CN110811830B - Analysis device and method based on femoral model - Google Patents

Abstract

The invention relates to an analysis method based on a femur model, which comprises the following steps: distinguishing a non-feature surface and a feature surface affected by necrotic tissue on a femoral head model surface of the merged femoral model; intercepting a femoral model displayed on a display device to segment the femoral model into a first segment with a femoral head and a second segment without a femoral head; constructing at least one of a rotation axis of the first section rotating relative to the second section and a flipping axis flipping relative to the second section; and controlling movement of the first segment displayed on the display device about at least one of the rotation axis and the flip axis to determine the relative position of the feature surface and the acetabulum by observing the relative position of the feature surface when the first segment is moved to the respective rotation angle and/or the respective flip angle. The invention also discloses a device for executing the method.

Description

Analysis device and method based on femoral model

Technical Field

The invention relates to the field of medical appliances, in particular to an analysis device and method based on a femur model.

Background

Femoral head necrosis refers to a serious complication of ischemic necrosis and collapse of bone cells caused by ischemic necrosis of femoral head due to various reasons, i.e., local blood supply disorder caused by interruption or substantial reduction of blood supply. The method is divided into traumatic femoral head necrosis and non-traumatic femoral head necrosis, the traumatic femoral head necrosis mostly causes interruption of femoral head blood circulation due to fracture of femoral neck, and even if fracture is healed, bones can also cause necrosis and collapse due to long femoral head bone ischemia time. Common causes of non-traumatic femoral head necrosis include: the blood circulation in the femoral head is changed due to the large use of hormone, long-term alcoholism and the like, the nutritional state of the femoral head skeleton is influenced, and the skeleton is necrotized and collapsed.

The treatment method of femoral head necrosis comprises surgical treatment and non-surgical treatment.

Non-surgical treatments typically involve several methods:

1. avoid bearing a burden: the method is only applied to femoral head necrosis before collapse, namely Ficat stage I and stage II, and the effect is not ideal by only adopting a treatment method for avoiding the load according to literature reports, the success rate is lower than 15 percent, and the method can be considered and applied to the A-type femoral head necrosis with pathological changes positioned on the inner side of the femoral head.

2. And (3) drug treatment: the reports of applying the medicine to treat the femoral head necrosis are few, and the treatment effect of the medicine is uncertain in a word, but the medicine is still an important research direction due to the non-invasive property.

3. Other methods of treatment: such as electrical stimulation therapy, phlebotomy therapy, hyperbaric oxygen therapy, etc., are not reported and the effect is to be further determined.

Surgical treatment generally has several methods:

1. operation for retaining femoral head

(1) Central decompression: the theory basis of central decompression treatment of femoral head ischemic necrosis is a osteonecrosis endosteal pressure increase theory, the endosteal pressure can be reduced through central decompression, the blood flow in the femoral head is increased, and the central decompression can stimulate the growth of blood vessels in a decompression tunnel to promote the creeping replacement of necrotic bones. There are many articles about central decompression, and the disputes about the curative effect are large, the curative effect has a great relationship with the stage of femoral head necrosis, but has little relationship with the etiology of femoral head necrosis.

(2) Osteotomy: the goal of the osteotomy is to alter the primary weight bearing area of the femoral head to replace necrotic bone with normal bone as the primary weight bearing area. The method comprises trochanter rotation osteotomy, intertrochanteric inversion osteotomy, intertrochanteric eversion osteotomy and the like, can be combined with bone grafting treatment, is mainly suitable for patients in Ficat stages II and III with smaller lesion range, and has the biggest defect that the difficulty of operation is increased when the patients need hip joint replacement again.

(3) Bone grafting: the bone grafting comprises autologous cancellous bone transplantation, autologous cortical bone transplantation, allogeneic bone transplantation and cartilage transplantation, and can be combined with other treatment methods such as central decompression, electrical stimulation, osteotomy and the like. The bone grafting method includes bone grafting after central decompression, slotting bone grafting in the joint of head and neck, windowing joint cartilage of femoral head, opening cartilage, and repositioning cartilage after opening cartilage for bone grafting. Bone grafting is available for patients in Ficat stage II, early stage III, and patients with central decompression failure. The method has more definite recent curative effect and controversial long-term curative effect, but the method is worthy of confirming that the femoral head repair is accelerated by means of bone transplantation and the time for lying in bed is shortened, and the curative effect can be improved by combining growth factors, electric stimulation and other methods for promoting bone healing.

(4) Bone grafting with blood supply: the bone graft with blood supply has more methods, the bone graft can be from ilium, greater trochanter or fibula, can be provided with muscle pedicle or vascular pedicle, and compared with the common bone graft, the bone graft with blood supply can increase the blood supply of femoral head and accelerate the bone healing. The clinical effect is better reported in the literature, but the X-ray improvement condition is not ideal, and a considerable part of patients still need joint replacement in long-term follow-up.

(5) Medullary core decompression, trabecular metal AVN reconstruction rod (tantalum rod): the trabecular bone metal AVN reconstruction rod is a porous tantalum metal prosthesis, has porosity, a three-dimensional structure and an elastic modulus similar to those of cancellous bone, is beneficial to maintaining initial stability after being implanted due to a high friction coefficient with the bone, can form structural support for a necrotic area after being implanted, is beneficial to vascularization of the necrotic area, can be implanted by a minimally invasive method, and is beneficial to preventing collapse and repairing of the necrotic area of the femoral head and delaying the age of hip joint replacement.

2. Joint replacement surgery

(1) Hip resurfacing: the hip joint surface replacement is to replace the joint surface with implant, to keep most of subchondral bone of acetabulum and femoral head, without invading femoral neck and femoral medullary cavity, and to keep normal physiological anatomy structure and relationship as far as possible while completing the treatment of diseases.

(2) Total hip replacement: is the only choice for treating the advanced femoral head necrosis. With the development of frictional interface studies and the application of new materials (e.g., ceramic prosthetic joints), the population for indications of total hip replacement has a tendency to become younger.

If the young people suffer from femoral head necrosis, joint replacement is adopted because the artificial joint does not have the ability to regenerate as much as the human bone joint, and the artificial joint is worn out in sections over time and risks to be rebuilt many times later in life. Therefore, for patients with a smaller age, if osteotomy can be used, the effect on their later normal lives will be reduced. The main purpose of osteotomy is to rotate the true normal bone mass on the femoral head to the weight bearing area and to remove the necrotic area on the femoral head from the weight bearing area to avoid collapse of the femoral head and to relieve the patient's pain. Usually, before surgery, surgeons need to obtain as accurate as possible anatomical images (bones, blood vessels, muscles, etc.) of the body structure of the subject to be operated, so as to perform surgical planning, such as determining the size and position of the incision, avoiding other organs and nerves, and optimizing osteotomy segments, osteotomy amount, displacement and rotation amount, to obtain perfect and successful operation.

