JP2011043489A - Image processing apparatus, program and method for evaluating local wall motion state of cardiac muscle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus, method and program, capable of quantitatively evaluating a state of a local wall motion of cardiac muscle. <P>SOLUTION: The image processing apparatus includes: an image acquisition unit for acquiring a series of electrocardiogram synchronous cardiac muscle SPEC image sets; a contour extraction unit for extracting the contour of cardiac muscle in each cardiac muscle tomographic image constituting each electrocardiogram synchronous cardiac muscle SPEC image set; a division unit for dividing the cardiac muscle into a plurality of segments by a boundary line drawn radially from a prescribed center point in cardiac muscle toward the contour of cardiac muscle, in each cardiac muscle tomographic image; and a parameter calculation unit for determining a parameter showing the state of the local wall motion of cardiac muscle based on change with time of a distance from the prescribed center point in cardiac muscle to the contour of cardiac muscle, relative to each segment. By adopting such a constitution, various parameters for showing the state of the local wall motion of cardiac muscle can be determined without damaging local information carried essentially by the cardiac muscle SPEC image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing program, and an image processing method for processing an electrocardiogram-synchronized dynamic medical image including ECG-synchronized SPECT. More specifically, the present invention relates to an image processing apparatus, an image processing program, and an image processing method for processing an electrocardiogram-synchronized dynamic medical image to obtain information reflecting a myocardial local wall motion.

  Heart disease is the leading cause of death, and the number of patients is increasing year by year, mainly in Europe and the United States. Against this background, various diagnostic imaging methods have been devised and applied clinically to help prevent heart disease and determine treatment strategies. Among them, nuclear medicine image diagnosis such as SPECT is widely used for diagnosing heart disease because it has an excellent feature not found in other modalities such as imaging of the function of the heart.

  Nuclear medicine image diagnosis is a method performed by administering a radiolabeled drug (hereinafter referred to as a radiopharmaceutical) to a subject, capturing the distribution with a dedicated camera, and generating an image. In nuclear medicine image diagnosis, images reflecting various biological functions can be obtained in accordance with the chemical properties of the radiopharmaceutical used and the difference in interaction with the living body.

Nuclear medicine images that have been used for a long time in the diagnosis of heart disease include myocardial SPECT images and ECG-synchronized cardiac pool scintigraphy. The former is a method in which a myocardial preparation such as thallium chloride-201 or 99mTc-tetrofosmin is administered to a subject, and a myocardial viability reduction site is detected as a defect from the obtained tomographic image. This method makes it possible to evaluate the local viability of the myocardium (for example, Non-Patent Document 1).
On the other hand, the latter method is a method in which a vascular retention radiopharmaceutical such as 99mTc-HSA or 99mTc-RBC is administered to a subject, and an electrocardiogram synchronous scintigraphy is imaged to evaluate the motion state of the heart lumen. By this method, it is possible to capture abnormalities in the wall motion of the myocardium as an image and obtain various parameters for the motion state of the myocardium by analyzing the time-volume curve (for example, Non-Patent Document 2). ).

  Recently, a myocardial preparation is administered to a subject, an electrocardiogram-synchronized SPECT image is taken, and the entire left ventricle is three-dimensionally reconstructed to image the myocardial motion. Using this method, it is possible to calculate the volume of the lumen of the left ventricle at each phase of wall motion from the reconstructed 3D image, so by using a method similar to ECG synchronous scintigraphy, Various parameters reflecting the motion state of the myocardium can be calculated (for example, Non-Patent Document 3).

Nishimura Shigetaka, edited by Hideki Kobayashi, “Nuclear Cardiology Complete Manual” (first edition), Medical View, November 10, 2004, p. 114-115 Nishimura Shigetaka, edited by Hideki Kobayashi, “Nuclear Cardiology Complete Manual” (first edition), Medical View, November 10, 2004, p. 156-157 Nishimura Shigetaka, edited by Hideki Kobayashi, “Nuclear Cardiology Complete Manual” (First Edition), Medical View, November 10, 2004, p. 132-142

  In the diagnosis of heart disease, in addition to the evaluation of myocardial viability, the evaluation of wall motion is also important. Using ECG-synchronized cardiac pool scintigraphy, it is possible to visually evaluate the state of myocardial wall motion and to quantitatively evaluate wall motion using various parameters obtained from time-volume curve analysis. (Non-patent document 2). However, since the time-volume curve used in this method is a curve that represents the change over time in the volume of the entire left ventricular lumen, the various parameters obtained by the analysis all reflect the motion state of the entire left ventricle. It becomes a parameter.

