WO2023198119A1

WO2023198119A1 - System and method for determining acetabular morphology

Info

Publication number: WO2023198119A1
Application number: PCT/CN2023/087882
Authority: WO
Inventors: Jianli Zhang; Xiaolei Wang
Original assignee: Beijing Zhuoyue Medical Technology Co., Ltd
Priority date: 2022-04-14
Filing date: 2023-04-12
Publication date: 2023-10-19
Also published as: EP4374315A1; CN114693666A

Abstract

The present invention relates to a system for determining acetabular morphology, at least comprising: a processing unit (1) configured to generate a three-dimensional image according to spiral CT scanning or MRI data, wherein the processing unit (1) is configured to generate a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human and to transmit processing results to an analyzing unit (2); the analyzing unit (2) configured to extract a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the received three-dimensional image of the hip joint, and to generate an acetabulum contour-line image and a femoral-head contour-line image by performing iso-value segmentation on the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head, respectively; and a comparing unit (3) configured to determine spatial morphology of the hip joint by analyzing whether the acetabulum and the femoral head match each other in the mutually corresponding surface areas in terms of contour line trend and morphology. The present invention also relates to a method for determining acetabular morphology.

Description

SYSTEM AND METHOD FOR DETERMINING ACETABULAR MORPHOLOGY

BACKGROUND OF THE INVENTION 1. Technical Field

The present invention relates to a technical field for analysis of acetabular morphology, and more particularly to a system and a method for determining acetabular morphology.

2. Description of Related Art

For diagnosis and pre-operative assessment of joint diseases in the hip, medical professionals usually need detailed information about the normal morphology of the acetabulum and the femoral head; the coverage of the acetabulum on the femoral head; and congruence between the acetabulum and the femoral head. Currently, such information is generally obtained from radiographs. However, in radiographs, the three-dimensional structure of the hip joint is flattened into a two-dimensional image. This means loss of information is unavoidable, and prevents the conventional means from reflecting the spatial morphology of the hip joint satisfyingly.

Some research institutions thus employ reconstruction approaches to recover information of the three-dimensional structure from the two-dimensional data, and conduct measurement and classification for the normal acetabulum and the acetabulum with dysplasia accordingly. Nevertheless, these approaches mainly rely on surface models formed in computers and focus on morphological observation and textual description, making the resulting assessment mired in the traditional research concepts rooted in two-dimensional image analysis, like those using radiographs. In other words, these existing reconstruction approaches remain investigating in a reconstructed three-dimensional model from its two-dimensional image taken from a certain angle or its certain cross-sectional view, but not comprehensively see the model as a three-dimensional unity. Besides, these approaches have bias when descripting spatial relationship of three-dimensional structures and need doctors to use extra spatial imagination as the presentation is not intuitive enough.

China Patent Publication No. CN107274389A discloses a femur and acetabular anatomic parameter acquiring method based on CT three-dimensional serial images, including the following steps: acquiring CT three-dimensional serial images of the femoral head and the acetabulum; separation between the femoral head and the acetabulum: roughly segmenting, separating, and finely segmenting the CT three-dimensional serial images successively, so as to obtain a finely segmented image of the femoral head and a finely segmented image of the acetabulum; calculation of anatomic parameters for the femoral head: constructing a triangular mesh surface model of the femoral head according to the finely segmented image of the femoral head, and calculating a diameter parameter of the femoral head, an inner diameter parameter of the medullary cavity, and an aspheric fitting parameter of the femoral head; and calculation of anatomic parameters for the acetabulum: constructing a triangular mesh surface model of the acetabulum from the selected finely segmented image of the acetabulum, and selecting points in the triangular mesh surface model for calculation of the anteroposterior diameter of the acetabulum. The prior-art method benefits from direct processing on CT three-dimensional serial images so as to fast and automatically achieve accurate separation of the femur and the acetabulum and acquisition of anatomic parameters.

