JP2006149446A - Medical image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing technique capable of accurately extracting a major psoas muscle region. <P>SOLUTION: A vertebra region is extracted (S21) by a binarization processing from a medical image which is a tomographic image photographed at the navel position of a testee body, in which a navel region, soft tissue including the major psoas muscle and the vertebra region are photographed. A prescribed threshold is set so as to extract the soft tissue including the major psoas muscle and it is extracted by the binarization processing (S22). A symmetry center line which divides the tomographic image in the left and right directions of the testee body is set and only pixel points present at symmetrical positions with the symmetry center line as a reference are extracted (S23). Approximate major psoas muscle regions are extracted as regions present on the left and right of the vertebra region (S24). On the basis of the approximate major psoas muscle regions, the entire major psoas muscle region including the pixel points present at asymmetrical positions with the symmetry center line as a reference is extracted from binary medical images (S25). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a medical image diagnostic display apparatus, and more particularly to a technique for extracting a psoas muscle region from a tomographic image of a subject.

  The volume of the psoas muscle decreases with age, and it begins to fall on a small protrusion. If it shrinks, it is necessary to inform the patient and encourage rehabilitation. In this case, it is convenient to extract the psoas muscle region using a CT image, and doctor demands are high. Note that the volume of the psoas muscle correlates with the psoas muscle area of the slice image in which the navel is reflected, and doctors often substitute this area measurement.

  Here, the psoas major will be described with reference to FIG. The psoas major is located on the left and right sides of the spine. Since the left and right psoas major muscles A and B are in contact with other surrounding organs A and B (for example, kidneys), they cannot be extracted by simple threshold processing.

Thus, as one technique for extracting the psoas major region from a medical image, for example, Patent Document 1 discloses an image processing technique for deleting a partial protruding region of a binarized image. As shown in FIG. 18A, the image processing technique of Patent Document 1 sets point sequences a1, a2, a3, a4, and a5 that are parallel to the x-axis and that are a plurality of pixel points, and if a1 = a5 = 0. It is assumed that a2 = a3 = a4 = 0. In addition, point sequences b1, b2, b3, and b4 made up of a plurality of pixel points parallel to the y-axis are set. If b1 = b4 = 0, b2 = b3 = 0. Thereby, the point sequence a1, a2, a3, a4, a5 and the point sequence b1, b2, b3, b4 are cut or deleted, and a partial protruding area of the binarized image is deleted.
JP 2002-325761 A

  However, when a partial protruding area of the binarized image is deleted by the image processing technique of Patent Document 1, there is a problem that the cut portion becomes a straight line as shown in FIG.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an image processing technique capable of accurately extracting a psoas major region.

  In order to achieve the above object, a medical image display device according to the present invention is a tomographic image taken at a navel position of a subject, and a medical image in which a navel region, a soft tissue including a psoas major muscle, and a spine region are imaged. Image acquiring means for acquiring an image, means for generating an extracted image obtained by extracting a soft tissue including the psoas muscle by setting a predetermined threshold value for the acquired medical image, and dividing the extracted image as desired Means for setting a symmetric center line; and first extraction means for extracting an approximated psoas muscle region by extracting only pixel points existing at positions symmetrical with respect to the symmetric center line in the extracted image; A second extracting means for extracting, based on the approximate psoas muscle region, all psoas muscle regions including pixel points existing at positions that are asymmetric with respect to the symmetry center line from the extracted image; Extract by two extraction means Comprising a display means for displaying the total O Goshi muscle region that is, a.

  The second extraction means expands line by line along the shape of the outline of the approximate psoas muscle region, and if the pixel point on the line satisfies the predetermined threshold, the pixel point is Extract as large psoas muscle region.

  Further, the apparatus further comprises position coordinate input means for designating a predetermined area of the extracted image displayed on the display means.

