JP5701556B2 - Image processing apparatus, method, and computer program - Google Patents

Description

  The present invention relates to an image processing technique for processing an RI planar image, and more particularly to a technique for automatically setting a mediastinum ROI.

  As radiopharmaceuticals having the property of accumulating in the myocardium (hereinafter sometimes referred to as RI (Radio Isotopes) drugs), MIBG (3-iodobenzylguanidine), MIBI (technetium hex-2-isoisotrimethyl), or lithium chloride ) Etc.

  For example, after administering MIBG to a subject, the heart / mediastinum comparing the mean count value of the heart region and the mean count value of the mediastinum region from an RI planer image obtained by detecting the radioactivity released from the subject. The ratio (Heart / Mediasteinum ratio, H / M ratio) is obtained. This H / M ratio is used for diagnosis, severity and prognosis evaluation of subjects with heart disease (Non-Patent Documents 1 to 3). Furthermore, even in neurological diseases, it is used when distinguishing Lewy body disease (Non-patent Document 4).

  In MIBI, it is used to evaluate myocardial injury in heart diseases such as ischemic heart disease, heart failure, and cardiac sarcoidosis by quantifying washing from the myocardium. In that case, from the myocardium obtained from the count value of the early image taken in the first time zone after the RI drug administration and the count value of the later image taken in the second time zone after the first time zone. A myocardial washout rate (Washout rate, WR) indicating the ratio of the RI drug washed out is used as an index. In other radiopharmaceuticals such as thallium chloride, the H / M ratio may be used for diagnosis to measure myocardial uptake.

Cardiovascular Society of Japan, Guidelines for Diagnosis and Treatment of Cardiovascular Diseases (2003-2004 Joint Research Group Report) “Cardiac Nuclear Medicine Examination Guidelines”, Circulation Journal Vol. 69, Suppl. IV, 1125-1202, 2006 Heart failure and sympathetic nerve function Image diagnosis from pathophysiology to prognosis evaluation "MIBG test and quantitative method", Kenichi Nakajima, 34-42, 2002, Medical View How to evaluate sympathetic nerve activity in clinical practice-Sympathetic nerve imaging of heart disease by MIBG, Naoya Fukuyama, Heart View, 14 (8) 14-20, 2010 Special issue: MIBG myocardial scintigraphy and neurological diseases "Position of MIBG scintigraphy in neurological diseases", Junichi Taki, Neurology, 64 (6): 585-592, 2006

  By the way, in order to calculate the H / M ratio or WR, it is necessary to accurately specify the heart region and the mediastinum region in an RI (Radio Isotope) planar image. Therefore, conventionally, an operator visually observes an RI planer image, encloses an area considered to be a heart area in the image with a heart ROI (Region of Interest), and encloses an area assumed to be a mediastinum area with the mediastinum ROI. Has been done.

  At this time, since the heart region has a high count value, the variation in the setting of the heart ROI by the operator is not a problem. On the other hand, since the mediastinum region has a low count value, it is difficult for the operator to set the mediastinum ROI correctly by visual observation, and further, it is given to the H / M ratio or WR when the mediastinal ROI is displaced. The impact is great.

  Therefore, an object of the present invention is to automatically set the mediastinum ROI, thereby eliminating variations due to manual setting by the operator.

  Another object of the present invention is to calculate the H / M ratio without automatically setting the mediastinal ROI by calculating the H / M ratio using the automatically set mediastinal ROI. It is.

  Yet another object of the present invention is to calculate the WR without setting the mediastinal ROI by calculating the WR using the automatically set mediastinal ROI.

  An image processing apparatus according to one embodiment of the present invention includes means for storing image data of an RI (Radio Isotope) planar image obtained by photographing a subject who has been administered a radiopharmaceutical, and a centerline of the subject's body in the RI planar image Means for determining a central region of the subject's body, means for generating a profile curve of the central region of the subject's body using image data of the RI planar image, and Based on a profile curve, a mediastinal ROI in the RI planer image based on a means for specifying a vertical mediastinal reference position in the subject's body, a center line of the subject's body, and the mediastinal reference position Means for setting.