  By the way, in most cases, the decrease in the wall motion of the myocardium accompanying heart disease occurs locally. The analysis using the ECG-gated myocardial SPECT image makes it possible to observe a state in which the wall motion is also reduced at a site where the viability is locally reduced. Since this method uses a myocardial SPECT image, the local viability of the myocardium can be quantitatively evaluated. However, since the parameter representing the wall motion state is obtained from a time-volume curve based on the entire left ventricular lumen, the motion state cannot be quantitatively evaluated locally.

In order to reduce the variability of diagnosis in heart disease and improve the accuracy of diagnosis, it is preferable to evaluate the local wall motion using quantitative parameters. It was not disclosed.
The present invention has been made in view of such a fact, and an object thereof is to provide an image processing apparatus, an image processing program, and an image processing method for evaluating the local wall motion state of the myocardium.

  As a result of the study, the inventor expresses the motion state of the myocardium for the segment divided on the tomographic image reconstructed from the ECG-gated myocardial SPECT data without using the time-volume curve based on the volume of the entire left ventricle. Thus, the local wall motion of the myocardium was found to be quantitatively evaluated, and the present invention was completed.

  An image processing apparatus according to the present invention includes an image acquisition unit that acquires a series of ECG-synchronized myocardial SPECT image sets, and contour extraction that extracts a myocardial contour in each myocardial tomographic image that constitutes the ECG-synchronized myocardial SPECT image set. A division part that divides the myocardial part into a plurality of segments by a boundary line radially created from a predetermined center point in the myocardium toward the outline of the myocardium in each myocardial tomographic image; A parameter calculation unit that obtains a parameter representing the state of the wall motion of the myocardium based on a change with time of the distance from the predetermined center point to the contour of the myocardium.

In the present invention, a series of electrocardiogram-synchronized myocardial SPECT image sets is a series of images obtained by imaging myocardial SPECT while synchronizing with the electrocardiogram, and reconstructing myocardial SPECT data accumulated for each phase in the electrocardiogram. The myocardial SPECT image. Since the SPECT image set is composed of myocardial SPECT images corresponding to the phases of the electrocardiogram, the motion state of the myocardium can be reproduced as a moving image by sequentially displaying the SPECT images corresponding to the phases of the electrocardiogram. Is possible.
The electrocardiogram-synchronized myocardial SPECT image originally includes local information. However, since the myocardial wall motion analysis method used in the past used a time-volume curve that uses the volume of the entire left ventricular chamber, parameters that reflected local wall motion could not be obtained. . In the present invention, by adopting the configuration as described above, it is possible to obtain various parameters representing the motion state of the myocardium without impairing the local information originally provided by the myocardial SPECT data.
In the present invention, as a myocardial tomographic image for obtaining a parameter indicating the state of the myocardial wall motion, a short-axis transverse image of the heart can be preferably used.

  In the image processing apparatus according to the present invention, the outline of the myocardium extracted by the outline extraction unit is created based on pixels indicating the maximum count value on a plurality of straight lines created radially from a predetermined division center point. Can be. That is, the image processing apparatus according to the present invention extracts, as a representative pixel, a pixel indicating the maximum count value on a plurality of straight lines created radially from the myocardial tomographic image centering on a predetermined division center point toward the myocardial contour. The image processing apparatus may further include a representative pixel extraction unit, and the contour extraction unit may obtain a myocardial contour based on the position of the representative pixel.

With this configuration, it is possible to automatically extract the outline of the myocardium. As the number of the straight lines created in a radial pattern increases, a smooth contour can be created. However, if the number is too large, it takes too much time for processing, which is not preferable. Further, even if scanning is performed more finely than the resolution of the myocardial SPECT image, the same portion is scanned twice, resulting in wasteful calculation. Therefore, it is sufficient that the radial step is sufficient to scan all the pixels of the myocardial contour in consideration of the size of the target myocardium.
The predetermined division center point may be set visually on the tomographic image, but is disclosed in Japanese Patent Laid-Open No. 2008-180555 in which a point obtained by calculation is used as the rotation center, the center of gravity, or the like. The same method may be used. It is also possible to extract the myocardial region as a region surrounded by pixels having a count value higher than a predetermined count value on the tomographic image, and obtain the rotation center and center of gravity of the region by calculation.

