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WO2018127949A1 - Dispositif, procédé et programme d'évaluation de la qualité osseuse, et dispositif, procédé et programme d'évaluation de risque de fracture osseuse - Google Patents

Dispositif, procédé et programme d'évaluation de la qualité osseuse, et dispositif, procédé et programme d'évaluation de risque de fracture osseuse Download PDF

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Publication number
WO2018127949A1
WO2018127949A1 PCT/JP2017/000061 JP2017000061W WO2018127949A1 WO 2018127949 A1 WO2018127949 A1 WO 2018127949A1 JP 2017000061 W JP2017000061 W JP 2017000061W WO 2018127949 A1 WO2018127949 A1 WO 2018127949A1
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bone
evaluation
bone quality
variation
subject
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PCT/JP2017/000061
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English (en)
Japanese (ja)
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佳知 高石
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佳知 高石
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Priority to JP2018560279A priority Critical patent/JP6836250B2/ja
Priority to PCT/JP2017/000061 priority patent/WO2018127949A1/fr
Publication of WO2018127949A1 publication Critical patent/WO2018127949A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment

Definitions

  • the present invention relates to a bone quality evaluation apparatus, method and program, and fracture risk evaluation apparatus, method and program, and in particular, based on an X-ray image (or also referred to as “X-ray image”) of a subject's mandible.
  • the present invention relates to a bone quality evaluation apparatus, method and program for evaluating bone quality, and a fracture risk evaluation apparatus, method and program for evaluating the risk of osteoporotic fractures (or also referred to as “fragile fractures”) in the subject.
  • Osteoporosis was once defined as a disease in which bone density decreases and fracture risk increases. For this reason, in the prevention and treatment of osteoporosis, bone density has been considered. However, there are many cases of fractures even though the bone density is within the normal range, and subsequent studies have revealed that fracture risk is related not only to bone density but also to bone quality. Accordingly, the current definition of osteoporosis is said to be a disease in which bone strength decreases and fracture risk increases.
  • the bone strength is related to the bone density of about 70% and the bone quality of about 30%.
  • bone quality is broadly divided into structural characteristics and material characteristics. Among these structural characteristics, bone size, bone morphology, bone microstructure, etc. are the elements, and material characteristics are bone matrix, bone turnover, and minute damage. (Micro fracture), calcification degree of bone tissue and the like.
  • DXA dual-energy X-ray absorption
  • Non-Patent Document 1 As a technique for evaluating bone quality, for example, one disclosed in Non-Patent Document 1 is known. According to the technique disclosed in Non-Patent Document 1, the variation in the density of each pixel in the X-ray images of the lumbar vertebra and the femoral neck by the DXA method is obtained by a function called an experimental variogram. A value of TBS (Trabecular Bone Score) is obtained from the calculation result of variation.
  • TBS Trabecular Bone Score
  • This TBS correlates with the bone quality, and more precisely with the cancellous bone microstructure, which is one of the elements of the bone quality. Therefore, the cancellous bone microstructure can be indirectly evaluated from the TBS. Specifically, it is evaluated that the greater the TBS, the stronger the cancellous bone microstructure, and the smaller the TBS, the more vulnerable the cancellous bone microstructure.
  • Non-Patent Document 2 it is not possible to accurately evaluate the fracture risk only by bone density, and it is desirable to accurately evaluate the fracture risk based on a combination of bone density and TBS.
  • the effect is disclosed. For example, even if the bone density is within a normal range, if the TBS is small, the risk of fracture is not small, and for example, there is a possibility of osteoporosis or at least one osteopenia before that. In other words, even if the bone density is equivalent, the fracture risk may not be equivalent, and TBS is useful to identify this.
  • Non-Patent Document 3 discloses that the discrimination ability of osteoporotic vertebral fractures by TBS is suitable for Japanese elderly women. The conclusion is that TBS has the ability to identify fractures independent of bone density, suggesting its usefulness especially in cases where the bone density of the lumbar spine is relatively high.
  • Non-Patent Documents 1 to 3 described above obtain a value of TBS from an X-ray image obtained by the DXA method, and evaluate bone quality from the TBS. That is, these conventional techniques are based on the premise that a relatively large inspection called the DXA method is performed. For this reason, the advent of a new technique that can evaluate the bone quality by a simpler examination and thereby evaluate the fracture risk is desired.
  • an object of the present invention is to provide a novel technique that can evaluate bone quality by a simpler examination than before, and thus can evaluate fracture risk.
  • the inventor of the present invention is also an inventor of the invention according to Japanese Patent No. 4077430, and an invention according to the publication in which the bone density of the subject is evaluated based on the X-ray image of the mandible of the subject (human). Based on the above X-ray image, the subject's bone quality may be evaluated, and it is confirmed by clinical experiments that this idea is valid. completed. Specifically, the inventor of the present invention described later that the variation in the intensity of the specific region corresponding to the specific portion of the mandible in the X-ray image of the mandible of the subject correlates with the bone quality of the subject. As described above, the present invention was confirmed by clinical experiments, and based on this variation, a technique for evaluating the bone quality of the subject was created.
  • the present invention uses the first invention related to the bone quality evaluation apparatus, the second invention related to the fracture risk evaluation apparatus using the first invention, the third invention related to the bone quality evaluation method, and the third invention.
  • 4th invention which concerns on a fracture risk evaluation method
  • 5th invention which concerns on a bone quality evaluation program
  • 6th invention which concerns on a fracture risk assessment program which uses this 5th invention are included.
  • the first invention is a bone quality evaluation apparatus for evaluating the bone quality of a subject based on an X-ray image of a mandible of the subject, and includes a variation calculation means and a bone quality evaluation means.
  • the variation calculating means obtains the variation in the intensity of the specific region corresponding to the specific portion of the mandible in the X-ray image of the mandible of the subject.
  • the bone quality evaluation means is based on the calculation result of the variation calculation means, that is, based on the variation in the intensity of the specific area corresponding to the specific portion of the mandible in the X-ray image of the subject's mandible. Assess the bone quality.
  • the bone quality of the subject is evaluated based on the X-ray image of the mandible of the subject.
  • the X-ray image referred to here is obtained, for example, at the time of a dental examination, that is, obtained by a simpler examination than the DXA method assumed in the above-described conventional technology. That is, according to the first aspect of the present invention, the bone quality can be evaluated by a simpler test than before.
  • the specific portion includes an alveolar bone portion around the first premolar.
  • the bone density of such a specific portion is closely related to the bone density of the whole body.
  • the bone quality is evaluated based on the variation in the intensity of the specific region corresponding to the specific portion in the X-ray image.
  • the variation calculating means may obtain a relative ratio between the standard deviation of the lightness of the specific area and the average value of the lightness of the specific area as the dispersion.
  • the bone quality evaluation means shall evaluate the bone quality based on the relative ratio.
  • a variation coefficient also referred to as “relative standard deviation” obtained by dividing the standard deviation of the intensity of the specific area by the average value of the intensity of the specific area is appropriate.
  • it may be the reciprocal of this coefficient of variation.
  • Such a relative ratio is a dimensionless number and represents a relative variation in the lightness of the specific area with respect to the average value of the lightness of the specific area.