  In a preferred embodiment, the radiopharmaceutical may be MIBG (3-iodobenzylguanidine).

  In a preferred embodiment, a chest region including left and right lung regions of the subject in the RI planer image is specified, and a profile curve of the chest region is generated using image data of the RI planer image of the chest region. Means for determining a centerline of the subject's body in the RI planer image based on a profile curve of the chest region, the means for determining the center region of the body comprising: The central region may be a belt-like region centered on the center line of the subject's body detected by the means for determining the central line.

  In a preferred embodiment, the orientation of the subject's body in the RI planer image is an orientation of a predetermined reference direction, and the means for determining the center line is respectively applied to the left and right lungs in the profile curve of the chest region. The center line of the body may be determined based on a position where a minimum value between two corresponding maximum values is taken and the reference direction.

  In a preferred embodiment, the means for specifying the mediastinum reference position may set a position having a minimum value in a profile curve of the central region of the body as the mediastinum reference position.

  In a preferred embodiment, the means for setting the mediastinum ROI may be set so that at least a part of the central region is included in the mediastinum ROI based on the mediastinum reference position.

  In a preferred embodiment, based on the means for setting a heart ROI for identifying the heart region of the subject in the RI planer image, and the image data in the heart ROI and the image data in the mediastinum ROI, And a means for calculating a separation ratio (H / M ratio).

  In a preferred embodiment, the display device further comprises display means for displaying the RI planar image on a display device, and the means for setting the heart ROI is configured to display the RI planar image in the RI planar image displayed on the display device in accordance with an operator instruction. The heart region of the subject may be specified.

  An image processing apparatus according to an embodiment of the present invention includes storage means for storing image data of an RI (Radio Isotope) planar image obtained by photographing a subject administered with a radiopharmaceutical at different time zones, and the subject in the RI planar image. A profile for generating a profile curve of the center region of the subject's body using the center region determining means for determining the center region of the subject's body, including the center line of the subject's body, and image data of the RI planar image Curve generating means; mediastinal reference position specifying means for specifying a vertical mediastinal reference position in the subject's body based on a profile curve of the center region of the body; a centerline of the subject's body; and Mediastinal ROI setting for setting mediastinal ROI in the RI planar image based on mediastinal reference position A heart ROI setting means for setting a heart ROI for specifying a heart region of the subject in the RI planer image; and first and second RI planer images obtained by photographing the subject in different time zones in the storage means. When image data is stored, the image data in the heart ROI of the first and second RI planar images set by the heart ROI setting unit, the center region determining unit, the profile curve generating unit, the longitudinal The myocardial washout rate (WR) is calculated based on the image data in the mediastinal ROI of the first and second RI planar images set by the processing of the median reference position specifying unit and the mediastinal ROI setting unit. And calculating means.

  In a preferred embodiment, the central region determining means determines a central region of the subject's body in the first RI planar image, and the profile curve generating means is the subject's body in the first RI planar image. Generating a profile curve of the central region of the body, wherein the mediastinal reference position specifying means specifies the mediastinal reference position in the vertical direction of the subject's body in the first RI planer image, and the mediastinal ROI setting means Sets the mediastinal ROI in the first RI planar image based on the center line of the subject's body in the first planar image and the mediastinal reference position in the first planar image. Based on the position and size of the mediastinal ROI set in one RI planar image, the mediastinal ROI in the second RI planar image is set. It may be.

  In a preferred embodiment, the center region determining means determines the center region of the subject's body in the first and second RI planer images, respectively, and the profile curve generating means is the first and second Profile curves of the center region of the subject's body in the RI planer image are respectively generated, and the mediastinal reference position specifying means is the mediastinal reference in the vertical direction in the subject's body in the first and second RI planer images. Each position is specified, and the mediastinal ROI setting means determines the first RI planner based on the center line of the subject's body in the first planar image and the mediastinal reference position in the first planar image. A mediastinal ROI in the image is set, the center line of the subject's body in the second planar image, and the second planar image Based on the mediastinum reference position in, it may be set mediastinal ROI in the second RI Plana image.