  In addition, the representative pixel extraction unit in the above configuration extracts a pixel indicating the maximum count value on each region partitioned from the myocardial tomographic image by a radial division boundary centered on a predetermined division center point. May be. By adopting such a configuration, it becomes possible to extract the representative pixel by simple calculation while being hardly affected by noise or the like.

The image processing apparatus according to the present invention further includes a smoothing unit that corrects the position of each representative pixel so that the distance from a predetermined center point of the myocardium to the representative pixel changes smoothly between adjacent representative pixels. The contour extraction unit may determine the contour of the myocardium based on the representative pixel corrected by the smoothing unit. Here, as the predetermined center point of the myocardium, the predetermined division center point used for extraction of the representative pixel may be used, or a center point separately determined by the same method as described above may be used. .
With such a configuration, it is possible to reduce the influence based on noise and the like.

Although various processes can be applied as the smoothing process executed by the smoothing unit, it is preferable to apply a periodic function such as a Fourier series. In this case, the smoothing unit according to the present invention corrects each representative pixel by applying a periodic function to a figure in which the representative pixel is displayed on two-dimensional coordinates.
By adopting such a configuration, even when the number of extracted representative pixels is small, it is possible to appropriately complement between adjacent pixels, so that a smooth contour can be extracted.

  In the image processing apparatus according to the present invention, the parameter representing the state of the myocardial wall motion calculated by the parameter calculation unit is based on a time-volume curve obtained for each segment obtained by dividing the tomographic image into a predetermined number by the dividing unit. It can be calculated as follows. For example, a boundary line is drawn radially from the center point of the myocardium determined as appropriate on the tomographic image, and the product of the area of the segment formed by the boundary line and the outline of the myocardium and the slice thickness of the tomographic image is obtained. This is used as the volume of the segment and plotted against the ECG phase. By using the figure obtained in this way as a time-volume curve, it is possible to calculate various parameters reflecting the state of local myocardial wall motion in each segment.

  In this case, the parameters representing the state of the myocardial wall motion can be various parameters calculated from the time-volume curve in the conventional method. Specifically, parameters such as ejection rate, maximum ejection speed, maximum filling speed, end-systolic arrival time, and maximum filling speed arrival time can be used.

The various parameters obtained in the image processing apparatus according to the present invention may be output in the form of a table or the like in comparison with the corresponding segment. For example, each segment divided as in a polar map display or the like. May be displayed on concentric circles corresponding to the slice positions on the short-axis image and displayed in the form of numerical values, brightness, or the like at the corresponding segment positions.
Therefore, the image processing apparatus according to the present invention may further include a display unit that displays a parameter representing the state of the myocardial wall motion at a corresponding position on the myocardial map.

In the above embodiment, the image to be processed is an ECG-synchronized myocardial SPECT image, but the present invention can also be applied to other myocardial medical images. That is, an image processing apparatus according to another aspect of the present invention includes an image acquisition unit that acquires a series of electrocardiogram-synchronized dynamic medical image sets of a myocardial part, and each myocardial tomographic image that constitutes the electrocardiogram-synchronized dynamic medical image set. The myocardial part is divided into a plurality of segments by a contour extracting unit that extracts a myocardial contour in the image, and a boundary line radially generated from a predetermined center point in the myocardium toward the myocardial contour in each myocardial tomographic image A division unit, a parameter calculation unit for obtaining a parameter indicating a state of myocardial wall motion based on a change over time of a distance from a predetermined center point of the myocardium to a contour of the myocardium for each segment, and a state of the myocardial wall motion And a display unit that displays a parameter representing the position at a corresponding position on the myocardial map. Various types of electrocardiogram-synchronized dynamic medical image data can be used. Specifically, data such as PET, MRI, and CT can be used. Various configurations in the image processing apparatus using the ECG-synchronized myocardial SPECT data described above can also be applied to the image processing apparatus of the present invention.

  An image processing program according to another aspect of the present invention provides a computer with an image acquisition step of acquiring a series of ECG-synchronized myocardial SPECT image sets, and myocardium in each myocardial tomographic image constituting the ECG-synchronized SPECT image set. A contour extracting step for extracting the contour of the myocardium, and a dividing step for dividing the myocardial portion into a plurality of segments by a boundary line radially generated from a predetermined center point in the myocardium toward the myocardial contour in each myocardial tomographic image And a parameter calculating step for obtaining a parameter representing the state of the wall motion of the myocardium based on a change with time of the distance from the predetermined center point of the myocardium to the contour of the myocardium for each segment.

