A method and system for automatic measurement of spine based on 3D CT
By employing an automatic spine measurement method based on 3D CT, and utilizing connected component analysis and principal component analysis, interfering structures in spine CT images are identified and removed, and the three-dimensional coordinate system of the spine is corrected. This solves the problem that the spine segmentation model cannot accurately segment the vertebral body, and achieves high-precision and efficient measurement of vertebral body rotation angle and Cobb angle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG UNIV QILU HOSPITAL
- Filing Date
- 2026-03-26
- Publication Date
- 2026-05-19
AI Technical Summary
In existing technologies, spinal segmentation models cannot accurately segment vertebrae, resulting in inaccurate measurements of the Cobb angle and vertebral rotation angle. This is especially true in cases of vertebral fusion, bone bridging, or interference from vertebral fragments, leading to poor consistency and low efficiency in measurement results.
An automatic spine measurement method based on 3D CT was adopted. By segmenting the spine CT image, connected component analysis and principal component analysis were used to identify and delete free osteophytes, soft tissue, bone bridges and vertebral body fragments. The vertebral body mask was renamed in combination with the anatomical order of the spine, the three-dimensional coordinate system of the spine was corrected, and the vertebral body rotation angle and Cobb angle were calculated.
It enables accurate measurement of vertebral rotation angle and Cobb angle, improves segmentation accuracy and measurement consistency, reduces human subjective error, and meets the need for rapid processing of large batches of image data.
Smart Images
Figure CN121904057B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of image processing technology, and in particular to an automatic spine measurement method and system based on 3D CT. Background Technology
[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.
[0003] Spinal measurements include Cobb angle measurement and vertebral rotation angle measurement; Cobb angle is the core indicator for assessing the degree of spinal deformity, while vertebral rotation angle is an important parameter to help determine the type and severity of deformity.
[0004] One related technology involves using a spinal segmentation model to identify and segment spinal CT images, obtaining vertebral body segmentation results, and then determining the Cobb angle and vertebral body rotation angle based on the vertebral body segmentation results.
[0005] However, due to the complexity of the spinal anatomy, such as vertebral fusion, bone bridging, and interference from vertebral fragments, the spinal segmentation models in related technologies cannot accurately segment the vertebrae, thus failing to guarantee the accuracy of Cobb angle and vertebral rotation angle measurements. Summary of the Invention
[0006] To address the aforementioned problems, this invention proposes an automatic spinal measurement method and system based on 3D CT, which enables accurate measurement of vertebral rotation angle and Cobb angle.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] Firstly, an automatic spine measurement method based on 3D CT is proposed, including:
[0009] Acquire spinal CT images;
[0010] The vertebral bodies and intervertebral discs in spinal CT images are segmented to obtain preliminary segmentation masks for the vertebral bodies, intervertebral discs, spinal cord, and femur;
[0011] Connectivity analysis of different structures was performed on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial mask of each intervertebral disc structure and the initial mask of the vertebral body structure.
[0012] The soft tissue in the initial mask of the intervertebral disc structure is deleted, and the initial masks of the intervertebral disc structure in the same segment are merged to obtain the intervertebral disc structure mask.
[0013] The osteophytes and vertebral fragments in the initial vertebral structure mask are removed, and the initial vertebral structure mask is separated from the bone bridge by expanding outward through the intervertebral disc structure mask to obtain the vertebral structure mask.
[0014] Based on the anatomical sequence of the spine, the intervertebral disc structure mask and the vertebral body structure mask are renamed to determine the final vertebral body mask;
[0015] Based on the final vertebral mask, determine the vertebral rotation angle and Cobb angle.
[0016] Furthermore, regions in the initial mask of the vertebral structure with a volume smaller than a set volume threshold are designated as osteophytes;
[0017] Calculate the distance between the initial mask of the intervertebral disc structure and the nearest initial mask of the vertebral body structure; define the regions in the initial mask of the intervertebral disc structure whose distance from the nearest initial mask of the vertebral body structure is greater than a set distance threshold as soft tissue;
[0018] The portion of the vertebral structure in the initial mask that exceeds the set z-axis range threshold is taken as a bone bridge.
[0019] Masks with a volume smaller than a multiple of the median volume of the initial mask for all vertebral structures are used as vertebral fragments.
[0020] Furthermore, when the z-axis range of the initial mask of the vertebral body structure exceeds the set z-axis range threshold, and there is an initial mask of the intervertebral disc within the set area of its z-axis range, it is determined that there is a bone bridge in the initial mask of the vertebral body structure.
[0021] Principal component analysis is performed on the initial mask of the intervertebral disc structure within the set range of the z-axis of the initial mask of the vertebral body structure. The direction of the third principal component is taken as the normal, and the centroid of the intervertebral disc corresponding to the initial mask of the intervertebral disc structure is taken as the center. The mask is expanded outward along the plane of the intervertebral disc to separate the initial mask of the vertebral body structure from the bone bridge.
[0022] Furthermore, the process of renaming the intervertebral disc structure mask and vertebral body structure mask according to the anatomical sequence of the spine includes:
[0023] Determine whether the arrangement order of the intervertebral disc structure mask and the vertebral body structure mask conforms to the anatomical order of the spine;
[0024] When the anatomical sequence of the spine is followed, determine whether the lowest structural mask is a vertebral body structure mask or an intervertebral disc structure mask.
[0025] When the bottommost structure mask is determined to be an intervertebral disc structure mask, the intervertebral disc structure mask is deleted, and the bottommost structure is a vertebral body structure mask.