China Patent Publication No. CN106388978A discloses a method for preparing acetabulum side model and guide plate based on three-dimensional reconstruction technology, comprising: Step 1, establishing a digital three-dimensional data model after three-dimensional CT data of a preoperative hip joint of a patient is processed, reconstructing a three-dimensional bony structure of an acetabulum side, and restoring an original state of a disease; Step 2, making an acetabulum mill filing and acetabulum screw embedding scheme by analyzing an acetabulum position, estimating an acetabulum state, clearing the mass of bones around an acetabulum and calculating the thickness of the bones around the acetabulum, and performing three-dimensional modelling on the guide plate and the model; Step 3, preparing a preoperative acetabulum side osseous model, an intra-operative grinding mortar guide plate, an intra-operative acetabulum screw guide plate and a postoperative acetabulum side osseous model by utilizing a three-dimensional printer; and Step 4, integrating and inspecting the guide plate and the model. Although the known method is capable of analyzing an acetabulum position, estimating an acetabulum state, clearing the mass of bones around an acetabulum and calculating the thickness of the bones around the acetabulum by building the three-dimensional data model, it fails to accurately calculate how well the acetabulum will cover the femoral head after the intended operation and thus is unable to predict the morphological stability of the connection between the acetabulum and the femoral head after the intended operation.

Therefore, there is a need for a system capable of calculating coverage of the acetabulum on the femoral head, describing the specific sunken form of the acetabulum, and determining the acetabular morphology that secures stability of the hip joint, so as to provide comprehensive consideration to the three-dimensional structure of the hip joint without any bias caused by two-dimensional measurement and calculation.

Since there is certainly discrepancy between the prior art comprehended by the applicant of this patent application and that known by the patent examiners and since there are many details and disclosures disclosed in literatures and patent documents that have been referred by the applicant during creation of the present invention not exhaustively recited here, it is to be noted that the present invention shall actually include technical features of all of these prior-art works, and the applicant reserves the right to supplement the application with the related art more existing technical features as support according to relevant regulations.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, the present invention adopts a technical scheme that provides a system for determining acetabular morphology, at least comprising a processing unit configured to generate a three-dimensional (three-dimensional) image according to spiral CT scanning or MRI data, wherein the processing unit is configured to generate a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human and to transmit processing results to an analyzing unit; the analyzing unit configured to extract a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the received three-dimensional image of the hip joint, and to generate an acetabulum contour-line image and a femoral-head contour-line image by performing iso-value segmentation on the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head, respectively; and a comparing unit configured to determine spatial morphology of the hip joint by analyzing whether the acetabulum and the femoral head match each other in a connecting area therebetween in terms of contour line trend and morphology. The system is advantageous because the morphological assessment of the hip joint is obtained through computer-based simulation and computational analysis, and thus free from inter-observer and intra-observer variability. The coverage of the connecting area of the hip joint obtained through the disclosed system is the actual coverage of the curved surface of the acetabulum on the femoral head. When acquiring the contour lines, the present invention incorporates the load-bearing lines into measurement, so the contour lines reflect the spatial correspondence of the load-bearing structure around the dome of the acetabulum that is usually the clinical focus placed on. At last, the present invention provides comprehensive consideration to the three-dimensional structure of the hip joint without any bias caused by two-dimensional measurement and calculation.

According to one preferred implementation, the analyzing unit generates the acetabulum contour-line image and the femoral-head contour-line image by performing spatial grid segmentation on the acetabulum and the femoral head in a direction of a gravity line of a longitudinal axis of the human body, wherein the acetabulum contour-line image and the femoral-head contour-line image are obtained by marking outlines of the acetabulum and the femoral head with equidistant spatial grid lines; the analyzing unit then projects the acetabulum contour-line image and the femoral-head contour-line image in the direction of the gravity line of the body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern.

According to one preferred implementation, the comparing unit is configured to determine the spatial morphology of the hip joint according to a match degree between contour loops of the partial acetabulum surface in the connecting area and contour loops of the partial femoral head surface in the connecting area.

According to one preferred implementation, the connecting area refers to an area at an end of the femoral head and covered by a sunken end surface of the acetabulum, and the contour loops refer to projection circles of plural contour lines in the three-dimensional image of the acetabulum and projection circles of plural contour lines in the three-dimensional image of the femoral head on a plane perpendicular to the direction of the gravity line of the body’s longitudinal axis, while the match degree refers to a coincidence degree between contour loops in the acetabulum contour-line pattern in the connecting area and contour loops in the femoral-head contour-line pattern in the connecting area.

According to one preferred implementation, the coincidence degree of the contour loops includes a coincidence degree between the annularly-distributed contour loops in the acetabulum contour-line pattern and the femoral-head contour-line pattern when being superimposed with each other, and include a coincidence degree between the variationally-distributed contour lines at an edge area where the acetabulum and the femoral head bordering each other.

According to one preferred implementation, a scanning slice thickness of the spiral CT scanning or MRI used to obtain the three-dimensional data of the hip joint matches a distance between the spatial grid that are used to define the contour lines on surfaces of the acetabulum and the femoral head, so that a unit width of each cell of the spatial grid is equal to at least one time of the slice thickness of the spiral CT scanning or MRI.