  Further, an area difference for determining whether or not the difference in area is within a desired range by calculating and comparing the areas of all psoas muscle regions divided by the symmetrical centerline extracted by the second extraction means And a notification means for notifying that the area difference is not in the desired range when the area difference determination means determines that the area difference is not in the desired range. In the case where it is done, the position coordinate input means designates and extracts the psoas muscle region included in the extracted image.

  The above-mentioned “second extraction means” calculates an inclination angle of the approximate psoas muscle region when the psoas muscle region is in contact with an adjacent soft tissue in the extracted image, and outputs the binarized image to the binarized image. Set a line segment that passes through any two points on the outline of the contained psoas muscle region and has an inclination angle determined based on the inclination angle, and calculates the position where the length of the line segment is minimal Then, a predetermined slope area outside the greater psoas muscle area than the position and having the slope angle may be deleted and extracted.

  Further, the “second extraction means” sets a concentric circle from the center of gravity of the soft tissue in contact with the psoas muscle region when the psoas muscle region is in contact with the adjacent soft tissue in the extracted image, and When the pixel value at any two points is 0, the pixel value of the pixel point on the arc connecting the two arbitrary points is set to 0 to separate the soft tissue and the psoas muscle region, and The inclination angle of the approximate psoas muscle region is calculated, and a line segment passing through any two points on the outline of the separated psoas region and having an inclination angle determined based on the inclination angle is set. Then, pixel points that satisfy the threshold on the line segment may be extracted as the psoas muscle region.

  The “medical image display device” may further include spine extraction means for extracting a spine region from the medical image. Then, the “first extraction means” uses the approximated psoas major as the pixel points located on both sides of the spine region extracted by the spine extraction means among the pixel points that are symmetric with respect to the symmetry center line. It may be extracted as a region.

  Furthermore, when the spine region extracted by the spine region extraction unit does not satisfy a desired condition, the image acquisition unit acquires another medical image obtained by photographing the vicinity of the part of the subject corresponding to the tomographic image. The whole psoas muscle region may be extracted based on the other medical image.

  Further, when the spine region extracted by the spine region extraction unit does not satisfy a desired condition, the spine region included in the extracted image may be specified and extracted by the position coordinate input unit.

  When the spine region extracted by the spine region extraction unit does not satisfy a desired condition, the image acquisition unit acquires another medical image obtained by capturing a tomographic image of the subject. And a selection means for causing the operator to select whether to perform a process of extracting a spine area based on the position, or to specify and extract a spine area included in the extracted image by the position coordinate input means. Also good.

  Further, when the spine region extracted by the spine region extraction unit does not satisfy a desired condition and the psoas major region forms a wide region adjacent to a part of the spine region, the spine extraction unit extracts A predetermined range from the center of gravity of the spine region extracted by the spine extraction means, on the straight line passing through the center of gravity of the spine region and the center of the body surface contour line in the tomographic image shown in the tomogram Is extracted as a temporary center point, the center of gravity of the wide area is calculated by calculating the distance from the temporary center point to the pixel point on the outline of the wide area, and the center of gravity of the wide area is By setting a concentric circle as the center point, and when the pixel value of any two points on the concentric circle is 0, by setting the pixel value of the pixel point on the arc connecting the two arbitrary points to 0, The psoas major region and the spinal territory Spinal region separating means for separating a portion of may further include a.

  When the spine region extracted by the spine region extraction unit does not satisfy a desired condition and the psoas muscle region forms a wide region adjacent to a part of the spine region, the first extraction unit includes Calculating an inclination angle of the extracted approximate psoas muscle region, setting a line segment passing through any two points on the outline of the wide area region and having an inclination angle determined based on the inclination angle; A spinal region separation means for separating the psoas muscle region and a part of the spine region by dividing the wide area at a position where the length of the line segment is minimal may be further provided.

  Moreover, you may further provide the fat area calculation means which calculates the area of the fat area | region contained in this all psoas muscle area from the all psoas muscle area extracted by said 2nd extraction means.

