JP2011239889A - Image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus improving work efficiency and diagnostic accuracy in diagnosing a valvular disease by a doctor or a medical technologist.SOLUTION: A storage section 11 stores a 3D image of a cardiac region of a subject. A cross section setting section 13 sets a cross section in a vascular region included in the cardiac region. A contour extracting section 15 extracts the contour of the vascular region from the vascular region in the cross section by image processing. An evaluation circle generating section 17 generates a schematic valve image for schematically expressing the shape of a cardiac valve on the basis of the shape of the contour. A valve pixel specifying section 19 searches in a defined direction valve pixels for the cardiac valve included in the 3D image for each of the pixels forming the schematic valve image, and specifies whether the valve pixels are present. A colored evaluation circle generating section 21 generates a color image for expressing with colors the opening/closing of the cardiac valve on the basis of the schematic valve image and information as to whether the valve pixels are present or not.

Description

  Embodiments described herein relate generally to an image processing apparatus that performs image processing on three-dimensional image data (volume data) relating to a heart region.

  A heart valve with valvular disease does not operate normally and does not close completely or open completely.

International Publication No. 2006/068271 Pamphlet

  When examining the treatment policy and treatment plan for valvular disease, doctors use the area of the valve orifice as a criterion. For example, in deciding on a treatment policy or treatment plan for valvular disease, a doctor uses a three-dimensional image data related to a heart valve to visually estimate the valve area, and based on the estimated valve area, the lesion area is weighted. Assessing severity. However, a technique for quantitatively evaluating the properties of each heart valve in the treatment policy or treatment plan for valvular disease has not been established.

  An object of the present invention is to provide an image processing apparatus capable of improving work efficiency and diagnostic accuracy related to valvular diseases by doctors and engineers.

  The image processing apparatus according to the present embodiment includes a storage unit that stores a three-dimensional image related to a heart region of a subject, a setting unit that sets a cross section in a blood vessel region included in the heart region, and the blood vessel region in the cross section. An extraction unit that extracts an outline of the blood vessel region by image processing, a first generation unit that generates a schematic valve image that schematically represents the shape of a heart valve based on the shape of the outline, and the schematic valve image For each pixel constituting the three-dimensional image, a valve pixel relating to the heart valve included in the three-dimensional image is searched along a predetermined direction, and a specifying unit for specifying whether or not the valve pixel is present, the schematic valve image, And a second generation unit that generates a color image that represents the degree of opening and closing of the heart valve with a color for each pixel based on information on whether or not there is the valve pixel.

1 is a diagram illustrating a configuration of an image processing apparatus according to an embodiment. The figure which shows typically the anatomical structure of the heart valve (aortic valve) which is the image diagnostic object of this embodiment. The figure which shows a mode when the aortic valve of FIG. 2 has opened completely. The figure which shows a mode when the aortic valve of FIG. 2 is closed completely. The figure which shows the typical flow of the quantitative evaluation process of the aortic valve performed under control of the control part of FIG. The figure for demonstrating the setting process of the evaluation cross section performed by the cross-section setting part in step S1 of FIG. The figure for demonstrating the extraction process of the valve opening position blood-vessel outline performed by the outline extraction part in step S2 of FIG. The 1st figure which shows the process of the production | generation process of the evaluation circle performed by the evaluation circle production | generation part in step S3 of FIG. FIG. 6 is a second diagram illustrating a process of generating an evaluation circle executed by an evaluation circle generating unit in step S3 of FIG. The 3rd figure which shows the process of the production | generation process of the evaluation circle performed by the evaluation circle production | generation part in step S3 of FIG. The figure for demonstrating the specific process of the valve pixel performed by the valve pixel specific part in step S4 of FIG. The figure which shows the evaluation circle to which open information or closed information was allocated by the valve pixel specific part in step S4 of FIG. The figure for demonstrating the calculation process of the opening / closing parameter | index performed by the opening / closing parameter | index calculation part in step S5 of FIG. The figure which shows the display pattern 1 of the colored evaluation circle displayed by the display part in step S7 of FIG. The figure which shows the display pattern 2 of the colored evaluation circle displayed by the display part in step S7 of FIG. The figure which shows the display pattern 3 of the colored evaluation circle displayed by the display part in step S7 of FIG. The figure which shows the display pattern 4 of the colored evaluation circle displayed by the display part in FIG.5 S7. The figure which shows the display pattern 5 of the colored evaluation circle displayed by the display part in step S7 of FIG. The figure which shows the display pattern 6 of the colored evaluation circle displayed by the display part in FIG.5 S7. The figure which shows an example of the colored MPR image displayed by the display part concerning the modification of this embodiment.