1 is a diagram illustrating an overall configuration of an image processing apparatus 1 according to a first embodiment of the present invention. An example of the ROI setting screen 100 is shown. It is explanatory drawing of the right end setting process by the right end setting part. It is explanatory drawing of the upper end setting process by the upper end setting part. It is explanatory drawing of the centerline detection process by the centerline determination part. It is explanatory drawing of the detection processing of the mediastinum reference position by the mediastinum reference position detection part 27. FIG. It is explanatory drawing of the mediastinal ROI setting process by the mediastinal ROI setting part 29. FIG. 3 is a flowchart showing a processing procedure of the image processing apparatus 1. It is a figure which shows the whole structure of the image processing apparatus 8 which concerns on the 2nd Embodiment of this invention.

  Hereinafter, an image processing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  The image processing apparatus according to the first embodiment processes an RI planar image obtained by imaging a subject who has administered a specific RI drug, and calculates an H / M ratio. The image processing apparatus includes a mediastinum ROI setting device that automatically detects a mediastinum region of the RI planar image and sets the mediastinum ROI for calculating the H / M ratio.

  FIG. 1 shows an overall configuration of an image processing apparatus 1 according to the first embodiment. As shown in the figure, in the image processing apparatus 1, an input device 2 and a display device 3 are connected to an image processing apparatus main body 10. The image processing apparatus main body 10 is configured by a general-purpose computer system including a processor and a memory, for example, and individual components or functions in the image processing apparatus main body 10 described below execute, for example, a computer program Is realized. This computer program can be stored in a computer-readable recording medium.

  The image processing apparatus main body 10 includes an image data storage unit 11, an image adjustment unit 12, a heart ROI setting unit 13, a mediastinal ROI setting processing unit 20, an ROI data storage unit 15, and an H / M ratio calculation unit 17. With.

  The image data storage unit 11 stores image data of an RI planar image obtained by imaging a subject who has been administered MIBG (3-iodobenzylguanidine). This RI planar image is, for example, a two-dimensional image obtained by imaging a subject to which MIBG has been administered using an imaging device for RI planar images (not shown). Each pixel value of the image indicates a count value of RI.

  Here, the orientation of the subject's body in the RI planar image may be adjusted to a predetermined reference direction. For example, when the horizontal direction of the rectangular RI planar image is the X axis and the vertical direction is the Y axis, the center line (median line) of the body is set to be parallel to the Y axis.

  The operator can display an RI planer image on the display device 3 and visually check whether the center line (median line) of the body is parallel to the Y axis. When the center line (median line) of the body is not parallel to the Y axis, the image adjustment unit 12 performs adjustment according to the operation of the input device 2 by the operator. For example, the image adjustment unit 12 can rotate or translate the image around the center point of the image or an arbitrary point according to an instruction from the operator.

  The heart ROI setting unit 13 sets a heart ROI that identifies the heart region of the subject in the RI planer image. For example, the cardiac ROI setting unit 13 acquires image data stored in the image data storage unit 11 and causes the display device 3 to display an ROI setting screen including an RI planer image. Then, in accordance with an instruction from the operator using the input device 2, the heart region in the RI planer image is specified on the ROI setting screen and the heart ROI is set. The heart ROI setting unit 13 may automatically detect the heart region in the RI planer image and automatically set the heart ROI, or temporarily set the heart ROI in the automatically detected heart region. The operator may adjust the heart ROI temporarily set to make this setting.

  An example of the ROI setting screen 100 is shown in FIG. As shown in the figure, when the ROI setting screen 100 including the RI planer image G is displayed on the display device 3, the heart ROI setting unit 13 displays the heart region in a polygon according to the operation of the input device 2 by the operator. Set the surrounding heart ROI5. Alternatively, a circular ROI having a radius specified by the operator may be displayed at a position specified by the operator, and then, according to the operation of the operator, the circular ROI may be moved and / or deformed to set the heart ROI 5 surrounding the heart region. Either method may be selected before setting. When the execution button 101 on the ROI setting screen 100 is pressed, the mediastinal ROI setting and H / M ratio calculation processing described below may be automatically executed. That is, in this case, the operator simply sets the heart ROI, and the subsequent processing is automatically executed.