According to one preferred implementation, the processing unit at least comprises a reconstructing unit configured to generate the three-dimensional images and a separating unit configured to separate soft tissue from osseous structure in the reconstructed three-dimensional images according to a predetermined threshold.

The technical scheme of the present invention further provides a method for determining acetabular morphology, at least comprising the following steps: generating a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human; extracting a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the generated three-dimensional image of the hip joint; using a spatial grid to segment the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in a direction of a gravity line of a longitudinal axis of the human body into layers; projecting the layers segmented from the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in the direction of the gravity line of the body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern; and superimposing the acetabulum contour-line pattern and the femoral-head contour-line pattern, and determining spatial morphology of the hip joint by comparing whether the acetabulum and the femoral head match each other in a connecting area therebetween in terms of contour line trend and morphology.

According to one preferred implementation, the contour lines are formed by connecting points on the segmented layers along an outline of the acetabulum or the femoral head.

According to one preferred implementation, the spatial morphology of the hip joint is determined according to a match degree between contour loops of the partial acetabulum surface in the connecting area and contour loops of the partial femoral head surface in the connecting area, wherein the connecting area refers to an area at an end of the femoral head and covered by a sunken end surface of the acetabulum, and the contour loops refer to projection circles of plural contour lines in the three-dimensional image of the acetabulum and projection circles of plural contour lines in the three-dimensional image of the femoral head on a plane perpendicular to the direction of the gravity line of the body’s longitudinal axis, while the match degree refers to a coincidence degree between contour loops in the acetabulum contour-line pattern in the connecting area and contour loops in the femoral-head contour-line pattern in the connecting area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a preferred system for determining acetabular morphology provided by the present invention.

List of reference numbers

1: Processing Unit 40 4: Controlling Unit

2: Analyzing Unit 11: Reconstructing Unit

3: Comparing Unit 12: Separating Unit

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be detailed with reference to the accompanying drawings.

Developmental dysplasia of the hip (DDH) is a common human disease related to diastrophic dysplasia, mainly including femoral head subluxation, luxation, and acetabular dysplasia. A poorly developed hip joint tends to deform due to unequal settlement of loads and leads to degraded match between the acetabulum and the femoral head and eventually serious osteoarthritis (OA) when the joint finally gets worn, significantly degrading the quality of life of patients. DDH is caused by abnormal alignment or poor coverage between the acetabulum and the femoral head. The hip joint is one of the most important joints in the human body that bears the weight of body and conduct movements, and is composed of the acetabulum and the femoral head, which normally formed concentric in the human body. In the event of DDH, the normal alignment of the concentric circles is broken. The acetabulum will become smaller and shallower, and have defects at its edge of various degrees of severity. Also, the anteversion angle at the neck of the femoral head can vary. Eventually, the loss of match at the hip joint will lead to OA, and seriously impact the life of patients. The traditional X-ray inspection has been popular clinically for its simple operation and easy interpretation. Radiographs represent three-dimensional structure of organisms in a two-dimensional plane, from which information about regions of patients to be treated can be read and provides guidance to diagnosis of diseases and selection of surgical operations. However, conversion from spatial information to plane image unavoidably causes lose information about some morphological characteristics, hindering medical professionals from making well-informed diagnosis and selection.

As compared to X-ray inspection, spiral CT scanning or MRI enables more intuitive observation, and is particularly contributive to, among others, diagnosis of abnormal soft tissue that tends to be overlooked in regular examinations. Original spiral CT scanning or MRI data are constructed into three-dimensional images by means of volume rendering. This technique makes effective use of volume data, thereby presenting the sum of all pixels without annotating surface information. Since the original data include spatial anatomical relationship of three-dimensional structures, the results are more realistic than that presented in the form of planar images. It not only provides lesions, surrounding tissue, and severity, but also clearly shows information about the type of calcification and the type of reduction for the joint, being proven to be highly accurate. The present invention, on the basis of three-dimensional images constructed from spiral CT scanning or MRI data, uses contour lines to achieve iso-value segmentation of the acetabulum and the femoral head, and uses directional light to project the image of the acetabulum and the femoral head after iso-value segmentation, thereby generating a contour-line pattern similar to a topographic map.