At present, the domestic and foreign diagnosis of femoral head necrosis mainly comes from CT/MR image examination, although a static three-dimensional image can be provided, an operator still only has a planar observation visual angle when watching the image, and cannot obtain data such as femoral head necrosis distribution and load bearing area necrosis rate in a three-dimensional environment. The spatial stereo relationship of femoral head necrosis is difficult to accurately judge, the necrosis rate of a femoral head load bearing area cannot be calculated to the maximum extent in a three-dimensional space, the simulation training of the femoral head necrosis operation of an orthopaedics doctor cannot be met, and the clinical requirements of the femoral head necrosis operation treatment cannot be completely met. In other words, the orthopedist only estimates the rotation angle and approximately estimates whether most necrotic bone regions are moved out of the weight bearing area and normal bone regions are moved into the weight bearing area after rotating the corresponding angle according to the CT/MR image, and even if the estimated result is obtained, some doctors may rotate to different angles to try to determine whether a better surgical plan is possible after cutting the bone in the actual operation process. Not only is the ability of the doctor in all aspects greatly tested, but even the experienced doctor is also inevitable that the obtained operation scheme may have certain defects due to estimation errors.

Moreover, on the one hand, since the skilled person in the art who is understood by the applicant is necessarily different from the examination department; on the other hand, since the inventor made the present invention while studying a large number of documents and patents, the disclosure should not be limited to the details and contents listed in the specification, but the present invention should not have the features of the prior art, but the present invention should have the features of the prior art, and the applicant reserves the right to increase the related art in the background art at any time according to the related specification of the examination guideline.

Disclosure of Invention

In response to the deficiencies of the prior art, the present invention provides a preoperative protocol primarily for use in osteotomies to quickly determine prior to performance of the osteotomy.

The invention provides an analysis method based on a femur model, which comprises the following steps: distinguishing a non-feature surface and a feature surface affected by necrotic tissue on a femoral head model surface of the merged femoral model; intercepting a femoral model displayed on a display device to segment the femoral model into a first segment with a femoral head and a second segment without a femoral head; constructing at least one of a rotation axis of the first section rotating relative to the second section and a flipping axis flipping relative to the second section; and controlling movement of the first segment displayed on the display device about at least one of the rotation axis and the flip axis to determine the relative position of the feature surface and the acetabulum by observing the relative position of the feature surface when the first segment is moved to the respective rotation angle and/or the respective flip angle. The method aims to acquire tomography data by using a computed tomography scanning technology, generate a three-dimensional visual image for a spatial stereo relationship capable of femoral head necrosis, and determine a surgical scheme and evaluate risks existing in the surgery based on the stereo relationship. The invention can construct a dynamic model capable of simulating the human body structure in a virtual space by importing the form of the inspection data, is convenient for a doctor to simulate the operation by means of three-dimensional cutting, three-dimensional interaction, three-dimensional measurement and the like, provides a reasonable operation scheme for the patient operation, and is used as a reference for searching a proper operation scheme before the operation.

An analysis device based on a femur model in the invention, under the condition that at least two femur head medical images different from each other are fused into the femur model, the femur model is divided into a first section with a femur head model and a second section with an acetabulum model, so that the relative position relationship between the femur head model and the acetabulum model under the condition of changing at least one relative included angle of the first section and the second section can be analyzed; the device comprises: a fusion module: which is capable of fusing data of at least two femoral head medical images that are distinct from each other to form a femoral model that is capable of being displayed in three dimensions; cutting the module: it is capable of segmenting the femoral model into a first section with a femoral head model and a second section with an acetabular model; a motion control module: the relative position relationship between the femoral head model and the acetabulum model can be changed by moving the first section and the second section; and a display module: the femur model, the cutting processes of the first section and the second section, the movement processes of the first section and the second section and the relative position relation can be displayed; the device comprises a shaft building module, which can build at least one of a rotating shaft and a turning shaft, wherein the rotating shaft rotates relative to the second section, and the turning shaft turns relative to the second section, and the rotating shaft and the turning shaft are built in a mode that at least one part of the femoral surface in the femoral head model can move out of the weight bearing area of the femoral head model when the first section displayed on the display module by the motion control module moves around at least one of the rotating shaft and the turning shaft, so that the display module can display the relative position relation of the femoral head model and the acetabulum model when the first section moves to the corresponding rotating angle and/or the corresponding turning angle to enable the at least one part of the femoral surface to move out of the weight bearing area.

According to a preferred embodiment, the axis modelling block constructs the axis of rotation of the first section relative to the second section as follows: identifying a dividing plane when the first section is intercepted; calculating the gravity center of the segmentation surface as a first characteristic point; calculating the gravity center of the first section as a second feature point; and constructing a straight line passing through the first feature point and the second feature point as a rotation axis.

According to a preferred embodiment, the axis modeling block constructs the flip axis of the first segment flipped relative to the second segment as follows: generating a directional bounding box capable of bounding the complete femur model; extracting the shortest line segment of all line segments forming the direction bounding box; normalizing the shortest line segment to obtain a first line segment; moving the first line segment to a first rotation point to obtain a second line segment; performing cross product operation on the rotating shaft and the second line segment to obtain a normalized third line segment; solving the intersection point of the third line segment and the surface of the complete femur model as a third feature point; and translating the second line segment along the third line segment to a third feature point as a flip axis.

According to a preferred embodiment, the fusion module generates the femoral model as follows: acquiring first image data generated in a first imaging mode and second image data generated in a second imaging mode; reconstructing a hip model and a complete femur model from the first image data; performing registration fusion on the first image data and the second image data to obtain third image data; extracting the at least a portion of the femoral surface build feature surface on the femoral head model based on the third image data; and merging the complete femoral model and the feature surface to form a merged femoral model to distinguish the feature surface from a non-feature surface on a femoral head model surface of the merged femoral model.