  Further, the area of the entire psoas muscle region extracted by the second extraction unit is calculated, and the area of the fat region calculated by the fat area calculation unit is subtracted from the area of the total psoas muscle region, and subtraction is performed. A psoas major area calculation means for calculating the area of the subsequent psoas major region may be further provided.

  According to the present invention, the approximate psoas muscle region is calculated using the asymmetry of the psoas muscle, and the psoas muscle region included in the medical image is accurately extracted based on the approximate psoas region. be able to. Then, the area of the psoas muscle can be obtained using the extracted psoas muscle region.

  Hereinafter, preferred embodiments of a medical image display apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.

  FIG. 1 is a hardware configuration diagram showing a configuration of a medical image display system 1 according to an embodiment of the invention.

  The medical image display system 1 in FIG. 1 includes an X-ray CT apparatus 2, an MR apparatus 3, an image database 4 that stores medical images obtained by the X-ray CT apparatus 2 and the MR apparatus 3, and medical images. The X-ray CT apparatus 2, the MR apparatus 3, the image database 4, and the medical image display apparatus 10 are connected to each other via a network such as a LAN 5.

  The medical image display apparatus 10 includes a central processing unit (CPU) 11 that mainly controls the operation of each component, a main memory 12 that stores a control program for the apparatus and that serves as a work area when the program is executed, and an operating system. System (OS), device drive of peripheral device, magnetic disk 13 storing various application software including a program for extracting the psoas muscle region from medical images, etc. and display data are temporarily stored. A display memory 14, a monitor 15 such as a CRT monitor or a liquid crystal monitor for displaying an image based on data from the display memory 14, a keyboard 16, a mouse 17 as a position coordinate input device, and a state of the mouse 17 are detected. And outputs signals such as the position of the mouse pointer on the monitor 15 and the state of the mouse 17 to the CPU 11. It includes a controller 18 for, and a common bus 19 for connecting the above components.

  In the present embodiment, the medical image display device 10 reads a medical image from the image database 4 via the LAN 5, but a storage device connected to the medical image display device 10, such as an FDD, CD-RW drive, or MO drive A medical image may be read from a ZIP drive or the like. Alternatively, a medical image may be acquired directly from the X-ray CT apparatus 2 or the MR apparatus 3 via the LAN 5.

  Next, a procedure for extracting a psoas muscle region from a medical image using the medical image display apparatus 10 according to the present embodiment will be described based on FIGS. 2 to 5, 15 and 16. FIG. 2 is a flowchart showing a procedure for extracting the psoas muscle region. FIG. 3 is a schematic diagram showing a region left after the process of setting the symmetry center line in the binarized image and leaving only the pixels satisfying the symmetry, which is the processing result image in step S23. FIG. 4A is a processing result image of step S24, and is a schematic diagram showing a state where an approximated psoas muscle region is extracted as an adjacent region on the left and right of the spine, and FIG. It is a schematic diagram which shows the method of calculating | requiring a psoas muscle area | region by applying the area | region expansion method to the approximate psoas muscle area of a). FIG. 5A is a schematic diagram showing a first processing method for separating the psoas muscle region and the spine region, and FIG. 5B is a diagram for separating the psoas region and the spine region. It is a schematic diagram which shows the 2nd processing method. FIG. 15 shows an example of an original image in which the spine region is clearly shown, and FIG. 16 shows an example of an original image in which the spine region is shown unclearly. In the following, description will be given in the order of each step in FIG.

(Step S21)
Threshold processing is performed by setting a threshold (for example, CT value is larger than t2) based on the CT value of the spine from the original image (for example, a medical image showing a tomographic image taken at the navel position of the subject shown in FIGS. 15 and 16). Then, the spinal region is binarized and extracted (S21). If the area is limited in advance by a rectangle surrounding a part of the spine, processing is reduced.

  At this time, an automatic check process is performed to determine whether the area of the extracted spine region is within a predetermined range and whether the barycentric coordinates of the spine region are within the predetermined range. For example, the high-concentration spine 151 is shown in the original image 150 shown in FIG. 15, but since the imaging slice position is located between the bones in the original image shown in FIG. This is because the image is captured at a low density, and the entire spine region may not be extracted only by threshold processing. This automatic spine region check process will be described later with reference to FIG.