  Returning to FIG. 1, the mediastinum ROI setting processing unit 20 sets the mediastinum ROI that specifies the mediastinum region of the subject in the RI planer image.

  The mediastinum ROI setting processing unit 20 further includes a processing range setting unit 21, a center line determination unit 25, a mediastinum reference position detection unit 27, and a mediastinum ROI setting unit 29.

  The processing range setting unit 21 sets the processing range in order to limit the region to be processed in the RI planer image in the mediastinal ROI setting processing. The processing range setting unit 21 includes a right end setting unit 22 and an upper end setting unit 23.

  The right end setting unit 22 sets the right end of the subject for limiting the processing range of subsequent processing in the RI planer image. For example, the right end setting unit 22 may detect the right end of the subject's liver. Since the subject's mediastinum is closer to the center of the body than the liver, in the following processing, the center of the body is set to the processing range from the detected right end of the liver.

  The right end setting process by the right end setting unit 22 will be described in detail with reference to FIG. The right end setting unit 22 is, for example, an image of a region A1 below a predetermined point in the Y axis direction within the heart ROI 5 such as the lower end of the heart ROI 5 set by the heart ROI setting unit 13 or the center point of the heart ROI 5 in the Y axis direction. A count profile curve P1 is drawn using the data, and the right end of the liver of the subject is detected based on the count profile curve P1.

  The count profile curve is drawn by the sum of all count values C in one column (or one row) of the same x (or y), where C (x, y) represents each pixel of the two-dimensional RI planar image. It is a profile curve. In this example, the count profile curve P1 is generated by the sum of the count values C in the Y-axis direction for each x in the region below the center height (heart center) 51 in the Y-axis direction in the heart ROI5.

  For example, in the example of FIG. 3, the right end setting unit 22 has a predetermined ratio value (for example, 20%) of the maximum value on the outside of the body (left side in the figure) from x1 that is the maximum value of the count profile curve P1. x2 is detected as the right edge of the liver. This is because MIBG has a property of accumulating in the liver, and the maximum value of the count profile curve below the heart is considered to be the liver. Hereinafter, the right end position of the liver becomes the right end 52 of the processing range.

  The count profile curve may be smoothed. The same applies to the case where the count profile curve is generated by the following processing. This is because a local maximum value or minimum value may exist in the count profile curve before smoothing, and a global maximum value or minimum value may not be detected.

  The upper end setting unit 23 sets the upper end of the subject that is the processing range in the RI planer image.

  The upper end setting process by the upper end setting unit 23 will be described in detail with reference to FIG. For example, the upper end setting unit 23 is higher than the center height (heart center) 51 in the Y axis direction of the heart ROI 5 and m times (for example, twice) the size of the heart ROI 5 in the Y axis direction from the heart center 51. The upper end 53 is set at the distance position. Empirically, the mediastinum exists below this position, so the region below the upper end position 53 is the processing target in the following processing.

  Returning to FIG. 1, the center line determination unit 25 determines the center line of the body of the subject in the RI planer image. For example, the center line determination unit 25 identifies a chest region including the left and right lung regions of the subject in the RI planer image, generates a count profile curve using the image data of this region, and the RI planer based on the profile curve. The center line of the subject's body in the image may be determined.

  The center line detection process performed by the center line determination unit 25 will be described in detail with reference to FIG. In the figure, the center line determination unit 25 sets a region A2 between the heart center 51 and the upper end position 53 as a processing target. That is, this region A2 is a chest region including the left and right lung regions of the subject. The center line determination unit 25 generates a profile curve P2 in the X-axis direction of this region A2. In the profile curve P2 of the chest region, the center line determination unit 25 determines a position that takes a minimum value between two maximum values respectively corresponding to the left and right lungs. This is because MIBG has the property of accumulating in the lung. Then, the center line determination unit 25 sets a line parallel to the Y axis passing through the position having the minimum value as the center line 55. The center line determination unit 25 further sets the left end 54 of the subject. For example, the center line determination unit 25 sets the left end 54 so that the distance from the center line 55 is equal to the distance from the right end 52 to the center line 55.