According to a preferred embodiment, the axis modeler, in the event that the rotational axis does not satisfy the first characteristic requirement, splits the femoral model into a first segment with a femoral head and a second segment without a femoral head in the form of a reformed split plane on the basis of the input signals; wherein the first characteristic requirement is used to determine whether an angle of the rotation axis to a femoral neck axis in the femoral model satisfies a first angle threshold.

According to a preferred embodiment, the device comprises an area ratio extraction module, wherein the motion control module is capable of extracting an area relationship between a characteristic surface and a non-characteristic surface of the femoral head model in the weight bearing region by controlling the motion of the first segment to at least one of the respective rotation angle and/or the respective flip angle.

According to a preferred embodiment, the area ratio extraction module obtains the area relationship of the characteristic surface and the non-characteristic surface of the femoral head model surface in the weight bearing region when the first section moves to the corresponding rotation angle and/or the corresponding flip angle according to at least one of the following ways: calculating the ratio of the area of the feature surface in the weight bearing area to the total area; calculating the ratio of the area of the non-characteristic surface in the load bearing area to the total area; and calculating the ratio of the area of the characteristic surface and the non-characteristic surface in the load bearing area; wherein the total area within the weight bearing region is the sum of the area of the feature surface within the weight bearing region and the area of the non-feature surface within the weight bearing region.

According to a preferred embodiment, the device comprises a command input module receiving input signals for the fusion module, the cutting module, the motion control module and the axis modeling block to execute commands.

According to a preferred embodiment, the present invention further provides a femur model-based analysis method, which, when at least two femur head medical images different from each other are fused into a femur model, segments the femur model into a first segment with a femur head model and a second segment with an acetabulum model, so as to be able to analyze a relative positional relationship between the femur head model and the acetabulum model in a case of changing a relative angle between at least one of the first segment and the second segment; the method comprises the following steps: fusing data of at least two femoral head medical images which are different from each other to form a femoral model capable of being displayed in three dimensions; segmenting the femoral model into a first segment with a femoral head model and a second segment with an acetabular model; changing the relative positional relationship between the femoral head model and the acetabular model by moving the first section and the second section; and displaying the femur model, the cutting process of the first section and the second section, the movement process of the first section and the second section and the relative position relation; constructing at least one of a rotation axis of the first section rotating relative to the second section and a flip axis flipped relative to the second section, the at least one of the rotation axis and the flip axis constructed in such a way that at least a part of a surface of the femoral head model can move out of the weight bearing zone of the femoral head model with a movement of the first section about the at least one of the rotation axis and the flip axis, so that a relative positional relationship of the femoral head model and the acetabular model with the at least a part of the surface moving out of the weight bearing zone when the first section is moved to the respective rotation angle and/or the respective flip angle can be displayed.

According to a preferred embodiment, the axis of rotation of the first section relative to the second section is constructed: identifying a dividing plane when the first section is intercepted; calculating the gravity center of the segmentation surface as a first characteristic point; calculating the gravity center of the first section as a second characteristic point; and constructing a straight line passing through the first feature point and the second feature point as a rotation axis; constructing a flip axis for flipping the first section relative to the second section comprises: generating a directional bounding box capable of bounding the complete femur model; extracting the shortest line segment of all line segments forming the direction bounding box; normalizing the shortest line segment to obtain a first line segment; moving the first line segment to a first rotation point to obtain a second line segment; performing cross product operation on the rotating shaft and the second line segment to obtain a normalized third line segment; solving the intersection point of the third line segment and the surface of the complete femur model as a third feature point; and translating the second line segment along the third line segment to a third feature point as a flip axis.

Drawings

FIG. 1 is a flow diagram of a preferred method of the present invention;

FIG. 2 is a schematic diagram of a preferred module of an apparatus of the present invention.

List of reference numerals

100: fusion module

200: cutting module

300: motion control module

400: display module

500: shaft modeling block

600: instruction input module

700: area ratio extraction module

Detailed Description

This is described in detail below with reference to figures 1 and 2.

Example 1

The present embodiment discloses an analysis device based on a femoral head model, which, when at least two femoral head medical images different from each other are fused into the femoral head model, divides the femoral head model into a first section with the femoral head model and a second section with an acetabular model, so as to be able to analyze a relative positional relationship between the femoral head model and the acetabular model when at least one relative angle between the first section and the second section is changed.

Medical image registration refers to seeking one or a series of spatial transformations for one medical image to bring it into spatial correspondence with corresponding points on another medical image. This coincidence means that the same anatomical point on the body has the same spatial position on the two matching images. The result of the registration should be such that all anatomical points, or at least all points of diagnostic significance and points of surgical interest, on both images are matched.

Volumetric reconstruction is the process of processing various series of images to construct a three-dimensional geometric model.

CT is an abbreviation of computed tomography and refers to computed tomography or computed tomography.

MR is an abbreviation for magnetic resonance imaging, or magnetic resonance tomography.

PET is an abbreviation for positron emission tomogry and refers to positron emission computed tomography.

SPECT is an abbreviation for Single-Photon Emission Computed Tomography, which refers to Single Photon Emission Computed Tomography.

Image Registration, is a process of mapping one Image to another by finding a spatial transformation so that points corresponding to the same position in space in the two images correspond one to one. Alternatively, image registration refers to the process of performing a best match on two or more images obtained from different image acquisition devices at different times.

Image fusion is the process of combining the useful information of two or more images to form one image. Thereby, a higher quality image is obtained.

Non-characteristic surface: normal tissue site on the femoral head.

Characteristic surface: the site of necrotic tissue on the femoral head, which is also the area of intense investigation based on the femoral model in this embodiment, needs to be partially removed from the weight bearing area by movement of the first segment.

The femur model: a three-dimensional model corresponding to the femur is generated based on the image data.

Rotation axis: the first segment is capable of rotating about a virtual axis established based on the femoral model.

A turnover shaft: the first segment is rotatable about another virtual axis established based on the femoral model.

The medical imaging technology is a comprehensive and practical subject field integrating various subject achievements and advanced technologies. Medical images in various modes provide abundant, intuitive, qualitative and quantitative human physiological information for doctors and researchers from the visual angle, and become an important technical means for diagnosing various diseases. Since different modes of devices have different sensitivities and resolutions for large to small molecular atoms in the human body, there are their respective ranges and limitations of applicability. Computed Tomography (CT) images have good spatial resolution and geometric properties, low contrast to human soft tissue, and clear bone response. The Computer Tomography (CT) image has clear skeleton and high resolution, can play a good reference role for the positioning of the focus, but has poor display on the focus. CT has poor ability to distinguish soft tissue structures with similar electron density. If these two images are fused, the advantages of both images can be combined. The positioning information of the skeleton and the soft tissue details are effectively displayed through image fusion, and the positioning accuracy of the focus is greatly improved.

