JP6057305B2 - Pelvic rotation angle calculation device, pelvic rotation angle calculation method, acetabular cover three-dimensional shape estimation device and acetabular cover three-dimensional shape estimation method, pelvic rotation angle calculation program, and acetabular cover three-dimensional shape estimation program - Google Patents

Description

  The present invention relates to a pelvic rotation angle calculation device, a pelvic rotation angle calculation method, an acetabular cover three-dimensional shape estimation device, an acetabular cover three-dimensional shape estimation method, a pelvic rotation angle calculation program, and an acetabular cover three-dimensional shape estimation program. It is an invention. Specifically, (1) a pelvic rotation angle calculation device that calculates a pelvic rotation angle from a simple X-ray front image of the pelvis using at least a tear mark or an obturator on the caudal side from the pelvic cavity as an anatomical landmark (2) a acetabular covering three-dimensional shape estimation device that estimates the three-dimensional shape of the acetabular covering using the pelvic rotation angle calculated by the pelvic rotation angle calculating device; (3) at least on the caudal side from the pelvic cavity; A pelvic rotation angle calculation method for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis using a tear mark or an obturator as an anatomical landmark, and (4) a pelvic rotation angle calculation method calculated by a pelvic rotation angle calculation method A acetabular cover three-dimensional shape estimation method for estimating the three-dimensional shape of the acetabular cover using the rotation angle, (5) a pelvic rotation angle calculation program for executing the calculation means of the pelvic rotation angle calculation device, and (6 ) 3D shape estimation device with acetabular coating Acetabulum coated three-dimensional shape estimation program for executing the arithmetic means, it relates to.

  The hip joint is a load joint and an important joint directly involved in walking. If the hip joint is damaged due to hip osteoarthritis (pathological condition causing hip joint pain due to deformation or damage of articular cartilage), walking difficulties occur, and the number of patients requiring care is expected to increase. There is concern about the increase. More than 80% of Japanese hip osteoarthritis is secondary hip arthropathy caused by dysplasia of the pelvis (insufficient coverage of the pelvic acetabulum). Evaluation of the form and dynamics

  In order to accurately evaluate the form of the hip joint, CT imaging (computer tomography) capable of three-dimensional evaluation is performed, but it is not possible to perform imaging in the standing position necessary to investigate the pathological condition of the hip joint that is the load joint. It is a problem. Moreover, since radiation exposure and medical costs are high, it is not realistic to perform CT imaging for patients with mild symptoms, medical examinations, and follow-up observations. Furthermore, while simple X-ray photographs can be taken at any size of facility from university hospitals to clinics, CT imaging devices are only available in medium-sized and larger hospitals. In some countries, there are no CT imaging apparatuses in the world, and there is a need for a system that can easily evaluate three-dimensional forms and dynamics of hip joint deformation from simple X-ray photographs.

  As a method of evaluating the three-dimensional shape and dynamics of the hip joint using only a simple X-ray front image, geometric calculation is used from the shape of the pelvic acetabulum (edge part of the acetabulum) on the simple X-ray image. A method of performing a three-dimensional evaluation of a hip joint is known (see Non-Patent Document 1).

  In the above method, the doctor manually inputs the anatomical landmarks on the PC monitor and geometrically calculates the acetabular covering. The acetabular covering is the pelvic position (inclination / rotation) during X-ray imaging. Therefore, it is necessary to calculate the pelvis position when calculating the covering amount. Regarding correction of pelvic rotation in a simple X-ray front image, a method of correcting pelvic rotation using the horizontal distance between the center of the sacroiliac joint and the upper edge of the pubic joint seen in the pelvic cavity is known (Non-Patent Document 2). reference). However, as shown in FIG. 1, the index used in the method is the absolute value of the distance between the center of the sacroiliac joint and the upper edge of the pubic joint (結合 in the figure), and is affected by the race and the scale of the image. There is a problem of receiving. In addition, as shown in FIG. 2, a simple X-ray front view of the pelvis is obtained by gonad protection (white part at the upper center of the photograph) worn by the subject (especially reproductive age) and / or intestinal gas etc. There is also a problem that there are many images in which the sacroiliac joint seen in the cavity cannot be visually recognized.

Konishi N., “Determination of Acetal Coverage of the Femoral Head with Use of a Single Radiograph. A New Computerized. Bone and Joint Surg. , 75-A (9), p1318-1333, 1993 M Tannast et al. , “Tilt and Rotation Correction of Acetal Version on Pelvic Radiographs”, Clin Orthod 407: 182-190, 2005.