(Step S22)
A threshold value is set from the original image based on the CT value of the psoas muscle and threshold processing is performed, and the soft tissue region including the psoas muscle is binarized and extracted (S22).

(Step S23)
A symmetric center line 40 is set, and only pixels that exist symmetrically with respect to the symmetric center line 40 are left (S23).

  The symmetry center line 40 is (1) a straight line passing through the center of gravity of the spine region and the navel position (the center of gravity of the recessed region indicating the navel), and (2) when the navel is not reflected, is located on the back side of the spine region. Detecting both ends of the muscle (muscles A and B in FIG. 17), passing through the midpoint of the line segment connecting both ends of the muscles A and B, and (3) the spine and the body tissue region of the subject It is obtained by setting a straight line passing through the center of gravity.

  And only the pixel which exists in the position which becomes symmetrical with respect to the symmetry center line 40 is left among the soft tissue regions stopped in step S22. The processing result of this step S23 is shown in FIG. As shown in FIG. 3, only pixel points that are symmetric with respect to the symmetric center line 40, such as the psoas major muscles 30A and 30B, the other organs 31A and 31B, and the muscle 32, are extracted. Further, when the CT value of the spine is high, the spine region is not extracted.

  Normally, the human body is configured such that the psoas major muscles, other organs, muscles, etc. are not located at positions completely symmetrical with respect to the symmetry center line 40, and the shape of each psoas major muscle, organ, muscle is asymmetric. There is no. On the other hand, in Step S23, since only the symmetric pixels are extracted with the symmetry center line 40 interposed therebetween, the region extracted as a result in Step S23 is extracted from the adjacent organs (in a non-contact state).

(Step S24)
By extracting only the regions present on the left and right of the spine region, approximated psoas muscle regions 30A and 30B are obtained as shown in FIG. 4A (S24). At this time, in order to determine whether the areas of the approximate psoas muscle regions 30A, 30B are within a predetermined range, and whether the barycentric coordinates of the approximate psoas muscle regions 30A, 30B are within a predetermined range. Perform automatic check processing. Accordingly, whether or not the approximate psoas muscle regions 30A and 30B are correctly extracted, for example, in the binarized image shown in FIG. 3, the organ regions 31A and 31B adjacent to the approximate psoas region 30A and 30B are extracted. It can be checked whether or not it has been erroneously extracted as an approximate psoas muscle region.

  This automatic check process will be described later with reference to FIG.

(Step S25)
Based on the information of the approximated psoas muscle regions 30A and 30B obtained in step S24, a high-precision psoas region extraction process is performed (S25). That is, the approximate psoas muscle regions 30A and 30B extract only pixel points located symmetrically with respect to the symmetry center line 40 in the psoas muscle region. Therefore, it is extracted smaller than the actual psoas muscle region. Therefore, pixel points located asymmetrically with respect to the symmetry center line 40 are also extracted, and all the pixel points constituting the psoas muscle region are extracted.

  As one method for this purpose, as shown in FIG. 4B, there is a method of extracting the psoas muscle region including asymmetric pixels with high accuracy by expanding the approximate psoas region 30A, 30B. More specifically, one line is expanded along the contour shape of the binarized approximated psoas muscle regions 30A and 30B extracted in step S23 (line 41), and the pixel points on the line 41 are expanded. Among these, pixel points that satisfy the threshold conditions set for extracting the approximated psoas muscle regions 30A and 30B are extracted. Then, the region expansion process is stopped at a position where the length of the line 41 is minimized.

  As another method, for example, as shown in FIG. 5, based on the information of the approximate psoas muscle regions 30A and 30B, the region other than the psoas muscle is deleted from the binarized image created in step S22. There is a method of leaving only the desired psoas muscle region.