Magnetic Resonance (MR) images can clearly reflect the anatomy of soft tissues, organs, blood vessels, etc., but are not sensitive to calcifications, exhibit poor sensitivity to rigid bone tissue, and are subject to magnetic interference, which can cause geometric distortions. Medical images of various modalities reflect human body information from different angles, and comprehensive diagnosis information cannot be obtained from one image alone. It is necessary to integrate the image information of different modalities together to obtain more abundant information so as to know more data of the diseased tissue or organ, thereby making an accurate judgment or making a proper treatment plan. The accuracy of various images is subjectively affected by the spatial conception and guess of doctors to comprehensively determine the information needed by the doctors, and more importantly, some information is possibly ignored. The medical image fusion technology replaces the manual comprehensive mode of doctors with a computer image processing method, can improve the diagnosis efficiency and reliability, and accurately guides neurosurgery operation, radiotherapy and the like.

Medical image fusion generally refers to matching and reconstructing images of the same lesion area obtained by 2 or more than 2 different medical imaging devices, so as to obtain complementary information, increase the information amount, and make clinical diagnosis and treatment more accurate and perfect. Medical image fusion is attracting attention of the clinical medicine field, some researches at that time generally adopt a relatively intuitive and simple fusion method, such as pixel-by-pixel weighting averaging, filtering by using a logical operator and the like, and the effect is not ideal.

The apparatus disclosed in the present embodiment includes a fusion module 100, a cutting module 200, a motion control module 300, a display module 400, and an axis modeling block 500.

The fusion module 100: which is capable of fusing data of at least two femoral head medical images that are distinct from each other to form a femoral model that is capable of being displayed in three dimensions.

The cutting module 200: it is capable of segmenting a femoral model into a first section with a femoral head model and a second section with an acetabular model.

The motion control module 300: the femoral head model and the acetabulum model can be changed in relative position by moving the first section and the second section.

The display module 400: the femur model display device can display the femur model, the cutting processes of the first section and the second section, the movement processes and the relative position relation of the first section and the second section.

An axis modeling block 500 capable of constructing at least one of a rotation axis of the first section relative to the second section and a flip axis flipped relative to the second section.

At least one of the rotation axis and the flipping axis is constructed in such a manner that at least a portion of a femoral surface in the femoral head model can move out of the weight bearing zone of the femoral model when the first section displayed on the display module 400 by the motion control module 300 moves around the at least one of the rotation axis and the flipping axis, so that the display module 400 can display a relative positional relationship of the femoral head model and the acetabular model when the first section moves to the corresponding rotation angle and/or the corresponding flipping angle to move the at least a portion of the femoral surface out of the weight bearing zone. Analyzing the area relation of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the corresponding rotation angle and/or the corresponding flip angle to serve as a reference for searching a proper surgical scheme before surgery. Preferably, the process of analyzing the area relationship of the non-characteristic surface and the characteristic surface of the femoral head model surface within the weight bearing region when the first segment is moved to the corresponding rotation angle and/or the corresponding flip angle as a reference for preoperatively finding a suitable surgical plan comprises at least one of the following steps: the ratio of the area of the non-characteristic surface in the load bearing area to the total area is calculated. The ratio of the area of the feature surface in the weight bearing area to the total area is calculated. Or calculating the ratio of the area of the non-feature surface to the area of the feature surface in the weight bearing area. Wherein the total area within the weight bearing region is the sum of the area of the non-characteristic surface within the weight bearing region and the area of the characteristic surface within the weight bearing region. Preferably, the area or area ratio of the femoral head feature surface can be obtained as follows: generating a necrosis surface model based on the original femoral head necrosis model and the region of the non-intersecting and overlapping part of the original femoral head model, and generating a first necrosis bearing area by comparing the necrosis surface model with the acetabulum lunar surface model. And generating a first share of bone load bearing area based on the comparison of the original femur head model and the acetabulum lunar surface model, and generating a second necrotic load bearing area consisting of a noise point set according to a mode of extracting noise points from the first share of bone load bearing area. Preferably, the original femur head model and the acetabulum lunar surface model are compared in a manner that each triangular patch mesh on the surface of the original femur head model is traversed, if a line segment formed by extending three vertexes along respective normal directions intersects with the acetabulum lunar surface model, the patch is taken out and placed in a formation set, and all triangular patch networks in the set form a first femoral bone load bearing area, preferably, the triangular patch is defined to at least comprise a fixed edge and two edges capable of elastic deformation, and the fixed edge and the two edges capable of elastic deformation form a rigid elastic system together. The two elastically deformable edges can be used to perform finite element calculations, such as differentiating the triangular patch to an infinite approximation unit by differentiation, thereby integrating a corresponding model that approximates the actual hip and femur indefinitely. And performing Boolean union operation on the first necrotic weight bearing area and the second necrotic weight bearing area to generate a calibrated third necrotic weight bearing area model, and extracting a necrotic outer weight bearing area through the third necrotic weight bearing area model. Generating an independent facet set by traversing each triangular facet mesh of a first femoral load bearing area, performing isolated noise point rejection based on the independent facet set to generate a second femoral head load bearing area formed by the rest triangular facet meshes, extracting and generating a femoral outer side load bearing area based on the second femoral head load bearing area, preferably, generating the independent facet set in a mode of traversing each triangular facet mesh of the first femoral head load bearing area, and taking out a facet and placing the facet in an initial independent facet set if a line segment formed by extending three vertexes along respective normal directions of the three vertexes is not intersected with an original femoral head necrosis model; and then traversing the initial independent patch set, if the line segments formed by extending the three vertexes of each traversed triangular patch along the reverse direction of the respective normal do not intersect with the original femoral head necrosis model, taking out the patch, and repeating the actions until all triangular patch networks meeting the conditions are screened out to form the independent patch set. The total lateral weight bearing region is generated based on the necrotic lateral weight bearing region and the femoral lateral weight bearing region, and the area ratio of the femoral lateral weight bearing region to the total lateral weight bearing region is taken as the area ratio of the bone feature surface.

Preferably, the apparatus includes a command input module 600 that receives input signals for the fusion module 100, the cutting module 200, the motion control module 300, and the axis modeling block 500 to execute commands.

