Method for determining osteotomy parameters on three-dimensional tibia image based on two-dimensional and three-dimensional registration

Abstract

The invention provides a method for determining osteotomy parameters on a tibia three-dimensional image based on two-dimensional and three-dimensional registration, and the method comprises the steps: determining a target conversion matrix and a simulated tibia two-dimensional image similar to an actual tibia two-dimensional image based on the tibia three-dimensional image and a simulated light source, the target transformation matrix represents the spatial transformation relation between the spatial attitude of the tibia when the tibia is matched with the tibia three-dimensional image and the spatial attitude of the tibia when the tibia is matched with the actual tibia two-dimensional image; determining simulated osteotomy points and simulated hinge points on the simulated tibia two-dimensional image based on planned osteotomy points and planned hinge points pre-marked on the actual tibia two-dimensional image by a user; performing spatial transformation on the simulated light source, the simulated osteotomy point and the simulated hinge point based on the target transformation matrix to obtain a transformation light source, a two-dimensional osteotomy point and a two-dimensional hinge point matched with the spatial attitude of the tibia three-dimensional image; and determining osteotomy parameters based on the conversion light source, the two-dimensional osteotomy points and the two-dimensional hinge points.

Description

Technical Field

[0001] The present disclosure relates to the field of computer-aided planning technologies, and particularly to a method for determining osteotomy parameters on a three-dimensional (3D) tibia image based on two-dimensional (2D)-3D registration. Background Art

[0002] High Tibial Osteotomy (HTO) is an important surgical method for treating early and mid-stage knee osteoarthritis. It mainly transfers the lower limb force line from the affected compartment to the normal compartment by osteotomy at the proximal tibia, so as to relieve knee pain and improve knee joint function.

[0003] Before the HTO surgery, the doctor will plan the osteotomy line based on the X-ray film of the patient in the weight-bearing position. However, the planning method based on 2D image data is difficult to reflect the complexity of the patient's 3D anatomical structure. Especially in complex cases, the 2D method has limitations in force line analysis and osteotomy positioning, which may cause the osteotomy surface to deviate from the ideal position in 3D space, thus affecting the postoperative effect. If the doctor plans on a 3D image, the design of the osteotomy surface will become complex, resulting in a longer time consumption. Summary of the Invention

[0004] In view of this, the present disclosure provides a method for determining osteotomy parameters on a 3D tibia image based on 2D-3D registration, including: determining a target transformation matrix and a simulated tibia 2D image similar to the actual tibia 2D image based on the 3D tibia image and a simulated light source, wherein the target transformation matrix represents the spatial transformation relationship between the spatial posture of the tibia when matching with the 3D tibia image and the spatial posture of the tibia when matching with the actual tibia 2D image, and the simulated light source is configured to simulate the actual light source used to form the actual tibia 2D image; determining a simulated osteotomy point and a simulated hinge point on the simulated tibia 2D image based on the pre-marked planned osteotomy point and planned hinge point on the actual tibia 2D image by a user; performing spatial transformation on the simulated light source, the simulated osteotomy point, and the simulated hinge point based on the target transformation matrix to obtain a transformed light source, a 2D osteotomy point, and a 2D hinge point that match the spatial posture of the 3D tibia image; and determining the osteotomy parameters based on the transformed light source, the 2D osteotomy point, and the 2D hinge point.

[0005] Optionally, based on the three-dimensional tibia image and the simulated light source, determining a target transformation matrix and a simulated two-dimensional tibia image similar to the actual two-dimensional tibia image includes: generating a predicted two-dimensional tibia image based on the simulated light source and the three-dimensional tibia image; performing a spatial transformation on the three-dimensional tibia image using a predetermined transformation matrix to update the predicted two-dimensional tibia image; and when the predicted two-dimensional tibia image is similar to the actual two-dimensional tibia image, determining the predetermined transformation matrix as the target transformation matrix and determining the predicted two-dimensional tibia image as the simulated two-dimensional tibia image.

[0006] Optionally, performing a spatial transformation on the simulated light source, the simulated osteotomy point, and the simulated hinge point based on the target transformation matrix to obtain a transformed light source, a two-dimensional osteotomy point, and a two-dimensional hinge point that match the spatial pose of the three-dimensional tibia image includes: determining the inverse matrix of the target transformation matrix based on the target transformation matrix; and performing a spatial transformation on the simulated light source, the simulated osteotomy point, and the simulated hinge point using the inverse matrix to obtain the transformed light source, the two-dimensional osteotomy point, and the two-dimensional hinge point.