  The image processing apparatus according to this embodiment will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an image processing apparatus 1 according to the present embodiment. The image processing apparatus 1 according to the present embodiment uses a heart valve as a target of image diagnosis. As is well known, heart valves include aortic valves, mitral valves, pulmonary valves, and tricuspid valves. Although the present embodiment can be applied to heart valves at all these sites, the heart valve is assumed to be an aortic valve in order to specifically describe the following embodiments.

  As shown in FIG. 2, the aortic valve 31 is located between the left ventricle 33 and the aorta 35 and plays a role of preventing the backflow of blood ejected from the left ventricle 33. The aortic valve 35 consists of three leaflets, although only two are shown in FIG. A space surrounded by the three leaflets 31 is called a valve opening 37. The area of the valve port 37 in the cross section passing through the three valve leaflets 31 is called the valve port area. In other words, the area within the valve port contour on the cross section is the valve port area. A space between each leaflet 31 and the inner wall of the aorta 35 is called an aortic sinus (so-called sinus of valsalva) 39.

  As shown in FIG. 3, when the left ventricle contracts (for example, at the end systole), the normal aortic valve 31 opens. On the other hand, when the left ventricle relaxes (for example, at the end diastole), the normal aortic valve 31 is closed as shown in FIG.

  An aortic valve with valvular disease does not operate normally and does not close completely or open completely. For example, in the case of valve stenosis, the aortic valve does not open completely even at the end systole. In the case of occlusion failure, the aortic valve does not close completely even at the end diastole. That is, the valve opening area can be an index for evaluating whether or not valvular disease has developed in the heart.

  As shown in FIG. 1, the image processing apparatus 1 includes a storage unit 11, a cross-section setting unit 13, a contour extraction unit 15, an evaluation circle generation unit 17, a valve pixel identification unit 19, a colored evaluation circle generation unit 21, and three-dimensional image processing. Unit 23, operation unit 25, display unit 27, and control unit 29.

  The storage unit 11 stores three-dimensional image data (volume data) related to the heart region of the subject. The three-dimensional image data is collected by a diagnostic modality such as an X-ray computed tomography apparatus, a magnetic resonance imaging apparatus, an X-ray diagnostic apparatus, or an ultrasonic diagnostic apparatus. In order to specifically carry out the following description, it is assumed that the diagnostic modality for collecting data of a three-dimensional image is an X-ray computed tomography apparatus. The X-ray computed tomography apparatus, for example, dynamically scans a heart contrasted with a contrast agent with X-rays and collects data of a plurality of three-dimensional images related to a plurality of cardiac phases corresponding to at least one heartbeat. The storage unit 11 stores the three-dimensional image data and the cardiac phase in association with each other.

  The cross-section setting unit 13 crosses the blood vessel region of the aorta where the contrast is enhanced by the contrast agent in accordance with an instruction through the image processing or the operation unit 25 by the user (hereinafter referred to as an evaluation cross-section). Is set in the three-dimensional image. In other words, the evaluation cross section is set in the vicinity of the valve opening and the aortic sinus.

  The contour extracting unit 15 extracts the contour of the blood vessel region from the blood vessel region on the evaluation section (hereinafter referred to as the valve position blood vessel contour) by existing image processing.

  The evaluation circle generation unit 17 generates an aortic valve template (hereinafter referred to as an evaluation circle) that schematically represents the shape of the aortic valve based on the valve position blood vessel contour. The evaluation circle is an image in which the shape of the normal aortic valve in the open state and the shape of the normal aortic valve in the closed state are drawn on the evaluation cross section.

  The valve pixel specifying unit 19 searches for pixels related to the aortic valve (hereinafter referred to as valve pixels) included in the three-dimensional image for each pixel constituting the evaluation circle along the predetermined direction. Specify whether it exists. The predetermined direction is set, for example, in the vertical direction of the cross section. Hereinafter, information on whether or not there is a valve pixel is referred to as valve opening / closing information. That is, the valve pixel specifying unit 19 generates valve opening / closing information for each pixel constituting the cross section.

  Based on the evaluation circle and the valve opening / closing information, the colored evaluation circle generating unit 21 represents an image (hereinafter, referred to as a colored evaluation circle) that expresses the degree of opening / closing of the aortic valve of the subject for each pixel. Generate. Specifically, the colored evaluation circle generation unit 21 includes an opening / closing index calculation unit 211 and a color information allocation unit 213. The opening / closing index calculation unit 211 calculates an index (hereinafter referred to as an opening / closing index) indicating the degree of opening / closing of the subject's aortic valve based on the evaluation circle and the valve opening / closing information. The open / close index represents, for example, the degree of difference between the open / closed degree of the subject's aortic valve and the normal open / closed degree of the aortic valve. The color information allocation unit 213 allocates color information corresponding to the calculated opening / closing index to pixels on the evaluation circle in order to generate a colored evaluation circle. Thereby, a colored evaluation circle is generated.