[0026] When the bottommost structural mask is a vertebral body structural mask, the bottommost structural mask is taken as the S1 vertebral body, and the structural masks of each vertebral body and intervertebral disc are named according to the anatomical order of the spine.
[0027] Furthermore, femoral and spinal cord masks are extracted from spinal CT images;
[0028] Based on the femoral mask, determine the center coordinates of the left and right femoral heads;
[0029] Connect the center coordinates of the left and right femoral heads to form the corrected X-axis;
[0030] The corrected three-dimensional coordinate system of the spine is obtained by correcting the X-axis;
[0031] Based on the vertebral body mask, calculate the centroid coordinates of the vertebral body in the corrected three-dimensional coordinate system of the spine, and use them as the centroid coordinates of the vertebral body.
[0032] Based on the coordinates of the vertebral centroid and the spinal cord mask, the vertebral rotation angle and Cobb angle are calculated and determined.
[0033] Furthermore, the coronal and sagittal planes are determined based on the coordinates of the vertebral centroid.
[0034] Determine the key points of the vertebral body in the coronal and sagittal planes;
[0035] The Cobb angle is calculated and determined based on the key points of the vertebral body in the coronal and sagittal planes;
[0036] The spinal cord mask is sliced at the level corresponding to the centroid coordinates of the vertebral body to obtain the spinal cord cross-sectional mask;
[0037] Calculate and determine the centroid coordinates of the spinal cord section mask;
[0038] The rotation angle of the vertebra is calculated and determined based on the centroid coordinates of the vertebral body and the centroid coordinates of the spinal cord cross-section mask.
[0039] Secondly, an automatic spine measurement system based on 3D CT is also proposed, including:
[0040] Image acquisition unit, used to acquire spinal CT images;
[0041] The mask segmentation unit is used to segment the vertebral body and intervertebral disc in spinal CT images to obtain preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur;
[0042] The initial structure mask determination unit is used to perform connected component analysis on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial structure mask of each intervertebral disc and the initial structure mask of the vertebral body.
[0043] The mask filtering unit is used to delete soft tissue in the initial mask of the intervertebral disc structure and merge the initial masks of the intervertebral disc structure in the same segment to obtain the intervertebral disc structure mask; it deletes osteophytes and vertebral body fragments in the initial mask of the vertebral body structure and expands outward through the intervertebral disc structure mask to separate the initial mask of the vertebral body structure from the bone bridge to obtain the vertebral body structure mask.
[0044] The mask renaming unit is used to rename the intervertebral disc structure mask and the vertebral body structure mask according to the anatomical order of the spine, and to determine the final vertebral body mask.
[0045] The measurement unit is used to determine the vertebral rotation angle and Cobb angle based on the final vertebral mask.
[0046] Thirdly, a computer device is proposed, the device comprising:
[0047] A processor, adapted to execute computer programs;
[0048] A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the automatic spine measurement method based on 3D CT proposed in the first aspect.
[0049] Fourthly, a computer-readable storage medium is proposed, which stores a computer program adapted to be loaded and executed by a processor, namely, an automatic spine measurement method based on 3D CT proposed in the first aspect.
[0050] Fifthly, a computer program product is proposed, which includes a computer program that, when executed by a processor, implements the automatic spine measurement method based on 3D CT proposed in the first aspect.
[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0052] This invention proposes an automatic spine measurement method and system based on 3D CT. After obtaining preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord, and femur, the method determines the initial masks of the intervertebral disc structure and the vertebral body structure based on a connected component algorithm. Then, free osteophytes, soft tissues, bone bridges, and vertebral body fragments in the initial masks of the intervertebral disc structure and the vertebral body structure are identified and deleted to ensure the accuracy of the segmentation of the intervertebral disc structure mask and the vertebral body structure mask. Then, according to the anatomical order of the spine, the intervertebral disc structure mask and the vertebral body structure mask are renamed to ensure the accuracy of the naming of the final obtained vertebral body mask. On this basis, the accurate measurement of the vertebral body rotation angle and Cobb angle is realized.
[0053] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0054] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.
[0055] Figure 1 This is a flowchart of an automatic spine measurement method based on 3D CT proposed in an embodiment of the present invention;
[0056] Figure 2 This is a schematic diagram of an irregular cross-section;
[0057] Figure 3 This is a schematic diagram of coronal plane misalignment.
[0058] Figure 4 This is a schematic diagram of the largest internal incisor ball and the center of the femoral head;
[0059] Figure 5 This is a schematic diagram of the Z-axis after correction.
[0060] Figure 6 This is a schematic diagram showing the coronal plane before and after correction;
[0061] Figure 7 This is a schematic diagram before and after sagittal plane correction;
[0062] Figure 8 Schematic diagram of vertebral body mask, femoral head mask, and key points of vertebral body;
[0063] Figure 9 A schematic diagram of the initial mask and segmented vertebral body and intervertebral disc structure;
[0064] Figure 10 A diagram illustrating soft tissue that was mistakenly identified as an intervertebral disc;
[0065] Figure 11 This is a schematic diagram of intervertebral disc fragments.