  • this relative ratio represents not the absolute variation of the intensity of the specific area itself but the relative variation of the intensity of the specific area based on the average value of the intensity of the specific area.
  • the relative ratio mentioned here is not the absolute variation of the intensity of the specific area as described above, but the relative intensity of the specific area based on the average value of the intensity of the specific area. Since the bone quality is evaluated based on such a relative ratio, the bone quality can be accurately evaluated regardless of the difference in the intensity of the entire X-ray image including the specific region. . In addition, even if the subjects are different, there is a difference in the intensity of the specific area and the absolute variation in the intensity of the specific area. Bone quality can be evaluated.
  • the second invention is a fracture risk evaluation apparatus for evaluating the risk of an osteoporotic fracture in a subject, comprising the bone quality evaluation apparatus of the first invention, and further comprising fracture risk evaluation means.
  • the fracture risk evaluation means evaluates the risk of an osteoporotic fracture in the subject based on the evaluation result by the bone quality evaluation means in the first invention, that is, based on the evaluation result of the bone quality of the subject by the bone quality evaluation means. .
  • this 2nd invention evaluates a fracture risk using the 1st invention.
  • this second invention evaluates whether or not a subject is suspected of having osteoporosis including osteopenia using the first invention.
  • a bone density evaluating means may be further provided.
  • This bone density evaluation means evaluates the bone density of the subject based on the intensity of the specific region in the X-ray image.
  • the fracture risk evaluation means evaluates the fracture risk based on the evaluation result by the bone density evaluation means in addition to the evaluation result by the bone quality evaluation means.
  • the fracture risk is evaluated based not only on the evaluation result on the bone quality but also on the evaluation result on the bone density, so that the fracture risk can be more accurately evaluated.
  • the intensity of the entire X-ray image including the specific region varies depending on various conditions such as when the X-ray image is captured. Therefore, the bone density evaluation by the bone density evaluation means may not be accurately performed from the density of the specific region in such an X-ray image. Therefore, it is desirable that the density of the X-ray image is appropriately corrected in an appropriate manner before the bone density is evaluated by the bone density evaluation means.
  • the X-ray image includes an image of a predetermined specimen arranged side by side with the mandible.
  • this specimen for example, there is a solid material whose transmittance for X-rays is constant and known, and an aluminum block disclosed in the above-mentioned Japanese Patent No. 4077430 is particularly suitable.
  • correction means for correcting the density of the entire X-ray image so that the intensity of the specimen image in the X-ray image matches a predetermined reference value is further provided.
  • the bone density evaluation means evaluates the bone density based on the density of the specific region in the corrected image after the correction by the correction means. That is, according to this configuration, the specimen is used as an index, so that the shade of the image of the specimen matches the predetermined reference value, that is, the shade that the shade of the image of the specimen should originally be.
  • the gray level of the entire X-ray image including the image of the specimen is corrected so as to be the degree.
  • the bone density is evaluated based on the density of the specific area in the corrected image. As a result, the bone density can be accurately evaluated regardless of the difference in intensity of the entire original (before correction) X-ray image.
  • the above-described variation calculation unit is not a variation in the density of the specific region in the X-ray image, but the specific region in the corrected image after the correction by the correction unit is performed. You may obtain
  • the third invention is a bone quality evaluation method for evaluating the bone quality of the subject based on an X-ray image of the mandible of the subject, and includes a variation calculation process and a bone quality evaluation process.
  • the variation calculation process the variation in the intensity of the specific region corresponding to the specific portion of the mandible in the X-ray image of the mandible of the subject is obtained.
  • the bone quality evaluation process based on the calculation result of the variation calculation process, that is, based on the variation in the intensity of the specific area corresponding to the specific part of the mandible in the X-ray image of the subject's mandible, Assess the bone quality.
  • the third invention is a method invention corresponding to the first invention. Therefore, according to the third aspect of the invention, the same action as that of the first aspect of the invention can be achieved.
  • the specific portion may include an alveolar bone portion around the first premolar as in the first invention.
  • the relative ratio between the standard deviation of the intensity of the specific area and the average value of the intensity of the specific area may be obtained as the variation.
  • the bone quality evaluation process the bone quality is evaluated based on the relative ratio.
  • the fourth invention is a fracture risk assessment method for assessing the risk of an osteoporotic fracture in a subject, comprising the bone quality assessment method of the third invention, and further comprising a fracture risk assessment process.
  • the risk of an osteoporotic fracture in the subject is evaluated based on the assessment result of the bone quality assessment process in the third invention, that is, based on the assessment result of the bone quality of the subject in the bone quality assessment process. .
  • the fourth invention is a method invention corresponding to the second invention. Therefore, according to the fourth aspect of the invention, the same operation as that of the second aspect of the invention can be achieved.
  • a bone density evaluation process may be further provided.
  • the bone density of the subject is evaluated based on the intensity of the specific region in the X-ray image.
  • the fracture risk evaluation process the fracture risk is evaluated based on the evaluation result of the bone density evaluation process in addition to the evaluation result of the bone quality evaluation process.
  • the X-ray image when a bone density evaluation process is provided, includes an image of a predetermined specimen arranged side by side with the mandible, as in the second invention. desirable.
  • a correction process is further provided for correcting the gray level of the entire X-ray image so that the gray level of the specimen image matches a predetermined reference value.
  • the bone density evaluation process the bone density is evaluated based on the density of the specific region in the corrected image after the correction process is performed.
  • the variation in the gray level of the specific area in the image corrected by the correction process may be obtained. More specifically, in the variation calculation process, the relative ratio between the standard deviation of the intensity of the specific area in the corrected image and the average value of the intensity of the specific area in the corrected image is obtained as the variation, and further, the bone quality evaluation In the process, the bone quality may be evaluated based on the relative ratio.
  • a fifth invention is a bone quality evaluation program for evaluating a bone quality of a subject based on an X-ray image of a mandible of a subject using a computer, and a variation calculation procedure and a bone quality assessment procedure are performed on the computer.
  • a variation calculation procedure the variation in the intensity of the specific region corresponding to the specific portion of the mandible in the X-ray image of the mandible of the subject is obtained.
  • the subject is based on the calculation result of the variation calculation procedure, that is, based on the variation in the intensity of the specific region corresponding to the specific portion of the mandible in the X-ray image of the subject's mandible. Assess the bone quality.
  • the fifth invention is a program invention corresponding to the first invention (and the third invention). Therefore, according to the fifth aspect of the invention, the same action as that of the first aspect of the invention (and the third aspect of the invention) is achieved.
  • the specific portion may include an alveolar bone portion around the first premolar.
  • the relative ratio between the standard deviation of the intensity of the specific area and the average value of the intensity of the specific area may be obtained as the variation.
  • the bone quality evaluation procedure the bone quality is evaluated based on the relative ratio.
  • a sixth invention is a fracture risk evaluation program for evaluating the risk of an osteoporotic fracture in a subject using a computer, comprising the bone quality evaluation program of the fifth invention, and further comprising a fracture risk evaluation procedure in the computer To be executed.
  • this fracture risk assessment procedure the risk of an osteoporotic fracture in the subject is evaluated based on the assessment result of the bone quality assessment procedure in the fifth invention, that is, based on the assessment result of the bone quality of the subject by the bone quality assessment procedure. To do.