Embodiment 1

The present invention relates to a system for determining acetabular morphology. The system is configured to construct three-dimensional images of the hip joint according to pre-collected spiral CT scanning or MRI data, and then performs iso-value segmentation and directional light projection on the three-dimensional image of the hip joint successively to obtain contour-line patterns that use distribution of contour lines to represent the spatial morphology of the acetabulum. By superimposing the acetabulum contour-line image and the femoral-head contour-line image together and analyzing the match degree of the superimposed contour lines and distance variation between adjacent contour lines, medical professionals can accurately determine the relative location of the acetabulum and the femoral head as well as how poorly the acetabulum has developed. The system at least comprises a processing unit 1, an analyzing unit 2, a comparing unit 3, and a controlling unit 4.

According to a specific implementation, the processing unit 1 is configured to generate a three-dimensional image of the hip joint according to pre-collected spiral CT scanning or MRI data of the hip joint, and perform secondary processing on the three-dimensional image of the hip joint to isolate the three-dimensional image of the osseous structure of the hip joint. The processing unit 1 transmits the processed three-dimensional image of the osseous structure of the hip joint to the analyzing unit 2 that quantifies the spatial morphology of the hip joint in the three-dimensional image. The analyzing unit 2 selectively extract a three-dimensional image of the acetabulum and a three-dimensional image of the femoral head, each having a predetermined spatial scale, from the received three-dimensional image of the hip joint. The analyzing unit 2 further performs iso-value segmentation on the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head, respectively, thereby generating an acetabulum contour-line image and a femoral-head contour-line image. The analyzing unit 2 uses directional light to project the contour-line images obtained through three-dimensional segmentation onto the same plane, thereby forming contour-line patterns having contour loops that represent the topographic changes of the surface outlines of the acetabulum and the femoral head. The comparing unit 3 receives the acetabulum contour-line pattern and the femoral-head contour-line pattern generated by the analyzing unit 2. Then the comparing unit 3 superimposes the acetabulum contour-line pattern and the femoral-head contour-line pattern together to analyze whether the contour lines in the acetabulum contour-line pattern and the femoral-head contour-line pattern match each other in terms of trend and form in the connecting area therebetween. Development of the acetabulum can thus be determined by analyzing the distance variation between the adjacent contour lines of the acetabulum and the femoral head in the connecting area and whether the contour loops in the center-facing areas in the two contour-line patterns form concentric circles, so as to accurately determine whether the connection between the acetabulum and the femoral head satisfies the need for bearing the weight of the human body, thereby obtaining a mathematical model representing the spatial relationship between the acetabulum and the femoral head in a quantitative way as well as the formulation and values of the mathematical model.

The reconstructing unit 11 and the separating unit 12 forming the processing unit 1 may each be one or more of a central processing unit (CPU) , a digital signal processor (DSP) , a microprocessor, a server, a cloud server, and an application-specific integrated circuit.

The analyzing unit 2 may be one or more of a central processing unit (CPU) , a digital signal processor (DSP) , a microprocessor, and an application-specific integrated circuit.

The comparing unit 3 may also be one or more of a central processing unit (CPU) , a digital signal processor (DSP) , a microprocessor, a server, a cloud server, and an application-specific integrated circuit.

Preferably, the processing unit 1 at least comprises a reconstructing unit 11 that is configured to reconstruct a three-dimensional image of the hip joint according to spiral CT scanning or MRI data and a separating unit 12 that is configured to separate the soft tissue and the osseous structure on the reconstructed three-dimensional image of the hip joint according to a predetermined threshold. Preferably, the scanning of the spiral CT or MRI is designed to directly output three-dimensional data of the scanned portion of a patient, so that the reconstructing unit 11 can directly reconstructing the three-dimensional images of the bones from the scanning three-dimensional data. Preferably, the bones include osseous tissue and bone connection. Therein, the latter refers to joints and their associated structures, such as cartilages, interarticular ligaments, articular capsules, etc. Therefore, after the reconstructing unit 11 reconstructs the three-dimensional image of bones corresponding to the hip joint, the separating unit 12 performs secondary processing on the reconstructed three-dimensional image of the bones so as to obtain a three-dimensional image that only contains the osseous structure of the hip joint. Specifically, the separating unit 12 is configured to separate the soft tissue and the osseous structure in the three-dimensional image of bones reconstructed by the reconstructing unit 11 according to a predetermined threshold, thereby outputting a three-dimensional image only having the osseous structure of the hip joint. Preferably, the threshold-based segmentation method for the separating unit 12 to conduct and separate the soft tissue and the osseous structure may be one as disclosed in China Patent Publication No. CN107016666A.

