Real-time puncture guidance evaluation system based on soft tissue deformation field

Abstract

The application discloses a real-time puncture guiding evaluation system based on soft tissue deformation field, which comprises a registration system for registering CT images and real-time ultrasonic images in operation and forming a point cloud graph through interpolation point supplementing, a deformation field determination system for determining a soft tissue deformation field, a guiding line simulation system for forming a new preoperative planning puncture guiding line in combination with the soft tissue deformation field and the registration system according to a real puncture guiding line of preoperative planning, and a comparison system for comparing the deviation of the new preoperative planning line from the real puncture guiding line with a set deviation threshold value. The application can automatically judge whether a preoperative puncture path is feasible, improves the efficiency of operation, converts the preoperative planning path to a real-time intraoperative scene, facilitates the operation of doctors, accurately registers local soft tissue deformation and reduces the operation burden of doctors.

Description

Technical Field

[0001] This invention relates to the field of puncture treatment guidance and evaluation technology, and in particular to a real-time puncture guidance and evaluation system based on soft tissue deformation field. Background Technology

[0002] Aspiration, a common medical surgical term, is a diagnostic and treatment technique that involves inserting a needle into a body cavity to extract secretions for testing, injecting gas or contrast agents into the cavity for imaging examinations, or injecting medication into the cavity. The purposes of aspiration include blood sampling, blood transfusions, intravenous infusions, and catheter placement for angiography.

[0003] Puncture surgery is highly dependent on the doctor's experience and condition. Therefore, purely manual puncture is being replaced by puncture stents. The method of using puncture stents often involves planning the puncture path by reviewing CT scans before the puncture surgery. During the surgery, the position of the puncture stent is adjusted to the previously planned path for puncture. However, since human soft tissues inevitably deform, real-time ultrasound imaging is often required to determine whether the path has deviated.

[0004] Currently, there is a lack of an evaluation system for real-time puncture guidance, and doctors are left to determine whether the puncture path is feasible. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a real-time puncture-guided evaluation system based on soft tissue deformation field.

[0006] The real-time puncture-guided evaluation system based on soft tissue deformation field proposed in this invention includes:

[0007] A registration system used to register CT images with real-time ultrasound images during surgery and to form a point cloud map by interpolation.

[0008] Deformation field determination system for determining the deformation field of soft tissue;

[0009] A guide line simulation system used to form a new preoperatively planned puncture guide line based on the actual puncture guide line planned in the preoperative procedure, combined with the soft tissue deformation field and the registration system;

[0010] A comparison system used to compare the deviation between the new preoperative planning line and the actual puncture guide line with a set deviation threshold.

[0011] The operating method of the real-time puncture-guided evaluation system based on soft tissue deformation field proposed in this invention includes the following steps:

[0012] S1: Registration is performed using a registration system to register preoperative CT images with intraoperative real-time ultrasound images, providing floating and target images. The ultrasound image point cloud map is converted to the coordinate system of the CT point cloud map, and points are filled between the converted ultrasound image points through interpolation for pixel recovery of deformed tissues.

[0013] S2: The deformation field of soft tissue is confirmed by the deformation field determination system. The gray values ​​of CT images and ultrasound images are used as random variables and their corresponding probability distributions are combined to obtain the similarity standard value. The registration success is evaluated by the similarity standard value. The deformation field is optimized to increase the similarity standard value. Based on the similarity standard value, the optimal deformation field is converged.

[0014] S3: Through the guide line simulation system, the preoperatively planned real puncture guide line is represented in the deformed real model to form a new preoperatively planned puncture guide line;

[0015] S4: The deviation E between the new preoperative planning line and the actual puncture guide line is set by the comparison system, and the deviation E is compared with the deviation threshold.

[0016] As a further optimization of this technical solution, the present invention provides an operation method for a real-time puncture-guided evaluation system based on soft tissue deformation field. In the registration process, S1 involves covering the image with a network, and the intersections of the network are the control points of the image, converting the control points on the ultrasound image grid into points on the CT image.

[0017] As a further optimization of this technical solution, the present invention provides an operation method for a real-time puncture-guided evaluation system based on soft tissue deformation field, wherein in S1, the points in the converted ultrasound images are filled by interpolation.