[0066] Figure 12 A schematic diagram of a bone bridge formed by coronal incision of the intervertebral space;
[0067] Figure 13 A schematic diagram of sagittal incision of intervertebral space osteophytes;
[0068] Figure 14 A schematic diagram showing the segmentation results of the intervertebral disc and vertebral body;
[0069] Figure 15 A schematic diagram of the maximum internal spherical diameter of the femoral head;
[0070] Figure 16 These are the four key points in the sagittal plane of the vertebral body;
[0071] Figure 17 These are the four key points on the coronal plane of the vertebral body;
[0072] Figure 18 This is a schematic diagram of a non-rotating vertebral body mask, where the yellow area represents the spinal cord and the green area represents the corroded vertebral body;
[0073] Figure 19 This is a schematic diagram of a rotating vertebral body mask, where the yellow area represents the spinal cord and the green area represents the corroded vertebral body. Detailed Implementation
[0074] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0075] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0076] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0077] It should be noted that all data acquisition is conducted in accordance with laws and regulations and with user consent, and the data is used legally.
[0078] First, the application background of the embodiments of the present invention will be explained.
[0079] The present invention proposes an automatic spine measurement method based on 3D CT, which is applied to the application scenario of spine measurement.
[0080] Spinal measurements include Cobb angle measurement and vertebral rotation angle measurement; Cobb angle is the core indicator for assessing the degree of spinal deformity, while vertebral rotation angle is an important parameter to help determine the type and severity of deformity.
[0081] Currently, the measurement of Cobb angle and vertebral rotation angle in clinical practice mainly relies on anteroposterior and lateral X-ray films of the spine, with doctors manually selecting key points on the vertebral body for angle calculation. This method has the following significant drawbacks: First, X-ray images are two-dimensional projection images, which are greatly affected by tissue overlap, and the selection of key points is prone to subjective errors, resulting in poor consistency of measurement results; second, manual measurement is inefficient and cannot meet the needs of rapid processing of large amounts of image data; third, for complex spinal deformities (such as lesions with bony bridges, intervertebral disc herniation, free osteophytes, etc.), X-ray images are difficult to clearly display anatomical structures, further reducing the accuracy of measurement.
[0082] With the development of medical imaging technology, CT images, due to their high spatial resolution and ability to clearly display three-dimensional anatomical structures, have made it possible to accurately measure spinal deformities. Current CT image-based spinal measurement techniques largely rely on manual or semi-automatic segmentation. Manual segmentation is time-consuming and labor-intensive, while semi-automatic segmentation often suffers from insufficient segmentation accuracy due to the complexity of spinal anatomy (such as vertebral fusion, bone bridging, and interference from vertebral fragments), thus affecting the accuracy of subsequent angle measurements. Furthermore, existing technologies lack effective correction mechanisms for the three-dimensional coordinates of CT images, making it difficult to eliminate the influence of scanning position differences on measurement results. Figure 2 , Figure 3 As shown, there is a lack of effective detection and processing mechanisms for structural abnormalities that occur after segmentation (such as multiple intervertebral discs or no intervertebral discs between adjacent vertebrae), which makes it difficult to guarantee the reliability of the measurement results.
[0083] To achieve accurate measurement of the spine based on CT images, this invention proposes an automatic spine measurement method based on 3D CT. By correcting the three-dimensional coordinate system of the spine, the influence of scanning position differences on the measurement is eliminated, and the accurate determination of the centroid coordinates of the vertebral body is achieved, thereby ensuring the accuracy of the measurement of the vertebral body rotation angle and Cobb angle.
[0084] like Figures 1-19 As shown in the embodiment of the present invention, an automatic spine measurement method based on 3D CT includes:
[0085] Acquire spinal CT images;
[0086] The vertebral bodies and intervertebral discs in spinal CT images are segmented to obtain preliminary segmentation masks for the vertebral bodies, intervertebral discs, spinal cord, and femur;
[0087] Connectivity analysis of different structures was performed on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial mask of each intervertebral disc structure and the initial mask of the vertebral body structure.
[0088] The soft tissue in the initial mask of the intervertebral disc structure is deleted, and the initial masks of the intervertebral disc structure in the same segment are merged to obtain the intervertebral disc structure mask.
[0089] The osteophytes and vertebral fragments in the initial vertebral structure mask are removed, and the initial vertebral structure mask is separated from the bone bridge by expanding outward through the intervertebral disc structure mask to obtain the vertebral structure mask.
[0090] Based on the anatomical sequence of the spine, the intervertebral disc structure mask and the vertebral body structure mask are renamed to determine the final vertebral body mask;
[0091] Based on the final vertebral mask, determine the vertebral rotation angle and Cobb angle.
[0092] In some embodiments, a DICOM format spinal CT image is obtained by scanning the patient's lumbar spine region using a hospital CT scanner. The spinal CT image contains three-dimensional anatomical information of the spine and surrounding tissues (such as the femur), specifically including L1-L5 vertebral bodies, corresponding intervertebral discs, spinal cord, and bilateral femoral upper structures. The CT scan slice thickness is 1 mm and the pixel pitch is 0.8 mm × 0.8 mm.
[0093] A pre-trained spinal segmentation model was used to segment the vertebral body, intervertebral disc, spinal cord, and femur in spinal CT images, obtaining preliminary segmentation masks for the vertebral body, intervertebral disc, spinal cord, and femur. The masks were binary images with a foreground of 1 and a background of 0. The preliminary segmentation mask of the spinal cord was used as the spinal cord mask, and the preliminary segmentation mask of the femur was used as the femur mask, which were then used in the subsequent determination of the center coordinates of the femoral head and the calculation of the vertebral body rotation angle.