  In FIG. 5A, two points having the longest distance are obtained from the two points on the outline of the approximated psoas muscle regions 30A and 30B calculated in step S24. Based on the coordinates of the two points, the inclination angles of the psoas major regions 50A and 50B in the binarized image are obtained. And the line segment D1 which has the inclination angle and connects two points on the outline of the psoas major region 50A, 50B is set. The line segment D1 is shifted line by line to the outside of the psoas major regions 50A and 50B, and the position where the length of the line segment D1 becomes 0 is obtained. Then, a predetermined region that is outside the greater psoas region 50A, 50B than the position where the length of the line segment D1 becomes 0 and has the same tilt angle as that of the psoas region 50A, 50B is deleted. 53 is set. By deleting the deletion region 53, only the psoas major regions 50A and 50B are extracted and separated from the adjacent organ regions 51A and 51B.

  In FIG. 5B, the psoas major regions 50A and 50B in the binarized image created in step S22 based on the approximate psoas major regions 30A and 30B are specified. Then, for example, the center of gravity 51Ap of another organ region 51A adjacent to the psoas major region 50A is calculated. When a circle centered on the center of gravity 51Ap is set, and the pixel value is 0 at two points p1 and p2 on the circumference, the arc p1p2 is cleared to zero so that the other organ region 51A is removed from the psoas muscle region 50A. To separate. Thereafter, only the psoas major region 50A is left by a region expansion method using the center point (center of gravity) of the approximate psoas major region 30A extracted in step S24 as a starting point. The same applies to the other psoas muscle region 50B.

  When the high-precision psoas muscle region extraction process based on the approximate psoas region information shown in FIG. 4 (b), FIG. 5 (a), or FIG. 5 (b) is finished, the large hips shown in FIG. The muscle extraction process ends.

  Next, based on FIG. 6, the automatic check process for determining whether or not the spine region is extracted in step S21 will be described.

(Step S61)
The area of the spine region extracted in step S21 is calculated, and it is determined whether or not the area is within a predetermined range (S61). If it is within the predetermined range, the process proceeds to step S62. If it is not within the predetermined range, the process proceeds to step S63.

(Step S62)
The barycentric coordinates of the spine region extracted in step S21 are calculated, and it is determined whether or not the barycentric coordinates are within a predetermined range (S62). If it is within the predetermined range, it is determined that the spine region has been correctly extracted, and the automatic check process is terminated. If it is not within the predetermined range, the process proceeds to step S63.

(Step S63)
A spine extraction process is performed on a part of the spine region that could not be extracted in step S21 (S63). A first processing method for extracting a part of the spine region will be described with reference to FIGS. FIG. 7 is a flowchart showing the procedure of the first spine separation processing method performed when the spine is not clearly visible and cannot be extracted by threshold processing. FIG. 8 is a schematic diagram showing a first spine separation processing method performed when the spine is not clearly visible and cannot be extracted by threshold processing.

(Step S71)
Similar to step S22, a threshold value for extracting the psoas major region is set for the original image 160, and binarization processing is performed (S71). As a result, if the spine is between bones, the CT value is low and close to the CT value of the psoas muscle, so that the spines are extracted simultaneously as shown in FIG. Therefore, below, the process which isolate | separates a spine area | region and a psoas muscle area | region is performed. Note that the processing speed can be further improved by setting the rectangular region 90 including the spine region.

(Step S72)
Similar to step S23, a symmetric center line L that connects a part (for example, the center of gravity) of the triangular spine region 83 on the back side and the navel position (the center of gravity of the navel region 81) is set, and this symmetric center line L is used as a reference. Only symmetrical pixels are left (S72). In general, the measurement of the psoas major area is a habit of using a slice in which the navel region 81 is reflected. Therefore, the center of gravity of the navel region 81 can be calculated and used to set the symmetric center line L. Instead of the straight line connecting the spine region 83 and the navel position 81, the center line of the body surface contour (the straight line connecting the center of gravity of the spine region 83 and the center of gravity of the body tissue) may be used.