  As a result of intensive research, the present inventors have used at least tear marks or obturator holes, which are anatomical landmarks on the caudal side from the pelvic cavity, to provide gonad protection, intestinal gas, etc. It is possible to calculate the pelvic rotation angle from a simple X-ray front image without being affected by the influence of the race, the scale of the image, etc. by calculating the pelvic rotation angle from the ratio of the anatomical landmark distance It was found that the rotation angle of the pelvis can be calculated without receiving the pelvis, and that the calculated pelvic rotation angle can be used to estimate the pelvic position and represent the three-dimensional shape of the acetabular cover. .

  That is, an object of the present invention is to provide a pelvic rotation angle calculation device, a pelvic rotation angle calculation method, an acetabular cover three-dimensional shape estimation device, an acetabular cover three-dimensional shape estimation method, a pelvic rotation angle calculation program, and an acetabular cover three-dimensional It is to provide a shape estimation program.

  The present invention provides the following pelvic rotation angle calculation device and pelvic rotation angle calculation method, acetabular cover three-dimensional shape estimation device and acetabular cover three-dimensional shape estimation method, pelvic rotation angle calculation program, and acetabular cover three-dimensional This is a shape estimation program.

(1) A pelvic rotation angle calculating device for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Anatomical landmark acquisition means for acquiring an anatomical landmark set with respect to the simple X-ray front image;
Calculating means for calculating the rotation angle of the pelvis based on the anatomical landmark,
The anatomical landmark includes at least a tear scar or an obturator;
The calculation means calculates a pelvic rotation angle based on the positional relationship or size of the anatomical landmarks ,
The computing means is
Means for calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating the rotation angle of the pelvis based on the ratio of the distance between the tear marks and the horizontal distance ,
Pelvic rotation angle calculation device.
( 2 ) A database that is created based on pelvic X-ray CT data acquired from a plurality of patients and that stores the relationship between the ratio of the distance between tear marks and the horizontal distance and the rotation angle of the pelvis, or a plurality of patients Created based on the pelvic X-ray CT data obtained from, including the regression equation showing the relationship between the ratio of the distance between the tear marks and the horizontal distance, and the rotation angle of the pelvis,
The calculation means calculates the rotation angle of the pelvis from the ratio of the distance between the tear marks of the simple X-ray front image and the horizontal distance by referring to the database or the regression equation.
The pelvic rotation angle calculation device according to ( 1 ) above.
( 3 ) A pelvic rotation angle calculation device for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Anatomical landmark acquisition means for acquiring an anatomical landmark set with respect to the simple X-ray front image;
Calculating means for calculating the rotation angle of the pelvis based on the anatomical landmark,
The anatomical landmark includes at least a tear scar or an obturator;
The calculation means calculates a pelvic rotation angle based on the positional relationship or size of the anatomical landmarks,
The computing means is
Means for calculating the lateral diameter of the left and right closed holes, and calculating the rotation angle of the pelvis based on the left-right ratio of the horizontal diameter of the closed holes,
Pelvic rotation angle calculation device.
( 4 ) Created based on pelvic X-ray CT data acquired from a plurality of patients, a database storing the relationship between the left-right ratio of the obturator foramen and the rotation angle of the pelvis, or acquired from a plurality of patients Created based on pelvic X-ray CT data, including a regression equation showing the relationship between the left-right ratio of the obturator lateral diameter and the rotation angle of the pelvis,
The calculation means calculates the rotation angle of the pelvis from the left / right ratio of the closed hole lateral diameter of the simple X-ray front image by referring to the database or the regression equation,
The pelvic rotation angle calculation device according to ( 3 ) above.
( 5 ) A device for estimating a three-dimensional shape of a pelvic acetabular cover from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Acetabular landmark acquisition means for acquiring a plurality of acetabular landmarks related to the pelvic acetabulum set with respect to the simple X-ray front image;
Calculating means for estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation means corrects the three-dimensional shape of the acetabular cover using the pelvic rotation angle calculated by the pelvic rotation angle calculation device according to any one of (1) to ( 4 ).
An acetabular covering 3D shape estimation device.
( 6 ) A pelvic rotation angle calculation method for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
An anatomical landmark acquisition step of acquiring an anatomical landmark set for the simple X-ray front view;
Calculating a pelvic rotation angle based on the anatomical landmark, and
The anatomical landmark includes at least a tear scar or an obturator;
The calculation step is a step of calculating a rotation angle of the pelvis based on a positional relationship or a size of the anatomical landmark, and the calculation step includes :
Calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating a rotation angle of the pelvis based on a ratio of the distance between the tear marks and the horizontal distance;
Or
Calculating left and right closure hole lateral diameters,
Calculating the rotation angle of the pelvis based on the left / right ratio of the lateral diameter of the closure hole,
including,
Pelvic rotation angle calculation method.
( 7 ) A method for estimating the three-dimensional shape of the pelvic cover from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
Obtaining a plurality of acetabular landmarks relating to the acetabulum of the pelvis set with respect to the simple X-ray front image; and
A calculation step of estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation step corrects the three-dimensional shape of the acetabular cover using the pelvic rotation angle calculated by the pelvic rotation angle calculation method of (6) .
A method for estimating a three-dimensional shape of a acetabular cover.
( 8 ) A program for executing a computing means of a pelvic rotation angle calculation device for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
An anatomical landmark acquisition step of acquiring an anatomical landmark set for the simple X-ray front view;
Calculating a pelvic rotation angle based on the anatomical landmark, and
The anatomical landmark includes at least a tear scar or an obturator;
The calculation step is a step of calculating a rotation angle of the pelvis based on a positional relationship or a size of the anatomical landmark, and the calculation step includes :
Calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating a rotation angle of the pelvis based on a ratio of the distance between the tear marks and the horizontal distance;
Or
Calculating left and right closure hole lateral diameters,
Calculating the rotation angle of the pelvis based on the left / right ratio of the lateral diameter of the closure hole,
including,
Pelvic rotation angle calculation program.
( 9 ) A program for executing the computing means of the acetabular covering three-dimensional shape estimating device for estimating the three-dimensional shape of the pelvic covering from the simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
Obtaining a plurality of acetabular landmarks relating to the acetabulum of the pelvis set with respect to the simple X-ray front image; and
A calculation step of estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation step corrects the three-dimensional shape of the acetabular cover using the pelvic rotation angle calculated by the pelvic rotation angle calculation program of ( 8) ,
3D shape estimation program for acetabular cover.