Preferably, the analyzing unit 2 generates an acetabulum contour-line image and a femoral-head contour-line image by performing spatial grid segmentation on the acetabulum and the femoral head in the direction of the gravity line of the human body’s longitudinal axis. Specifically, the acetabulum contour-line image and the femoral-head contour-line image are obtained by annotating outlines of the acetabulum and the femoral head with equidistant spatial grid lines. By projecting the acetabulum contour-line image and the femoral-head contour-line image in the direction of the gravity line of the body’s longitudinal axis, respectively, an acetabulum contour-line pattern and a femoral-head contour-line pattern can be obtained directly. Stated differently, the acetabulum contour-line image and the femoral-head contour-line image are preferably obtained by segmenting the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head into layers in the normal direction of a planar grid that is parallel to the direction of the gravity line of the body’s longitudinal axis. Preferably, the slice thickness for scanning the three-dimensional data of the hip joint in spiral CT or MRI matches the line interval of the spatial grid defining the contour lines on the surfaces of the acetabulum and the femoral head, so that the cell width of the spatial grid is at least one scanning slice thickness of spiral CT or MRI. Preferably, the line interval of the spatial grid and the line interval of the planar grid may both be equal to the slice thickness of the spiral CT scanning. In other words, the layer interval for layered segmentation is equal to the slice thickness of spiral CT or MRI scanning. Preferably, according to investigation made by relevant industrial associations, the diameter of the femoral head of normal people ranges between 40 and 55mm. The scanning slice thickness of spiral CT or MRI scanning used in the present invention is 0.5-2mm. Therefore, the distance between the adjacent contour lines in the contour-line images obtained by the analyzing unit 2 in the direction of the gravity line of the body’s longitudinal axis ranges between 0.5 and 2mm. Thus, the acquired acetabulum image having a certain spatial scale is set based on the number of layers of the acetabulum in segmentation according to the diameter of the femoral head, so that the acquired acetabulum can be used to calculate the morphological stability between the acetabulum and the femoral head, and can prevent iso-value segmentation of the acetabulum being interference by other osseous structures of the hip bone, thereby eliminating the defect of inaccurate calculation of coverage caused by too large layers while accurately obtaining the three-dimensional coverage of the hip joint.

Preferably, the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head are obtained by segmenting the three-dimensional structure into layers in the direction of the gravity line of the body’s longitudinal axis with equidistant spatial grid lines. Thereby, the plane edge line of the bone section obtained in the segmentation process conducted by the analyzing unit 2 is a contour line. Preferably, a contour line nay be a curve formed by linking points equal to the slice thickness of spiral CT scanning or MRI. Preferably, the pattern having plural contour lines in the form of concentric circles obtained by using directional light to project the contour-line image in the direction of the gravity line of the body longitudinal axis is a contour-line pattern. Preferably, the acetabulum contour-line pattern and the femoral-head contour-line pattern when superimposed can be used to assess the match degree of the contour lines. Preferably, the connecting area refers to an area at an end of the femoral head that is covered by a sunken end surface of the acetabulum. Preferably, the acetabulum and the femoral head have mutual matching “dome-like” profiles for connecting each other, and the zenith of the dome is inward and thus off the edge. The contour lines at the periphery of the dome are relatively distant from each other or are relatively dispersed, which means that the profile in this portion has a relatively small curvature, or a relatively gentle surface change. The contour lines at the bottom edge of the acetabulum and at the periphery of the femoral head are relatively close to each other or are relatively dense, which means that the profiles in these portions have relative great curvatures, or have significant changes in spatial morphology, or the surface are relatively steep. Preferably, the contour lines each form a “V” shape at the front or back edge of the acetabulum. The inflection points of the “V” shapes and the contour lines at the outer upper edge of the acetabulum form smooth extension.

The comparing unit 3 is configured to assess the spatial morphology of the hip joint according to the match degree between the contour loops of the acetabulum in the connecting area and the contour loops of the femoral head in the connecting area. Preferably, the contour loops refer to the circles as the projection of the plural contour lines in the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head on the plane perpendicular to the direction of the gravity line of the body’s longitudinal axis. The contour loops are plural contour lines that form concentric “C” shapes and oval “O” shapes in the acetabulum contour-line pattern and the femoral-head contour-line pattern. Preferably, the match degree refers to the coincidence degrees of the contour loops in the connecting area both of the acetabulum contour-line pattern and the femoral-head contour-line pattern. Preferably, the coincidence degree of the contour loops includes the coincidence degree of the annularly-distributed contour loops in the acetabulum contour-line pattern and the femoral-head contour-line pattern when being superimposed with each other, and the coincidence degree between the variationally-distributed contour lines at an edge area where the acetabulum and the femoral head bordering each other. Preferably, the annularly-distributed contour loops may be the contour lines forming concentric “C” shapes and oval “O” shapes. The variationally-distributed contour lines may be the C-shaped contour lines connected to the V-shaped contour lines at the front and back edge of the acetabulum. If the contour lines forming plural concentric “C” shapes and oval “O” shapes in the acetabulum contour-line pattern and the contour lines forming oval “O” shapes in the femoral-head contour-line pattern coincide and/or jointly form concentric contour loops, the match degree in the connecting area between the acetabulum and the femoral head is high. At this time, the acetabulum and the femoral head can form a complete dome structure, so the hip joint has good morphological stability.