[0094] The spine segmentation model can use the open-source TotalSegmentator model or other deep learning pre-trained models with equivalent spinal structure segmentation accuracy. The DICOM format spine CT images are converted into NumPy array format and then input into the spine segmentation model.
[0095] Subsequently, a connected component analysis algorithm was used to perform connected component analysis on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord, and femur for different structures. This initially separated the intervertebral disc and vertebral body structures, obtaining the initial mask for each intervertebral disc structure and the initial mask for each vertebral body structure, such as... Figure 9 As shown, the initial mask may contain interfering structures such as vertebral body fragments, free osteophytes, soft tissue, and bone bridges. Figure 12 , Figure 13 As shown, in order to ensure the accuracy of subsequent angle measurements, this embodiment of the invention deletes the free osteophytes, soft tissue, bone bridges, and vertebral body fragments in the initial mask of the intervertebral disc structure and the initial mask of the vertebral body structure in the order of deleting soft tissue, free osteophytes, bone bridges, and vertebral body fragments.
[0096] The connected component analysis algorithm used is the connected component analysis function (connectedComponentsWithStats) from the OpenCV library.
[0097] Regions with volumes smaller than a set volume threshold in the initial mask of the intervertebral disc structure and the initial mask of the vertebral body structure are considered as free osteophytes.
[0098] Calculate the distance between the initial mask of the intervertebral disc structure and the nearest initial mask of the vertebral body structure; define the regions in the initial mask of the intervertebral disc structure whose distance from the nearest initial mask of the vertebral body structure is greater than a set distance threshold as soft tissue;
[0099] The portion of the vertebral structure in the initial mask that exceeds the set z-axis range threshold is taken as a bone bridge.
[0100] Masks with a volume smaller than a multiple of the median volume of the initial mask for all vertebral structures are used as vertebral fragments.
[0101] Specifically:
[0102] Based on a volume threshold screening mechanism, the initial mask of the vertebral structure is screened; according to the statistics of clinical anatomical data, a volume threshold for free osteophytes is set, and regions in the initial mask of the vertebral structure with a volume smaller than the volume threshold are deleted, thereby realizing the automatic exclusion of free osteophytes.
[0103] The mask volume is calculated as: mask volume = number of primes × pixel pitch × scan layer thickness. Based on clinical data, the volume threshold for free osteophytes is set to 0.5 cm³. Connected regions with a volume less than 0.5 cm³ are deleted to eliminate free osteophytes.
[0104] After calculating the volume threshold, the distance between the initial mask of each intervertebral disc structure and the nearest initial mask of the vertebral body structure is set, and a distance threshold is set. The regions in the initial mask of the intervertebral disc structure whose distance from the nearest initial mask of the vertebral body structure is greater than the set distance threshold are deleted as soft tissue that has been mis-segmented as intervertebral discs, and the initial mask of the intervertebral disc structure after soft tissue deletion is obtained.
[0105] In this embodiment of the invention, the distance between the initial mask of the intervertebral disc structure and the nearest initial mask of the vertebral body structure is calculated using the Euclidean distance formula. A distance threshold of 1 cm is set, and regions with a distance greater than 1 cm are deleted to exclude incorrectly segmented soft tissue. Figure 10 As shown.
[0106] Initial mask merging of intervertebral disc structures within the same segment: Principal component analysis (PCA) is performed on the initial masks of intervertebral disc structures after soft tissue removal to obtain the spatial distribution characteristics of the intervertebral discs; by calculating the spatial distance between the initial masks of intervertebral disc structures after soft tissue removal, and combining the results of PCA, the initial masks of intervertebral disc structures after soft tissue removal belonging to the same segment are merged to obtain the mask of each single segment intervertebral disc structure.
[0107] In this embodiment of the invention, the Euclidean distance formula is used to calculate the spatial distance between the initial masks of the intervertebral disc structure after the removal of each soft tissue. The merging threshold is set to 0.8cm. The initial masks of the intervertebral disc structure after the removal of soft tissue with a spatial distance of less than 0.8cm and the principal component direction are consistent are merged to obtain a complete intervertebral disc structure mask.
[0108] Bone bridge identification and removal: Z-axis range analysis is performed on the initial mask of the vertebral body structure, and a Z-axis range threshold (5cm) is set. Any portion of the initial mask of the vertebral body structure exceeding the set Z-axis range threshold is considered a bone bridge and deleted. Specifically: when the Z-axis range of the initial mask of the vertebral body structure exceeds the set Z-axis range threshold, and an initial mask of the intervertebral disc exists within its set Z-axis range, a bone bridge is determined to exist in the initial mask of the vertebral body structure. Taking a Z-axis range threshold of 5cm and the set area as the middle 1 / 2 region as an example, for a Z-axis range exceeding 5cm and containing a bone bridge within its middle 1 / 2 region... In the initial structure mask of the intervertebral disc, the initial structure mask of the intervertebral disc is determined to have a bone bridge. The portion of the initial structure mask of the vertebral body that exceeds the Z-axis range is taken as the bone bridge. Principal component analysis is performed on the initial structure mask of the intervertebral disc that exists within the Z-axis range of the initial structure mask of the vertebral body. The direction of the third principal component is taken as the normal. The centroid of the intervertebral disc corresponding to the initial structure mask of the intervertebral disc is taken as the center. A cutting surface is generated by expanding outward along the plane of the intervertebral disc until the bone bridge structure is cut off, so that the initial structure mask of the vertebral body is separated from the bone bridge. The bone bridge in the initial structure mask of the vertebral body is removed to obtain the initial structure mask of the vertebral body without the bone bridge.