  The three-dimensional image processing unit 23 performs three-dimensional image processing on the three-dimensional image data and generates two-dimensional CT image data. As the three-dimensional image processing, for example, MPR (multi planar reconstruction) or volume rendering is employed. For example, the three-dimensional image processing unit 23 generates MPR image data related to the evaluation slice based on the three-dimensional image data.

  The operation unit 25 receives various commands and information input from the user. As the operation unit 25, a pointing device such as a mouse or a trackball, a selection device such as a mode switch, or an input device such as a keyboard can be used as appropriate.

  The display unit 27 displays a colored evaluation circle, an MPR image, a volume rendering image, and the like on a display device. As the display device, for example, a CRT display, a liquid crystal display, an organic EL display, a plasma display, or the like can be used as appropriate.

  The control unit 29 functions as the center of the image processing apparatus 1. When the control unit 29 receives a request for starting the quantitative evaluation process from the operation unit 25, the control unit 29 controls each unit in the image processing apparatus 1 to execute the quantitative evaluation process of the aortic valve.

  Note that the image processing apparatus 1 can use a general-purpose computer device as basic hardware. The image processing device 1 can realize quantitative evaluation processing of the aortic valve by a processor (CPU: central processor unit) mounted on the computer device executing an image processing program. The image processing program is preinstalled in the computer device. Alternatively, the image processing program may be recorded on a removable recording medium such as a magnetic disk, a magneto-optical disk, an optical disk, or a semiconductor memory and distributed to the computer apparatus 1 or distributed to the computer apparatus 1 via a network. May be. The distributed image processing program is implemented by being appropriately installed in the computer apparatus 1. Note that part or all of the above-described units can be realized by hardware such as a logic circuit. Each of the above units can also be realized by combining hardware and software control.

  Next, an operation example of the image processing apparatus 1 will be described. FIG. 5 is a diagram showing a typical flow of the aortic valve quantitative evaluation processing executed under the control of the control unit 29.

  When the user gives an instruction to start quantitative evaluation processing of the aortic valve via the operation unit 25, the control unit 29 performs processing from a plurality of three-dimensional image data stored in the storage unit 11. Read the data of the target three-dimensional image. The three-dimensional image to be processed can be applied to any cardiac phase. Further, the number of three-dimensional images to be processed is not limited to one and may be plural. In the case of a plurality, the following processing is performed on each three-dimensional image. The three-dimensional image to be processed can be arbitrarily set by the user, for example, by specifying the cardiac phase via the operation unit 25.

  When the three-dimensional image data is read, the control unit 29 supplies the read three-dimensional image data to the cross-section setting unit 13 and causes the cross-section setting unit 13 to perform cross-section setting processing (step S1). In step S1, the cross section setting unit 13 sets an evaluation cross section in the blood vessel region in accordance with an instruction from the user via the operation unit 25 or by image processing. Some specific examples of the cross-section setting process are given below.

    Section setting processing 1: The user directly designates the position of the evaluation section via the operation unit 25. For example, as shown in FIG. 6, the user moves the operation unit 25 to a position that is in the vicinity of the aortic valve region 41 or the valve mouth region 43 and that has advanced from the valve mouth region 43 to the back side of the aortic region 45 by about several millimeters. To specify. When the position is designated, the cross-section setting unit 13 sets the evaluation cross-section 47 so as to include the designated position. For example, the cross-section setting unit 13 sets the evaluation cross-section 47 so as to include the designated position and to be orthogonal to the blood vessel core line 49. The aortic valve region 41 is a pixel region belonging to a CT value range that can be taken by the aortic valve. The valve opening region 43 is a pixel region that belongs to a CT value range that can be taken by the blood vessel of the valve opening portion in which the contrast is enhanced by the contrast agent. The aorta region 45 is a pixel region belonging to a CT value range that can be taken by an aortic blood vessel whose contrast is enhanced by a contrast agent. The left ventricular region 51 is a pixel region belonging to a CT value range that can be taken by the blood flow path in the left ventricle in which the contrast is enhanced by a contrast agent. That is, the valve mouth region 43, the aorta region 45, and the left ventricle region 51 belong to substantially the same CT value range.

    Section setting process 2: The user indirectly specifies an evaluation section via the operation unit 25. For example, the user designates an aortic arch in the aortic region that is easy to visually recognize on the CT image. The cross-section setting unit 13 executes region generation processing starting from the designated position of the aortic arch, and extracts the aortic arch and left ventricular region from the three-dimensional image. The cross-section setting unit 13 specifies the valve region based on the anatomical structure from the extracted aortic arch and left ventricular region. Then, the cross-section setting unit 13 sets an evaluation cross-section at a position that has advanced to the back side of the aorta by several millimeters from the identified valve opening region. Also in this case, the evaluation cross section is set to be orthogonal to the blood vessel core line, for example.