  • the sixth invention is a program invention corresponding to the second invention (and the fourth invention). Therefore, according to the sixth aspect of the invention, the same action as that of the second aspect of the invention (and the fourth aspect of the invention) is achieved.
  • the computer may further execute a bone density evaluation procedure.
  • this bone density evaluation procedure the bone density of the subject is evaluated based on the intensity of a specific area in the X-ray image.
  • the fracture risk evaluation procedure the fracture risk is evaluated based on the evaluation result by the bone density evaluation procedure in addition to the evaluation result by the bone quality evaluation procedure.
  • the computer executes the bone density evaluation procedure. Similar to the second invention (and the fourth invention), it is desirable that the X-ray image includes an image of a predetermined specimen arranged side by side with the mandible. Then, the computer is further caused to execute a correction procedure for correcting the gray level of the entire X-ray image so that the gray level of the specimen image matches a predetermined reference value. In addition, in the bone density evaluation procedure, the bone density is evaluated based on the intensity of the specific region in the corrected image after the correction by the correction procedure.
  • the variation in the gray level of the specific area in the image corrected by the correction procedure may be obtained. More specifically, in the variation calculation procedure, a relative ratio between the standard deviation of the intensity of the specific area in the corrected image and the average value of the intensity of the specific area in the corrected image is obtained as the variation, and further, the bone quality evaluation In the procedure, the bone quality may be evaluated based on the relative ratio.
  • FIG. 1 It is a figure showing the schematic structure of the whole fracture risk evaluation system concerning one embodiment of the present invention. It is a figure which shows the one aspect
  • FIG. 9 is a graph different from FIG. 8 based on the inspection data of FIG.
  • FIG. 9 is still another graph based on the inspection data of FIG.
  • FIG. 10 is another graph different from FIG. 10 based on the inspection data of FIG. It is a list which shows the correlation between each parameter in the test
  • FIG. 20 is an illustrative view showing another aspect different from FIG. 19 of the sub-screen in the same embodiment.
  • FIG. 20 is an illustrative view showing another aspect different from FIG. 17 of the main screen in the same embodiment;
  • FIG. 1 An embodiment of the present invention will be described by taking a fracture risk evaluation system 10 for dental care shown in FIG. 1 as an example.
  • the fracture risk evaluation system 10 is based on the invention disclosed in the above-mentioned Japanese Patent No. 4077430, and is particularly based on the bone density evaluation system according to the second embodiment.
  • descriptions of the same parts as those disclosed in the publication will be omitted as appropriate.
  • the fracture risk evaluation system 10 includes a personal computer (hereinafter referred to as “PC”) 12.
  • the PC 12 functions as a fracture risk evaluation device by executing a fracture risk evaluation program provided by an appropriate storage medium 14 such as a DVD-ROM (Digital Versatile Disk Read Only Memory).
  • the PC 12 includes an input device 12a as a command input unit and a display 12b as a display unit.
  • the input device 12a includes a keyboard and a pointing device such as a mouse.
  • a film scanner 16 as an image input unit and a color printer 18 as a printing unit are connected to the PC 12.
  • the X-ray image of the mandible of the subject (patient) imaged on the X-ray film 20 is read by the film scanner 16 and converted into digital image data.
  • the converted image data is input to the PC 12 and stored in, for example, an 8-bit or 24-bit bitmap format in a hard disk (not shown) in the PC 12.
  • a plurality of image data obtained from a plurality of subjects are stored in the hard disk. Some of these image data were obtained from the same subject on different days.
  • the X-ray image of the mandible of the subject is taken on the X-ray film 20.
  • the first premolars 30, the adjacent canines 32 and the first teeth Images of the two premolars 34 and the alveolar bone 36 that supports these teeth 30 to 34 are taken.
  • a horizontally long rectangular reference bar 38 is also photographed above the images.
  • the reference bar 38 is also referred to as an aluminum block (or “phantom”) as a specimen as shown in FIG. 3.
  • this block will also be described with the same reference numerals as the reference bar 38.
  • the block 38 has a rectangular flat bottom surface 38a, and has a stepped shape in which the thickness dimension (dimension in the direction perpendicular to the bottom surface 38a) changes stepwise in the longitudinal direction of the bottom surface 38a.
  • the height dimension (step) ⁇ T of each step is constant, and the length dimension (depth) P of each step is also constant.
  • the number of stages is about 7 to 9 stages.
  • an aluminum foil 40 as an X-ray blocking means for blocking X-rays 50 (see FIG.
  • the length dimension (longitudinal dimension of the bottom surface 38a) L of the block 38 is about 20 [mm]
  • the width dimension (dimension in the short direction of the bottom surface 38a) W is about 10 [mm]. is there.
  • the thickness dimension of the lowermost part (height dimension from the bottom surface 38a to the upper surface of the lowermost part) Ta is around 1 [mm]
  • the height dimension (Tb) to the upper surface is about 6 [mm] to 8 [mm].
  • This block 38 is attached to the imaging surface (exposure surface) 20a of the rectangular X-ray film 20 as shown in FIG. 4 before X-ray imaging.
  • the block 38 has a longitudinal direction (of the bottom surface 38 a) along the short direction of the X-ray film 20, and the bottom surface 38 a faces the imaging surface 20 a of the X-ray film 20. Then, it is attached to a portion near the upper edge, which is one edge of the photographing surface 20a, with an appropriate adhesive. Then, the X-ray film 20 to which the block 38 is adhered is, as shown in FIG. 5, at the time of X-ray photography, the upper side edge (the edge on the side close to the part to which the block 38 is adhered).
  • the portion with lower X-ray transmittance is shown brighter (whiter), and the portion with higher X-ray transmittance is darker (blackish).
  • the reference bar 38 which is an image of the block 38, is indicated by the shade (brightness / darkness) corresponding to the thickness dimension of the block, and more specifically, the portion corresponding to the portion having the larger thickness dimension.
  • the part corresponding to the part where the thickness dimension is small is shown darker.
  • the portion to which the aluminum foil 40 is adhered hardly transmits the X-ray 50, so that the portion corresponding to this portion is shown brightest (to be pure white).
  • the enamel and dentin portions have a relatively high transmittance with respect to the X-ray 50, and the portions corresponding to these portions are shown relatively brightly. It is.
  • the portion corresponding to the alveolar bone 36 is indicated by a lightness corresponding to the bone density (bone mineral content) of the alveolar bone 36, and more specifically, the higher the bone density, the brighter it is shown. Smaller is darker.
  • the PC 12 evaluates the bone density and bone quality of the subject based on the X-ray image photographed on the X-ray film 20, strictly based on the image data, and thus has a risk of causing an osteoporotic fracture in the subject. evaluate. Specifically, as shown by a broken line 60 in FIG. 2, a specific region corresponding to the alveolar bone 36 around the lower half of the root 30a of the first premolar 30 is set as an evaluation target region, and this evaluation target region 60 The bone density is evaluated from the intensity of the image. At the same time, the bone quality is evaluated from the variation in the intensity of the image of the evaluation target region 46. Further, the fracture risk is evaluated based on the evaluation result of the bone density and the evaluation result of the bone quality.
  • the lower end edge of the evaluation target region 60 is set at a position corresponding to the root apex of the first premolar tooth 30.