[0109] In this context, the z-axis refers to the vertical direction of the CT scan, and the z-axis range threshold is set to 5cm. A bony bridge structure formed by the fusion of L3-L4 vertebrae was detected, with a z-axis range of 6.2cm. An L3-L4 intervertebral disc mask was found in the middle 1 / 2 region, which was determined to be a vertebra with a bony bridge. PCA was performed again on the intervertebral disc mask in this region. The third principal component direction was the horizontal direction (normal). With the centroid of the intervertebral disc (coordinates x=120, y=85, z=420) as the center, a cutting surface was generated by extending outward along the horizontal direction. The cutting surface extended to the edge of the bony bridge (range from z=415 to z=425), cutting off the bony bridge structure and separating the initial mask of the L3 and L4 vertebral bodies with the bony bridge removed.
[0110] Secondary exclusion of vertebral body mask fragments: The initial vertebral body structure masks with deleted bone bridges are subjected to a second volume threshold screening; the median volume of all initial vertebral body structure masks with deleted bone bridges is calculated, and masks with a volume less than 1 / 10 of the median volume of all initial vertebral body structure masks are deleted as vertebral body fragments. Figure 11 As shown, the accuracy of the vertebral structure mask was further optimized to obtain a vertebral structure mask without bone bridges, osteophytes, and vertebral fragments.
[0111] For example, if the median volume is 8.2 cm³, set the filtering threshold to 0.82 cm³ (1 / 10 of the median), delete the initial mask of the L4 vertebral body structure with a volume of 0.3 cm³ that has had its bone bridge removed, and optimize the vertebral body mask quality.
[0112] In some embodiments, the process of renaming the intervertebral disc structure mask and the vertebral body structure mask according to the anatomical order of the spine includes:
[0113] Determine whether the arrangement order of the intervertebral disc structure mask and the vertebral body structure mask conforms to the anatomical order of the spine;
[0114] When the anatomical sequence of the spine is followed, determine whether the lowest structural mask is a vertebral body structure mask or an intervertebral disc structure mask.
[0115] When the bottommost structure mask is determined to be an intervertebral disc structure mask, the intervertebral disc structure mask is deleted, and the bottommost structure is a vertebral body structure mask.
[0116] When the bottommost structural mask is a vertebral body structural mask, the bottommost structural mask is taken as the S1 vertebral body, and the structural masks of each vertebral body and intervertebral disc are named according to the anatomical order of the spine.
[0117] Specifically: The anatomical sequence of the spine is "vertebral body - intervertebral disc - vertebral body - intervertebral disc"; when it conforms to the anatomical sequence of the spine, it is further determined whether the bottommost structural mask is a vertebral body structure mask or an intervertebral disc structure mask: if the bottommost is an intervertebral disc structure mask, such as determining that the intervertebral disc structure mask is the S1 / S2 intervertebral disc, then the intervertebral disc mask is deleted; if the bottommost is a vertebral body structure mask, then the segmentation result is determined to be correct, and the bottommost vertebral body structure mask is named as the S1 vertebral body; then starting from the S1 vertebral body and the L5S1 intervertebral disc, the intervertebral disc structure masks and vertebral body structure masks are anatomically named sequentially from the bottom up along the spine; if the detection finds two or more intervertebral discs located between adjacent vertebral bodies, or an abnormal arrangement of no intervertebral discs between adjacent vertebral bodies, then the segmentation is determined to be incorrect, an error message is output, and manual adjustment is required; after experimental verification, the error reporting rate of this step is as low as 0.4%.
[0118] For example: if the arrangement order is "L1 vertebral body - L1L2 intervertebral disc - L2 vertebral body - L2L3 intervertebral disc - L3 vertebral body - L3L4 intervertebral disc - L4 vertebral body - L4L5 intervertebral disc - L5 vertebral body", which conforms to the anatomical order of the spine, and the lowest structure is the L5 vertebral body, then the segmentation result is considered correct. When the lowest structure is an intervertebral disc mask, starting from the S1 vertebral body (below the L5 vertebral body), L5S1 intervertebral disc, it is named upwards sequentially as L5 vertebral body, L4L5 intervertebral disc, L4 vertebral body... L1 vertebral body, T12L1 intervertebral disc, etc. Figure 14 As shown.
[0119] In some embodiments, femoral and spinal cord masks are extracted from spinal CT images;
[0120] Based on the femoral mask, determine the center coordinates of the left and right femoral heads;
[0121] Connect the center coordinates of the left and right femoral heads to form the corrected X-axis;
[0122] The corrected three-dimensional coordinate system of the spine is obtained by correcting the X-axis;
[0123] Based on the vertebral body mask, calculate the centroid coordinates of the vertebral body in the corrected three-dimensional coordinate system of the spine, and use them as the centroid coordinates of the vertebral body.
[0124] Based on the coordinates of the vertebral centroid and the spinal cord mask, the vertebral rotation angle and Cobb angle are calculated and determined.
[0125] In this embodiment of the invention, after accurately separating the vertebral body mask, femoral mask, and spinal cord mask, as follows: Figure 8As shown, in the femoral mask, the upper inner regions of the left and right femurs are located (z-axis range 450-510, x-axis range 80-160); within this region, the maximum medial sphere is solved within a 6cm range along a 45° direction (making a 45° angle with the x-axis), as shown. Figure 4 , Figure 15 As shown, the center coordinates of the left and right femoral heads are determined by the center coordinates of the largest internal sphere, and the center coordinates of the left and right femoral heads are connected to form the corrected X-axis.