  When there are a plurality of three-dimensional images to be processed, a plurality of evaluation sections related to the plurality of three-dimensional images are set at the same position or the same coordinates anatomically.

  When step S1 is executed, the control unit 29 causes the contour extraction unit 15 to perform contour extraction processing (step S2). In step S <b> 2, the contour extraction unit 15 extracts the valve-position blood vessel 53 from the aorta region 45 on the evaluation section 47 as shown in FIG. 7. Specifically, the contour extraction unit 15 performs binarization processing on the aorta region 45 on the evaluation section 47, and extracts the outer contour 53 of the aorta region 45 as the valve position blood vessel contour. The valve opening position blood vessel contour 53 typically has a shape in which three arcs are combined. Data of an image (hereinafter referred to as a contour image) in which the valve-position blood vessel contour 53 is drawn is supplied to the evaluation circle generation unit 17 by the control unit 29.

  When step S2 is executed, the control unit 29 causes the evaluation circle generation unit 17 to execute an evaluation circle generation process (step S3). In step S3, the evaluation circle generation unit 17 generates an evaluation circle based on the valve position blood vessel contour extracted in step S2. First, as shown in FIG. 8, the evaluation circle generation unit 17 specifies three cusps 55 on the valve mouth position blood vessel contour 53. The cusp 55 is specified, for example, according to an instruction from the user via the operation unit 25 or by image processing. Here, the three cusps 55 are referred to as a cusp 55A, a cusp 55B, and a cusp 55C, respectively. When the three cusps 55 (the cusp 55A, the cusp 55B, and the cusp 55C) are specified, the evaluation circle generation unit 17 calculates a circle 57 that is in contact with the three specified cusps 55, and is calculated. A circle 57 is drawn on the contour image. The circle 57 is a circle having the maximum diameter among the circles that fit within the valve opening position blood vessel contour 53. When the circle 57 is drawn, the evaluation circle generation unit 17 connects all two points of the center point 59, the point 55A, the point 55B, and the point 55C of the circle 57 as shown in FIG. A straight line 61 (straight line 61A, straight line 61B, straight line 61C, straight line 61D, straight line 61E, straight line 61F) is drawn on the contour image. When the straight line 61 is drawn, the evaluation circle generation unit 17 deletes the valve-position blood vessel contour from the contour image as shown in FIG. As a result, an evaluation circle 63 is generated. Note that the valve position blood vessel contour does not necessarily need to be deleted in the generation process of the evaluation circle 63, and an evaluation circle having the valve position blood vessel contour remaining as shown in FIG. 9 may be used.

  Triangle 65A (triangle formed by straight lines 61A, 61D, and 61E), triangle 65B (triangle formed by straight lines 61B, 61E, and 61F), triangle 65C (triangle formed by straight lines 61C, 61F, and 61D) As schematically shown in FIG. 4, the shape of the normal leaflet at the end diastole is schematically represented. The triangle inscribed in the circle 57 (the triangle formed by the straight lines 61A, 61B, and 61C) is a normal valve leaflet shape at the end systole, in other words, the valve mouth contour, as can be seen from comparison with FIG. The shape of is schematically represented. Here, the triangle 65A, the triangle 65B, and the triangle 65C are assumed to be estimated normal leaflets. As described above, the evaluation circle 63 schematically represents the estimated shape of the normal heart valve at the time of opening and the estimated shape of the normal heart valve at the time of occlusion.

  Note that the triangle 65A, the triangle 65B, and the triangle 65C on the evaluation circle are formed based on the actual valve mouth position blood vessel contour of the subject, and may not have the same shape. In this case, the evaluation circle generation unit 17 may adjust (normalize) the shapes of the triangle 65A, the triangle 65B, and the triangle 65C so that the triangle 65A, the triangle 65B, and the triangle 65C all have the same shape. .