[0007] Optionally, determining the simulated osteotomy point and the simulated hinge point on the simulated two-dimensional tibia image based on the planned osteotomy point and the planned hinge point pre-marked by the user on the actual two-dimensional tibia image includes: establishing a first coordinate system with the vertex of the actual two-dimensional tibia image as the origin; establishing a second coordinate system with the center point of the three-dimensional tibia image as the origin; and based on the positional relationship between the actual light source, the tibia, and the actual two-dimensional tibia image when forming the actual two-dimensional tibia image, converting the coordinates of the planned osteotomy point and the planned hinge point in the first coordinate system into coordinates in the second coordinate system to obtain the simulated osteotomy point and the simulated hinge point.

[0008] Optionally, the method further includes: cropping the region of interest in the three-dimensional leg image to obtain the three-dimensional tibia image; and cropping the region of interest in the two-dimensional leg image to obtain the actual two-dimensional tibia image.

[0009] Optionally, determining the osteotomy parameters based on the transformed light source, the two-dimensional osteotomy point, and the two-dimensional hinge point includes: establishing a third coordinate system with the reference point of the three-dimensional tibia image as the origin; converting the coordinates of the transformed light source, the two-dimensional osteotomy point, and the two-dimensional hinge point in the second coordinate system into coordinates in the third coordinate system to obtain a target light source, a target osteotomy point, and a target hinge point; and determining the osteotomy parameters based on the target light source, the target osteotomy point, the target hinge point, and the coronal plane of the tibia.

[0010] Optionally, the osteotomy parameters include the normal vector of the osteotomy plane. Based on the target light source, the target osteotomy point, the target hinge point, and the coronal plane of the tibia, determining the osteotomy parameters includes: determining a first direction vector based on the target light source and the target osteotomy point; determining a second direction vector based on the target light source and the target hinge point; and determining the normal vector of the osteotomy plane based on the first direction vector and the second direction vector.

[0011] Optionally, the osteotomy parameters include a three-dimensional hinge point, and the intersection point of the second direction vector and the coronal plane is the three-dimensional hinge point.

[0012] Optionally, the osteotomy parameters include a rotation axis, and the rotation axis passes through the three-dimensional hinge point and is perpendicular to the coronal plane.

[0013] Optionally, the method further includes performing noise reduction processing on the three-dimensional tibia image.

[0014] According to an embodiment of the present disclosure, based on the three-dimensional tibia image and the simulated light source, a target transformation matrix and a simulated two-dimensional tibia image similar to the actual two-dimensional tibia image can be determined. Since the spatial pose of the simulated two-dimensional tibia image is the same as that of the actual two-dimensional tibia image, the pre-marked planned osteotomy point and planned hinge point on the actual two-dimensional tibia image can be mapped to the simulated two-dimensional tibia image, so that the simulated osteotomy point and simulated hinge point corresponding to the three-dimensional tibia image can be determined. Performing a spatial transformation on the simulated light source, the simulated osteotomy point, and the simulated hinge point based on the target transformation matrix can obtain a transformed light source, a two-dimensional osteotomy point, and a two-dimensional hinge point that match the spatial pose of the three-dimensional tibia image. Since the two-dimensional osteotomy point and the two-dimensional hinge point match the spatial pose of the three-dimensional tibia image, the planned osteotomy point and the planned hinge point match the spatial pose of the actual two-dimensional tibia image, and the positional relationship between the planned osteotomy point and the planned hinge point can be represented by the positional relationship between the two-dimensional osteotomy point and the two-dimensional hinge point, the osteotomy parameters can be determined on the three-dimensional tibia image by using the two-dimensional osteotomy point and the two-dimensional hinge point. Description of the Drawings

[0015] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0016] Figure 1 Schematically shows a flowchart of a method for determining osteotomy parameters on a three-dimensional tibia image based on two-dimensional and three-dimensional registration according to an embodiment of the present invention.

[0017] Figure 2 Schematically shows an actual two-dimensional tibia image according to an embodiment of the present invention.