  The center line determination unit 25 may determine the center line by other methods. For example, on the ROI setting screen 100, a single point designation may be accepted from the operator as a center position, and a line passing through the accepted center position and parallel to the Y axis may be designated as the center line. The line passing through these two points may be used as the center line.

  Returning to FIG. 1, the mediastinal reference position detection unit 27 determines a mediastinal reference position for setting the mediastinal ROI. For example, the mediastinum reference position detection unit 27 generates a profile curve of the central region of the subject's body using image data of the RI planar image. The mediastinum reference position detection unit 27 specifies the mediastinum reference position in the vertical direction in the body of the subject based on the profile curve of the center region of the body. At this time, the mediastinal reference position detection unit 27 may set a position that takes the minimum value in the profile curve of the center region of the body as the mediastinal reference position. In addition, when determining the center region of the subject's body, the mediastinum reference position detection unit 27 uses the center line of the subject's body in the RI planer image, and determines the center region of the body so that this center line is included. May be.

  The mediastinal reference position detection process by the mediastinal reference position detection unit 27 will be described in detail with reference to FIG. The mediastinum reference position detection unit 27 sets the center region A3 including the center line 55 based on the center line 55 determined by the center line determination unit 25, for example. The center region A3 is a belt-like region centered on the center line 55, and the distance from the center line may be the same on the left and right. The width of the center region A3 may be set to a predetermined ratio (for example, 20%) of the width from the center line 55 to the right end 52, for example. The mediastinum reference position detection unit 27 generates a count profile curve P3 in the Y-axis direction of the center area A3. A position in the Y-axis direction where the value of the count profile curve P3 is minimum between the heart center 51 and the upper end position 53 is defined as a mediastinal reference position 57. This is because the mediastinum is the region where MIBG is most difficult to accumulate and the count value is small. The mediastinum reference position 57 substantially corresponds to the position of the upper end of the lung.

  The mediastinum ROI setting unit 29 sets the mediastinum ROI in the RI planar image based on the mediastinum reference position. The mediastinum ROI setting unit 29 may set the mediastinum ROI based on the mediastinum reference position 57 so as to include at least a part of the center region A3. For example, the mediastinum ROI setting unit 29 sets a rectangular mediastinum ROI having sides parallel to the X axis and the Y axis so that the upper end thereof coincides with the mediastinum reference position 57.

  The mediastinal ROI setting process by the mediastinal ROI setting unit 29 will be described in detail with reference to FIG. The mediastinum ROI setting unit 29 generates a profile curve P4 in the X-axis direction of the region A4 between the heart center 51 and the mediastinum reference position 57. The mediastinal ROI setting unit 29 sets the local minimum value between the two local maximum values of the profile curve P4 as the center position 59 of the mediastinal ROI6. As the center position, the center line 55 determined by the center line determination unit 25 may be used. The width in the X-axis direction of the mediastinum ROI 6 is a predetermined ratio (for example, 20%) of the distance from the right end 52 to the left end 54 so that the center position in the X-axis direction of the mediastinum ROI 6 coincides with the center position 59. It may be. The width of the mediastinal ROI 6 in the Y-axis direction is a predetermined ratio (for example, 30%) of the distance from the heart center 51 to the mediastinal reference position 57, and the upper end thereof coincides with the mediastinal reference position 57. Also good.

  Returning to FIG. 1, the ROI data storage unit 15 stores cardiac ROI data indicating the heart ROI 5 set by the heart ROI setting unit 13 and mediastinal ROI data indicating the mediastinum ROI 6 set by the mediastinal ROI setting processing unit 20. Remember. For example, the heart ROI data is a set of coordinates of points constituting a closed curve of the heart ROI, and the mediastinum ROI data is a set of coordinates of vertices of a rectangular mediastinum ROI.