Example 2

The embodiment provides an analysis method based on a femur model. The method may be in addition to the execution steps of the corresponding modules in embodiment 1.

Preferably, the method comprises:

s1: the femoral head model surface of the femoral model is distinguished from a non-characteristic surface and a characteristic surface affected by necrotic tissue.

S2: the femoral model displayed on the display module 500 is cut out to segment the femoral model into a first segment with a femoral head and a second segment without a femoral head.

S3: at least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed.

S4: the first segment displayed on the display device is controlled to move about at least one of the rotation axis and the flip axis to move to the feature surface relative to the acetabulum by observing the relative position of the feature surface when the first segment moves to the respective rotation angle and/or the respective flip angle.

With the method of S1-S4, it is intended to acquire tomographic data using a computed tomography technique, generate a three-dimensional visualization image for enabling spatial relationship of femoral head necrosis, and thus enable determination of a surgical plan and assessment of risks present in surgery based on the spatial relationship. The invention can construct a dynamic model capable of simulating the human body structure in a virtual space by importing the form of the inspection data, is convenient for a doctor to simulate the operation by means of three-dimensional cutting, three-dimensional interaction, three-dimensional measurement and the like, provides a reasonable operation scheme for the patient operation, and is used as a reference for searching a proper operation scheme before the operation.

Preferably, the method further comprises:

s5: analyzing the area relation of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the corresponding rotation angle and/or the corresponding flip angle to serve as a reference for searching a proper surgical scheme before surgery. Preferably, the process of analyzing the area relationship of the non-characteristic surface and the characteristic surface of the femoral head model surface within the weight bearing region when the first segment is moved to the corresponding rotation angle and/or the corresponding flip angle as a reference for preoperatively finding a suitable surgical plan comprises at least one of the following steps: the ratio of the area of the non-characteristic surface in the load bearing area to the total area is calculated. The ratio of the area of the feature surface in the weight bearing area to the total area is calculated. Or calculating the ratio of the area of the non-feature surface to the area of the feature surface in the weight bearing area. Wherein the total area within the weight bearing region is the sum of the area of the non-characteristic surface within the weight bearing region and the area of the characteristic surface within the weight bearing region. Preferably, the area or area ratio of the femoral head feature surface can be obtained as follows: generating a necrosis surface model based on the original femoral head necrosis model and the region of the non-intersecting and overlapping part of the original femoral head model, and generating a first necrosis bearing area by comparing the necrosis surface model with the acetabulum lunar surface model. And generating a first share of bone load bearing area based on the comparison of the original femur head model and the acetabulum lunar surface model, and generating a second necrotic load bearing area consisting of a noise point set according to a mode of extracting noise points from the first share of bone load bearing area. Preferably, the original femur head model and the acetabulum lunar surface model are compared in a manner that each triangular patch mesh on the surface of the original femur head model is traversed, if a line segment formed by extending three vertexes along respective normal directions intersects with the acetabulum lunar surface model, the patch is taken out and placed in a formation set, and all triangular patch networks in the set form a first femoral bone load bearing area, preferably, the triangular patch is defined to at least comprise a fixed edge and two edges capable of elastic deformation, and the fixed edge and the two edges capable of elastic deformation form a rigid elastic system together. The two elastically deformable edges can be used to perform finite element calculations, such as differentiating the triangular patch to an infinite approximation unit by differentiation, thereby integrating a corresponding model that approximates the actual hip and femur indefinitely. And performing Boolean union operation on the first necrotic weight bearing area and the second necrotic weight bearing area to generate a calibrated third necrotic weight bearing area model, and extracting a necrotic outer weight bearing area through the third necrotic weight bearing area model. Generating an independent facet set by traversing each triangular facet mesh of a first femoral load bearing area, performing isolated noise point rejection based on the independent facet set to generate a second femoral head load bearing area formed by the rest triangular facet meshes, extracting and generating a femoral outer side load bearing area based on the second femoral head load bearing area, preferably, generating the independent facet set in a mode of traversing each triangular facet mesh of the first femoral head load bearing area, and taking out a facet and placing the facet in an initial independent facet set if a line segment formed by extending three vertexes along respective normal directions of the three vertexes is not intersected with an original femoral head necrosis model; and then traversing the initial independent patch set, if the line segments formed by extending the three vertexes of each traversed triangular patch along the reverse direction of the respective normal do not intersect with the original femoral head necrosis model, taking out the patch, and repeating the actions until all triangular patch networks meeting the conditions are screened out to form the independent patch set. The total lateral weight bearing region is generated based on the necrotic lateral weight bearing region and the femoral lateral weight bearing region, and the area ratio of the femoral lateral weight bearing region to the total lateral weight bearing region is taken as the area ratio of the bone feature surface.

Preferably, the method comprises: an input signal of an input device is received. Preferably, the input device may be at least one of a mouse, a keyboard, a touch screen, a joystick, and a trackball, for example. The display device may be, for example, at least one of a display, a projector, and VR glasses. Performing at least one of the following steps in dependence on an input signal of an input device: a femoral model displayed on a display device is cut out to divide the femoral model into a first segment with a femoral head and a second segment without a femoral head. The first segment displayed on the display device is controlled to move about at least one of the rotation axis and the flip axis. Preferably, the movement of the first section about at least one of the rotation axis and the flip axis is controlled on the display device in dependence on the received signal of the input device to serve as a first reference for preoperatively finding a suitable surgical plan by observing the relative position of the characteristic surface and the acetabulum when the first section is moved to the respective rotation angle and/or the respective flip angle. Analyzing the area relation of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the corresponding rotation angle and/or the corresponding flip angle according to the received signals of the input device so as to be used as a reference for searching a proper surgical scheme before surgery.

Preferably, the method may comprise constructing a rotation axis and/or a flip axis. The process of constructing the rotating shaft includes: a splitting plane is identified when the first section is cut. The barycenter of the division plane is calculated as a first feature point. The center of gravity of the first segment is calculated as a second feature point. A straight line passing through the first feature point and the second feature point is constructed as a rotation axis. Preferably, the first feature point is calculated, for example, in the following manner: and identifying an intersection set formed by the intersection points of the partition surface and the surface of the first section, traversing coordinates of all the intersection points in the intersection set, adding and summing the coordinates, and dividing the sum by the total number of the intersection points in the intersection set to obtain a first feature point.