  • the right edge of the evaluation target region 60 is aligned with a position corresponding to the middle between the mutually opposite edges of the first premolar 30 and the canine 32 on the straight line L connecting the tooth necks of the teeth 30 to 34. It is done.
  • the left end edge of the evaluation target region 60 is aligned with a position corresponding to the middle between the corresponding end edges of the first premolar tooth 30 and the second premolar tooth 34 on the straight line L.
  • the region corresponding to the root 30 a of the first premolar 30 is excluded from the evaluation target region 60.
  • the specific region corresponding to the portion of the alveolar bone 36 around the lower half of the root 30a of the first premolar 30 is set as the evaluation target region 60 as disclosed in the above-mentioned Japanese Patent No. 4077430.
  • the bone density of the alveolar bone 36 corresponding to the evaluation target region 60 is closely related to the bone density of the whole body.
  • the upper part of the alveolar bone 36 is easily affected by periodontal disease, and, for example, the bone density of this part decreases when suffering from the periodontal disease.
  • the region corresponding to the upper portion of the alveolar bone 36 is removed from the evaluation target region 60.
  • the component of the root 30a itself of the first premolar 30 is not particularly related to the bone density of the whole body. Therefore, even if the region corresponding to the tooth root 30a is included in the evaluation target region 60, there is no particular influence on the evaluation result of the bone density. However, in the present embodiment, it is excluded from the evaluation target region 60 as described above. Also, in the evaluation of bone quality, the same evaluation target area 60 is set following the evaluation of bone density.
  • the bone density evaluation system according to the second embodiment in the above-mentioned Japanese Patent No. 4077430, regarding the X-ray image similar to that in FIG.
  • the intensity of the entire X-ray image including the reference bar is corrected so that the intensity is the intensity that should originally be.
  • the bone density of the alveolar bone is evaluated based on the average value of the intensity of the evaluation target region in the X-ray image after correction, and as a result, the bone density of the whole body is evaluated.
  • the bone density of the whole body can be evaluated based on the average value of the density of the evaluation target region because the average value of the density of the evaluation target region is the bone density measured by the above-described DXA method, that is, the whole body.
  • the osteoporosis diagnosis is conventionally performed based on the T value.
  • the T value is the average bone density (Young Adult Mean; hereinafter referred to as “YAM”) of young people aged 20 to 44 years, and the ratio of the bone density of the subject to this YAM is expressed as a percentage. This is the value expressed (strictly referred to as “comparative percentage for young adults”).
  • YAM Young Adult Mean
  • the average value of the intensity of the evaluation target region shows a strong correlation with the T value.
  • the reference bar 38 is set so that the intensity of the reference bar 38 is the original intensity.
  • the gray level of the entire X-ray image including is corrected.
  • the bone density of the alveolar bone 36 is evaluated based on the average value of the intensity of the evaluation target region 60 in the corrected X-ray image, and the bone density of the whole body is evaluated.
  • the standard deviation of the intensity of the evaluation target area 60 is obtained, and in addition, the coefficient of variation obtained by dividing this standard deviation by the average value of the intensity of the evaluation target area 60 is obtained. It is done.
  • This variation coefficient represents the variation in the intensity of the evaluation target region 60, but is a so-called dimensionless number. Therefore, it is not the absolute variation of the intensity itself, but the relative value of the intensity to the average value of the intensity. Variation.
  • the bone quality of the alveolar bone 36 is evaluated, and as a result, the bone quality of the whole body is evaluated. The reason why the whole body bone quality can be evaluated based on the coefficient of variation will be described in detail later.
  • the fracture risk is evaluated based on the evaluation result of the bone density and the evaluation result of the bone quality.
  • the fracture risk evaluation result is displayed on the display 12b shown in FIG. 1 together with the bone density evaluation result and the bone quality evaluation result, and printed on an appropriate piece of paper 22 such as a medical chart by the color printer 18 as necessary. Is done.
  • the average value of the intensity of the evaluation target region 60 correlates with the bone density of the alveolar bone 36 as described above, and further correlates with the bone density of the whole body.
  • the coefficient of variation CV is a value obtained by dividing the standard deviation D by al-BMD as a percentage.
  • the “T value” is a value when the above-mentioned YAM is 1.011, that is, a value obtained by dividing the L-BMD by the YAM of 1.011 as a percentage.
  • “historical fracture” if this value is 1, it indicates that there is a history of osteoporotic fracture, and if this value is 0, it indicates that there is no history of the osteoporotic fracture.
  • the “number of fine damages” is the number of fine damages actually confirmed visually from the evaluation target region 60 in the X-ray image.
  • FIG. 7 shows the relationship between L-BMD, al-BMD, and variation coefficient CV with respect to this T value, for example, using the T value in FIG. 6 as a reference.
  • FIG. 7 (a) shows a test subject with a T value of less than 70%, a subject with a T value of 70% or more and less than 80%, and a subject with a T value of 80% or more.
  • the average value of L-BMD is represented by a graph.
  • FIG. 7 (b) shows a subject with a T value of less than 70%, a subject with a T value of 70% or more and less than 80%, and a subject with a T value of 80% or more.
  • the average value of al-BMD is represented by a graph.
  • FIG. 7C shows the coefficient of variation CV for each of a subject having a T value of less than 70%, a subject having a T value of 70% or more and less than 80%, and a subject having a T value of 80% or more.
  • the average value of is represented by a graph.
  • a subject having a T value of less than 70% is a subject who is suspected of having osteoporosis in the current diagnosis of osteoporosis based on the T value.
  • a subject having a T value of 70% or more and less than 80% is a subject who is suspected of having osteopenia in the same diagnosis, and a subject having a T value of 80% or more is normal in the diagnosis. It is a test subject.
  • the L-BMD increases as the T value increases, that is, the L-BMD is proportional to the T value.
  • the al-BMD also increases as the T value increases, that is, the al-BMD is approximately proportional to the T value.
  • the variation coefficient CV is smaller as the T value is larger, that is, is approximately in inverse proportion to the T value. From this, the coefficient of variation CV seems to have some relationship with the bone strength in addition to the bone density.
  • FIG. 8A is a graph showing an average value of T values for each of a subject with a history of fracture and a subject with no history of fracture. It should be noted that the relationship of L-BMD with respect to the presence or absence of a fracture history is also shown in FIG. 8A.
  • FIG. 8B is a graph showing the average value of al-BMD for each of a subject with a history of fracture and a subject with no history of fracture.
  • FIG. 8C is a graph showing the average value of the coefficient of variation CV for each of a subject with a history of fracture and a subject with no history of fracture.
  • the T value is smaller for subjects with a history of fracture, and the T value is smaller for subjects without a history of fracture.
  • the greater the T value that is, the greater the bone density
  • the smaller the fracture risk in other words, the greater the bone strength.
  • the coefficient of variation CV is larger for subjects with a history of fracture and smaller for subjects without a history of fracture. Also from this, the coefficient of variation CV seems to have some relationship with the fracture risk, that is, the bone strength.
  • FIG. 9 (a) shows a case where a T value is less than 70%, a T value is 70% or more and less than 80%, and a T value is 80% or more.
  • the ratio (number of persons) of subjects with a history of fracture is shown in a graph.
  • FIG. 9B shows the number of fine damages for each of a subject having a T value of less than 70%, a subject having a T value of 70% or more and less than 80%, and a subject having a T value of 80% or more.