  When step S3 is executed, the control unit 29 causes the valve pixel specifying unit 19 to execute a valve pixel specifying process (step S4). In step S4, as shown in FIG. 11, the valve pixel specifying unit 19 searches the valve pixels included in the three-dimensional image within a limited range along the predetermined search direction for each pixel constituting the evaluation circle, Whether or not there is a pixel, that is, whether the heart valve is opened or closed is specified. Here, the valve pixel is a pixel on the aortic valve region 41. The search direction is defined, for example, in the direction perpendicular to the cross section 47 (that is, the evaluation cross section) of the evaluation circle. The limit range is about 30 mm. The search direction and the limit range can be arbitrarily set by the user via the operation unit 25. For example, the aortic valve region 41 exists within a limited range along the search direction A from the pixel A on the evaluation circle 63. Therefore, the pixel A is specified as having a valve pixel. In this case, the valve pixel specifying unit 19 assigns to the pixel A on the evaluation circle 63 close information indicating that a valve pixel exists. Further, the aortic valve region 41 does not exist within the limited range along the search direction B from the pixel B on the evaluation circle 63. Accordingly, the pixel B is specified as having no valve pixel. The valve pixel specifying unit 19 assigns to the pixel B open information indicating that no valve pixel exists. Here, a pixel area to which open information is assigned is referred to as a leaflet non-existing area, and a pixel area to which closed information is assigned is referred to as a valve leaflet existing area. By assigning the opening / closing information to the evaluation circle 63 in this way, a leaflet non-existing region 67 and a leaflet presenting region 69 are provided on the evaluation circle 63, for example, as shown in FIG.

  When step S4 is executed, the control unit 29 causes the open / close index calculation unit 211 of the colored evaluation circle generation unit 21 to execute an open / close index calculation process (step S5). In step S5, the open / close index calculation unit 211 calculates the open / close index of the heart valve of the subject based on the open / close information and the evaluation circle specified in step S4. The calculated opening / closing index is stored in the storage unit 11 in association with the cardiac phase. The opening / closing index is calculated as follows, for example.

  First, as shown in FIG. 13, the open / close index calculation unit 211 examines the open / close state of the heart valve in the vertical direction from the bases 61A, 61B, 61C of the triangles 65 (triangles 65A, 65B, 65C). Specifically, the open / close index calculation unit 211 searches the leaflet non-existing region 67 along the search direction for each unit pixel constituting the bases 61A, 61B, 61C. The search direction is, for example, the vertical direction of the bottom side. The unit pixel is a pixel group including a predetermined number (for example, 10) of pixels on the bottom side. Note that the search direction and unit pixel can be arbitrarily set by the user via the operation unit 25. The opening / closing index calculation unit 211 calculates an opening / closing index based on the search result. The opening / closing index is calculated based on, for example, the shortest distance x between the unit pixel on the bottom side and the side facing the bottom side, and the shortest distance y from the pixel on the bottom side to the leaflet non-existing region along the search direction. . More specifically, the opening / closing index z is an index calculated based on the following equation (1), for example, and is expressed as a percentage.

z = (y / x) × 100 (1)
Note that if the leaflet non-existing region is not searched, y = x. Therefore, when the aortic valve is completely closed, the opening / closing index z = 100%. On the other hand, when the aortic valve is completely open, y = 0 and the opening / closing index z = 0%.

  The open / close index calculation unit 211 may calculate an open / close index for each triangle 65. The open / close index for each triangle 65 is a simple average value of the open / close indices of a plurality of unit pixels on the base of the triangle to be calculated, or a weighted average value corresponding to the position on the base.

  Note that the opening / closing index is not limited to that defined by the above-described equation (1) as long as it represents the degree of difference between the opening / closing degree of the subject's aortic valve and the normal opening / closing degree of the aortic valve. For example, the opening / closing index may be expressed by a simple ratio between the shortest distance x and the shortest distance y. The open / close index is calculated based on the difference between the shortest distance x and the shortest distance y (the amount of positional deviation between the normal leaflet contour and the actual leaflet contour), and is calculated according to the distance in units of millimeters or pixels. It may be expressed. Alternatively, the open / close index may be simply expressed by the shortest distance y in units of millimeters or pixels.

  When step S5 is executed, the control unit 29 causes the color information assigning unit 213 of the colored evaluation circle generating unit 21 to execute the color information assigning process (step S6). In step S6, the color information assigning unit 213 plots the calculated opening / closing index on the corresponding pixels on the evaluation circle. Specifically, the color information allocating unit 213 holds a table in which opening / closing indexes and color information are associated with each other. The color information allocation unit 213 identifies color information associated with the calculated opening / closing index on the table, and plots the identified color information on the allocation target pixels. The pixel to be allocated is a pixel on the evaluation circle, and is a pixel on the search path when the opening / closing index is calculated. That is, one color information is allocated on one search path. If the position of the base is different, different color information may be assigned.

  When step S6 is executed, the control unit 29 causes the display unit 27 to execute display processing (step S7). In step S7, the display unit 27 displays a colored evaluation circle with a preset display pattern. The display unit 27 prepares various display patterns for improving the evaluation accuracy and efficiency of the degree of opening and closing. Hereinafter, a specific display pattern of the colored evaluation circle by the display unit 27 will be described.