[0018] Figure 3 Schematically shows a three-dimensional image of the tibia according to an embodiment of the present invention.

[0019] Figure 4 Schematically shows a relationship diagram of a three-dimensional image of the tibia, a simulated two-dimensional image of the tibia, and the position of a simulated light source according to an embodiment of the present invention. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments and the accompanying drawings. However, the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated, and the same reference numerals throughout the drawings denote the same elements.

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0022] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0023] All terms used herein (including technical and scientific terms) 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.

[0024] To facilitate the understanding of the technical solutions of the present invention by those skilled in the art, the following technical terms are now explained.

[0025] In the case of using an expression such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). In the case of using an expression such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0026] Figure 1 A flowchart of a method for determining osteotomy parameters on a three-dimensional tibia image based on two-dimensional and three-dimensional registration according to an embodiment of the present invention is schematically shown. Figure 2 An actual two-dimensional tibia image according to an embodiment of the present invention is schematically shown. Figure 3 A three-dimensional tibia image according to an embodiment of the present invention is schematically shown. Figure 4 A positional relationship diagram of a three-dimensional tibia image, a simulated two-dimensional tibia image, and a simulated light source according to an embodiment of the present invention is schematically shown.

[0027] As Figures 1 - 4 shown, an embodiment of the present invention provides a method 100 for determining osteotomy parameters on a three-dimensional tibia image based on two-dimensional and three-dimensional registration. The method 100 may include the following operations S110 to S140.

[0028] In operation S110, based on the three-dimensional tibia image and the simulated light source, a target transformation matrix and a simulated two-dimensional tibia image similar to the actual two-dimensional tibia image are determined.

[0029] According to the implementation of the present disclosure, the simulated light source can be used to simulate the actual light source for forming the actual two-dimensional tibia image. The three-dimensional tibia image can be used to simulate the human tibia. The positional relationship between the simulated light source and the three-dimensional tibia image can be the same as the positional relationship between the actual light source and the human tibia when forming the actual two-dimensional tibia image. The process of generating the simulated two-dimensional tibia image using the simulated light source and the three-dimensional tibia image can be a process of simulating the process of imaging the human tibia with the actual light source to form the actual two-dimensional tibia image.

[0030] According to the implementation of the present disclosure, the target transformation matrix can represent the spatial transformation relationship between the spatial posture of the tibia when matching with the three-dimensional tibia image and the spatial posture of the tibia when matching with the actual two-dimensional tibia image. Further, during the two-dimensional imaging and three-dimensional imaging of the human tibia, the spatial postures of the human body may not be consistent, which may lead to different spatial postures of the tibia reflected by the three-dimensional tibia image and the actual two-dimensional tibia image. The target transformation matrix can be used to transform the three-dimensional tibia image into a posture with the same spatial posture as that represented by the actual two-dimensional tibia image.

[0031] In operation S120, based on the planned osteotomy points and planned hinge points pre-marked by the user on the actual two-dimensional tibia image, the simulated osteotomy points and simulated hinge points on the simulated two-dimensional tibia image are determined.

[0032] According to the embodiments of the present disclosure, since the spatial posture of the simulated two-dimensional tibia image is the same as that of the actual two-dimensional tibia image, the planned osteotomy points and planned hinge points pre-marked on the actual two-dimensional tibia image can be mapped to the simulated two-dimensional tibia image, so that the simulated osteotomy points and simulated hinge points matching the spatial posture of the three-dimensional tibia image can be determined.

[0033] In operation S130, based on the target transformation matrix, spatial transformation is performed on the simulated light source, simulated osteotomy points, and simulated hinge points to obtain a transformed light source, two-dimensional osteotomy points, and two-dimensional hinge points that match the spatial posture of the three-dimensional tibia image.

[0034] According to the embodiments of the present disclosure, since the two-dimensional osteotomy points and two-dimensional hinge points are determined by the planned osteotomy points and planned hinge points, the relationship between the two-dimensional osteotomy points and two-dimensional hinge points can be characterized as the relationship between the planned osteotomy points and planned hinge points.

[0035] In operation S140, based on the transformed light source, two-dimensional osteotomy points, and two-dimensional hinge points, osteotomy parameters are determined.