  • the average value of is represented by a graph.
  • subjects with a T history of less than 80% and subjects with a T value of less than 80% are more likely to have subjects with a history of fracture.
  • the ratio is large. This means that the greater the T value, that is, the greater the bone density, the lower the risk of fracture, in other words, the greater the bone strength.
  • the subject whose T value is 70% or more and less than 80% has many fine damage numbers rather than the subject whose T value is less than 70%.
  • This fine damage is one of the bone elements as described above. From this, it can be seen that bone quality including fine damage is an independent element different from bone density with respect to bone strength, in other words, fracture risk.
  • FIG. 10 (a) shows that a subject with an al-BMD of less than 71.4, a subject with an al-BMD of 71.4 or more and less than 82.0, and an al-BMD of 80.2 or more.
  • the ratio of the subjects who have a history of fractures with respect to each of the subjects is shown in a graph.
  • a subject whose al-BMD is less than 71.4 corresponds to a subject whose T value is less than 70%, that is, a subject who is suspected of having osteoporosis in the current diagnosis of osteoporosis based on the T value, in other words, For example, this corresponds to a subject who is deemed “careful” in the second embodiment of the aforementioned Japanese Patent No. 4077430.
  • a subject with al-BMD of 71.4 or more and less than 82.0 corresponds to a subject with a T value of 70% or more and less than 80%, that is, osteopenia in current osteoporosis diagnosis based on the T value.
  • This is equivalent to a subject who is suspected to be “attention” in the second embodiment of Japanese Patent No. 4077430.
  • a subject whose al-BMD is 80.2 or more corresponds to a subject whose T value is 80% or more, that is, a subject who is normal in the current diagnosis of osteoporosis based on the T value, in other words, a patent.
  • the boundary values (threshold values) of 71.4 and 82.0 for al-BMD here are determined by experience, including a comparison with the boundary values of 70% and 80% for the T value.
  • a subject with al-BMD of 71.4 or more and less than 82.0 is more fractured than a subject with al-BMD of less than 71.4.
  • the proportion of subjects with a history is large. This means that the greater the al-BMD, that is, the greater the bone density, the lower the risk of fracture, in other words, the greater the bone strength. This is the same as the meaning of the relationship between the T value shown in FIG. 9A and the ratio of subjects with a history of fracture.
  • the subject with al-BMD of 71.4 or more and less than 82.0 has a smaller number of fine damage than the subject with al-BMD of less than 71.4, The difference between the two is small. From this, it can be seen that bone quality including fine damage is an independent element different from bone density with respect to bone strength, in other words, fracture risk.
  • FIG. 11A shows that a subject with a coefficient of variation CV of 15.4% or more, a subject with a coefficient of variation CV of 12.2% or more and less than 15.4%, and a coefficient of variation CV of 12.2.
  • the graph shows the ratio of subjects with a history of fracture with respect to less than 2% of subjects.
  • FIG. 11B shows a subject whose coefficient of variation CV is 15.4% or more, a subject whose coefficient of variation CV is 12.2% or more and less than 15.4%, and a coefficient of variation CV of less than 12.2%.
  • the average value of the number of fine damages for each of the test subjects is represented by a graph.
  • the boundary values of 15.4% and 12.2% for the variation coefficient CV are values determined based on the relationship between the T value and the variation coefficient CV shown in FIG. 7C, for example. is there. That is, the boundary value of 15.4% is an average value (17.13%) of the coefficient of variation CV for subjects whose T value is less than 70% (that is, subjects who are suspected of having osteoporosis), and the T value is This is a value determined based on the average value (13.66%) of the coefficient of variation CV for subjects who are 70% or more and less than 80% (that is, subjects who are suspected of having osteopenia). Is an intermediate value between these two average values.
  • the boundary value of 12.2% is an average value (13.66%) of the coefficient of variation CV for subjects whose T value is 70% or more and less than 80%, and subjects whose T value is 80% or more (that is, normal) And the average value (10.66%) of the coefficient of variation CV for the subject), specifically, an intermediate value between these two average values.
  • the number of fine damage is so large that the variation coefficient CV is large, and the number of fine damage is so small that the said variation coefficient CV is small. From this, it can be seen that the coefficient of variation CV correlates with the number of fine damages, that is, correlates with bone quality including the number of fine damages.
  • a subject having a coefficient of variation CV of 15.4% or more can be evaluated as having a weak bone quality, that is, “careful”.
  • a subject with a coefficient of variation CV of 12.2% or more and less than 15.4% can be evaluated as having a slightly fragile bone and requiring some “caution”.
  • a subject having a coefficient of variation CV of less than 12.2% can be evaluated as having a strong bone quality, that is, “normal”.
  • FIG. 12 shows the correlation coefficient between the parameters in FIG.
  • the numerical value of the upper stage of each numerical value column in this FIG. 12 is a correlation coefficient
  • the numerical value of a lower stage is the significance probability in a two-sided test.
  • each parameter including the coefficient of variation CV is correlated with each other. That is, it can be seen that the coefficient of variation CV correlates with the other parameters L-BMD, al-BMD, the presence or absence of a fracture history, and the number of micro-injuries.
  • FIG. 13 shows the results of ROC analysis of the discrimination ability of the presence or absence of a fracture for each of L-BMD, al-BMD, and coefficient of variation CV.
  • L-BMD the longest ROC analysis of the discrimination ability of the presence or absence of a fracture for each of L-BMD, al-BMD, and coefficient of variation CV.
  • the discrimination ability by al-BMD is the highest (the farthest from the linear reference line).
  • the coefficient of variation CV correlates with the bone quality including the number of minute lesions, and the coefficient of variation CV has the ability to identify the presence or absence of a fracture. Therefore, in the present embodiment, based on the coefficient of variation CV as described above. Systemic bone quality. Further, the fracture risk is evaluated based on the evaluation result of the bone quality and the evaluation result of the bone density by al-BMD. Specifically, as shown in FIG. 14, for example, it is considered normal only when the coefficient of variation CV is less than 12.2% and al-BMD is 82.0% or more. Is evaluated.
  • a plurality of image data is stored in the hard disk in the PC 12, and in particular, image data of four or more X-ray images obtained from the same subject on different days is stored.
  • a main screen 100 as shown in FIG. 15 is displayed on the display 24 of the PC 12.
  • a horizontally long title bar 102 is displayed at the top of the main screen 100.
  • a horizontally written character string here, a character string “ musicians No. 00001”
  • a button with a “x” mark for closing the main screen 100 a so-called close button 105 is displayed.
  • a horizontally long menu bar 106 similar to the title bar 102 is displayed below the title bar 102.
  • a plurality of character strings 108, 108,... Representing the contents of menus that can be operated on the main screen 100 are displayed in a horizontal row.
  • a horizontally long toolbar 110 is displayed below the menu bar 106.
  • a plurality of tool buttons 112, 112,... Which are designed menus in the menu bar 106 are displayed in a horizontal row.
  • a rectangular frame area 114 is displayed below the toolbar 110.