Preferably, the controlling unit 4 is configured to show the stability of the connection between the acetabulum and the femoral head according to the comparison results provided by the comparing unit 3, so as to help medical professionals assess acetabular morphology according to the analysis results shown by the controlling unit 4 and predict whether the morphological adjustment to be made to the acetabulum with respect to the femoral head will form stable connection. Preferably, the controlling unit 4 allows medical professionals to conduct manual adjustment on the three-dimensional image of the hip joint, so as to find out the location of the acetabulum for optimal support.

Embodiment 2

The present embodiment involves further improvements in Embodiment 1, and repeated description is omitted herein for terseness.

In a patient with DDH, the acetabulum is unable to effectively cover the end of the femoral head, so the acetabulum and the femoral head cannot form mutual matching “dome-like” spatial profiles. In such a case, although the end of the femoral head is located in the socket of the acetabulum, the acetabulum is angled with respect to the axis of the femoral head. In other words, instead of being aligned with the zenith of the dome of the femoral head, the zenith of the dome of the acetabulum is very inward and off the edge, and this prevents the acetabulum and the femoral head from matching at their “dome-like” spatial profiles. Consequently, when the patient stands, the pressure acting on the hip joint caused by the body weight can have a large horizontal component that creates the tendency that the end of the femoral head departs form the socket of the acetabulum, thereby breaking stability of the connection between the acetabulum and the femoral head.

In the prior art, for diagnosis of conditions of a patient, radiographs of the hip joint are taken in the directions perpendicular to the coronal plane and the sagittal plane of the patient, so that the forward and lateral stability of the hip joint can be assessed according to how well the outer edge of the acetabulum covers the end of the femoral head and how well the front edge of the acetabulum covers the end of the femoral head. However, since the acetabulum is a three-dimensional structure, even if the observation angles for the forward and lateral directions are completely the same, the calculated stability of the hip joint may be very different from the actual stability of the hip joint due to different three-dimensional structures, leaving the effectiveness of the planned acetabular adjustment in creating stable connection with the femoral head dubious.

In view of the shortcomings of the prior art, in the present invention, the comparing unit 3 is further configured to assess the coverage of the socket of the acetabulum to the end surface of the femoral head using the coincidence degree between the contour loops of the acetabulum and the femoral head in the connecting area from the superimposed contour-line patterns of the acetabulum and the femoral head, thereby achieving reliable assessment of the stability of the three-dimensional structure of the hip joint according to quantitative data.

Embodiment 3

In addition to the method for determining acetabular morphology, the present invention further provides a method for measuring the hip joint in terms of stability, which at least comprises the following steps:

generating a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human;

extracting a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the generated three-dimensional image of the hip joint;

using a spatial grid to split the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in a direction of a gravity line of a longitudinal axis of the human body into layers;

projecting the layers split from the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in the direction of the gravity line of the body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern; and

superimposing the acetabulum contour-line pattern and the femoral-head contour-line pattern, and determining spatial morphology of the hip joint by comparing whether the acetabulum and the femoral head match each other in a connecting area therebetween in terms of contour line trend and morphology.

Preferably, the contour lines are formed by connecting points on the split layers along an outline of the acetabulum or the femoral head. The points when linked forming a contour line are located on the same segmented layer. Preferably, the contour line may be a curve formed by linking points having the same spiral CT scanning or MRI slice thickness successively. Preferably, the pattern of the concentric circles formed by the contour lines of the contour-line image projected by the directional light in the direction of the gravity line of the body longitudinal axis is the contour-line pattern. Preferably, the acetabulum contour-line pattern and the femoral-head contour-line pattern when superimposed can be used to assess the match degrees of the contour lines. Preferably, the connecting area between the acetabulum and the femoral head refers to the area at the end of the femoral head covered by the socket end of the acetabulum.