  In the present invention, the rotation angle of the pelvis can be accurately calculated from a simple X-ray front image without using a CT with a large amount of exposure. Further, in the present invention, the pelvis using at least a tear mark or an obturator that is an anatomical landmark caudal to the pelvic cavity and that is not affected by gonad protection or intestinal gas or the like that is worn during simple radiography. Therefore, the rotation angle of the pelvis can be calculated from a simple X-ray front image taken without considering the pelvic position. Further, since the pelvic rotation angle is calculated based on the positional relationship or size of the anatomical landmarks, the pelvic rotation angle is not affected by race, image scale, or the like.

  In the present invention, since simple X-ray imaging is a method that has been generally used in the past, if there is a simple X-ray front image taken in the past, there is no need to take a new image, and the same patient When there are a plurality of past simple X-ray front images, it is possible to evaluate the aging of the hip joint form, the progress of arthropathy progression, and the like by the evaluation using the present invention.

  The pelvic rotation angle of the present invention can be calculated without being affected by gonad protection, intestinal gas, and the like, and by the race and image scale. Therefore, the rotation angle of the pelvis calculated according to the present invention can be used as a correction value when estimating the three-dimensional shape of the pelvic cover of the pelvis, which has conventionally been difficult to calculate.

FIG. 1 shows an index for calculating a correction value in a conventional pelvic rotation correction method. FIG. 2 is a drawing-substituting photograph showing a simple X-ray front view when the gonadal protection is attached. FIG. 3 is a block diagram showing an outline of the configuration of an apparatus for calculating the rotation angle of the pelvis from a simple X-ray front image of the present invention. FIG. 4 is a diagram showing an outline of an X-ray image used in the present invention. FIG. 5 shows the location of tear marks, pubic bone connections and obturator holes, which are anatomical landmarks of the present invention. FIG. 6 shows an example of an index for calculating the pelvic rotation angle using tear marks and pubic bone connection as anatomical landmarks. FIG. 7 shows an example of an index when the rotation angle of the pelvis is calculated using the closed hole as an anatomical landmark. FIG. 8 shows an example of calculation steps in the case of calculating the pelvic rotation angle using tear marks and pubic bone connections as anatomical landmarks. FIG. 9 is a graph showing the relationship between the ratio of the horizontal distance between the midpoint of the tear mark and the pubic bone connection, the distance between the tear marks, and the rotation. FIG. 10 is a graph showing the relationship between the right / left ratio of the lateral diameter of the female closed hole and the rotation. FIG. 11 is a graph showing the relationship between the ratio of the horizontal distance between the midpoint of the tear mark and the pubic bone, the distance between the tear marks, and the rotation of a male. FIG. 12 is a graph showing the relationship between the left-right ratio of the male closed hole lateral diameter and the rotation. FIG. 13 is a drawing-substituting photograph, which is an image in which the positions of the acetabular landmark and the peripheral portion of the closing hole are set on the simple X-ray front image displayed on the display unit. FIG. 14 shows the rotation angle θ of the pelvis. FIG. 15 is a diagram for explaining a correction method using the rotation angle θ when estimating the three-dimensional shape of the acetabular cover.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  The pelvic rotation angle calculation method for calculating the pelvic rotation angle from the simple X-ray front image of the pelvis according to the present invention is implemented by, for example, an apparatus as shown in FIG.