    Display Pattern 1: FIG. 14 is a diagram showing a display pattern 1 of a colored evaluation circle displayed by the display unit 27. As shown in FIG. 14, the display unit 27 displays a colored evaluation circle 71 related to the end diastole of one heartbeat, displays a colored evaluation circle 73 related to the end systole, or both colored evaluation circles 71 and 73. Are displayed at the same time. The end-diastolic colored evaluation circle 71 is specified as having the maximum valve area among a plurality of colored evaluation circles for one heartbeat, and the end-systolic colored evaluation circle 73 is a plurality of colored evaluation circles for one heartbeat. For example, the display unit 27 identifies the one having the smallest valve opening area. The end diastole and end systole can be arbitrarily designated via the operation unit 25. The display unit 27 may display an end-diastolic MPR image 75 aligned with the colored evaluation circle 71 and an end-systolic MPR image 77 aligned with the colored evaluation circle 73. The MPR images 75 and 77 are generated by the three-dimensional image processing unit 23. This relates to the same cross section as the colored evaluation circles 71 and 73 (that is, the evaluation cross section set in step S1). The display unit 27 superimposes the triangular outline (estimated normal leaflet position) on the colored evaluation circles 71 and 73 on the MPR images 75 and 77 so that the degree of opening and closing can be visually evaluated on the MPR images 75 and 77 as well. Should be displayed.

  As shown in FIG. 14, the colored evaluation circles 71 and 73 represent the spatial distribution of the degree of opening and closing of the aortic valve by the difference in color. Therefore, the user can grasp the partial opening / closing degree of the aortic valve by the color by observing the colored evaluation circles 71 and 73. Therefore, the user can sensuously evaluate the degree of opening and closing. At this time, in the vicinity of the colored evaluation circles 71 and 73, the display unit 27 has color bars 79 and 81 indicating the correspondence between the opening / closing index and the color in order to show the correspondence between the opening / closing index and the color to the user. It should be displayed. The display unit 27 may display the triangle opening / closing index calculated in step S5 (for example, the average opening / closing index within the triangle) in the vicinity of each triangle in the colored evaluation circles 71 and 73. For example, in the end-diastolic colored evaluation circle 71, 50% is displayed near the left triangle, 90% is displayed near the right triangle, and 70% is displayed near the lower triangle. Thus, by displaying the triangular opening / closing index, the user can evaluate the opening / closing degree of the heart valve not only as a color but also as a number. The cardiac phase of the colored evaluation circle to be displayed in the display pattern 1 is not limited to the end diastole or the end systole but may be any cardiac phase.

    Display Pattern 2 FIG. 15 is a diagram showing a display pattern 2 of colored evaluation circles displayed by the display unit 27. As shown in FIG. 15, the colored evaluation circles 83 and 85 of the display pattern 2 are colored according to the magnitude relationship with the threshold value. Specifically, a pixel having an opening / closing index larger than a threshold is displayed in a first color (for example, red), and a pixel having an opening / closing index smaller than the threshold is displayed in a second color (for example, blue). The In other words, the color information assigning unit 213 assigns color information corresponding to the first color to pixels having an opening / closing index larger than the threshold, and corresponds to the second color to pixels having an opening / closing index smaller than the threshold. Color information to be assigned. This threshold value is displayed by the display unit 27. For example, the display unit 27 displays sliders 87 and 89 indicating threshold values on the color bars 91 and 93. In this case, the sliders 87 and 89 are slid on the color bars 91 and 93 via the operation unit 25, whereby the threshold value is changed to a numerical value corresponding to the position of the sliders 87 and 89. Alternatively, the display unit 27 may simply display a numerical value indicating the threshold value. In this case, the threshold value is changed by inputting a numerical value indicating the threshold value via the operation unit 25. As described above, in the display pattern 2, the evaluation circle is colored according to the magnitude relationship with the threshold value. By observing the coloring evaluation circles 83 and 85, the valve leaflet portion having a better opening / closing degree than the threshold value and the bad valve leaflet. The site can be easily grasped visually. By setting the threshold appropriately clinically, it is possible to easily identify the leaflet portion having a functional disorder. Note that the number of thresholds is not limited to one and may be plural. As the number of thresholds increases, the number of display colors of the colored evaluation circle also increases. For example, when there are two threshold values, there are three display colors. The cardiac phase of the colored evaluation circle to be displayed in the display pattern 2 is not limited to the end diastole or the end systole but may be any cardiac phase.