Embodiment 4

Based on the extracted three-dimensional images of the acetabulum and the femoral head, the match degree between the end surface of the acetabulum and the end surface of the femoral head of the patient in the initial state and the shape of the connecting area can be obtained by means of iso-value segmentation. Through progressive adjustment specific to the acetabulum, multiple three-dimensional images showing the connection between the acetabulum and femoral head corresponding to locational changes of the acetabulum with respect to the femoral head can be generated. Preferably, the locational changes of the acetabulum may be rotation about a certain axis or about a certain point, so that not only a connection structure formed by the acetabulum with the femoral head allows relative locational changes, but also ensures that with the assistance of external fasteners, the acetabulum can form complete and stable bone connection with the hip bone.

Preferably, with different three-dimensional images of the connection between the acetabulum and the femoral head at different relative locations between the acetabulum and the femoral head, iso-value segmentation is performed on different pairs of the acetabulum and the femoral head in the three-dimensional images of the acetabulum and the femoral head, respectively, so as to obtain the respective contour-line patterns. By superimposing the acetabulum contour-line pattern and the femoral-head contour-line pattern in the same pair, the trendies and forms of the contour lines in the connecting area between the acetabulum and the femoral head can be analyzed, thereby assessing the match degree between each pair of the acetabulum and the femoral head as well as the stability of the hip joint under such a connection form. Preferably, by comparing the match degrees of multiple pairs of the acetabulum and the femoral head in contour-line patterns, the optimal location of the acetabulum with respect to the femoral head can be determined, so that medical professionals can conduct pre-operative analysis and predict the operation result according to the analysis-based correction parameters corresponding to the optimal location of the acetabulum. This helps medical professionals determine the correction parameters of the acetabulum more intuitively, and predict the match degree between the acetabulum and the femoral head as well the stability of the hip joint after operation more accurately according to quantitative data.

It is to be noted that the embodiments described above are exemplificative. Various modifications thereof are apparent to people skilled in the art with the enlightenment of the present disclosure, and all of these modifications form a part of the disclosure of the present invention as they all fall within the scope of the present invention. It is thus to be understood by people skilled in the art that the description and accompanying drawings provided by the present invention are only illustrative but not limiting to claims of the present application. The scope of the present invention shall be defined by the claims and their equivalents. Throughout the disclosure, any feature following the term “preferably” is optional but not necessary, and the applicant of the present application reserves the rights to withdraw or delete any of the preferred features any time.

Claims

A system for determining acetabular morphology, at least comprising:

a processing unit (1) configured to generate a three-dimensional image according to spiral CT scanning or MRI data, wherein the processing unit (1) is configured to generate a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human and to transmit processing results to an analyzing unit (2) ;

the analyzing unit (2) configured to extract a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the received three-dimensional image of the hip joint, and to generate an acetabulum contour-line image and a femoral-head contour-line image by performing iso-value segmentation on the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head, respectively; and

a comparing unit (3) configured to determine spatial morphology of the hip joint by analyzing whether the acetabulum and the femoral head match each other in a connecting area therebetween in terms of contour line trend and morphology.
The system for determining acetabular morphology of claim 1, wherein the analyzing unit (2) generates the acetabulum contour-line image and the femoral-head contour-line image by performing spatial grid segmentation on the acetabulum and the femoral head in a direction of a gravity line of a longitudinal axis of the human body, wherein

the acetabulum contour-line image and the femoral-head contour-line image both are obtained by marking outlines of the acetabulum and the femoral head with equidistant spatial grid lines; the analyzing unit (2) then projects the acetabulum contour-line image and the femoral-head contour-line image in the direction of the gravity line of the human body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern.
The system for determining acetabular morphology of claim 1 or 2, wherein the comparing unit (3) is configured to determine the spatial morphology of the hip joint according to a match degree between contour loops of the partial acetabulum surface in the connecting area and contour loops of the partial femoral head surface in the connecting area.
The system for determining acetabular morphology of any of claims 1 to 3, wherein the connecting area refers to an area at an end of the femoral head and covered by a sunken end surface of the acetabulum, and the contour loops refer to respective projection circles of plural contour lines in the three-dimensional image of the acetabulum and in the three-dimensional image of the femoral head on a plane perpendicular to the direction of the gravity line of the human body’s longitudinal axis, while the match degree refers to a coincidence degree between contour loops in the acetabulum contour-line pattern in the connecting area and contour loops in the femoral-head contour-line pattern in the connecting area.
The system for determining acetabular morphology of any of claims 1 to 4, wherein the coincidence degree of the contour loops includes a coincidence degree between the annularly-distributed contour loops in the acetabulum contour-line pattern and the femoral-head contour-line pattern when being superimposed with each other, and include a coincidence degree between the variationally-distributed contour lines at an edge area where the acetabulum and the femoral head bordering each other.
The system for determining acetabular morphology of any of claims 1 to 5, wherein a scanning slice thickness of the spiral CT scanning or MRI used to obtain the three-dimensional data of the hip joint matches a distance between the spatial grid that are used to define the contour lines on surfaces of the acetabulum and the femoral head, so that a unit width of each cell of the spatial grid is equal to at least one time of the slice thickness of the spiral CT scanning or MRI.
The system for determining acetabular morphology of any of claims 1 to 6, wherein the processing unit (1) at least comprises a reconstructing unit (11) configured to generate the three-dimensional images and a separating unit (12) configured to separate soft tissue from osseous structure in the reconstructed three-dimensional images according to a predetermined threshold.
The system for determining acetabular morphology of any of claims 1 to 7, wherein the system is configured that:

the contour lines are formed by connecting points on the segmented layers along an outline of the acetabulum or the femoral head.
A method for determining acetabular morphology, at least comprising steps of:

generating a three-dimensional image of a hip joint of a human according to pre-collected spiral CT scanning or MRI data of the hip joint of the human;

extracting a three-dimensional image of an acetabulum of the human and a three-dimensional image of a femoral head of the human from the generated three-dimensional image of the hip joint;

using a spatial grid to segment the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in a direction of a gravity line of a longitudinal axis of the human body into layers;

projecting the layers segmented from the three-dimensional image of the acetabulum and the three-dimensional image of the femoral head in the direction of the gravity line of the human body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern; and

superimposing the acetabulum contour-line pattern and the femoral-head contour-line pattern, and determining spatial morphology of the hip joint by comparing whether the acetabulum and the femoral head match each other in a connecting area therebetween in terms of contour line trend and morphology.
The method for determining acetabular morphology of claim 9, wherein the contour lines are formed by connecting points on the segmented layers along an outline of the acetabulum or the femoral head.
The method for determining acetabular morphology of claim 9 or 10, wherein the spatial morphology of the hip joint is determined according to a match degree between contour loops of the partial acetabulum surface in the connecting area and contour loops of the partial femoral head surface in the connecting area, wherein

the connecting area refers to an area at an end of the femoral head and covered by a sunken end surface of the acetabulum, and the contour loops refer to projection circles of plural contour lines in the three-dimensional image of the acetabulum and in the three-dimensional image of the femoral head on a plane perpendicular to the direction of the gravity line of the human body’s longitudinal axis, while the match degree refers to a coincidence degree between contour loops in the acetabulum contour-line pattern in the connecting area and contour loops in the femoral-head contour-line pattern in the connecting area.
The method for determining acetabular morphology of any of claims 9 to 11, wherein the method further comprises:

generating the acetabulum contour-line image and the femoral-head contour-line image by performing spatial grid segmentation on the acetabulum and the femoral head in a direction of a gravity line of a longitudinal axis of the human body, wherein

the acetabulum contour-line image and the femoral-head contour-line image both are obtained by marking outlines of the acetabulum and the femoral head with equidistant spatial grid lines; projecting the acetabulum contour-line image and the femoral-head contour-line image in the direction of the gravity line of the human body’s longitudinal axis, so as to obtain an acetabulum contour-line pattern and a femoral-head contour-line pattern.
The method for determining acetabular morphology of any of claims 9 to 12, wherein the method further comprises:

determining the spatial morphology of the hip joint according to a match degree between contour loops of the partial acetabulum surface in the connecting area and contour loops of the partial femoral head surface in the connecting area.
The method for determining acetabular morphology of any of claims 9 to 13, wherein the coincidence degree of the contour loops includes a coincidence degree between the annularly-distributed contour loops in the acetabulum contour-line pattern and the femoral-head contour-line pattern when being superimposed with each other, and include a coincidence degree between the variationally-distributed contour lines at an edge area where the acetabulum and the femoral head bordering each other.
The method for determining acetabular morphology of any of claims 9 to 14, wherein a scanning slice thickness of the spiral CT scanning or MRI used to obtain the three-dimensional data of the hip joint matches a distance between the spatial grid that are used to define the contour lines on surfaces of the acetabulum and the femoral head, so that a unit width of each cell of the spatial grid is equal to at least one time of the slice thickness of the spiral CT scanning or MRI.