(Step S73)
The center of a wide region composed of the psoas major region and the spine region is obtained by distance conversion (the shortest distance to the edge is the density at that point) (S73).

  From a anatomical point of view, the circular spine region 82 is a straight line (in this embodiment) that connects a part (center of gravity) of the triangular spine region 83 on the back side to the navel position (center of gravity of the navel region 81). It coincides with the symmetry center line L calculated in step S72) and is located at a certain percentage of points (referred to as C1, C2,..., Cn) from the triangular spine region 83 on the back side. The shortest distance from the points C1, C2,..., Cn to the edge of the wide area (pixel point on the contour line) is calculated, and this shortest distance is defined as the density (pixel value) at the points C1, C2,. Then, the process of converting the distance to the shortest edge into the density is performed on all the points C1, C2,...

(Step S74)
The boundary between the wide regions, that is, the circular spine region 82 and the psoas muscle regions 50A and 50B are cut (S74).

  If the concentric circle is drawn from the center C point of the wide area obtained in step S73 and drawn, and if the pixel values of any two points p1 and p2 on the concentric circle are both 0, the pixel value of the pixel point on the arc p1p2 is 0. Is stored. As a result, the circular spine region 82 and the psoas muscle regions 50A and 50B are separated.

(Step S75)
The circular spine region 82 is deleted to prevent contact with the psoas muscle regions 50A and 50B (S75). Note that instead of deleting the spine region 82, the numerical value 1 may be recorded in the psoas major regions 50A and 50B, and the numerical value 2 may be recorded in the spine region 82. And the extraction process about a part of spine area | region is complete | finished. Thereafter, the process proceeds to step S24 to obtain an approximate psoas muscle region, and further proceeds to step S25 to perform high-accuracy psoas muscle region extraction.

  A second processing method for extracting a part of the spine region that could not be extracted in step S21 will be described with reference to FIGS. In the following, description will be given in the order of steps in FIG. FIG. 9 is a flowchart showing the procedure of the second spine separation processing method performed when the spine is not clearly visible and cannot be extracted by the threshold processing. 10 is a schematic diagram showing a second spine separation processing method performed when the spine is not clearly visible and cannot be extracted by threshold processing. FIG. 11 is a screen display example showing a display for allowing the operator to select a process when the spine region is not correctly extracted. FIG. 12 is a flowchart showing a procedure for automatically checking whether or not the approximate psoas muscle region is correctly extracted. FIG. 13 is a schematic diagram showing a method for deleting unnecessary protrusions from the psoas muscle region.

  In the following, description will be given along the order of steps in FIG.

(Steps S91 and S92)
As in steps S71 and S72, binarization is performed in order to extract the psoas muscle region from the original image (S91), and only the pixels that are symmetric with respect to the symmetric center line L connecting the spine region 83 and the navel region 81 are left (S91 through S91). S92).

(Step S93)
A line segment D2 passing through two points on the edge of the circular spine region 82 is set in parallel with the inclination angles of the psoas muscle regions 50A and 50B, and the length of the line segment D2 is calculated. The line segment D2 is expanded line by line toward the psoas major region 50A or 50B, and the length D is calculated each time.

(Step S94)
By storing the pixel value 0 at the pixel point on the line segment D2 at the position where the length of the line segment D2 obtained in step S93 is minimal, the wide spine region 82 and the psoas muscle region 50A or 50B is cut (S94).

(Step S95)
Similar to step S75, the spine region 82 is deleted or distinguished from the psoas muscle regions 50A and 50B (S95). Thereafter, the spine extraction process is terminated, and the process proceeds to step S64.

(Step S64)
It is determined whether or not the spine region has been extracted in step S63 (S64).

  If the spine region 82 can be extracted, the automatic check process is terminated. If the spine region 93 cannot be extracted, the process proceeds to step S65.