  By adopting such a configuration, it is possible to obtain various parameters representing the motion state of the myocardium without damaging the local information originally provided by the myocardial SPECT data. Note that various configurations of the above-described image processing apparatus can be applied to the program of the present invention.

  An image processing method according to yet another aspect of the present invention includes an image acquisition step of acquiring a series of electrocardiogram-synchronized myocardial SPECT image sets by a computer, and a myocardium in a myocardial tomographic image constituting the electrocardiogram-synchronized myocardial SEPCT image set. A contour extracting step for extracting the contour of the myocardium, and a dividing step for dividing the myocardial portion into a plurality of segments by a boundary line radially generated from a predetermined center point in the myocardium toward the myocardial contour in each myocardial tomographic image And, for each of the segments, a parameter calculation step for sequentially obtaining a parameter representing a state of the wall motion of the myocardium based on a change with time of a distance from a predetermined center point of the myocardium to the contour of the myocardium.

  By adopting such a configuration, it is possible to obtain various parameters representing the motion state of the myocardium without damaging the local information originally provided by the myocardial SPECT data. Note that various configurations of the image processing apparatus described above can be applied to the image processing method of the present invention.

  The present invention makes it possible to quantitatively evaluate the state of local wall motion of the myocardium.

Functional block diagram of a preferred embodiment of an image processing apparatus according to the present invention The flowchart which shows an example of the flow of the process in the preferable aspect of the image processing method which concerns on this invention. The flowchart which shows an example of the flow of the process in the preferable aspect of a myocardial outline extraction process The flowchart which shows another example of the flow of a process in the preferable aspect of a myocardial outline extraction process The flowchart which shows an example of the flow of the process in the preferable aspect of a parameter calculation process The figure which shows an example of the image division | segmentation in parameter calculation The figure which shows an example of a time-volume curve. An example of displaying the locally calculated maximum ejection speed on the polar map. The example which displayed the ejection ratio calculated locally on the polar map.

Hereinafter, an image processing apparatus and an image processing method according to preferred embodiments of the present invention will be described with reference to the drawings. In addition, the following description is the description in a preferable aspect to the last, and does not intend to limit the content of this invention.
FIG. 1 is a diagram showing a configuration of an image processing apparatus 10 in a preferred embodiment of the present invention, and FIGS. 2 to 5 are diagrams showing a process flow in an image processing method according to the present invention. In a preferred embodiment, the image processing method according to the present invention is executed by operating the image processing apparatus 10 according to the present invention.

  As shown in FIG. 1, the image processing apparatus 10 according to the present embodiment includes an image acquisition unit 12 that acquires a series of electrocardiogram-synchronized myocardial SPECT image sets, and each myocardial tomogram that constitutes the acquired electrocardiogram-synchronized SPECT image set. A contour extracting unit 14 for extracting the contour of the myocardium in the image; a smoothing unit 16 built in the contour extracting unit 14; a parameter calculating unit 18 for calculating a parameter representing the local wall motion state of the myocardium based on the time volume curve; Built in the parameter calculation unit 18, the dividing unit 20 for dividing each myocardial tomographic image into predetermined segments, and the TVC creation for creating a time-volume curve for each divided segment built in the parameter calculation unit 18. And a display unit 24 for outputting the calculated parameters.

  For example, the image acquisition unit 12 acquires a series of ECG-synchronized myocardial SPECT image sets acquired by the SPECT apparatus (step S1). As described above, in the present specification, a series of ECG-synchronized myocardial SPECT image sets (hereinafter referred to as SPECT image sets in this section) is obtained by imaging myocardial SPECT while synchronizing with the ECG, and integrating each phase in the ECG It is a series of myocardial SPECT images obtained by reconstructing the processed myocardial SPECT data. Each phase myocardial SPECT image in the SPECT image set is composed of a plurality of continuous tomographic images. In a preferred embodiment, the SPECT image set is stored in a computer readable format, such as DICOM format. The SPECT image set can be provided in a state stored in a computer-readable medium such as a CD, a DVD, a hard disk, or a semiconductor memory. In this case, the data acquisition unit 12 can acquire the data by reading the medium storing the data by the reading device of the computer constituting the image processing apparatus. The data may also be taken directly into the image processing apparatus via a network.