    Display Pattern 3 FIG. 16 is a diagram showing a display pattern 3 of colored evaluation circles displayed by the display unit 27. As shown in FIG. 16, in the case of the display pattern 3, the display unit 27 displays a leaflet region contour (hereinafter referred to as a leaflet contour) 95 relating to the same cardiac phase as the evaluation circle 95 as a colored evaluation circle 71. Display overlaid on top. The leaflet contour 95 is extracted by the contour extraction unit 15 from the MPR image related to the evaluation cross section. Thus, by displaying the leaflet contour 95 on the colored evaluation circle 71, the user can more easily and accurately evaluate the degree of opening and closing of the heart valve, and the reliability of the evaluation of the degree of opening and closing. Improves. Note that the colored evaluation circle to be displayed in the display pattern 3 is not limited to the colored evaluation circle at the end diastole, and can be applied to a colored evaluation circle having an arbitrary cardiac phase. Note that the cardiac phase of the colored evaluation circle to be displayed in the display pattern 3 is not limited to the end diastole, and may be any cardiac phase. The display unit 27 may display a plurality of leaflet contours related to a plurality of cardiac phases on one colored evaluation circle.

    Display Pattern 4: FIG. 17 is a diagram showing a display pattern 4 of colored evaluation circles displayed by the display unit 27. As shown in FIG. 17, the colored evaluation circles 97 and 99 of the display pattern 4 are colors corresponding to the amount of positional deviation from the normal leaflet contour (the difference between the shortest distance x and the shortest distance y in equation (1)). Is displayed. The displacement amount is displayed in millimeters [mm].

  By using the display patterns 1 to 4, the user can easily and quantitatively evaluate the properties of the heart valve by observing the colored evaluation circle related to the cardiac phase being displayed. Therefore, the image processing apparatus 1 can improve the user's work efficiency and diagnosis accuracy in the determination of the treatment policy for valvular disease and the treatment plan.

    Display Pattern 5: FIG. 18 is a diagram showing a display pattern 5 of colored evaluation circles displayed by the display unit 27. As shown in FIG. 18, in the case of the display pattern 5, the display unit 27 displays a plurality of colored evaluation circles related to a plurality of cardiac phases as a moving image. Specifically, under the control of the control unit 29 described above, colored evaluation circles relating to a plurality of cardiac phases for at least one heartbeat are generated and stored in the storage unit 11. The display unit 27 displays the colored evaluation circle stored in the storage unit 11 as a moving image in time series. At this time, the colored evaluation circle may be displayed together with the color bar as described above. For example, the display speed is not limited to normal 1 × speed, but can be low speed playback such as 0.5 × speed and high speed playback such as 2 × speed. The display speed can be arbitrarily changed via the operation unit 25. The moving image display allows the user to grasp the temporal change in the degree of opening and closing the heart valve as a color change. In addition, when an instruction to stop moving image display is issued via the operation unit 25, the display unit 27 can stop displaying the moving image and continue to display the colored evaluation circle that was displayed when the stop instruction was issued. It is. The colored evaluation circle of the display pattern 5 can correspond to any of the display patterns 1 to 4.

    Display Pattern 6 FIG. 19 is a diagram showing a display pattern 6 of colored evaluation circles displayed by the display unit 27. As shown in FIG. 19, in the case of the display pattern 6, the display unit 27 displays an electrocardiogram waveform and a waveform of an opening / closing index together with a moving image of a colored evaluation circle. More specifically, a display area 101 for the electrocardiogram waveform 107, a display area 103 for the waveform 109 of the opening / closing index, and a display area 105 for the colored evaluation circle 71 are arranged on the display screen. In the display area 103, in addition to the waveform 109 of the opening / closing index relating to the subject, a waveform 111 of the opening / closing index relating to the healthy subject may be displayed for comparison between the healthy subject and the subject. The waveform 111 may be generated by the above-described steps, may be calculated theoretically, or may be created empirically. The open / close index waveforms 109 and 111 are defined such that the horizontal axis is time and the vertical axis is the open / close index.

  Knowing which position on the electrocardiogram waveform 107 or the waveform 109 or 111 of the open / close indicator waveform the heart phase of the colored evaluation circle being displayed is useful for evaluating the degree of open / close. As described above, the colored evaluation circle 71 and the opening / closing index are stored in the storage unit 11 in association with the cardiac phase. Using this association, the display unit 27 displays the slider 113 indicating the cardiac phase of the colored evaluation circle 71 being displayed on the electrocardiogram waveform 107 and the graphs 109 and 111 of the open / close index. The slider 113 is moved along the horizontal axis of the electrocardiogram waveform 107 and the waveform 109 and 111 of the open / close indicator according to the switching of the displayed colored evaluation circle 71. The colored evaluation circle 71 of the display pattern 6 can correspond to any of the display patterns 1 to 4.