(Step S65)
The spine region 82 is extracted by tracing the spine region 82 with the mouse 17. Alternatively, a substitute image is selected (S65). There are many cases where the spine region is clearly shown in the nearby image (adjacent slice image) outside the gap between the bones. Therefore, an MIP (maximum value projection) image may be created using images near both. In the above-described example, when it is determined in step S61 or S62 that the spine region has not been correctly extracted, the spine region automatic extraction process (S63) is performed. Alternatively, the order was determined in advance so as to capture a substitute medical image (S65), and the processing was automatically performed sequentially. However, as shown in FIG. 11, a message 111 for selecting capturing of a medical image to be substituted for the monitor 15, for example, “Use the adjacent slice” and a message 112 for selecting tracing with the mouse 17 are used. For example, a message 113 for designating the center of the spine region, for example, “indicates the center of the spine”, may be displayed and “operate with the mouse” may be displayed.

  Next, an automatic check process for determining whether or not the approximate psoas muscle region is correctly extracted in step S24 will be described with reference to FIG. FIG. 12 is a flowchart showing a procedure for automatically checking whether or not the approximate psoas muscle region is correctly extracted. In the following, description will be given in the order of steps in FIG.

(Step S1201)
It is determined whether the areas of the left and right approximated psoas muscle regions 30A and 30B extracted in step S24 are within a predetermined range (S1201). If it is within the predetermined range, the process proceeds to step S1202, and if it is not within the predetermined range, the process proceeds to step S1203.

(Step S1202)
It is determined whether or not the barycentric coordinates of the areas of the left and right approximate psoas muscle regions 30A and 30B are within a predetermined range (S1202). The predetermined range may be set based on, for example, an angle and a distance viewed from the barycentric coordinates of the spinal region. If it is within the predetermined range, it is determined that the approximate psoas muscle region has been correctly extracted, and the automatic check process is terminated. If it is not within the predetermined range, the process proceeds to step S1203.

(Step S1203)
Since the psoas major region cannot be extracted, a message prompting the operator to trace with the mouse 17 is displayed. Then, the operator extracts the psoas muscle region by tracing the psoas muscle region with the mouse 17 (S1203). Then, the automatic check process for the approximate psoas muscle region is terminated.

  If unnatural protrusions or the like remain in the psoas muscle region extracted in the above embodiment, point sequences P1, P2, P3 and a point sequence Q1, on the outline of the psoas region as shown in FIG. Q2 and Q3 may be set, and spline interpolation may be performed between the point sequence P1, P2, and P3 and the point sequence Q1, Q2, and Q3, and the interpolated curve may be cut. Thereby, an unnecessary processus | protrusion can be cut | disconnected in a curvilinear form from the psoas major region.

  Once the psoas muscle region is extracted, the areas of the left and right psoas muscle regions are calculated, and the difference in area is calculated. If the area difference is outside the desired range, a message to that effect may be displayed, and the operator may manually input the psoas muscle region using the mouse 17.

  When the psoas muscle region can be normally extracted as described above, the fat region is extracted by specifying the psoas muscle region and setting the threshold based on the CT value along the adipose tissue. Can do. Then, the areas of the extracted fat region and psoas muscle region are respectively calculated, and the area of the psoas muscle region is subtracted from the area of the psoas muscle region, thereby calculating the area of only the muscle region in the psoas muscle region. be able to. When the area of only the muscle region of the psoas muscle region is less than or equal to a predetermined value, a message 141 that prompts rehabilitation may be displayed as shown in FIG. Furthermore, the area 142 and the psoas major area 143 of the extracted fat region may be displayed.

  Further, for each tomographic image obtained by imaging a plurality of large psoas muscle regions of the subject along the body axis direction, the large psoas muscle region extraction processing and large psoas muscle area calculation processing according to the above embodiment are performed. The volume of the psoas muscle region may be calculated by performing the integration and integrating the areas in the body axis direction.

