath motion trajectory curve, and output or visualize the calculation results.

6. The system according to claim 5, characterized in that The left atrium segmentation module is specifically used for: Reading CT image data of a patient, and performing mean filtering on the CT image data using a three-dimensional mean filter; Draw a distribution map for the pixel distribution on a straight line passing through the left atrium in the current CT image data, and read the segmentation threshold determined by the user using the distribution map; Use the segmentation threshold to perform binary segmentation on the current CT image data, and retain the maximum connected domain in the binary segmentation result; The holes are filled using the closing operation to obtain the segmentation results of the left atrium and left atrial appendage.

7. The system according to claim 6, characterized in that The geometric parameters of the left atrial appendage opening include: the shape of the left atrial appendage opening, the center coordinates, the maximum and minimum diameters, the equation of the left atrial appendage opening plane and the normal vector parameters; The left atrial appendage parameter calculation module is specifically used for: Read the coordinates of several left atrial appendage opening marking points set by the user on the left atrium three-dimensional model; The equation of the left atrial appendage opening plane is obtained by fitting the least square method, and the normal vector of the left atrial appendage opening plane and a group of basis vectors in the left atrial appendage opening plane are calculated according to the equation; Performing region growing in the plane determined by the basis vectors to obtain the shape and boundary of the left atrial appendage opening, and calculating the center of the left atrial appendage opening; All line segments passing through the center of the left atrial appendage opening and with endpoints on the opening boundary are traversed, and the maximum and minimum values ​​of all line segments are calculated as the maximum and minimum diameters of the left atrial appendage opening.

8. The system according to claim 7, characterized in that The surgical path calculation module is specifically used for: Reading the inferior vena cava opening mark point and another mark point on the inferior vena cava specified by the user in the CT image; Based on the CT image data, all points located on the left atrium boundary and whose distance from the initial atrial septal puncture site is less than a preset threshold are calculated as candidate atrial septal puncture sites, and all candidate atrial septal puncture sites are traversed to calculate the corresponding motion trajectory curve of the left atrial appendage occluder delivery sheath before entering the left atrium; For each atrial septal puncture site, the possible rotation angles of the delivery sheath after atrial septal puncture are traversed with a preset step length, and the corresponding motion trajectory curve of the delivery sheath after entering the left atrium is calculated; For the obtained motion trajectory curve, the angle between the tangent vector at the intersection of the motion trajectory curve with the left atrial appendage opening plane and the normal vector of the left atrial appendage opening plane, the shortest distance between the motion trajectory curve and the left atrial appendage opening boundary, and the length of the motion trajectory curve in the inner part of the left atrial appendage are calculated, and the combination of the candidate atrial septal puncture site and the rotation angle after puncture is scored according to the angle, the shortest distance and the length; The combination with the highest score is selected, the data in the selected combination is determined as the optimal atrial septum puncture site and the rotation angle after puncture, and the delivery sheath motion trajectory curve corresponding to the selected combination is determined as the optimal delivery sheath motion trajectory curve.

9. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to execute the method according to any one of claims 1 to 4 when executed.

10. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to perform the method according to any one of claims 1 to 4.

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