  • radio buttons 126, 126,... For selecting which of the picture boxes 116, 116,. Are displayed in a vertical line. Then, on the right side of each radio button 124, a character string 128 representing “image A” (A: any one of 1 to 4) corresponding to the radio button 124 is displayed. Further, a character string “image selection” representing the function of each radio button 126, 126,... Is displayed above the arrangement of the radio buttons 126, 126,.
  • a value serving as a boundary between “attention” and “attention” for al-BMD is input, and the above-described value “71.4” is input as a default value.
  • two boundary values for inputting two boundary values for the variation coefficient CV related to the fracture risk evaluation are input to the right side of the arrangement of the character strings 122, 122,...
  • Edit boxes 144 and 146 are displayed. That is, in the edit box 144 on the left side, a value serving as a boundary between “normal” and “caution” for the coefficient of variation CV is input, and the above-described value “12.2” is input as a default value.
  • a value serving as a boundary between “attention” and “attention” for the variation coefficient CV is input, and the above-described value “15.4” is input as a default value.
  • a histogram display area 148 is displayed in the lower part of the frame area 114.
  • vertical scale lines 150, 150,... are written at regular intervals in the direction along the horizontal axis.
  • a character string 152 representing the indicated value of the scale line 150 is displayed below each scale line 150.
  • the main screen 100 has substantially the same configuration as that of the second embodiment in the above-mentioned Japanese Patent No. 4077430, and a character string 120, 120,... Representing al-BMD and a character representing a variation coefficient CV.
  • the columns 122, 122,... Are different from the character strings 124, 124,... Representing the fracture risk evaluation results, and the four edit boxes 136, 138, 144, and 146, and the two characters associated therewith. Only the portions of the columns 140 and 142 are different.
  • the radio button 126 corresponding to “image 1” is turned on (clicked) by the operation of the pointing device described above, that is, the picture box 116 corresponding to “image 1” is valid.
  • arbitrary image data is read from the hard disk by operating the pointing device.
  • an X-ray image 154 according to the image data is displayed in the picture box 116 of “image 1”.
  • the X-ray image 154 is displayed in gray scale. If the original image data is color data, the image data is converted into grayscale data when read from the hard disk.
  • the command for reading the image data is stored in, for example, a “file” menu in the menu bar 106.
  • the image data can also be read by operating the corresponding tool button 112 in the toolbar 110.
  • the method for reading the image data is the same as that of the second embodiment in the above-mentioned Japanese Patent No. 4077430.
  • the radio button 126 corresponding to “image 1” is turned on.
  • a sub-screen (dialog box) 200 as shown in FIG. 18 is displayed on the display 12b. Note that the command for starting the evaluation of the fracture risk is stored in, for example, an “edit” menu in the menu bar 106.
  • a horizontally long title bar 202 is displayed at the top of the sub-screen 200.
  • a horizontally written character string in this case, “Chart No. 00001-Image 1”
  • Column 204 is displayed left justified.
  • a close button 205 for closing the sub screen 200 is displayed at the right end portion in the title bar 202.
  • a rectangular frame area 206 is displayed below the title bar 202.
  • a rectangular area selection area 208 is displayed with a small space in the lower part thereof.
  • an enlarged image 210 obtained by enlarging the X-ray image 154 of the currently activated “image A” (here, “image 1”) is displayed.
  • radio buttons 222, 222,... are displayed in a single vertical row on the right side of the area selection area 208 and in the upper part of the frame area 206.
  • Individual character strings representing the headings of the radio buttons 222, 222,... For example, “reference bar”, “maximum value (white)”, The character strings 224, 224,... "Minimum value (black)” and "Evaluation object" are displayed.
  • a note area 230 for displaying a note 228 is provided on the right side of the group of radio buttons 222, 222,... Immediately after the sub screen 200 is displayed, in other words, when each of the radio buttons 222, 222,... Is in an OFF state, the character string “unprocessed” is displayed as the note 228.
  • two edit boxes 232 and 234 are displayed side by side.
  • two character strings 236 and 238 representing the headings of the edit boxes 232 and 234, which are “reference maximum value” and “reference minimum value”, are displayed.
  • a reference maximum value Ysmax (to be described later) is input to one of the edit boxes 232 and 234, for example, an edit box 232 with a heading (character string) 236 of “reference maximum value”, and “180” is set as a default value. Is entered.
  • a reference minimum value Ysmin described later is input, and a value “30” is input as a default value.
  • a horizontally long rectangular reference bar display area 240 is displayed below the edit boxes 232 and 234.
  • a substantially square evaluation target display area 244 is displayed below the left side of the reference bar display area 240.
  • a substantially square histogram display area 248 is displayed on the right side of the evaluation target display area 244.
  • vertical graduation lines 250, 250,... are written at regular intervals in the direction along the horizontal axis.
  • three radio buttons 252, 252,... are displayed in a horizontal row.
  • There is an individual character string representing the heading of each of the radio buttons 252, 252,. 254, 254,... are displayed.
  • a character string 256 “histogram” representing the function of each radio button 252, 252,... Is displayed above each radio button 252, 252,.
  • the sub-screen 200 has the same configuration as that of the second embodiment in the above-mentioned Japanese Patent No. 4077430, and the radio button 222 to which the character string 224 of “evaluation target” is attached is turned on. Only the contents of the note 228 displayed in the note area 230 are different.
  • the radio button 222 marked with is turned on.
  • an area corresponding to the reference bar 38 shown in FIG. 19 an area corresponding to the reference bar 38 shown in FIG.
  • 260 is selected to be rectangular.
  • one side of the rectangular region 258 coincides with one end edge of the reference bar 260 and faces one side of the rectangular region 258.
  • the rectangular area 258 is selected so that the other side of the rectangular area 258 matches the other edge of the reference bar 260.
  • the remaining sides (upper side and lower side) of the rectangular region 258 are inside the peripheral edge of the reference bar 260, and FIG. It suffices that the regions corresponding to the uppermost portion and the lowermost portion of the block 38 shown in (1) are included in the rectangular region 258 (at least only a portion thereof).
  • the intensity within the set reference bar area 258, for example, the luminance Y [i, j] ([i, j ]; Coordinates of each pixel constituting the enlarged image 210), and the maximum value and the minimum value are detected.
  • the maximum value the luminance Y [i, j] of the region basically corresponding to the uppermost portion of the block 38, that is, the region corresponding to the portion where the aluminum foil 40 is adhered is detected.
  • the lowest value basically the luminance Y [i, j] of the area corresponding to the lowermost part of the block 38 is detected.
  • the maximum value and the minimum value of the brightness Y [i, j] detected in this way are recorded in the table 300 shown in FIG. 20 as the brightness maximum value Ybmax and the brightness minimum value Ybmin, respectively.
  • the table 300 is formed in the hard disk when the fracture risk evaluation program is started.
  • the table 300 also records the above-described reference maximum value Ysmax and reference minimum value Ysmin.
  • the brightness Y [i, of the enlarged image 210 displayed in the area selection area 208 is displayed.
  • j] is corrected.
  • the corrected luminance Y ′ [i, j] is obtained based on the following equation (1).
  • the enlarged image is such that the maximum luminance value Ybmax matches the reference maximum value Ysmax as the reference value, and the minimum luminance value Ybmin matches the reference minimum value Ysmin as the reference value.
  • the overall luminance Y [i, j] 210 is corrected.