  The H / M ratio calculation unit 17 calculates the H / M ratio based on the image data in the heart ROI 5 and the image data in the mediastinal ROI 6. For example, the H / M ratio calculator 17 calculates the average value of the count values in the heart ROI 5 (the value obtained by dividing the sum of the count values in the ROI by the number of pixels in the ROI, the same applies hereinafter), and the count in the mediastinal ROI 6 The average value of the values is calculated, and the ratio between the two is calculated using the average value of the count values in the mediastinum ROI 6 as the denominator. The H / M ratio calculated by the H / M ratio calculation unit 17 may be displayed on the display device 3.

  Next, the processing procedure of the image processing apparatus 1 having the above-described configuration will be described with reference to the flowchart of FIG.

  First, when the ROI setting screen 100 is displayed on the display device 3, the heart ROI setting unit 13 sets the heart ROI in the RI planar image G according to the operation of the operator (S10). The cardiac ROI setting unit 13 stores cardiac ROI data in the ROI data storage unit 15.

  After the setting of the heart ROI, when the execution button 101 is operated by the operator, the H / M ratio calculation process is started (S12).

  That is, the right end setting unit 22 sets the right end of the subject in the RI planar image G, and the upper end setting unit 23 sets the upper end of the processing range (S14).

  Next, the center line determination unit 25 detects the center line of the subject's body according to the distribution of the count values of the subject's chest region in the RI planar image G (S16). Further, the mediastinum reference position detection unit 27 sets the mediastinum reference position in the vertical direction according to the distribution of count values in the center region of the subject's body including the center line (S18).

  The mediastinum ROI setting unit 29 sets the mediastinum ROI based on the mediastinum reference position (S20). The mediastinal ROI setting unit 29 stores mediastinal ROI data in the ROI data storage unit 15.

  The H / M ratio calculation unit 17 calculates the H / M ratio based on the image data of the RI planar image G, the heart ROI data and the mediastinal ROI data in the ROI data storage unit 15 (S22). The H / M ratio calculated here is displayed and output on the display device 3.

  Thereby, when the operator sets the heart ROI in the RI planer image G, the image processing apparatus 1 automatically sets the mediastinum ROI, and the H / M ratio is automatically calculated using the mediastinum ROI. As a result, it is possible to suppress variations in the H / M ratio due to variations in the position setting of the mediastinal ROI. That is, the H / M ratio can be calculated stably regardless of the operator.

  Next, an image processing apparatus according to the second embodiment will be described. The image processing apparatus according to the second embodiment calculates a WR by processing a plurality of RI planar images obtained by photographing subjects to whom a specific RI drug has been administered in different time zones. The image processing apparatus according to the present embodiment includes the same mediastinal ROI setting apparatus as that of the image processing apparatus according to the first embodiment. In the following description, the same components as those of the image processing apparatus of the first embodiment may be denoted by the same reference numerals as those of the first embodiment, and description thereof may be omitted.

  FIG. 9 shows the overall configuration of the image processing apparatus 8 according to the second embodiment. As shown in the figure, in the image processing device 8, the input device 2 and the display device 3 are connected to the image processing device main body 80. The image processing apparatus main body 80 is configured by, for example, a general-purpose computer system including a processor and a memory. Individual components or functions in the image processing apparatus main body 80 described below execute, for example, a computer program. Is realized. This computer program can be stored in a computer-readable recording medium.

  The image processing device 8 includes an image data storage unit 11, an image adjustment unit 12, a cardiac ROI setting unit 13, a mediastinal ROI setting processing unit 20, an ROI data storage unit 15, and a WR calculation unit 19. The WR calculator 19 calculates a WR by processing a planar image obtained by imaging a subject to whom a specific RI drug is administered a plurality of times in different time zones.

  For example, the image data storage unit 11 includes an RI planer image (early image) taken in a first time zone after RI drug administration and an RI planer taken in a second time zone after the first time zone. Image data of an image (late image) is stored.

  The image adjustment unit 12 rotates and translates the early image and the late image around the center point of the image, or an arbitrary point, or a parallel point according to an instruction from the operator. Thereby, for example, it may be set so that the subjects of the early image and the late image are completely overlapped by visual observation by the operator.