Preferably, the process of constructing the flipping axis by the axis construction unit 500 includes: a directional bounding box is generated that can enclose the complete femoral model. The shortest line segment of the three line segments constituting the directional bounding box is extracted. And carrying out normalization processing on the shortest line segment to obtain a first line segment. Moving the first segment to the first rotation point results in a second segment. And performing cross product operation on the rotating shaft and the second line segment to obtain a normalized third line segment. Solving an intersection point of the extension line of the third line segment or the third line segment and the surface of the complete femur model as a third characteristic point; and translating the second line segment to a third characteristic point along the third line segment to be used as a turnover shaft.

Preferably, the method comprises: the femoral head model surface of the femoral model is distinguished from a non-characteristic surface and a characteristic surface affected by necrotic tissue. The femur model displayed on the display device is intercepted according to the received signal of the input device to divide the second femur model into a first section with a femoral head and a second section without a femoral head. At least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed. Controlling the movement of the first section displayed on the display device about at least one of the rotation axis and the flip axis in accordance with the received signal of the input device to serve as a reference for preoperatively finding a suitable surgical plan by observing the relative position of the characteristic surface and the acetabulum when the first section is moved to the corresponding rotation angle and/or the corresponding flip angle.

Preferably, the fusing step of the fusing module 100 includes: first image data generated in the first imaging mode and second image data generated in the second imaging mode are acquired. The hip model and the first femoral model are reconstructed from the first image data. And performing registration fusion on the first image data and the second image data to obtain third image data. And extracting necrotic tissue on the femoral head based on the third image data to construct a necrosis model. The first femoral model and the necrosis model are merged to form a second femoral model to distinguish a non-feature surface and a feature surface affected by necrotic tissue on a femoral head model surface of the second femoral model. Controlling an osteotomy tool to intercept a second femoral model displayed on a display device based on the received signal of the input device to divide the second femoral model into a first segment with a femoral head and a second segment without the femoral head. At least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed. Controlling, on the display device, the movement of the first section about at least one of the rotation axis and the flip axis in accordance with the received signal of the input device to serve as a first reference for preoperatively finding a suitable surgical plan by observing the relative position of the characteristic surface and the acetabulum when the first section is moved to the respective rotation angle and/or the respective flip angle. And/or analyzing the area relation of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the corresponding rotation angle and/or the corresponding flip angle according to the received signals of the input device so as to be used as a second reference for searching a proper surgical scheme before surgery.

Preferably, the imaging principle of the first imaging modality is different from the imaging principle of the second imaging modality. Thus, the characteristics of the images acquired by the first imaging mode and the second imaging mode are different. The image acquired by the first imaging modality can more clearly reflect the bony structure than the image acquired by the second imaging modality. The image acquired by the imaging principle of the second imaging method can more clearly reflect the structures of soft tissues and organs than the image acquired by the first imaging method. The image acquired by the imaging principle of the second imaging mode can more clearly reflect the structure of the lesion tissue than the image acquired by the first imaging mode. Diseased tissue includes necrotic tissue on bone.

Preferably, the first imaging modality may be at least one of CT, SPECT and PET, for example.

Preferably, the second imaging modality may be at least one of MR, PET and SPECT, for example.

Preferably, the construction of the axis of rotation of the first section relative to the second section by the axis building module 500 is achieved as follows: a set of points of the cutting surface and the femoral head model is calculated. At this time, the cut surface and the point set of the first section of the femur model form a closed plane figure. The center of gravity of the closed plane figure is taken as a first feature point constructing the rotation axis. The cutting surface and the femoral head model form a space body, and the gravity center of the space body serves as a second characteristic point. A straight line formed by the first characteristic point and the second characteristic point is taken as a rotation axis.

Preferably, the construction of the overturning axis of the first section overturned relative to the second section by the axis construction module 500 is generated as follows: an orientation bounding box is generated that can enclose a surface of a first segment of the complete femoral model. The shortest line segment among all the line segments constituting the directional bounding box is extracted. And carrying out normalization processing on the shortest line segment to obtain a first line segment. Moving the first line segment to the first marking point results in the second line segment. And performing cross product operation on the rotating shaft and the second line segment to obtain a normalized third line segment. And solving the intersection point of the third line segment and the surface of the complete first section as a third mark point. The second line segment is translated along the third line segment to a third index point as a flip axis.

Preferably, the fusion module 100 may further perform the fusion step of: first image data generated in a first imaging mode and second image data generated in a second imaging mode are acquired. The hip model and the first femoral model are reconstructed from the first image data. And performing registration fusion on the first image data and the second image data to obtain third image data. And extracting necrotic tissue on the femoral head based on the third image data to construct a necrosis model. The first femoral model and the necrosis model are merged to form a second femoral model to distinguish a non-feature surface and a feature surface affected by necrotic tissue on a femoral head model surface of the second femoral model. Controlling an osteotomy tool to intercept a second femoral model displayed on a display device based on the received signal of the input device to divide the second femoral model into a first segment with a femoral head and a second segment without the femoral head. At least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed. Controlling on the display device the movement of the first section about at least one of the rotation axis and the flip axis in dependence on the received signals of the input means to serve as a first reference for preoperatively finding a suitable surgical plan by observing the change in position of the feature surface when the first section is moved to a specific rotation angle and/or a specific flip angle. And calculating the area relationship of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the specific rotation angle and/or the specific flip angle in response to the position change of the characteristic surface so as to serve as a second reference for searching a suitable surgical scheme before surgery. Preferably, the method comprises: first image data generated in a first imaging mode and second image data generated in a second imaging mode are acquired. The hip model and the first femoral model are reconstructed from the first image data. And performing registration fusion on the first image data and the second image data to obtain third image data. And extracting necrotic tissue on the femoral head based on the third image data to construct a necrosis model. The first femoral model and the necrosis model are merged to form a second femoral model to distinguish a non-feature surface and a feature surface affected by necrotic tissue on a femoral head model surface of the second femoral model. A second femoral model is sectioned through an osteotomy tool to divide the second femoral model into a first segment with a femoral head and a second segment without a femoral head. At least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed. The first section is operated to move about at least one of the rotation axis and the flip axis to obtain a corresponding rotation angle and/or flip angle. The area relationship of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing region at the corresponding rotation angle and/or the corresponding flip angle is calculated for preoperative reference.