  That is, FIG. 3 shows an example of a pelvic rotation angle calculation device 1 (hereinafter also simply referred to as “device 1”) that calculates a pelvic rotation angle from a simple X-ray front image of the pelvis using a computer. FIG. The apparatus 1 can display (1) an X-ray image input means 10 for inputting a simple X-ray front image obtained by photographing the vicinity of the subject's pelvis, and (2) an input simple X-ray front image. The display unit 11 can display the set anatomical landmarks based on the simple X-ray front image, and (3) calculate the rotation angle of the pelvis based on the positional relationship or size of the anatomical landmarks A rotation angle calculation unit 12, (4) an X-ray image input means 10, a display unit 11, a control unit 13 for controlling the rotation angle calculation unit 12, and (5) a program memory 14 accessed from the control unit 13. . In the present invention, the simple X-ray front image means an image representing the amount of X-rays transmitted through the vicinity of the human pelvis from the X-ray irradiation tube in black and white as shown in FIG. May be simply referred to as “X-ray image”.

  The X-ray image input means 10 inputs X-ray image data in the vicinity of the patient's pelvis. An X-ray image data input using the X-ray image input means 10 is performed by an operator such as a doctor by the device 1. May be used to input an X-ray image from a DB or a recording medium, or may be input via a communication network such as the Internet by transmission / reception means of the apparatus 1. The X-ray image data is not particularly limited as long as the position of an anatomical landmark to be described later can be confirmed and the position information can be input. For example, the X-ray image data may be obtained as a radiation image (CR image) including an image near the pelvis using a CR (Computed Radiographic) system. That is, in an imaging apparatus, X-rays emitted from an X-ray irradiation tube are irradiated toward a patient as a subject, and the X-rays transmitted through the subject are incident on an imaging plate having a storage phosphor and transmitted. The radiographic image may be accumulated and recorded as energy information, and the transmitted radiographic image may be read from the imaging plate on which the transmitted radiographic image is accumulated and recorded and input to the X-ray image input unit 10. The X-ray image input means 10 may input X-ray image data from a digital X-ray imaging apparatus equipped with an FPD (Flat-Panel Detector), or may be input from an image server via a network. Image data may be input, or X-ray image data may be input from a recording medium such as a CD-ROM.

  The display unit 11 has a display screen such as an LCD and displays an X-ray image input using the X-ray image input means 10. The display unit 11 preferably has a touch input function so that the doctor can set the position of the anatomical landmark on the displayed X-ray image. The position of the anatomical landmark may be set by operating the display unit 11 to display an arrow or the like. Further, the anatomical landmark may be automatically set by detecting an edge from the contour of the X-ray image by using an image edge detection unit included in the apparatus 1. Further, the display unit 11 displays the result of calculation by the rotation angle calculation unit 12 described later. At least one result such as an angle may be displayed. Of course, in addition to the result calculated by the rotation angle calculation unit 12, information necessary for diagnosis and the like such as patient information may be displayed on the display unit 11. A user such as a doctor may make a diagnosis by looking at the result of the rotation angle or the like displayed on the display unit 11, and displays a three-dimensional image corrected based on the calculated result on the display unit 11. Diagnosis may be performed. Although not shown, a printer that prints out an image or the like displayed on the display unit 11, a storage device that stores various data, or a recording unit that records these data on various recording media may be provided.

  The rotation angle calculation unit 12 includes an anatomical landmark acquisition unit that acquires the set anatomical landmark, and (2) a calculation unit that calculates the rotation angle of the pelvis based on the anatomical landmark. In addition, the rotation angle calculation unit 12 is a database that is created based on pelvic X-ray CT data acquired from a plurality of patients and stores the relationship between the ratio of the distance between tear marks and the horizontal distance and the rotation angle of the pelvis. And / or a database that accumulates the relationship between the left-right ratio of the lateral diameter of the obturator and the rotation angle of the pelvis, created based on pelvic X-ray CT data acquired from a plurality of patients. The calculation means calculates the rotation angle of the pelvis while referring to the database based on the positional relationship or size of the anatomical landmark. As will be described later, the ratio of the distance calculated using the anatomical landmarks of the present invention and the rotation angle of the pelvis are highly correlated. Therefore, instead of accumulating individual data in the database, the regression equation obtained from the existing data is stored in the calculation means, and the distance ratio calculated by the calculation means is directly applied to the regression expression, so that the pelvis is directly The rotation angle may be obtained.