  The mediastinum ROI setting processing unit 20 sets the mediastinum ROI of each image based on the image data of the early image and the late image stored in the image data storage unit 11. For example, the mediastinum ROI setting processing unit 20 may set the mediastinum ROI of each image by performing the processing described in the first embodiment individually on each of the early image and the later image. .

  The heart ROI setting unit 13 sets the heart ROI of each image based on the image data of the early image and the late image stored in the image data storage unit 11. For example, the heart ROI setting unit 13 may set the heart ROI in accordance with an instruction from the operator for each of the early image and the late image.

  The mediastinum ROI setting processing unit 20 and the heart ROI setting unit 13 set the mediastinum ROI and the heart ROI in the procedure described in the first embodiment for either the early image or the late image, and then The image may be set based on the mediastinal ROI and heart ROI set in advance. For example, when the mediastinal ROI setting processing unit 20 and the cardiac ROI setting unit 13 set the heart ROI and the mediastinum ROI according to the processing procedure described in the first embodiment for the early image, the early image set here Based on the position and size of the heart ROI and mediastinal ROI in the heart, the heart ROI and mediastinal ROI of the same size may be set at the same position in the late stage image. At this time, the positional relationship among the heart ROI and mediastinal ROI and the late image may be further corrected by the image adjustment unit 12.

  The WR calculating unit 19 calculates a WR between the time when the early image is captured and the time when the late image is captured based on the image data of the early and late images. For example, the WR calculation unit 19 calculates the average value of the count values in the heart ROI 5 and the average value of the count values in the mediastinal ROI 6 for each of the early image and the late image. Then, the WR is calculated by a known calculation method using the average value of the count values in the heart ROI 5 of the early image and the late image and the average value of the count values in the mediastinal ROI 6.

  Thus, when the operator sets the heart ROI in the RI plan image of the early image or the late image, the image processing apparatus automatically sets the mediastinal ROI for the early image and the late image, and automatically uses these mediastinal ROIs. Thus, WR is calculated. As a result, it is possible to suppress variations in WR due to variations in medial ROI position setting.

  The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

  For example, in the above-described embodiment, the case where MIBG is used as the RI agent has been described as an example. However, the present invention is also applicable when an RI agent other than MIBG is used.

11 Image data storage unit 12 Image adjustment unit 13 Heart ROI setting unit 15 ROI data storage unit 17 H / M ratio calculation unit 17
25 Centerline determination unit 27 Mediastinal reference position detection unit 29 Mediastinal ROI setting unit

Claims (13)