  • the enlarged image 210 in the area selection area 208 is displayed again based on the corrected luminance Y ′ [i, j] obtained by this equation 1. That is, the enlarged image 210 after the brightness Y [i, j] is corrected is displayed again.
  • all the pixels of the enlarged image 210 are distributed according to the gradation x of each corrected luminance Y ′ [i, j], for example, 256 gradations x. Then, based on the following Equation 2, the frequency Ha ′ [x] for each gradation x is obtained.
  • Equation 2 Na is the total number of pixels of the enlarged image 210, and na '[x] is the number of pixels assigned to the gradation x in the total number of pixels Na.
  • the frequency Ha ′ [x] based on the number 2 is also recorded in the table 300 described above.
  • a so-called normalized frequency Ha ′ [x] is obtained.
  • each pixel constituting the reference bar area 258 is sorted according to the gradation x of each luminance Yb ′ [i, j]. Then, a corrected frequency Hb ′ [x] for each gradation x is obtained based on the following Equation 3.
  • Equation 3 Nb is the total number of pixels constituting the reference bar region 258, and nb '[x] is the number of pixels assigned to the gradation x in the total number of pixels Nb.
  • the corrected frequency Hb ′ [x] based on Equation 3 is also recorded in the table 300.
  • the average value Mb ′ of the corrected luminance Yb ′ [i, j] in the reference bar region 258 is obtained.
  • the corrected average value Mb ′ is obtained based on the following equation (4).
  • the corrected average value Mb ′ based on this number 4 is also recorded in the table 300.
  • the corrected average value Mb ′ based on the equation 4 is set as a reference average value SMb ′ described later.
  • the standard deviation Db ′ of the corrected luminance Yb ′ [i, j] in the reference bar area 258 is obtained.
  • the corrected standard deviation Db ′ is obtained based on the following equation (5).
  • the corrected standard deviation Db ′ based on this number 5 is also recorded in the table 300.
  • the corrected standard deviation Db ′ based on this equation 5 is set as a reference standard deviation SDb ′ described later.
  • corrected average value Mb ′ and corrected standard deviation Db ′ are displayed as a note 228 in the note area 230.
  • a character string representing a heading “reference bar” is displayed as the note 228 in the upper portion of the note area 230.
  • the heading 224 “Evaluation target” of the four radio buttons 222, 222 Assume that the radio button 222 marked with is turned on. Then, the boundary line of the reference bar area 258 indicated by the broken line in FIG. In this state, on the enlarged image 210 of the area selection area 208, as shown by a broken line 266 in FIG. 21, an area corresponding to the evaluation target area 60 shown in FIG. And That is, the evaluation target area 266 is selected on the enlarged image 210 in the area selection area 208. Thereby, the evaluation target area 266 is set, and the corrected frequency Ho ′ [x] of the evaluation target area 266 is obtained based on the following equation (6).
  • No is the total number of pixels constituting the evaluation target area 266, and no '[x] is the number of pixels of the gradation x among the total number of pixels No.
  • the corrected frequency Ho ′ [x] based on Equation 6 is recorded in the table 300 described above.
  • the corrected average value Mo ′ is obtained based on the following equation (7). Note that the corrected average value Mo ′ based on Equation 7 is treated as the above-described al-BMD. The corrected average value Mo ′ as al-BMD is also recorded in the table 300.
  • the standard deviation Do ′ of the corrected luminance Yo ′ [i, j] in the evaluation target region 266 is obtained.
  • the corrected standard deviation Do ′ is obtained based on the following equation (8).
  • the corrected standard deviation Do ′ based on this equation 8 is also recorded in the table 300.
  • the corrected standard deviation Do ′ based on the equation 8 is divided by the corrected average value Mo ′ based on the above equation 7, that is, the coefficient of variation CV is obtained based on the following equation 9.
  • the coefficient of variation CV based on Equation 9 is also recorded in the table 300.
  • an enlarged image 268 of the evaluation target area 266 is displayed in the evaluation target display area 244 as shown in FIG.
  • a character string representing al-BMD (corrected average value Mo ′) and variation coefficient CV is displayed as a note 228 in the note area 230.
  • a character string representing the heading “evaluation target” is also displayed as the note 228 at the top of the note area 230.
  • the above-described reference average value SMb and reference standard deviation SDb are displayed by the character strings 132 and 134 in the right part of the frame area 114.
  • the X-ray image 154 in the picture box 116 of “Image 1” is displayed again based on the corrected luminance Y ′ [i, j].
  • the X-ray image 154 after the luminance Y [i, j] is corrected is displayed in the picture box 116.
  • the character string 120, 122, and 124 below the picture box 116 of “image 1” displays the al-BMD, the coefficient of variation CV, and the fracture risk evaluation result RF for the “image 1”.
  • the al-BMD is 88.14, that is, the al-BMD is 82.0 or more, and the variation coefficient CV is 14.77, that is, the variation coefficient CV is Since it is 12.2% or more and less than 15.4%, the evaluation result RF of “caution” is given by collation with the evaluation criteria shown in FIG.
  • a histogram 156 according to the corrected frequency Ho ′ [x] is displayed in the histogram display area 148. This histogram 156 is similar to the histogram 264 in the sub-screen 200 shown in FIG.
  • the sub screen 200 is displayed for the other “image A”, that is, “image 2”, “image 3”, and “image 4”, and the operation on the sub image 200 is performed.
  • correction processing is performed in a manner different from that in “image 1”.
  • each pixel constituting the reference bar area 258 is classified according to the gradation x of each luminance Yb [i, j]. Sorted. Then, based on the following Equation 10, the frequency Hb [x] for each gradation x is obtained.
  • Nb is the total number of pixels constituting the reference bar area 258, and nb [x] is the number of pixels allocated to the gradation x in the total number of pixels Nb.
  • the frequency Hb [x] based on the equation 10, that is, the normalized frequency Hb [x] is recorded in the table 300 described above.
  • the average value Mb and the standard deviation Db of the luminance Yb [i, j] in the reference bar area 258 are obtained. Specifically, the average value Mb is obtained based on Equation 11, and the standard deviation Db is obtained based on Equation 12. The average value Mb and the standard deviation Db are also recorded in the table 300.
  • the luminance Y [i, j] of the entire enlarged image 210 in the area selection area 208 is corrected based on the following Equation 13 including the average value Mb and the standard deviation Db, that is, the corrected luminance Y '[I, j] is determined.
  • the corrected luminance Yb ′ [i, j] of the reference bar area 258 of “image 1” is used as a reference.
  • Luminance Y [i, j] is corrected, that is, correction processing is performed.
  • the enlarged image 210 in the area selection area 208 is displayed again based on the corrected luminance Yb ′ [i, j].
  • an enlarged image 262 of the reference bar area 258 based on the corrected luminance Yb ′ [i, j] is displayed.
  • the X-ray image 154 in the picture box 116 of each “image A” is displayed again based on the corrected luminance Y ′ [i, j].
  • the corrected luminances Y ′ [i, j] are substantially uniform among the X-ray images 154, 154,... In the picture boxes 116, 116,.
  • the corrected luminance Y ′ [i, j] of the region to be corrected becomes uniform.
  • the character strings 120, 122, and 124 below the picture box 116 of each “image A” display the al-BMD, the variation coefficient CV, and the fracture risk evaluation result RF for the “image A”. .