[0036] According to an embodiment of the present disclosure, based on a three-dimensional tibia image and a simulated light source, a target transformation matrix and a simulated two-dimensional tibia image similar to the actual two-dimensional tibia image can be determined. Since the spatial pose of the simulated two-dimensional tibia image is the same as that of the actual two-dimensional tibia image, the pre-marked planned osteotomy points and planned hinge points on the actual two-dimensional tibia image can be mapped onto the simulated two-dimensional tibia image, so that the simulated osteotomy points and simulated hinge points corresponding to the three-dimensional tibia image can be determined. Based on the target transformation matrix, spatial transformation is performed on the simulated light source, simulated osteotomy points, and simulated hinge points, and a transformed light source, two-dimensional osteotomy points, and two-dimensional hinge points that match the spatial pose of the three-dimensional tibia image can be obtained. Since the two-dimensional osteotomy points and two-dimensional hinge points match the spatial pose of the three-dimensional tibia image, the planned osteotomy points and planned hinge points match the spatial pose of the actual two-dimensional tibia image, and the positional relationship between the planned osteotomy points and the planned hinge points can be represented by the positional relationship between the two-dimensional osteotomy points and the two-dimensional hinge points, osteotomy parameters can be determined on the three-dimensional tibia image by using the two-dimensional osteotomy points and the two-dimensional hinge points.

[0037] In some embodiments, operation S110 may include the following operations S111 to S113.

[0038] In operation S111, based on the simulated light source and the three-dimensional tibia image, a predicted two-dimensional tibia image is generated.

[0039] According to an embodiment of the present disclosure, the process of generating a predicted two-dimensional tibia image by using the simulated light source and the three-dimensional tibia image may simulate the process of imaging the human tibia with an actual light source to form an actual two-dimensional tibia image.

[0040] In operation S112, the three-dimensional tibia image is spatially transformed by using a predetermined transformation matrix to update the predicted two-dimensional tibia image.

[0041] In operation S113, when the predicted two-dimensional tibia image is similar to the actual two-dimensional tibia image, the predetermined transformation matrix is determined as the target transformation matrix, and the predicted two-dimensional tibia image is determined as the simulated two-dimensional tibia image.

[0042] According to an embodiment of the present disclosure, based on a similarity metric function, it can be determined whether the predicted two-dimensional tibia image is similar to the actual two-dimensional tibia image. For example, the normalized mutual information can be used to determine whether the predicted two-dimensional tibia image is similar to the actual two-dimensional tibia image.

[0043] According to an embodiment of the present disclosure, the predetermined transformation matrix may be a variable transformation matrix. When the predicted two-dimensional tibia image is not similar to the actual two-dimensional tibia image, the predetermined transformation matrix is adjusted to make the predicted two-dimensional tibia image similar to the actual two-dimensional tibia image, so as to achieve the registration of the two-dimensional / three-dimensional of the three-dimensional tibia image.

[0044] In some embodiments, the actual two-dimensional tibia image can be obtained by cropping the two-dimensional leg image. Specifically, the region of interest in the two-dimensional leg image can be cropped to obtain the actual two-dimensional tibia image. The two-dimensional leg image can be an X-ray image.

[0045] In some embodiments, the three-dimensional tibia image can be obtained by cropping the three-dimensional leg image. Specifically, the region of interest in the three-dimensional leg image can be cropped to obtain the three-dimensional tibia image. The three-dimensional leg image can be a CT image.

[0046] According to an embodiment of the present disclosure, the region of interest can be set by a doctor according to the need of osteotomy line planning.

[0047] According to an embodiment of the present disclosure, the doctor can manually select points in the two-dimensional leg image or use the trained "two-dimensional force line key point recognition model" to obtain the center of the femoral head, the highest point of the greater trochanter of the femur, the lateral point of the tangent line of the distal femur, the medial point of the tangent line of the distal femur, the lateral point of the tangent line of the proximal tibia, the medial point of the tangent line of the proximal tibia, the lateral point of the tangent line of the distal tibia, the medial point of the tangent line of the distal tibia, etc. Further, the lower limb mechanical axis, the femoral mechanical axis, the tibial mechanical axis, the line connecting the center of the femoral head and the highest point of the greater trochanter of the femur, the medial and lateral condyle tangent lines of the distal femur, the medial and lateral tibial plateau tangent lines, the distal tibia tangent line, etc. are generated. According to the connection lines, information such as the length of the lower limbs, the lateral proximal femoral angle (LPFA), the lateral distal femoral angle (LDFA), the medial proximal tibial angle (MPTA), the lateral distal tibial angle (LDTA), the joint line convergence angle (JLCA), etc. is further generated.