[0126] For example, the coordinates of the center of the left femoral head are (x=95, y=78, z=480), and the coordinates of the center of the right femoral head are (x=145, y=79, z=482). Taking the line connecting the centers of the left and right femoral heads as the corrected x-axis, the direction vector of the line is calculated as (50, 1, 2), which is then normalized and used as the unit vector of the x-axis.
[0127] In the original three-dimensional coordinate system of the spine, within the plane containing the Z-axis and the corrected X-axis, the direction perpendicular to the corrected X-axis is selected as the corrected Z-axis, such as... Figure 5 As shown, the direction perpendicular to both the corrected X-axis and Z-axis is selected as the corrected Y-axis. The corrected X-axis, Y-axis and Z-axis form the corrected three-dimensional coordinate system of the spine.
[0128] For example, the coordinates of the center of the left femoral head are (x=95, y=78, z=480), and the coordinates of the center of the right femoral head are (x=145, y=79, z=482). Taking the line connecting the centers of the left and right femoral heads as the corrected x-axis, the direction vector of the connecting line is calculated as (50, 1, 2), which is normalized and used as the unit vector of the x-axis. In the plane containing the original z-axis and the connecting line, the direction vector perpendicular to the x-axis is calculated as (2, -248, 49), which is used as the unit vector of the corrected z-axis. The corrected y-axis unit vector is obtained by cross product as (-10017, -196, 12401), and the corrected three-dimensional coordinate system of the spine is established.
[0129] The process involves eroding the vertebral mask along the corrected X-axis to obtain an eroded vertebral mask; and then determining the centroid coordinates of the vertebra based on the eroded vertebral mask.
[0130] During the corrosion treatment, a 3×3×3 cubic structure was used for the corrosion nucleus.
[0131] In some embodiments, the coronal and sagittal planes are determined based on the coordinates of the vertebral centroid, such as... Figure 6 and Figure 7 As shown;
[0132] Determine the key points of the vertebral body in the coronal and sagittal planes;
[0133] The Cobb angle is calculated and determined based on the key points of the vertebral body in the coronal and sagittal planes;
[0134] The spinal cord mask is sliced at the level corresponding to the centroid coordinates of the vertebral body to obtain the spinal cord cross-sectional mask;
[0135] Calculate and determine the centroid coordinates of the spinal cord section mask;
[0136] The rotation angle of the vertebra is calculated and determined based on the centroid coordinates of the vertebral body and the centroid coordinates of the spinal cord cross-section mask.
[0137] Taking the L3 vertebral body as an example, the calculation of the vertebral body rotation angle and Cobb angle is explained.
[0138] The determined coordinates of the L3 vertebral body centroid are (x=122, y=86, z=405). The coronal plane determined based on these coordinates is as follows:
[0139] -10017(x-122) -196(y-86) +12401(z-405)=0;
[0140] The sagittal plane determined based on the coordinates of the L3 vertebral centroid is as follows:
[0141] 50(x-122) +1(y-86) +2(z-405)=0.
[0142] Vertebral body key point extraction: Principal component analysis was performed on the L3 vertebral body mask to obtain three principal component directions, with the principal axis direction being the z-axis. At the four 45° angular directions of the principal axis (0°, 45°, 90°, 135°), straight lines perpendicular to each direction were used to approximate the vertebral body cross-section, and four key points A, B, C, and D were extracted on the coronal plane, as shown below. Figure 16 As shown, the coordinates of keypoint A are x=118, y=86, z=400; the coordinates of keypoint B are x=126, y=86, z=400; the coordinates of keypoint C are x=118, y=86, z=410; and the coordinates of keypoint D are x=126, y=86, z=410. Four keypoints E, F, G, and H are extracted on the sagittal plane, as follows: Figure 17 As shown, the coordinates of key point E are x=122, y=82, z=400; the coordinates of key point F are x=122, y=90, z=400; the coordinates of key point G are x=122, y=82, z=410; and the coordinates of key point H are x=122, y=90, z=410.
[0143] The Cobb angles were calculated using the L2 and L3 vertebral bodies. The Cobb angles include the coronal Cobb angle and the sagittal Cobb angle.
[0144] The Cobb angle in the coronal plane is calculated as follows:
[0145] The line connecting the upper end of the L2 vertebral body on the coronal plane is y=85, and the line connecting the lower end of the L3 vertebral body on the coronal plane is y=86. The angle between the projections of the two lines on the total coronal plane is 3°, that is, the Cobb angle of the coronal plane is 3°.
[0146] The Cobb angle in the sagittal plane is calculated as follows:
[0147] The line connecting the upper end of the L2 vertebral body in the sagittal plane is x=121, and the line connecting the lower end of the L3 vertebral body in the sagittal plane is x=122. The included angle of the projection is 2°, that is, the Cobb angle in the sagittal plane is 2°.
[0148] The vertebral rotation angle is calculated as follows:
[0149] The spinal cord mask was sliced at the L3 vertebral centroid level (z=405) to obtain a cross-sectional mask of the spinal cord, as shown below. Figure 18 As shown, the centroid coordinates of the spinal cord section mask are x=122, y=87, z=405; connecting this centroid with the centroid of the L3 vertebral body (x=122, y=86, z=405), the direction of the connecting line is along the positive y-axis; the angle between this connecting line and the corrected y-axis is 0°, that is, the rotation angle of the L3 vertebral body is 0°.