  The contour extraction unit 14 performs myocardial contour extraction for each myocardial tomographic image constituting the ECG-synchronized myocardial SPECT image set acquired by the image acquisition unit 12. The myocardial contour extraction by the contour extracting unit 14 can be performed by various methods. For example, the method illustrated in FIG. 3 can be used. First, for each myocardial tomographic image, a plurality of straight lines are created radially from a predetermined division center point (step S11) determined inside the myocardium toward the myocardial contour (step S12), and the maximum count on each straight line is created. Pixels indicating values are extracted and set as representative pixels on each straight line (step S13). Then, smoothing processing is performed on the representative pixels extracted on each straight line by a method described later (step S14), and the figure formed by the representative pixels after the smoothing processing is used as the contour of the extracted myocardium (step S15). ). At this time, as the number of the straight lines created radially increases, a smooth contour can be created. However, if the number is too large, it takes too much time for processing, which is not preferable. Further, even if scanning is performed more finely than the resolution of the myocardial SPECT image, the same portion is scanned twice, resulting in wasteful calculation. Therefore, it is sufficient that the step of the straight line in the radial shape is such that all the pixels in the myocardial contour can be scanned in consideration of the size of the target myocardium. Specifically, in a short-axis tomogram with a resolution of 10 mm, when the diameter of the myocardium is about 10 cm at the maximum, it is sufficient to create the radial straight line in 3 ° steps and scan the maximum value. .

  As another method of contour extraction, a method similar to that disclosed in Japanese Patent Laid-Open No. 2008-180555 can be used (FIG. 4). Specifically, the short-axis tomographic image of the heart is divided into a plurality of segments by boundary lines that are radially formed from the predetermined division center point (step S21) of the myocardium toward the contour (step S22). And the pixel which shows the largest count value in each segment is extracted as a representative pixel (step S23), and a smoothing process is performed by the method mentioned later (step S24). The figure formed by the representative pixels after the smoothing process is set as the extracted myocardial contour (step S25). Since this method extracts the pixel having the highest signal strength from all the pixels in the segment, an appropriate pixel can be selected even if some data in the segment is missing.

  The predetermined division center point of the myocardium in contour extraction may be manually input from the outside via a user interface, but a known method, for example, a method disclosed in Japanese Patent Laid-Open No. 2008-180555 is used. May be determined.

  In a preferred embodiment, the contour extraction unit 14 has a smoothing unit 16 inside. The smoothing unit performs a smoothing process on the representative pixels extracted by the above method in advance, so that the distance from a predetermined center point to the representative pixel changes smoothly between adjacent representative pixels. Correct the position. The contour extraction unit performs contour extraction processing using the representative pixel after smoothing. By performing such processing, it is possible to prevent the contour shape extracted due to the influence of noise or the like from being shaken. As the predetermined center point in the smoothing process, the division center point of the myocardium in the contour extraction may be used as it is, or a center point determined separately may be used. However, considering the processing load on the computer, it is preferable to use the division center point of the myocardium.

  As the smoothing process, various known methods such as a method of performing a three-point smoothing process or approximating data to a periodic function such as a Fourier series can be used. As a preferred embodiment, the smoothing process is performed by a process using a known periodic function typified by Fourier series approximation. By applying processing using a periodic function, even if the number of extracted representative pixels is small, it is possible to complement between adjacent pixels as appropriate, so a smooth contour can be extracted It becomes.

  The parameter calculation unit 18 calculates various parameters that reflect the state of local wall motion (step S3). In a preferred embodiment, the parameter calculation unit 18 includes a dividing unit 20 that divides each myocardial tomographic image into predetermined segments, and a TVC creating unit 22 that creates a time-volume curve for each divided segment. .

  FIG. 5 shows a flowchart of a parameter calculation method performed by operating the parameter calculation unit 18. In a preferred embodiment, the parameter calculation unit 18 determines a predetermined center point in the myocardial portion for each myocardial tomographic image for which contour extraction has been completed (step S31), operates the dividing unit 20, and starts the myocardial contour from the center point. The myocardial part on the tomographic image is divided into a plurality of segments by a plurality of boundary lines directed to (step S32). Here, the predetermined center point may be input from the outside via a user interface or the like, but may be determined using a known method, for example, a method disclosed in Japanese Patent Laid-Open No. 2008-180555. . It is of course possible to use a predetermined division center point in the contour extraction process described above. FIG. 6 shows an example of image division. In the example shown in FIG. 6, the myocardium is divided into 16 segments Seg1 to Seg16 (FIG. 6) by radial boundaries b1 to b16 from the center point O (not shown) toward the myocardial contour (indicated as C in FIG. 6). 6 is divided into Seg1 only). As the number of image divisions increases, it becomes possible to perform quantitative analysis of fine local wall motion. However, if the number is too large, the calculation burden increases, so care must be taken.