  FIG. 5 shows the location of the pubic joint used in combination with tear marks or obturator holes, which are anatomical landmarks of the present invention, and the tear marks. FIG. 6 shows an example of an index for calculating the rotation angle using tear marks and pubic bone connections as anatomical landmarks. The horizontal distance between the midpoint of the tear mark distance and the pubic bond and the distance between the tear marks The ratio is the index. The index is not particularly limited as long as the distance between the tear marks and the pubic bone can be expressed as a ratio, and the ratio between the distance between the right tear mark and the pubic bone-the distance between the left tear mark and the pubic bone) and the distance between the tear marks. Etc., as appropriate.

  FIG. 7 shows an example of an index when the rotation angle is calculated using the closed hole as an anatomical landmark, and a horizontal line (horizontal diameter) is placed in the closed hole so as to be parallel to the line connecting the tear marks. The left / right ratio of the length of the longest horizontal line is used as an index.

  In the program memory 14, for example, a program for causing the computer to function as the device 1 for calculating the rotation angle of the pelvis from a simple X-ray front image is stored in advance, and this program is read and executed by the control unit 13. Thus, the operation control of this apparatus is performed. The program may be recorded on a recording medium and stored in the program memory 14 using an installation unit.

  Below, the procedure of the pelvic rotation angle calculation method using the apparatus 1 of this invention and the pelvic rotation angle calculation program are demonstrated.

  FIG. 8 shows an example of calculation steps in the case of calculating the pelvic rotation angle using tear marks and pubic bone connections as anatomical landmarks.

  First, in step S100, an X-ray image is input by the X-ray image input means 10. As described above, the X-ray image may be input by an operator such as a doctor, or may be input via a communication network by transmission / reception means included in the apparatus 1. The input X-ray image is displayed on the display screen of the display unit 11 in step S110.

  Next, in step S <b> 120, the doctor inputs the lowermost portion of the left and right tear marks and the upper edge portion of the pubic joint in the X-ray image displayed on the display unit 11. As described above, the anatomical landmark automatically changes the lowermost portion of the left and right tear marks and the upper edge portion of the pubic bone connection by the edge detection means of the device 1 instead of the input by human power. May be determined automatically.

  Next, in step S130, the position information of the tear marks and pubic bone set in step S120 is acquired by the anatomical landmark acquisition unit and sent to the calculation unit of the rotation angle calculation unit 12, and the left and right of the calculation unit The means for calculating the distance between the tear marks calculates the distance between the tear marks, and the means for calculating the horizontal distance between the midpoint between the tear marks and the pubic bone connection calculates the horizontal distance. And a calculating means calculates | requires ratio of the calculated distance between the said tear marks, and the said horizontal distance. In step S140, the calculation means refers to a database or a regression equation that stores the relationship between the ratio between the distance between tear marks and the horizontal distance and the rotation angle of the pelvis, thereby obtaining the rotation angle of the pelvis. Finally, in step S150, desired data calculated by the rotation angle calculation unit 12, such as the distance between tear marks, the ratio of the distances, and the rotation angle of the pelvis, are displayed on the display unit 11, and the procedure ends.

  When the left / right ratio of the obturator diameter is used as the anatomical landmark, a plurality of peripheral portions of the obturator of the X-ray image displayed on the display unit 11 are provided in place of the tear marks and the pubic bone in step S120. , And the lowermost part of the left and right tear marks. Then, in step S130, the means for calculating the left and right closing hole lateral diameters of the calculating means calculates the closing hole lateral diameter which is the longest diameter of the closing hole parallel to the line connecting the left and right tear marks. The calculated ratio of the left and right closure hole lateral diameters is calculated, and in step S140, except for referring to the database or the regression equation in which the relation between the right and left ratio of the closure hole lateral diameter and the rotation angle of the pelvis is accumulated, What is necessary is just to process according to the procedure shown by FIG. In the above method, a plurality of peripheral portions of the closed hole of the X-ray image are input, an approximate line of the closed hole outline is created by a computer, and the closed hole lateral diameter is calculated from the approximate line. A lateral diameter that is the longest of the closed hole may be determined in advance using auxiliary means such as a ruler, and a doctor or the like may input only the determined lateral diameter portion. Further, instead of inputting manually, the lateral diameter that becomes the longest closed hole may be automatically determined by edge detection using the edge detection means of the apparatus 1. The rotation angle of the pelvis thus obtained can be used as a correction value when estimating the three-dimensional shape of the acetabular cover of the pelvis from a simple X-ray front image of the pelvis.