Preferably, the image registration may employ a template-based matching algorithm, a grayscale-based matching algorithm, a feature-based matching algorithm, and a threshold-change-based matching algorithm. Specifically, the image registration may employ at least one of a mean absolute difference algorithm (MAD), a sum of absolute differences algorithm (SAD), a sum of squared errors algorithm (SSD), a sum of squared average errors algorithm (MSD), a normalized product correlation algorithm (NCC), a Sequential Similarity Detection Algorithm (SSDA), a hadamard transform algorithm (SATD), a local gray value encoding algorithm, a Harris algorithm, a Moravec algorithm, a KLT algorithm, a Harr-like algorithm, a HOG algorithm, an LBP algorithm, a SIFT algorithm, a SURF algorithm, a BRIEF algorithm, a SUSAN algorithm, a FAST algorithm, a CENSUS algorithm, a FREAK algorithm, a BRISK algorithm, an ORB algorithm, an optical flow method, an a-KAZE algorithm, a LoG operator, a Robert operator, a Prewitt operator, a Canny operator. These algorithms enable volume reconstruction based on first image data and second image data to obtain a three-dimensional first model when the first image data is generated in a first imaging mode and the second image data is generated in a second imaging mode. And the hip model and the femur model can be reconstructed from the first model. And performing registration fusion of the first image data and the second image data to obtain third image data. A necrosis model representing a characteristic surface on the femoral head is reconstructed based on the third image data. Three-dimensional image data corresponding to an image of a bone is acquired, wherein the three-dimensional image data includes first image data acquired using a first imaging device and second image data acquired using a second imaging device. A femoral model and a hip model are identified based on the three-dimensional image data. Preferably, a common coordinate system is defined for the first imaging modality and the second imaging modality before the image data is acquired for the first imaging modality and the second imaging modality.

Preferably, the analysis method of the femur model further comprises: three-dimensional image data corresponding to the bone image is acquired. A region of interest representing a feature surface is extracted from the three-dimensional image data. A femoral model generated from the three-dimensional image data is truncated to segment the femoral model into a first segment with a femoral head and a second segment without the femoral head. At least one of a rotation axis and a flip axis for movement of the first section relative to the second section is generated. The first section is operated to move about at least one of the rotation axis and the flip axis. And calculating a rate of necrosis within the weight bearing zone at the respective rotation angle and/or the respective flip angle in response to movement of the first section about at least one of the rotation axis and the flip axis.

Example 3

This example is a further supplement to examples 1 and 2.

Preferably, the axis of rotation is an axis parallel or substantially parallel to the axis of the femoral neck. It is desirable that the axis of rotation be parallel to the femoral neck axis. However, in the actual calculation process, the calculated rotation axis may deviate from the femoral neck axis to be substantially parallel to the femoral neck axis. Preferably, the axis of the rotation axis being substantially parallel to the axis of the femoral neck may mean that the deviation of the included angle between the rotation axis and the axis of the femoral neck is within 5 °, particularly preferably within 2 °. When the first section rotates around the rotating shaft, the first section rotates around the rotating shaft at the intercepted position. In this case, the angle between the first section and the second section is unchanged or substantially unchanged. The overturning shaft is an axis of the first section overturning relative to the second section. When the first section overturns around the overturning shaft, the first section does nodding motion relative to the second section. At this time, the angle between the first section and the second section is changed. Preferably, other definitions of the axis of rotation for rotation of the femoral head in osteotomy in the medical field shall also be taken as an alternative definition of the axis of rotation of the present invention. Other definitions of the axis of rotation for femoral head inversion in osteotomy within the medical field should also be considered as an alternative definition of the axis of rotation of the present invention.

To this end, the present embodiment provides a method for determining the angle of the rotation axis to the femoral neck axis in a femoral model. In particular, the rotation axis and the femoral neck axis satisfy a first angular threshold, i.e. a first characteristic requirement needs to be satisfied. In the case of a rotation axis which does not meet the first characteristic requirement, the femoral model is segmented into a first segment with a femoral head and a second segment without a femoral head on the basis of the input signals in the form of a reconstruction of the segmentation plane.

Since the femoral neck axis is difficult to construct or determine in the system. In this embodiment, the femoral neck axis is abstracted as the normal vector of the segmentation plane. Namely: the normal vector of the rotation axis and the division plane needs to satisfy the first angle threshold. In order to be able to reduce the spatial position error between the femoral neck axis and the normal vector of the segmentation plane, the present embodiment further constrains the segmentation plane. Namely: the position of the dividing plane needs to satisfy the second characteristic requirement. Preferably, the second characteristic requirement is used to determine whether the position of the cutting surface relative to the hip joint surface meets the construction requirement for the axis of rotation. Preferably, the second characteristic requirement is for determining whether the position of the cutting surface relative to the spatial volume formed by the socket configuration of the hip joint surface meets the construction requirement of the rotation axis. And if the angle of the gravity center line of the space body formed by the normal vector of the cutting surface and the hip joint surface is smaller than a second angle threshold value, the cutting surface meets a second characteristic requirement. Otherwise, the cutting surface is not satisfied with the second characteristic requirement.

Through the judgment arrangement, the position of the rotating shaft can be restrained, so that the femoral head model can rotate in the socket-shaped structure of the hip joint surface when the femoral head model rotates around the rotating shaft model; secondly, the judgment is carried out based on the angle of the gravity line of the space body formed by the hip joint surface, which is beneficial to improving the accuracy of the rotating angle required by the femoral head characteristic surface moving out of the weight bearing area.

Example 4

The present embodiment discloses an analysis apparatus for performing the methods provided in embodiments 1 and/or 2. The analysis device is configured as one or more processors. Which can be pursuant to instructions stored in a readable storage medium, for performing the following operations:

the femoral head model surface of the merged femoral model is distinguished from non-feature surfaces and feature surfaces affected by necrotic tissue.

A femoral model displayed on a display device is cut out to segment the femoral model into a first segment with a femoral head and a second segment without a femoral head.

At least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section is constructed. And

the first segment displayed on the display device is controlled to move about at least one of the rotation axis and the flip axis to move to the feature surface relative to the acetabulum by observing the relative position of the feature surface when the first segment moves to the respective rotation angle and/or the respective flip angle.

Preferably, the apparatus is further configured as follows:

analyzing the area relationship of the non-characteristic surface and the characteristic surface of the femoral head model surface in the weight bearing area when the first section moves to the corresponding rotation angle and/or the corresponding flip angle.