[0018] As a further optimization of this technical solution, the present invention provides an operation method for a real-time puncture guidance evaluation system based on soft tissue deformation field. In step S3, the preoperatively planned real puncture guidance line is converted into a real-time ultrasound image using the deformation field, becoming a new preoperatively planned puncture guidance line.

[0019] As a further optimization of this technical solution, the present invention provides an operating method for a real-time puncture-guided evaluation system based on soft tissue deformation field, wherein the deviation in S4... distance(x) is the shortest distance from a point on one curve to another curve. If E is not greater than the set deviation threshold, the planned puncture path can be used for puncture. Otherwise, the planned path is not conducive to puncture and the path should be replanned based on ultrasound during the operation.

[0020] In summary, the beneficial effects of this invention are as follows:

[0021] 1. This evaluation method can automatically determine whether the puncture path is feasible before the operation, thus improving the efficiency of the operation.

[0022] 2. By using a deformation field, the preoperative planned path can be transferred to the real-time intraoperative scene, which also facilitates the doctor's operation.

[0023] 3. By utilizing deformation fields, precise registration of local soft tissue deformations can be achieved, reducing the surgical burden on doctors. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a CT image used in this invention;

[0025] Figure 2 This is a schematic diagram of an ultrasound image used in this invention;

[0026] Figure 3 This is a schematic diagram of the ultrasound image after coordinate transformation in this invention;

[0027] Figure 4 This is a schematic diagram of the actual puncture guide line L and the new preoperative planning puncture guide line L' in this invention. Detailed Implementation

[0028] The following will refer to the appendices in the embodiments of the present invention. Figures 1-4 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] The real-time puncture-guided evaluation system based on soft tissue deformation field proposed in this invention includes:

[0030] A registration system used to register CT images with real-time ultrasound images during surgery and to form a point cloud map by interpolation.

[0031] Deformation field determination system for determining the deformation field of soft tissue;

[0032] A guide line simulation system used to form a new preoperatively planned puncture guide line based on the actual puncture guide line planned in the preoperative procedure, combined with the soft tissue deformation field and the registration system;

[0033] A comparison system used to compare the deviation between the new preoperative planning line and the actual puncture guide line with a set deviation threshold.

[0034] Reference Figure 1-4 The operating method of the real-time puncture-guided evaluation system based on soft tissue deformation field proposed in this invention is characterized by the following steps:

[0035] S1: Perform registration, registering the preoperative CT images with the intraoperative real-time ultrasound images;

[0036] S1.1: Obtain preoperative CT images such as Figure 1 With real-time ultrasound images during surgery, such as Figure 2 Provides floating images and target images;

[0037] S1.2: Convert the ultrasound image point cloud map to the coordinate system of the CT point cloud map;

[0038] S1.2.1: During the registration process, a mesh is placed over the image, and the intersections of the mesh are the control points of the image;

[0039] S1.2.2: Convert points on the ultrasound image grid to points on the CT image using the following coordinate formula:

[0040]

[0041] in, For points on the CT image grid, Let R be a point on an ultrasound image grid, T be a rotation matrix, and T be a translation matrix. After coordinate transformation, the image becomes as follows: Figure 3 As shown, with the transformation of the coordinate system, the details inside the soft tissue will show local deformation. The ultrasound image is aligned with the CT image by using the points that do not undergo deformation.

[0042] S1.3: Fill the gaps between the points in the converted ultrasound image using interpolation.

[0043] S1.3.1: Given n three-dimensional control points, the formula for calculating the coordinates of the three-dimensional control points is as follows:

[0044]

[0045] Where c i (x i ,y i ,z i ), where i = 1, 2, ..., n are the coordinates of the control points;

[0046] S1.3.2: Given the regularization parameter λ, solve for the interpolation function and calculate the parameter values ​​w and a of the interpolation function, as shown in the following formula:

[0047]

[0048] Where K, P, and O are submatrices, and w, a, v, and o are column vectors, given by the following formula:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] S1.3.3: For any point in the z-interpolation, after calculating the parameter values ​​w and a of the interpolation function, the deformed ultrasound image can be obtained through interpolation.

[0056]

[0057] Pixel recovery for deformed tissues

[0058] S2: Soft tissue deformation field confirmation

[0059] S2.1: Measurement, based on similarity criteria, measures whether the registration was successful.