  Next, it was verified whether the anatomical landmark used in the present invention is excellent as an index for determining the rotation angle of the pelvis.

  Among cases in which CT images of the pelvis were taken due to trauma or disease, 40 cases (20 males and 20 females) in which the pelvic deformity change was not remarkable were targeted. The THA3D preoperative planning software Zed Hip was used to reconstruct a three-dimensional image from the CT data, and a pseudo X-ray image (DRR image) was created using an antenna pelvic plane (APP) as a reference plane. In the APP coronal image, (1) the ratio of the horizontal distance between the tear mark midpoint and the pubic bone connection and the distance between the tear marks, and (2) the left-right ratio of the lateral diameter of the obturator were measured. On the Zed Hip, the pelvis was rotated by 3 ° to the left and right by 12 °, and (1) and (2) were measured on the DRR images at each pelvic position, and the correlation with the pelvic rotation angle was examined. In addition, about the left-right ratio of the closed hole lateral diameter, the vertical axis is expressed in logarithm in order to increase the approximation accuracy.

  FIG. 9 is a graph showing the relationship between the ratio of the horizontal distance between the tear mark midpoint and the pubic bone connection and the distance between the tear marks and the rotation of a woman, the horizontal axis is the rotation angle, and the vertical axis is the tear mark midpoint and the pubic bone connection. The ratio of the horizontal distance to the distance between tear marks. The correlation coefficient was 0.972. In addition, as is apparent from the graph, the graph representing the relationship between the ratio of the horizontal distance between the midpoint of the tear mark and the pubic bone joint and the distance between the tear marks and the rotation is almost a straight line, and the inclination of the graph ((pubic bone connection-in the tear mark) Point) / distance between tear marks / rotation angle of pelvis) was -0.00637. Therefore, when the ratio of the horizontal distance between the midpoint of the tear mark and the pubic bone and the distance between the tear marks is B, the rotation angle θ of the pelvis can be calculated from the regression equation: θ = B / −0.00637. . Note that the slope shown in FIG. 9 is data calculated from the 20 women, and the slope changes depending on the number of people who acquire the data, so the slope may be another numerical value. The same applies to the slopes shown in FIGS.

  FIG. 10 is a graph showing the relationship between the left-right ratio of the female closed hole lateral diameter and the rotation, where the horizontal axis represents the rotation angle and the vertical axis represents the log of the left-right ratio of the closed hole lateral diameter. The correlation coefficient was 0.950. The slope of the graph was 0.0732.

  FIG. 11 is a graph showing the relationship between the ratio of the horizontal distance between the midpoint of the tear mark and the pubic bone of the male and the distance between the tear marks and the rotation, the horizontal axis is the rotation angle, and the vertical axis is the tear mark midpoint and the pubic bone connection. The ratio of the horizontal distance to the distance between tear marks. The correlation coefficient was 0.967. The slope of the graph was -0.00676.

  FIG. 12 is a graph showing the relationship between the right / left ratio of the male closed hole lateral diameter and the rotation, in which the horizontal axis represents the rotation angle, and the vertical axis represents the log of the left / right ratio of the closed hole lateral diameter. The correlation coefficient was 0.959. The slope of the graph was 0.0918.

  As shown in the above results, the ratio between the horizontal distance between the midpoint of the tear mark and the pubic joint and the distance between the tear marks in both men and women (correlation coefficient = 0.972 (female), 0.967 (male)) The left-right ratio of the closed hole lateral diameter (correlation coefficient = 0.950 (female), 0.959 (male)) was highly correlated with the pelvic rotation angle.

  The pelvic rotation angle calculated by the pelvic rotation angle calculation device of the present invention is corrected for pelvic rotation in the acetabular cover three-dimensional shape estimation device, the acetabular cover three-dimensional shape estimation method, and the acetabular cover three-dimensional shape estimation program. Can be used as a value. The acetabular covering three-dimensional shape estimation apparatus includes an X-ray image input means for inputting a simple X-ray front image, and a mortar for acquiring a plurality of acetabular landmarks related to the pelvic acetabulum set for the simple X-ray front image. Lid landmark acquisition means, and arithmetic means for estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark are included.

  As the X-ray image input means for inputting a simple X-ray front image, the same X-ray image input means as that of the pelvic rotation angle calculation device can be used. The X-ray image input means of the acetabular covering three-dimensional shape estimation apparatus may be shared with the X-ray image input means of the pelvic rotation angle calculation apparatus or may be provided as a separate body.