Means for storing image data of an RI (Radio Isotope) planar image obtained by imaging a subject administered with a radiopharmaceutical;
Means for determining a central region of the subject's body that includes a centerline of the subject's body in the RI planar image;
Means for generating a profile curve of the central region of the subject's body using the image data of the RI planar image;
Means for identifying a mediastinal reference position in the vertical direction in the body of the subject based on a profile curve of the central region of the body;
An image processing apparatus comprising: a mediastinal ROI in the RI planar image based on a center line of the subject's body and the mediastinal reference position.   The image processing apparatus according to claim 1, wherein the radiopharmaceutical is MIBG (3-iodobenzylguanidine). Means for identifying a chest region including left and right lung regions of the subject in the RI planer image, and using the image data of the RI planer image of the chest region to generate a profile curve of the chest region;
Means for determining a centerline of a subject's body in the RI planer image based on a profile curve of the chest region;
The means for determining the center region of the body is a band-like region centered on the center line of the subject's body detected by the means for determining the center line. The image processing apparatus described. The body orientation of the subject in the RI planer image is a direction of a predetermined reference direction,
The means for determining the centerline determines the centerline of the body based on the position of the local maximum value corresponding to the left and right lungs in the profile curve of the chest region and the reference direction. The image processing apparatus according to claim 3, which is determined.   5. The image processing apparatus according to claim 1, wherein the means for specifying the mediastinum reference position sets a position having a minimum value in a profile curve of a center region of the body as the mediastinum reference position.   The means for setting the mediastinum ROI is set so that at least a part of the central region is included in the mediastinum ROI based on the mediastinum reference position. Image processing apparatus. Means for setting a cardiac ROI for identifying a heart region of the subject in the RI planar image;
7. A means for calculating a heart / mediastinum ratio (H / M ratio) based on image data in the heart ROI and image data in the mediastinum ROI. Image processing apparatus. Further comprising display means for displaying the RI planar image on a display device;
The image processing device according to claim 7, wherein the means for setting the heart ROI specifies a heart region of the subject in the RI planar image displayed on the display device in accordance with an instruction from an operator. Storage means for storing image data of an RI (Radio Isotope) planar image obtained by imaging a subject administered with a radiopharmaceutical at different time zones;
A center region determining means for determining a center region of the subject's body, including a center line of the subject's body in the RI planer image;
Profile curve generating means for generating a profile curve of the central region of the subject's body using the image data of the RI planar image;
Mediastinal reference position specifying means for specifying a mediastinal reference position in the vertical direction in the body of the subject based on the profile curve of the central region of the body;
Mediastinal ROI setting means for setting mediastinal ROI in the RI planer image based on the center line of the subject's body and the mediastinal reference position;
Cardiac ROI setting means for setting a cardiac ROI for specifying the heart region of the subject in the RI planer image;
The first and second RI planar images set by the cardiac ROI setting unit when the image data of the first and second RI planar images obtained by photographing the subject in different time zones are stored in the storage unit. Image data in the heart ROI, and the first and second RI planers set by the processing of the central region determining means, the profile curve generating means, the mediastinal reference position specifying means, and the mediastinal ROI setting means An image processing apparatus comprising: calculation means for calculating a myocardial washout rate (WR) based on image data in the mediastinum ROI of an image. The central region determining means determines a central region of the subject's body in the first RI planar image;
The profile curve generating means generates a profile curve of a central region of the subject's body in the first RI planar image;
The mediastinal reference position specifying means specifies a vertical mediastinal reference position in the subject's body in the first RI planer image,
The mediastinal ROI setting means calculates a mediastinal ROI in the first RI planar image based on a center line of the subject's body in the first planar image and a mediastinal reference position in the first planar image. The image processing apparatus according to claim 9, wherein the image processing apparatus sets the mediastinal ROI in the second RI planar image based on the position and size of the mediastinal ROI set in the first RI planar image. . The central region determining means determines a central region of the subject's body in the first and second RI planar images,
The profile curve generation means generates a profile curve of a center region of the subject's body in the first and second RI planar images,
The mediastinal reference position specifying means specifies the mediastinal reference position in the vertical direction in the subject's body in the first and second RI planer images,
The mediastinal ROI setting means calculates a mediastinal ROI in the first RI planar image based on a center line of the subject's body in the first planar image and a mediastinal reference position in the first planar image. And setting the mediastinal ROI in the second RI planar image based on the center line of the subject's body in the second planar image and the median reference position in the second planar image. Item 10. The image processing apparatus according to Item 9. An image processing method performed by an image processing apparatus including a storage unit that stores image data of an RI (Radio Isotope) planar image obtained by photographing a subject who has been administered a radiopharmaceutical,
Determining a central region of the subject's body that includes a centerline of the subject's body in the RI planar image;
Generating a profile curve of the central region of the subject's body using the image data of the RI planar image;
Identifying a mediastinal reference position in the vertical direction in the subject's body based on a profile curve of the central region of the body;
Setting a mediastinal ROI in the RI planar image based on the mediastinal reference position. A computer program for image processing performed by an image processing apparatus having storage means for storing image data of an RI (Radio Isotope) planar image obtained by photographing a subject administered with a radiopharmaceutical,
Determining a central region of the subject's body that includes a centerline of the subject's body in the RI planar image;
Generating a profile curve of the central region of the subject's body using the image data of the RI planar image;
Identifying a mediastinal reference position in the vertical direction in the subject's body based on a profile curve of the central region of the body;
A computer program for causing the image processing apparatus to execute a step of setting a mediastinal ROI in the RI planar image based on the mediastinal reference position.

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