[0150] The Cobb angle measured by the method proposed in this invention has an error of ±0.5° compared with the Cobb angle measured manually based on CT images, and an error of ±1° compared with the measurement result of clinical X-ray films, which meets the requirements of accurate clinical measurement. The entire processing takes about 8 minutes, which is significantly more efficient than the 2 hours required for manual segmentation and manual measurement.
[0151] The automatic spine measurement method based on 3D CT proposed in this invention has the following advantages:
[0152] (1) High segmentation accuracy and strong anti-interference ability: Through the progressive segmentation strategy of "initial segmentation - connected domain separation - deletion of free osteophytes, soft tissue, bone bridge and vertebral body fragments", the interference structures such as free osteophytes, soft tissue, bone bridge and vertebral body fragments are effectively eliminated. At the same time, the bone bridge is specifically treated as a disease structure, which significantly improves the segmentation accuracy of key structures such as vertebral body and intervertebral disc. According to the anatomical order of the spine, the intervertebral disc structure mask and vertebral body structure mask are renamed to ensure the accuracy of the final vertebral body mask name, which lays a reliable foundation for subsequent angle measurement.
[0153] (2) High accuracy and objectivity in measurement: This invention is based on 3D CT images for measurement, avoiding tissue overlap interference from X-ray two-dimensional projection; by correcting the coordinate system through the femoral head connection, the influence of scanning position differences on the measurement results is eliminated; the extraction of key points is automatically completed based on principal component analysis and linear approximation algorithm, reducing human subjective error and making the measurement results more objective and consistent.
[0154] (3) High degree of automation and excellent efficiency: From the input of CT images to the final output of Cobb angle and rotation angle, the present invention achieves full automation, except for a very few error cases that require manual intervention. Compared with the traditional manual measurement method, it greatly improves the measurement efficiency and can meet the needs of rapid processing of large batches of image data.
[0155] (4) The error detection mechanism is reliable and highly secure: The present invention has set up a structural layout error detection step, which can accurately identify abnormal segmentation situations and has an error rate as low as 0.4%, effectively avoiding invalid measurements based on erroneous segmentation results and ensuring the safety and reliability of clinical applications.
[0156] (5) Strong compatibility and wide clinical applicability: This invention is applicable to CT data of multiple spinal segments such as lumbar spine, thoracic and lumbar spine, and cervical, thoracic and lumbar spine. It can process spinal images with complex lesions such as bone bridge, intervertebral disc herniation, and free osteophytes. It can meet the measurement needs of different types of spinal deformities and has wide clinical applicability.
[0157] This invention also proposes an automatic spine measurement system based on 3D CT, comprising:
[0158] Image acquisition unit, used to acquire spinal CT images;
[0159] The mask segmentation unit is used to segment the vertebral body and intervertebral disc in spinal CT images to obtain preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur;
[0160] The initial structure mask determination unit is used to perform connected component analysis on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial structure mask of each intervertebral disc and the initial structure mask of the vertebral body.
[0161] The mask filtering unit is used to delete soft tissue in the initial mask of the intervertebral disc structure and merge the initial masks of the intervertebral disc structure in the same segment to obtain the intervertebral disc structure mask; it deletes osteophytes and vertebral body fragments in the initial mask of the vertebral body structure and expands outward through the intervertebral disc structure mask to separate the initial mask of the vertebral body structure from the bone bridge to obtain the vertebral body structure mask.
[0162] The mask renaming unit is used to rename the intervertebral disc structure mask and the vertebral body structure mask according to the anatomical order of the spine, and to determine the final vertebral body mask.
[0163] The measurement unit is used to determine the vertebral rotation angle and Cobb angle based on the final vertebral mask.
[0164] It should be noted that the above-described embodiment of the automatic spine measurement system based on 3D CT is only illustrative of the division of functional units described above when performing spine measurements. In practical applications, the functions described above can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. Furthermore, the automatic spine measurement system based on 3D CT and the automatic spine measurement method based on 3D CT provided in the above embodiment belong to the same concept, and their specific implementation process is detailed in the method embodiment, which will not be repeated here.
[0165] The present invention also discloses a computer device, the device comprising:
[0166] A processor, adapted to execute computer programs;
[0167] A computer-readable storage medium storing a computer program, which, when executed by the processor, implements an automatic spine measurement method based on 3D CT disclosed in an embodiment of the present invention.
[0168] The present invention also discloses a computer-readable storage medium storing a computer program adapted for loading and execution by a processor of an automatic spine measurement method based on 3D CT disclosed in the embodiments of the present invention.
[0169] The present invention also discloses a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements an automatic spine measurement method based on 3D CT disclosed in the embodiments of the present invention.
[0170] The method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.
[0171] Those skilled in the art will recognize that the units and algorithm steps described in conjunction with the embodiments herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0172] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.
Claims
1. An automatic spine measurement method based on 3D CT, characterized in that, include: Acquire spinal CT images; The vertebral bodies and intervertebral discs in spinal CT images are segmented to obtain preliminary segmentation masks for the vertebral bodies, intervertebral discs, spinal cord, and femur; Connectivity analysis of different structures was performed on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial mask of each intervertebral disc structure and the initial mask of the vertebral body structure. The soft tissue in the initial mask of the intervertebral disc structure is deleted, and the initial masks of the intervertebral disc structure in the same segment are merged to obtain the intervertebral disc structure mask; The osteophytes and vertebral fragments in the initial vertebral structure mask are removed, and the initial vertebral structure mask is separated from the bone bridge by expanding outward through the intervertebral disc structure mask to obtain the vertebral structure mask. Based on the anatomical sequence of the spine, the intervertebral disc structure mask and the vertebral body structure mask are renamed to determine the final vertebral body mask; Based on the final vertebral mask, determine the vertebral rotation angle and Cobb angle.