[0048] Furthermore, the doctor can manually plan and select the osteotomy point and the hinge point according to the information obtained above, or use the trained "two-dimensional force line key point recognition model" to obtain the osteotomy point and the hinge point. Taking the medial opening wedge high tibial osteotomy as an example, the hinge point can be set at about 1.5 cm below the lateral tibial plateau, and the osteotomy point can be set at about 4 cm below the medial tibial plateau.

[0049] In some embodiments, operation S120 may include the following operations S121 to S124.

[0050] In operation S121, a first coordinate system is established with the vertex of the actual two-dimensional tibia image as the origin.

[0051] According to an embodiment of the present disclosure, the size of the actual tibia two-dimensional image can be expressed as . Among them, can be expressed as the width of the actual tibia two-dimensional image. can be expressed as the height of the actual tibia two-dimensional image.

[0052] According to an embodiment of the present disclosure, the origin coordinates of the first coordinate system can be expressed as . The origin coordinates of the first coordinate system can be determined by the position of the actual tibia two-dimensional image in the world coordinate system.

[0053] In operation S122, a second coordinate system is established with the center point of the tibia three-dimensional image as the origin.

[0054] According to an embodiment of the present disclosure, the size of the tibia three-dimensional image can be expressed as . can be expressed as the width of the tibia three-dimensional image. can be expressed as the height of the tibia three-dimensional image. can be expressed as the length of the tibia three-dimensional image.

[0055] According to an embodiment of the present disclosure, the origin coordinates of the second coordinate system in the second coordinate system can be expressed as .

[0056] According to an embodiment of the present disclosure, the coordinates of the vertex of the simulated tibia two-dimensional image in the second coordinate system can be expressed by the following expression (1).

[0057] (1).

[0058] Among them, can be expressed as the source image distance when generating the actual tibia two-dimensional image. can be expressed as the source center distance when generating the actual tibia two-dimensional image.

[0059] According to an embodiment of the present disclosure, the coordinates of the simulated light source in the second coordinate system can be expressed by the following expression (2).

[0060] (2).

[0061] In operation S123, based on the positional relationship among the actual light source, the tibia, and the actual two-dimensional tibia image when forming the actual two-dimensional tibia image, the coordinates of the planned osteotomy point and the planned hinge point in the first coordinate system are converted into the coordinates in the second coordinate system to obtain the simulated osteotomy point and the simulated hinge point.

[0062] According to an embodiment of the present disclosure, the planned osteotomy point in the first coordinate system can be represented by the following expression (3).

[0063] (3).

[0064] Wherein, is 0, and are set by the doctor when planning the osteotomy line.

[0065] According to an embodiment of the present disclosure, the planned hinge point in the first coordinate system can be represented by the following expression (4).

[0066] (4).

[0067] Wherein, is 0, and are set by the doctor when planning the osteotomy line.

[0068] According to an embodiment of the present disclosure, the coordinates of the simulated osteotomy point in the second coordinate system can be represented by the following expression (5).

[0069] (5).

[0070] According to an embodiment of the present disclosure, the coordinates of the simulated hinge point in the second coordinate system can be represented by the following expression (6).

[0071] (6).

[0072] In some embodiments, operation S130 may include the following operations S131 to S132.

[0073] In operation S131, based on the target transformation matrix, the inverse matrix of the target transformation matrix is determined.

[0074] According to an embodiment of the present disclosure, the target transformation matrix can be represented by the following expression (7).

[0075] (7).

[0076] Among them, , , , , , , , , , , and are the parameters of the target transformation matrix and can be adjusted as needed.

[0077] According to an embodiment of the present disclosure, the inverse matrix of the target transformation matrix can be represented by the following expression (8). (8).

[0078] (8).

[0079] In operation S132, the inverse matrix is used to perform a spatial transformation on the simulated light source, the simulated osteotomy point, and the simulated hinge point to obtain the transformed light source, the two-dimensional osteotomy point, and the two-dimensional hinge point.