  • histograms 156 according to the corrected frequencies Ho ′ [x] of each “image A”, that is, a total of four histograms 156, 156,. These histograms 156, 156,... Are displayed in different modes, for example, colors and line types, for differentiating each other.
  • step S3 the luminance Y [i, j] of the entire enlarged image 210 including the reference bar area 258 is corrected. Specifically, for example, when “image 1” is validated, the luminance Y [i, j] is corrected based on the above-described equation 1, that is, the corrected luminance Y ′ [i, j] is corrected. Ask.
  • step S5 when the evaluation target area 266 is selected by operating the pointing device as described with reference to FIG. 21, the selected evaluation target area 266 is set (to itself). After that, the PC 12 proceeds to step S7, and calculates the corrected average value Mo ′ of the evaluation target region 266 based on the above-described formula 7, specifically based on the formula 7 including the calculation result of the above-described formula 6. Ask. As described above, the corrected average value Mo ′ is handled as al-BMD.
  • step S9 the PC 12 proceeds to step S9, and obtains the corrected standard deviation Do 'of the evaluation target area 266 based on the above-described equation 8. Then, the process proceeds to step S11, and the coefficient of variation CV of the evaluation target area 266 is obtained based on the above formula 9.
  • step S13 the corrected standard deviation Do 'obtained in step S9 and the coefficient of variation CV obtained in step S11 are compared with the evaluation criteria shown in FIG.
  • the bone quality and bone density of the subject are evaluated based on the X-ray image of the mandible taken for dentistry, and the fracture risk is evaluated.
  • the evaluation of bone quality and bone density is realized by a simpler examination for dentistry, and consequently the risk of fracture Evaluation is realized. This is expected to be extremely useful in the prevention and treatment of osteoporosis including osteopenia.
  • the alveolar bone of the mandible that is the subject of X-ray imaging in this embodiment starts to decrease in bone density (bone mass) earlier than the lumbar spine that is subject to imaging in the DXA method, and more rapidly.
  • the spine including the lumbar spine may show a false increase in bone density due to metamorphic changes due to aging or intense exercise.
  • the bone density is evaluated more accurately than the above-described conventional technique based on the X-ray image of the lumbar spine or the like by the DXA method. Therefore, it is expected that fracture risk can be evaluated more accurately. This is also expected for bone quality assessment.
  • the evaluation of the bone quality in the present embodiment is based on the coefficient of variation CV, which is a dimensionless number, in particular, when the intensity of the original X-ray image (X-ray film 20) differs for each original X-ray image. Regardless of this, the bone quality can be accurately evaluated. That is, although the coefficient of variation CV referred to here represents the variation in the lightness of the evaluation target region 60 shown in FIG. 2, it is not an absolute lightness of the lightness, but the lightness of the lightness relative to the average value of the lightness. Represents relative variation. On the other hand, the intensity of the entire X-ray image including the evaluation target region 60 may vary depending on various conditions such as the time of imaging.
  • the coefficient of variation CV does not represent the absolute variation in the intensity of the evaluation target region 60 as described above, but represents the relative variation in the intensity with respect to the average value of the intensity. Even if the intensity of the entire X-ray image changes, it is basically constant. Therefore, bone quality can be accurately evaluated based on such a variation coefficient CV. Note that even when the subjects are different, the intensity of the evaluation target region 60 itself and the absolute variation in the intensity of the evaluation target region 60 change. In this case as well, the bone quality is evaluated based on the coefficient of variation CV. Can be realized accurately.
  • the intensity of the entire X-ray image including the reference bar 38 is corrected so that the intensity of the reference bar 38 as an index is constant.
  • the bone density is evaluated based on the corrected X-ray image. Therefore, even in the evaluation of the bone density, even if the intensity of the original X-ray image differs from one original X-ray image to another, it is possible to eliminate the influence of the original X-ray image and realize an accurate evaluation.
  • this embodiment is a specific example of this invention until it gets tired, and does not limit the scope of the present invention.
  • the bone quality is evaluated based on the coefficient of variation CV after the correction processing described above, but the bone quality based on the coefficient of variation CV may be evaluated before the correction processing.
  • the bone quality may be evaluated based on the reciprocal (1 / CV) of the coefficient of variation CV instead of the coefficient of variation CV.
  • the fracture risk is evaluated based on the coefficient of variation CV and al-BMD. Based on either one of the coefficient of variation CV or al-BMD, for example, based on only the coefficient of variation CV. Fracture risk may be assessed. However, it goes without saying that more accurate evaluation of fracture risk can be realized based on both the coefficient of variation CV and al-BMD.
  • the fracture risk evaluation criteria shown in FIG. 14 are merely examples, and are not limited thereto.
  • the coefficient of variation CV is 12.2% or more and less than 15.4%
  • al-BMD is 71.4% or more and less than 82.0%
  • An evaluation of “Needs attention” is given, but an evaluation of “attention” may be given instead.
  • the boundary values of 15.4% and 12.2% for the coefficient of variation CV are also examples, and are not limited to these values.
  • the boundary values of 71.4 and 82.0 for al-BMD are examples, and are not limited to these values.
  • the evaluation criteria of FIG. 14 are determined by so-called retrospective research. However, more appropriate evaluation criteria are determined by performing more clinical experiments including prospective studies. It is expected.
  • the fracture risk assessment program installed in the PC 12 may be provided not only by the storage medium 14 such as a DVD-ROM but also through an electric communication line such as the Internet.
  • the fracture risk evaluation apparatus is realized by the fracture risk evaluation program executed by the PC 12, that is, the so-called general-purpose computer PC12. It may be realized.

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Abstract

Le problème décrit par la présente invention est de pouvoir évaluer la qualité osseuse avec un examen plus simple. La solution selon la présente invention permet d'évaluer la qualité osseuse d'un sujet sur la base d'une image radiographique de la mandibule du sujet, plus spécifiquement, sur la base de la variance de densité d'une région d'évaluation 60 qui comprend une partie osseuse alvéolaire 36 entourant une première prémolaire molaire 30. L'image radiographique mentionnée ci-dessus est obtenue, par exemple, pendant un examen dentaire. Un exemple connu de l'état de la technique pour évaluer la qualité osseuse, en même temps, est basé sur des images radiologiques provenant de la DXA. C'est-à-dire que la qualité osseuse peut être évaluée par un examen plus simple selon la présente invention que la technique précédente qui suppose que la DXA, qui est un examen relativement élaboré, serait réalisée. Selon la présente invention, la densité osseuse est également évaluée, en plus de l'évaluation de la qualité osseuse. Le risque que le sujet subisse une fracture ostéoporotique, c'est-à-dire le risque de fracture osseuse, est également évalué sur la base des résultats de la qualité osseuse et des évaluations de densité osseuse.
PCT/JP2017/000061 2017-01-05 2017-01-05 Dispositif, procédé et programme d'évaluation de la qualité osseuse, et dispositif, procédé et programme d'évaluation de risque de fracture osseuse WO2018127949A1 (fr)

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PCT/JP2017/000061 WO2018127949A1 (fr) 2017-01-05 2017-01-05 Dispositif, procédé et programme d'évaluation de la qualité osseuse, et dispositif, procédé et programme d'évaluation de risque de fracture osseuse

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