  A plurality of acetabular landmarks related to the pelvic acetabulum are provided with a display unit similar to that of the pelvic rotation angle calculation device, and the position of the acetabular landmark is displayed on the displayed X-ray image using a touch function or a mouse. Should be set. As the acetabular landmark, known acetabular landmarks such as the acetabular joint surface, the femoral head, the acetabular front edge, and the acetabular rear edge may be used. The display unit of the acetabular covering three-dimensional shape estimation device may be shared with the display unit of the pelvic rotation angle calculation device, or may be provided as a separate body. FIG. 13 shows a common display part of the acetabular covering 3D shape estimation device and the pelvic rotation angle calculation device, and sets the positions of the peripheral part of the acetabular landmark and the closed hole in the X-ray image displayed on the display part. It is an image.

  The position information of the set acetabular landmark is acquired by the acetabular landmark acquisition means, and is sent to the calculation means for estimating the three-dimensional shape of the acetabular cover. The calculation means estimates the three-dimensional shape of the acetabular cover. To do. At that time, in the method described in Non-Patent Document 2, the rotation angle θ of the pelvis shown in FIG. 14 is corrected using the horizontal distance between the center of the sacroiliac joint and the upper edge of the pubic joint. In the acetabular covering three-dimensional shape estimation apparatus, correction is performed using the pelvic rotation angle θ calculated by the pelvic rotation angle calculation apparatus.

  FIG. 15 is a view for explaining a correction method using the rotation angle θ when estimating the three-dimensional shape of the acetabular cover of the present invention. In the method described in Non-Patent Document 1, assuming that the left and right virtual head center positions are equidistant from the X-ray film, the acetabular cover is calculated by drawing the acetabular border on the virtual head. Yes. On the other hand, in the acetabular cover 3D shape estimation apparatus, acetabular cover 3D shape estimation method, and acetabular cover 3D shape estimation program of the present invention, as shown in FIG. 15, pelvic rotation θ (θ = in FIG. 15). 2.5 °), the center of the left and right virtual skulls is offset from the X-ray film, that is, the center position of the left and right virtual skulls is estimated not to be equidistant from the X-ray film. The coverage area is calculated by drawing the edge of the acetabulum.

  As described above, when the pelvic rotation angle calculation device of the present invention is used, the rotation angle θ of the pelvis can be calculated without being affected by the effects of gonadal protection, intestinal gas, etc., age, and race or image scale. Therefore, it can be used as a correction value when estimating the three-dimensional shape of the pelvic cover of the pelvis, which has conventionally been difficult to calculate.

  The acetabular covering three-dimensional shape estimation device can be used for estimating the setting state (position and angle) of an artificial hip joint cup from a simple X-ray front image, in addition to estimating the shape of the pelvic acetabular covering. The cup placement position can be accurately evaluated by correcting the pelvis position using the calculated pelvic rotation angle at the time of confirmation of the placement position after the operation of placing the hip joint in the body and the progress confirmation.

  As an apparatus for estimating the three-dimensional shape of the pelvic cover of the pelvis, in addition to the above correction of the rotation angle, pelvic inclination correction can also be performed. Regarding pelvic inclination, the obturator foramen diameter / distance between tear marks described in Non-Patent Document 1, or the pubic joint upper edge-sacro-joint vertical distance described in Non-Patent Document 2, as necessary. Correction may be performed using

By using the anatomical landmark of the present invention, the rotation angle of the pelvis can be accurately and easily determined from the X-ray image. Therefore, it can be used as correction data for the pelvic position when developing software that can perform three-dimensional evaluation of the acetabular cover in the hip joint using one simple X-ray front image. Useful for diagnosis.

Claims (9)