[0060] S2.1.1: Based on pixel value registration, the gray values ​​of CT images and ultrasound images are taken as random variables A and B, respectively. Their corresponding probability distributions p(a) and p(b) can be obtained from the histogram.

[0061]

[0062] Where n(a) represents the number of pixels in the CT image with a gray value of a, and n(b) represents the number of pixels in the ultrasound image with a gray value of a.

[0063] S2.1.2: Assess whether registration was successful

[0064]

[0065] P(a,b) is the similarity criterion; the larger the value, the more successful the registration.

[0066] S2-2: Optimize the deformation field, let [xyz] T and [x' y' z'] T Let V represent the three-dimensional coordinates of the same point on soft tissue in CT and ultrasound images. Then the deformation field V between them is:

[0067]

[0068] in Represents the rotation matrix. Let w represent the translation vector, and w represent the dimension of the deformation, which is a constant of 3, indicating that there is displacement along the x-axis, y-axis, and z-axis.

[0069] By iteratively optimizing the deformation field V to maximize P(a,b), the optimal deformation field V is converged based on the similarity criterion.

[0070] S3: The preoperatively planned real puncture guide line is represented in the deformed real model. The preoperatively planned real puncture guide line L is transformed into the real ultrasound image using the deformation field V, becoming the new preoperatively planned puncture guide line L', as detailed below. Figure 4 As shown;

[0071] S4: Calculate the deviation E between the new preoperative plan L' and the actual puncture guide line.

[0072]

[0073] distance(x) is the shortest distance from a point on one curve to another curve;

[0074] If E is not greater than a certain threshold, the planned puncture path can be used for puncture; otherwise, the planned path is not conducive to puncture and the path should be replanned based on ultrasound during the operation.

[0075] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0076] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0077] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A real-time puncture-guided evaluation system based on soft tissue deformation field, characterized in that, include: A registration system used to register CT images with real-time ultrasound images during surgery and to form a point cloud map by interpolation. Deformation field determination system for determining the deformation field of soft tissue; A guide line simulation system used to form a new preoperatively planned puncture guide line based on the actual puncture guide line planned in the preoperative procedure, combined with the soft tissue deformation field and the registration system; A comparison system used to compare the deviation between the new preoperative planning line and the actual puncture guide line with a set deviation threshold.

2. The operation method of the real-time puncture-guided evaluation system based on soft tissue deformation field according to claim 1, characterized in that, Includes the following steps: S1: Registration is performed using a registration system to register preoperative CT images with intraoperative real-time ultrasound images, converting the ultrasound image point cloud map to the coordinate system of the CT point cloud map, and filling the points between the converted ultrasound image points using interpolation. S2: The deformation field of soft tissue is confirmed by the deformation field determination system. The gray values ​​of CT images and ultrasound images are used as random variables and their corresponding probability distributions are combined to obtain the similarity standard value. The registration success is evaluated by the similarity standard value, and the deformation field is optimized to increase the similarity standard value. S3: Through the guide line simulation system, the preoperatively planned real puncture guide line is represented in the deformed real model to form a new preoperatively planned puncture guide line; S4: The deviation E between the new preoperative planning line and the actual puncture guide line is set by the comparison system, and the deviation E is compared with the deviation threshold.

3. The operation method of the real-time puncture-guided evaluation system based on soft tissue deformation field according to claim 2, characterized in that, During the registration process, S1 overlays a network onto the image, and the intersections of the network are the control points of the image, converting the control points on the ultrasound image grid into points on the CT image.

4. The operation method of the real-time puncture-guided evaluation system based on soft tissue deformation field according to claim 3, characterized in that, In step S1, the points in the converted ultrasound image are filled by interpolation.

5. The operation method of the real-time puncture-guided evaluation system based on soft tissue deformation field according to claim 2, characterized in that, In step S3, the preoperatively planned actual puncture guide line is transformed into a real-time ultrasound image using a deformation field, becoming a new preoperatively planned puncture guide line.

6. The operation method of the real-time puncture-guided evaluation system based on soft tissue deformation field according to claim 2, characterized in that, The deviation in S4 distance(x) is the shortest distance from a point on one curve to another curve. If E is not greater than the set deviation threshold, the planned puncture path can be used for puncture. Otherwise, the planned path is not conducive to puncture and the path should be replanned based on ultrasound during the operation.

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