  By using the display patterns 5 and 6, the user can determine a treatment policy or a treatment plan for valvular disease in consideration of the degree of opening and closing related to a plurality of cardiac phases. Therefore, even if it seems to be severe in one cardiac phase, if it is mild in multiple cardiac phases, the necessity / unnecessity of treatment can be examined.

  Thus, the image processing apparatus according to the present embodiment can improve the work efficiency and diagnostic accuracy related to valvular diseases by doctors and engineers.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

(Modification 1)
The display unit 27 according to the first modification displays a colored MPR image 115 as shown in FIG. The colored MPR image 115 is an MPR image in which color information is assigned by the color information assigning unit 213 according to the opening / closing information specified in step S4 described above. A method for generating the colored MPR image 115 will be described below.

  First, the valve pixel specifying unit 19 maps information on whether or not there is a valve pixel in the MPR image related to the evaluation section. Specifically, the valve pixel specifying unit 19 opens and closes the heart valve (that is, whether there is a valve pixel in the vertical direction of the evaluation section) for the pixels of the MPR image related to the evaluation section by the same method as in step S4. Identify. Close information is assigned to the pixel specified if there is a valve pixel, and open information is assigned to the pixel specified if there is no valve pixel. When the open information or the close information is assigned to the MPR image, the coloring information assigning unit 33 corresponds to the color information corresponding to the open information to the pixel to which the open information is assigned, and corresponds to the close information to the pixel to which the close information is assigned. Assign color information. As a result, a colored MPR image 115 is generated. The display unit 27 displays the colored MPR image 115. For example, a pixel region (valve leaflet existing region) 67 to which closed information is assigned is displayed in blue, and a pixel region (valve leaflet non-existing region) 69 to which open information is assigned is displayed in red. By displaying the colored MPR image, the user can determine the three-dimensional open / close state of the heart valve by color on the two-dimensional MPR image.

(Modification 2)
In the present embodiment, the heart valve is an aortic valve. Therefore, the number of leaflets is assumed to be three. However, the number of leaflets in the present embodiment is not limited to three and can be changed as appropriate according to the type of heart valve. Along with this, the shape of the leaflets can be changed from a triangle to another geometric shape such as a quadrangle.

  In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 11 ... Memory | storage part, 13 ... Section setting part, 15 ... Contour extraction part, 17 ... Evaluation circle production | generation part, 19 ... Valve pixel specific | specification part, 21 ... Colored evaluation circle production | generation part, 211 ... Opening / closing index calculation Part, 213 ... color information assigning part, 23 ... three-dimensional image processing part, 25 ... operation part, 27 ... display part, 29 ... control part

Claims (7)

A storage unit for storing a three-dimensional image related to the heart region of the subject;
A setting unit for setting a cross section in a blood vessel region included in the heart region;
An extraction unit that extracts an outline of the blood vessel region from the blood vessel region in the cross section by image processing;
A first generation unit that generates a schematic valve image that schematically represents the shape of the heart valve based on the shape of the contour;
For each pixel constituting the schematic valve image, a search unit that searches for a valve pixel related to the heart valve included in the three-dimensional image along a predetermined direction, and specifies whether or not the valve pixel exists;
A second generation unit that generates a color image that expresses the degree of opening and closing of the heart valve for each pixel based on the schematic valve image and information on whether or not the valve pixel exists;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, further comprising a display unit that displays the color image.   The image processing apparatus according to claim 1, wherein the schematic valve image schematically represents an estimated shape of a normal heart valve in an open state and an estimated shape of a normal heart valve in a closed state.   The image processing apparatus according to claim 1, wherein the second generation unit assigns color information corresponding to a degree of difference between an opening / closing degree related to a heart valve of the subject and an opening / closing degree related to a normal heart valve for each pixel. The second generation unit generates the color image for a plurality of cardiac phases.
The display unit displays a moving image of the color images related to the plurality of cardiac phases.
The image processing apparatus according to claim 2. The extraction unit further extracts an outline of the heart valve region from the heart valve region on the evaluation section by image processing,
The display unit displays the contour of the heart valve region on the color image,
The image processing apparatus according to claim 2. A storage unit for storing a three-dimensional image related to the heart region of the subject;
A setting unit for setting a cross section that intersects a blood vessel region included in the heart region in the three-dimensional image;
A first generator that generates a cross-sectional image related to the cross-section based on the three-dimensional image;
Searching for a valve pixel related to a heart valve included in the three-dimensional image along a predetermined direction from the cross section, and a specifying unit for specifying the presence or absence of the valve pixel for each pixel constituting the cross section image;
A second generation unit that generates a color image expressing whether or not the valve pixel exists for each pixel based on the cross-sectional image and the presence or absence of the valve pixel;
An image processing apparatus comprising:

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