2. The automatic spine measurement method based on 3D CT as described in claim 1, characterized in that, Regions in the initial mask of the vertebral structure with a volume smaller than a set volume threshold are designated as osteophytes. Calculate the distance between the initial mask of the intervertebral disc structure and the nearest initial mask of the vertebral body structure; define the regions in the initial mask of the intervertebral disc structure whose distance from the nearest initial mask of the vertebral body structure is greater than a set distance threshold as soft tissue; The portion of the vertebral structure in the initial mask that exceeds the set z-axis range threshold is taken as a bone bridge. Masks with a volume smaller than a multiple of the median volume of the initial mask for all vertebral structures are used as vertebral fragments.
3. The automatic spine measurement method based on 3D CT as described in claim 1, characterized in that, When the z-axis range of the initial mask of the vertebral body structure exceeds the set z-axis range threshold, and there is an initial mask of the intervertebral disc within the set area of its z-axis range, it is determined that there is a bone bridge in the initial mask of the vertebral body structure. Principal component analysis is performed on the initial mask of the intervertebral disc structure within the set range of the z-axis of the initial mask of the vertebral structure. The direction of the third principal component is taken as the normal, and the centroid of the intervertebral disc corresponding to the initial mask of the intervertebral disc structure is taken as the center. The mask is expanded outward along the plane of the intervertebral disc to separate the initial mask of the vertebral structure from the bone bridge, thus obtaining a vertebral structure mask without bone bridge.
4. The automatic spine measurement method based on 3D CT as described in claim 1, characterized in that, The process of renaming the intervertebral disc structure mask and vertebral body structure mask according to the anatomical order of the spine includes: Determine whether the arrangement order of the intervertebral disc structure mask and the vertebral body structure mask conforms to the anatomical order of the spine; When the anatomical sequence of the spine is followed, determine whether the lowest structural mask is a vertebral body structure mask or an intervertebral disc structure mask. When the bottommost structure mask is determined to be an intervertebral disc structure mask, the intervertebral disc structure mask is deleted, and the bottommost structure is a vertebral body structure mask. When the bottommost structural mask is a vertebral body structural mask, the bottommost structural mask is taken as the S1 vertebral body, and the structural masks of each vertebral body and intervertebral disc are named according to the anatomical order of the spine.
5. The automatic spine measurement method based on 3D CT as described in claim 1, characterized in that, Extracting femoral and spinal cord masks from spinal CT images; Based on the femoral mask, determine the center coordinates of the left and right femoral heads; Connect the center coordinates of the left and right femoral heads to form the corrected X-axis; The corrected three-dimensional coordinate system of the spine is obtained by correcting the X-axis; Based on the vertebral body mask, calculate the centroid coordinates of the vertebral body in the corrected three-dimensional coordinate system of the spine, and use them as the centroid coordinates of the vertebral body. Based on the coordinates of the vertebral centroid and the spinal cord mask, the vertebral rotation angle and Cobb angle are calculated and determined.
6. The automatic spine measurement method based on 3D CT as described in claim 5, characterized in that, Determine the coronal and sagittal planes based on the coordinates of the vertebral centroid. Determine the key points of the vertebral body in the coronal and sagittal planes; The Cobb angle is calculated and determined based on the key points of the vertebral body in the coronal and sagittal planes; The spinal cord mask is sliced at the level corresponding to the centroid coordinates of the vertebral body to obtain the spinal cord cross-sectional mask; Calculate and determine the centroid coordinates of the spinal cord section mask; The rotation angle of the vertebra is calculated and determined based on the centroid coordinates of the vertebral body and the centroid coordinates of the spinal cord cross-section mask.
7. An automatic spine measurement system based on 3D CT, characterized in that, include: Image acquisition unit, used to acquire spinal CT images; The mask segmentation unit is used to segment the vertebral body and intervertebral disc in spinal CT images to obtain preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur; The initial structure mask determination unit is used to perform connected component analysis on the preliminary segmentation masks of the vertebral body, intervertebral disc, spinal cord and femur to determine the initial structure mask of each intervertebral disc and the initial structure mask of the vertebral body. The mask filtering unit is used to delete soft tissue in the initial mask of the intervertebral disc structure and merge the initial masks of the intervertebral disc structure in the same segment to obtain the intervertebral disc structure mask. The osteophytes and vertebral fragments in the initial vertebral structure mask are removed, and the initial vertebral structure mask is separated from the bone bridge by expanding outward through the intervertebral disc structure mask to obtain the vertebral structure mask. The mask renaming unit is used to rename the intervertebral disc structure mask and the vertebral body structure mask according to the anatomical order of the spine, and to determine the final vertebral body mask. The measurement unit is used to determine the vertebral rotation angle and Cobb angle based on the final vertebral mask.
8. An electronic device, characterized in that, The device includes: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the automatic spine measurement method based on 3D CT as described in any one of claims 1-6.
9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program adapted to be loaded by a processor and executed by an automatic spine measurement method based on 3D CT as described in any one of claims 1-6.
10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the automatic spine measurement method based on 3D CT as described in any one of claims 1-6.