  Next, the parameter calculation unit 18 operates the TVC creation unit 22 to create a time-volume curve for each segment created by the division unit 20 (step S33). The time-volume curve for each segment is created as follows. First, the area of each segment divided, that is, the portion surrounded by two boundary lines and the outline of the myocardium divided by the boundary lines is obtained. The obtained segment area is multiplied by the slice thickness of each tomographic image to obtain the volume of the segment portion. By plotting the obtained volume of each segment against the phase of the electrocardiogram, a time-volume curve of each segment can be created.

  The parameter calculation unit 18 uses the time-volume curve created by the TVC creation unit 22 to calculate various parameters that reflect the state of myocardial wall motion (step S34). FIG. 7 shows an example of a time-volume curve. 7A is a time-volume curve, and FIG. 7B is a differential graph thereof. As parameters that reflect the state of myocardial wall motion, various parameters that are normally used in the analysis of myocardial wall motion can be used. Preferably, ejection fraction (EF), maximum ejection speed (PER), maximum filling speed (PFR), end systole arrival time (TES), and maximum filling speed arrival time (TPF) are used. These parameters can be calculated from a time-volume curve or its differential graph using a known method. For example, ejection fraction (EF) can be determined by reading end-diastolic volume and end-systolic volume from a time-volume curve and dividing end-diastolic volume by the difference between end-diastolic volume and end-systolic volume. . The maximum ejection speed (PER), maximum filling speed (PFR), end systolic arrival time (TES) and maximum filling speed arrival time (TPF) are as shown in FIG. 7, from the time-volume curve or its differential graph, Can be read directly.

  The display unit 24 displays the calculated parameters on a display or the like (step S4). Various display methods can be used. For example, each segment is pre-classified with a number, etc., and displayed in a table format corresponding to the number, etc., or a part corresponding to each segment in a polar map display, etc., with a numerical value, luminance corresponding to the numerical value, etc. A display method can be used. 8 and 9 show examples displayed on the polar map by luminance. Here, FIG. 8 shows an example of the maximum ejection speed and FIG. 9 shows the ejection ratio displayed on the polar map. 8 and 9, a short axis image having a matrix size of 64 × 64 and a pixel size of 6 mm was used. The number of processed slices was 14 slices, and each parameter was calculated by creating a time volume curve for each 3 ° step for each slice. This parameter was displayed by performing a complementary process on a polar map with 36 divisions in the circumferential direction. Thus, it can be seen that the local wall motion state of the myocardium can be quantitatively evaluated by the image processing method according to the present invention.

  In the above-described embodiments, examples of the image processing apparatus and the image processing method have been described. However, a program including a module that implements each configuration of the above-described image processing apparatus, and a module that executes each step of the above-described image processing method are provided. The program which has is also included in the scope of the present invention.

  The present invention can be used in the field of manufacturing medical image processing apparatuses.

DESCRIPTION OF SYMBOLS 10 Image processing apparatus 12 Image acquisition part 14 Outline extraction part 16 Smoothing part 18 Parameter calculation part 20 Dividing part 22 TVC preparation part 24 Display part

Claims (15)