[0080] According to an embodiment of the present disclosure, the coordinates of the transformed light source in the second coordinate system can be represented by the following expression (9).

[0081] (9).

[0082] According to an embodiment of the present disclosure, the coordinates of the two-dimensional osteotomy point in the second coordinate system can be represented by the following expression (10).

[0083] (10).

[0084] According to an embodiment of the present disclosure, the coordinates of the two-dimensional hinge point in the second coordinate system can be represented by the following expression (11).

[0085] (11).

[0086] In some embodiments, operation S140 may include the following operations S141 to S143.

[0087] In operation S141, a third coordinate system is established with the reference point of the three-dimensional tibia image as the origin.

[0088] According to an embodiment of the present disclosure, the coordinates of the reference point of the three-dimensional tibia image in the third coordinate system can be expressed as The reference points of the three-dimensional tibia image are in the third coordinate system The coordinates in the third coordinate system can be determined by the position of the three-dimensional tibia image in the world coordinate system. The reference points can be set by the doctor according to experience.

[0089] According to the embodiments of the present disclosure, the coordinates of the center of the three-dimensional tibia image in the third coordinate system can be expressed as .

[0090] In operation S142, the coordinates of the simulated light source, the two-dimensional osteotomy point, and the two-dimensional hinge point in the second coordinate system are converted into the coordinates in the third coordinate system to obtain the target light source, the target osteotomy point, and the target hinge point.

[0091] According to the embodiments of the present disclosure, the target light source can be represented by the following expression (12).

[0092] (12).

[0093] According to the embodiments of the present disclosure, the target osteotomy point can be represented by the following expression (13).

[0094] (13).

[0095] According to the embodiments of the present disclosure, the target hinge point can be represented by the following expression (14).

[0096] (14).

[0097] In operation S143, based on the target light source, the target osteotomy point, the target hinge point, and the coronal plane of the tibia, the osteotomy parameters are determined.

[0098] In some embodiments, the osteotomy parameters include the normal vector of the osteotomy plane. Operation S143 may include the following operations.

[0099] Based on the target light source and the target osteotomy point, a first direction vector is determined.

[0100] Based on the target light source and the target hinge point, a second direction vector is determined.

[0101] Based on the first direction vector and the second direction vector, the normal vector of the osteotomy plane is determined.

[0102] According to the embodiments of the present disclosure, the first direction vector can be represented by the following expression (15).

[0103] (15).

[0104] According to an embodiment of the present disclosure, the second direction vector can be represented by the following expression (16).

[0105] (16).

[0106] According to an embodiment of the present disclosure, the normal vector of the osteotomy surface can be represented by the following expression (17).

[0107] (17).

[0108] In some embodiments, the osteotomy parameters include a three-dimensional hinge point, and the intersection of the second direction vector and the coronal plane is the three-dimensional hinge point.

[0109] According to an embodiment of the present disclosure, the coronal plane can be directly determined by the user on the three-dimensional tibia image, or can be determined based on the three-dimensional leg image. Preferably, the coronal plane is determined based on the three-dimensional leg image, and information of other parts of the leg can be referred to, thereby improving the accuracy.

[0110] According to an embodiment of the present disclosure, the three-dimensional hinge point can be represented by the following expression (18).

[0111] (18).

[0112] In some embodiments, the osteotomy parameters include a rotation axis, and the rotation axis passes through the three-dimensional hinge point and is perpendicular to the coronal plane.

[0113] According to an embodiment of the present disclosure, the rotation axis can be expressed as .

[0114] In some embodiments, the method may further include performing noise reduction processing on the three-dimensional tibia image to reduce the influence of noise.

[0115] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0116] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A method for determining osteotomy parameters on a three-dimensional image of a tibia based on two-dimensional and three-dimensional registration, characterized in that: include: Based on the three-dimensional image of the tibia and the simulated light source, determining a target transformation matrix and a simulated two-dimensional image of the tibia that is similar to the actual two-dimensional image of the tibia, wherein the target transformation matrix represents a spatial transformation relationship between a spatial posture of the tibia when matching the three-dimensional image of the tibia and a spatial posture of the tibia when matching the actual two-dimensional image of the tibia, and the simulated light source is configured to simulate an actual light source used to form the actual two-dimensional image of the tibia; Determine a simulated osteotomy point and a simulated hinge point on the simulated tibia two-dimensional image based on the planned osteotomy point and the planned hinge point pre-marked by the user on the actual tibia two-dimensional image; Based on the target transformation matrix, the simulated light source, the simulated osteotomy point and the simulated hinge point are spatially transformed to obtain a transformed light source, a two-dimensional osteotomy point and a two-dimensional hinge point that match the spatial posture of the three-dimensional image of the tibia; The osteotomy parameters are determined based on the conversion light source, the two-dimensional osteotomy point and the two-dimensional hinge point.