A pelvic rotation angle calculating device for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Anatomical landmark acquisition means for acquiring an anatomical landmark set with respect to the simple X-ray front image;
Calculating means for calculating the rotation angle of the pelvis based on the anatomical landmark,
The anatomical landmark includes at least a tear scar or an obturator;
The calculation means calculates a pelvic rotation angle based on the positional relationship or size of the anatomical landmarks ,
The computing means is
Means for calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating the rotation angle of the pelvis based on the ratio of the distance between the tear marks and the horizontal distance ,
Pelvic rotation angle calculation device. Created based on pelvic X-ray CT data acquired from a plurality of patients, a database that accumulates the relationship between the ratio of the distance between tear marks and the horizontal distance, and the rotation angle of the pelvis, or acquired from a plurality of patients Created based on pelvic X-ray CT data, including a regression equation indicating the relationship between the ratio of the distance between tear marks and the horizontal distance, and the rotation angle of the pelvis
The calculation means calculates the rotation angle of the pelvis from the ratio of the distance between the tear marks of the simple X-ray front image and the horizontal distance by referring to the database or the regression equation.
The pelvic rotation angle calculation device according to claim 1 . A pelvic rotation angle calculating device for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Anatomical landmark acquisition means for acquiring an anatomical landmark set with respect to the simple X-ray front image;
Calculating means for calculating the rotation angle of the pelvis based on the anatomical landmark,
The anatomical landmark includes at least a tear scar or an obturator;
The calculation means calculates a pelvic rotation angle based on the positional relationship or size of the anatomical landmarks,
The computing means is
Means for calculating the lateral diameter of the left and right closed holes, and calculating the rotation angle of the pelvis based on the left-right ratio of the horizontal diameter of the closed holes,
Pelvic rotation angle calculation device. Created based on pelvic X-ray CT data acquired from a plurality of patients, a database storing the relationship between the left / right ratio of the closed hole lateral diameter and the rotation angle of the pelvis, or pelvic X-rays acquired from a plurality of patients Created based on CT data, including a regression equation showing the relationship between the left-right ratio of the lateral diameter of the obturator and the rotation angle of the pelvis,
The calculation means calculates the rotation angle of the pelvis from the left / right ratio of the closed hole lateral diameter of the simple X-ray front image by referring to the database or the regression equation,
The pelvic rotation angle calculation device according to claim 3 . An apparatus for estimating a three-dimensional shape of a pelvic acetabular cover from a simple X-ray front image of the pelvis,
X-ray image input means for inputting a simple X-ray front image;
Acetabular landmark acquisition means for acquiring a plurality of acetabular landmarks related to the pelvic acetabulum set with respect to the simple X-ray front image;
Calculating means for estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation means corrects the three-dimensional shape of the acetabular cover using the pelvic rotation angle calculated by the pelvic rotation angle calculation device according to any one of claims 1 to 4 .
An acetabular covering 3D shape estimation device. A pelvic rotation angle calculation method for calculating a pelvic rotation angle from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
An anatomical landmark acquisition step of acquiring an anatomical landmark set for the simple X-ray front view;
Calculating a pelvic rotation angle based on the anatomical landmark, and
The anatomical landmark includes at least a tear scar or an obturator;
The calculation step is a step of calculating a rotation angle of the pelvis based on a positional relationship or a size of the anatomical landmark, and the calculation step includes :
Calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating a rotation angle of the pelvis based on a ratio of the distance between the tear marks and the horizontal distance;
Or
Calculating left and right closure hole lateral diameters,
Calculating the rotation angle of the pelvis based on the left / right ratio of the lateral diameter of the closure hole,
including,
Pelvic rotation angle calculation method. A method for estimating the three-dimensional shape of the pelvic cover of a pelvis from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
Obtaining a plurality of acetabular landmarks relating to the acetabulum of the pelvis set with respect to the simple X-ray front image; and
A calculation step of estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation step uses the pelvic rotation angle calculated by the pelvic rotation angle calculation method according to claim 6 to correct the three-dimensional shape of the acetabular cover.
A method for estimating a three-dimensional shape of a acetabular cover. A program for executing a computing means of a pelvic rotation angle calculation device for calculating a rotation angle of a pelvis from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
An anatomical landmark acquisition step of acquiring an anatomical landmark set for the simple X-ray front view;
Calculating a pelvic rotation angle based on the anatomical landmark, and
The anatomical landmark includes at least a tear scar or an obturator;
The calculation step is a step of calculating a rotation angle of the pelvis based on a positional relationship or a size of the anatomical landmark, and the calculation step includes :
Calculating the distance between the left and right tear marks,
Calculating a horizontal distance between the midpoint between the tear marks and the pubic joint,
Calculating a rotation angle of the pelvis based on a ratio of the distance between the tear marks and the horizontal distance;
Or
Calculating left and right closure hole lateral diameters,
Calculating the rotation angle of the pelvis based on the left / right ratio of the lateral diameter of the closure hole,
including,
Pelvic rotation angle calculation program. A program for executing the computing means of the acetabular covering three-dimensional shape estimating device for estimating the three-dimensional shape of the pelvic covering from a simple X-ray front image of the pelvis,
An X-ray image input step for inputting a captured simple X-ray front image;
Obtaining a plurality of acetabular landmarks relating to the acetabulum of the pelvis set with respect to the simple X-ray front image; and
A calculation step of estimating a three-dimensional shape of the acetabular cover from the simple X-ray front image and the acetabular landmark,
The calculation step uses the pelvic rotation angle calculated by the pelvic rotation angle calculation program according to claim 8 to correct the three-dimensional shape of the acetabular cover.
3D shape estimation program for acetabular cover.

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