The hardware block diagram which shows the structure of a medical image display system. The flowchart which shows the extraction procedure of a psoas muscle area. The schematic diagram which shows the area | region which remained after the process which is a process result image of step S23, sets a symmetrical centerline to a binarized image, and leaves only the pixel which satisfy | filled symmetry. FIG. 4A is a processing result image of step S24, and is a schematic diagram showing a state where an approximated psoas muscle region is extracted as adjacent regions on the left and right sides of the spine, and FIG. 4B is a diagram showing FIG. The schematic diagram which shows the method of calculating | requiring a psoas muscle region by applying the area expansion method to the approximate psoas muscle region. FIG. 5A is a schematic diagram showing a first processing method for separating the psoas muscle region and the spine region, and FIG. 5B is a diagram for separating the psoas muscle region and the spine region. The schematic diagram which shows the 2nd processing method. The flowchart which shows the procedure of the process which automatically checks whether the spine area | region performed correctly by step S22 was extracted. The flowchart which shows the procedure of the 1st spine isolation | separation processing method performed when the spine is not clear and cannot be extracted by threshold processing. The schematic diagram which shows the 1st spine isolation | separation processing method performed when the spine is not reflected clearly and cannot be extracted by threshold processing. The flowchart which shows the procedure of the 2nd spine isolation | separation processing method performed when the spine is not reflected clearly and cannot be extracted by threshold processing. The schematic diagram which shows the 2nd spine isolation | separation processing method performed when the spine is not reflected clearly and cannot be extracted by threshold processing. The example of a screen display which shows the display for making an operator select a process when the spine area | region is not extracted correctly. The flowchart which shows the procedure which automatically checks whether the approximated psoas muscle region was correctly extracted. The schematic diagram which shows the method of deleting an unnecessary processus | protrusion from a psoas muscle area | region. The schematic diagram which shows the example of a screen display which extracted the fat area | region from the psoas muscle area | region, and displayed the message. Example of original image with clear spine area. An example of an original image in which the spine region is blurred. The schematic diagram which shows the position of the psoas major region in the tomogram of a subject. The schematic diagram explaining the psoas muscle region process by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Medical image display system, 2 ... X-ray CT apparatus, 3 ... MR apparatus, 4 ... Image database, 5 ... LAN, 10 ... Medical image display apparatus, 11 ... CPU, 12 ... Main memory, 13 ... Magnetic disk, 14 ... display memory, 15 ... monitor, 16 ... keyboard, 17 ... mouse, 18 ... controller, 19 ... common bus

Claims (4)

An image acquisition means for acquiring a medical image in which a tomographic image is taken at the navel position of a subject and the navel region, soft tissue including the psoas major muscle, and the spinal region are imaged;
Means for generating an extracted image obtained by extracting a soft tissue including the psoas muscle by setting a predetermined threshold value in the acquired medical image;
Means for setting a symmetric center line for dividing the extracted image as desired;
In the extracted image, a first extracting means for extracting an approximated psoas muscle region by extracting only pixel points existing at positions symmetrical with respect to the symmetry center line;
Based on the approximate psoas muscle region, a second extraction means for extracting all psoas muscle regions including pixel points existing at positions that are asymmetric with respect to the symmetry center line from the extracted image;
Display means for displaying the entire psoas muscle region extracted by the second extraction means;
A medical image display device comprising: The second extraction means expands one line at a time along the shape of the outline of the approximate psoas muscle region, and if the pixel point on the line satisfies the predetermined threshold, the pixel point is Extract as a muscle region,
The medical image display apparatus according to claim 1. A position coordinate input unit for designating a predetermined region of the extracted image displayed on the display unit;
The medical image display device according to claim 1, wherein the medical image display device is a medical image display device. Area difference determining means for calculating and comparing areas of all psoas major areas divided by the symmetrical centerline extracted by the second extracting means and determining whether or not the difference in area is within a desired range When,
A notification means for notifying that the difference in area is not in the desired range when the area difference determination means determines that the difference in area is not in the desired range;
When the notification is given, the position coordinate input means specifies and extracts the psoas muscle region included in the extracted image,
The medical image display apparatus according to claim 3.
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