2. The method according to claim 1, characterized in that Determining a target transformation matrix and a simulated tibia two-dimensional image similar to an actual tibia two-dimensional image based on the tibia three-dimensional image and the simulated light source includes: generating a predicted two-dimensional image of the tibia based on the simulated light source and the three-dimensional image of the tibia; Performing spatial transformation on the three-dimensional tibia image using a predetermined transformation matrix to update the predicted two-dimensional tibia image; and In a case where the predicted tibia two-dimensional image is similar to the actual tibia two-dimensional image, the predetermined transformation matrix is ​​determined as the target transformation matrix, and the predicted tibia two-dimensional image is determined as the simulated tibia two-dimensional image.

3. The method according to claim 2, characterized in that The simulated light source, the simulated osteotomy point and the simulated hinge point are spatially transformed based on the target transformation matrix to obtain a transformed light source, a two-dimensional osteotomy point and a two-dimensional hinge point that match the spatial posture of the three-dimensional image of the tibia, including: Based on the target transformation matrix, determining an inverse matrix of the target transformation matrix; and The simulated light source, the simulated osteotomy point and the simulated hinge point are spatially transformed by using the inverse matrix to obtain a converted light source, the two-dimensional osteotomy point and the two-dimensional hinge point.

4. The method according to claim 1, characterized in that: Determining a simulated osteotomy point and a simulated hinge point on the simulated tibia two-dimensional image based on the planned osteotomy point and the planned hinge point pre-marked by the user on the actual tibia two-dimensional image includes: Establishing a first coordinate system with the vertex of the actual tibia two-dimensional image as the origin; Establishing a second coordinate system with the center point of the tibia three-dimensional image as the origin; Based on the positional relationship between the actual light source and the tibia and the actual two-dimensional image of the tibia when forming the actual two-dimensional image of the tibia, the coordinates of the planned osteotomy point and the planned hinge point in the first coordinate system are converted into coordinates in the second coordinate system to obtain the simulated osteotomy point and the simulated hinge point.

5. The method according to claim 1, characterized in that Also includes: Cutting the region of interest in the three-dimensional image of the leg to obtain the three-dimensional image of the tibia; as well as The region of interest in the two-dimensional image of the leg is cropped to obtain the actual two-dimensional image of the tibia.

6. The method according to claim 4, characterized in that Determining the osteotomy parameters based on the conversion light source, the two-dimensional osteotomy point and the two-dimensional hinge point includes: Establishing a third coordinate system with the reference point of the tibia three-dimensional image as the origin; Convert the coordinates of the conversion light source, the two-dimensional osteotomy point and the two-dimensional hinge point in the second coordinate system into coordinates in the third coordinate system to obtain a target light source, a target osteotomy point and a target hinge point; and The osteotomy parameters are determined based on the target light source, the target osteotomy point, the target hinge point, and the coronal plane of the tibia.

7. The method according to claim 6, characterized in that The osteotomy parameters include a normal vector of the osteotomy surface. The osteotomy parameters are determined based on the target light source, the target osteotomy point, the target hinge point, and the coronal plane of the tibia, including: Determining a first direction vector based on the target light source and the target osteotomy point; Determining a second direction vector based on the target light source and the target hinge point; and Based on the first direction vector and the second direction vector, a normal vector of the osteotomy surface is determined.

8. The method according to claim 7, characterized in that The osteotomy parameters include a three-dimensional hinge point, and the intersection of the second direction vector and the coronal plane is the three-dimensional hinge point.

9. The method according to claim 8, characterized in that The osteotomy parameters include a rotation axis, which passes through a three-dimensional hinge point and is perpendicular to the coronal plane.

10. The method according to claim 1, characterized in that The method also includes performing noise reduction processing on the three-dimensional image of the tibia.

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