An image acquisition unit for acquiring a series of ECG synchronized myocardial SPECT image sets;
A contour extracting unit for extracting a myocardial contour in each myocardial tomographic image constituting the ECG-synchronized myocardial SPECT image set;
In each of the myocardial tomographic images, a dividing unit that divides the myocardial part into a plurality of segments by a boundary line radially created from a predetermined center point in the myocardium toward the outline of the myocardium,
For each of the segments, a parameter calculation unit for obtaining a parameter representing a state of the wall motion of the myocardium based on a change over time of a distance from a predetermined center point of the myocardium to the contour of the myocardium,
An image processing apparatus comprising: In the myocardial tomographic image, further comprising a representative pixel extracting unit for extracting, as a representative pixel, a pixel indicating the maximum count value on a plurality of straight lines created radially around a predetermined division center point,
The contour extraction unit obtains the contour of the myocardium based on the position of the representative pixel.
The image processing apparatus according to claim 1. The representative pixel extraction unit extracts a pixel indicating a maximum count value on each region partitioned from a myocardial tomographic image by a plurality of radial division boundaries centered on a predetermined division center point.
The image processing apparatus according to claim 1. A smoothing unit that corrects the position of each representative pixel so that the distance from a predetermined center point of the myocardium to the representative pixel changes smoothly between adjacent representative pixels;
The contour extraction unit obtains the contour of the myocardium based on the representative pixel corrected by the smoothing unit.
The image processing apparatus according to claim 2. The image processing apparatus according to claim 4, wherein the smoothing unit corrects each representative pixel by applying a periodic function to a figure in which the representative pixel is displayed on two-dimensional coordinates. The parameter representing the wall motion state of the myocardium calculated by the parameter calculation unit is calculated based on the time-volume curve obtained for each segment obtained by dividing the tomographic image into a predetermined number by the dividing unit. The image processing apparatus according to any one of claims 1 to 5. The image processing apparatus according to claim 6, wherein the parameter representing the state of wall motion of the myocardium calculated by the parameter calculation unit is an ejection ratio. The image processing apparatus according to claim 6, wherein the parameter representing the state of the myocardial wall motion calculated by the parameter calculation unit is a maximum ejection speed. The image processing apparatus according to claim 6, wherein the parameter representing the state of the myocardial wall motion calculated by the parameter calculation unit is a maximum filling speed. The image processing apparatus according to claim 6, wherein the parameter representing the state of the myocardial wall motion calculated by the parameter calculation unit is an end-systolic arrival time. The image processing apparatus according to claim 6, wherein the parameter representing the state of the wall motion of the myocardium calculated by the parameter calculation unit is a maximum filling speed arrival time.   The image processing apparatus according to claim 1, further comprising a display unit that displays a parameter representing a state of wall motion of the myocardium at a corresponding position on the map of the myocardium. An image acquisition unit for acquiring a series of electrocardiogram-synchronized dynamic medical image sets of the myocardium;
A contour extraction unit that extracts a contour of the myocardium in each myocardial tomographic image constituting the electrocardiogram-synchronized dynamic medical image set;
In each of the myocardial tomographic images, a dividing unit that divides the myocardial part into a plurality of segments by a boundary line radially created from a predetermined center point in the myocardium toward the outline of the myocardium,
For each of the segments, a parameter calculation unit for obtaining a parameter representing a state of the wall motion of the myocardium based on a change over time of a distance from a predetermined center point of the myocardium to the contour of the myocardium,
A display unit that displays a parameter representing a state of wall motion of the myocardium at a corresponding position on the myocardial map;
An image processing apparatus comprising: On the computer,
An image acquisition step for acquiring a series of ECG-synchronized myocardial SPECT image sets;
A contour extracting step for extracting a myocardial contour in each myocardial tomographic image constituting the electrocardiogram-synchronized myocardial SPECT image set;
In the myocardial tomographic image, a dividing step of dividing the myocardial part into a plurality of segments by a boundary line radially created from a predetermined center point in the myocardium toward the outline of the myocardium;
For each segment, a parameter calculation step for obtaining a parameter representing the state of the wall motion of the myocardium based on the change over time of the distance from the predetermined center point of the myocardium to the contour of the myocardium;
A display step for displaying a parameter representing the state of wall motion of the myocardium at a corresponding position on a map of the myocardium;
An image processing program for executing By computer
An image acquisition step for acquiring a series of ECG-synchronized myocardial SPECT image sets;
A contour extracting step for extracting a myocardial contour in each myocardial tomographic image constituting the electrocardiogram-synchronized myocardial SPECT image set;
In each myocardial tomographic image, a dividing step of dividing the myocardial part into a plurality of segments by a boundary line radially created from a predetermined center point in the myocardium toward the outline of the myocardium;
For each segment, a parameter calculation step for obtaining a parameter representing the state of the wall motion of the myocardium based on the change over time of the distance from the predetermined center point of the myocardium to the contour of the myocardium;
A display step for displaying a parameter representing the state of wall motion of the myocardium at a corresponding position on a map of the myocardium;
An image processing method characterized by sequentially executing.

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