The invention consists of virtual reality equipment and osteotomy operation planning software. The working process is as follows:

(1) importing hip joint CT sequence images and nuclear Magnetic Resonance (MR) data;

(2) reconstructing the volume;

(3) designing a threshold value to distinguish bones and other tissues in the image, and reconstructing a three-dimensional model of pelvis and femur through a data preparation module;

(4) setting a threshold value to segment a single femur and hip bone model;

(5) carrying out registration fusion on the nuclear Magnetic Resonance (MR) data and the Computed Tomography (CT) data to obtain registered data M;

(6) performing three-dimensional reconstruction of a femoral head necrosis model based on the data M;

(7) cutting the femoral head on the femoral neck base by using a plane cutting tool, cutting the femoral head and a femoral shaft, and simultaneously determining a femoral neck central rotating shaft and a turnover shaft;

(8) adding a plane for distinguishing a load area on the outer side of the femoral head;

(9) calculating the integrity rate of the lateral load bearing area of the current femoral head, and displaying a surface projection area and a necrosis projection area of the current intact femoral part through VR display equipment;

(10) outputting the current femoral head rotation, inversion and integrity rate to an operation plan report;

(11) using a VR operation tool to rotate the femoral head around the central rotating shaft of the femoral neck or to perform invagination for a certain angle around the turnover shaft of the femoral neck according to needs, and repeating the operations (9) and (10);

the above operations are all realized on the virtual reality device (12);

the word "module" as used herein describes any type of hardware, software, or combination of hardware and software that is capable of performing the functions associated with the "module".

It should be noted that the above-mentioned embodiments are exemplary, and that those skilled in the art, having benefit of the present disclosure, may devise various arrangements that are within the scope of the present disclosure and that fall within the scope of the invention. It should be understood by those skilled in the art that the present specification and figures are illustrative only and are not limiting upon the claims. The scope of the invention is defined by the claims and their equivalents.

Claims (7)

1. An analysis device based on a femoral head model, wherein the analysis device divides the femoral head model into a first section with a femoral head model and a second section with an acetabular model under the condition that at least two femoral head medical images different from each other are fused into the femoral head model, so that the relative position relationship between the femoral head model and the acetabular model under the condition that at least one relative included angle of the first section and the second section is changed can be analyzed;

the device comprises:

fusion module (100): which is capable of fusing data of at least two femoral head medical images that are distinct from each other to form a femoral model that is capable of being displayed in three dimensions;

cutting module (200): it is capable of segmenting the femoral model into a first section with a femoral head model and a second section with an acetabular model;

motion control module (300): the relative position relationship between the femoral head model and the acetabulum model can be changed by moving the first section and the second section; and

display module (400): the femur model, the cutting processes of the first section and the second section, the movement processes of the first section and the second section and the relative position relation can be displayed;

it is characterized in that the preparation method is characterized in that,

the apparatus comprises an axis building module (500) capable of building at least one of a rotation axis of the first section relative to the second section and a flipping axis flipped relative to the second section,

at least one of the rotation axis and the flipping axis is constructed in such a way that at least a part of a femoral surface in the femoral head model can be moved out of a weight bearing zone of the femoral head model when the first section displayed on the display module (400) by the motion control module (300) moves around at least one of the rotation axis and the flipping axis, so that the display module (400) can display a relative positional relationship of the femoral head model and the acetabular model when the first section moves to a corresponding rotation angle and/or a corresponding flipping angle to move the at least a part of the femoral surface out of the weight bearing zone;

the axis building module (500) builds a rotation axis for the first section to rotate relative to the second section as follows:

identifying a dividing plane when the first section is intercepted;

calculating the gravity center of the segmentation surface as a first characteristic point;

calculating the gravity center of the first section as a second feature point; and

a straight line passing through the first feature point and the second feature point is constructed as a rotation axis.

2. The femoral model-based analysis apparatus according to claim 1, wherein the axis construction module (500) constructs a rollover axis for a first segment to rollover relative to a second segment as follows:

generating a directional bounding box capable of bounding the complete femur model;

extracting the shortest line segment of all line segments forming the direction bounding box;

normalizing the shortest line segment to obtain a first line segment;

moving the first line segment to a first rotation point to obtain a second line segment;

performing cross product operation on the rotating shaft and the second line segment to obtain a normalized third line segment;

solving the intersection point of the third line segment and the surface of the complete femur model as a third feature point; and

and translating the second line segment to a third characteristic point along the third line segment to be used as a turnover shaft.

3. The femoral model-based analysis apparatus according to claim 1, wherein the fusion module (100) generates the femoral model as follows:

acquiring first image data generated in a first imaging mode and second image data generated in a second imaging mode;

reconstructing a hip model and a complete femur model from the first image data;

performing registration fusion on the first image data and the second image data to obtain third image data;

extracting the at least a portion of the femoral surface build feature surface on the femoral head model based on the third image data; and

merging the full femoral model and the feature surface to form a merged femoral model to distinguish the feature surface from a non-feature surface on a femoral head model surface of the merged femoral model.

4. The femoral model-based analysis apparatus according to claim 1, wherein the axis construction module (500) segments the femoral model into a first segment with a femoral head and a second segment without a femoral head in the form of a reformed segmentation plane based on an input signal in case the rotational axis does not meet a first characteristic requirement;

wherein the first characteristic requirement is used to determine whether an angle of the rotation axis to a femoral neck axis in the femoral model satisfies a first angle threshold.

5. The femoral model-based analysis apparatus according to claim 1, wherein the apparatus comprises an area ratio extraction module (700),

wherein the area ratio extraction module (700) is capable of extracting an area relationship of a characteristic surface and a non-characteristic surface in the femoral head model within the weight bearing region by controlling the movement of the first segment to at least one of a corresponding rotation angle and/or a corresponding flip angle by the motion control module (300).

6. The femoral model-based analysis apparatus according to claim 5, wherein the area ratio extraction module (700) obtains the area relationship of the characteristic surface and the non-characteristic surface of the femoral head model surface in the weight bearing region when the first section moves to the respective rotation angle and/or the respective flip angle in at least one of the following ways:

calculating the ratio of the area of the feature surface in the weight bearing area to the total area;

calculating the ratio of the area of the non-characteristic surface in the load bearing area to the total area; or

Calculating the area ratio of the characteristic surface and the non-characteristic surface in the load bearing area;

wherein the total area within the weight bearing region is the sum of the area of the feature surface within the weight bearing region and the area of the non-feature surface within the weight bearing region.

7. The femoral model-based analysis apparatus according to claim 1, comprising a command input module (600) receiving input signals for the fusion module (100), the cutting module (200), the motion control module (300) and the axis construction module (500) to execute commands.

Images