WO2013047496A1 - Technique d'évaluation du contour du myocarde - Google Patents

Technique d'évaluation du contour du myocarde Download PDF

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Publication number
WO2013047496A1
WO2013047496A1 PCT/JP2012/074516 JP2012074516W WO2013047496A1 WO 2013047496 A1 WO2013047496 A1 WO 2013047496A1 JP 2012074516 W JP2012074516 W JP 2012074516W WO 2013047496 A1 WO2013047496 A1 WO 2013047496A1
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point
axis
short
center
pixel value
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PCT/JP2012/074516
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English (en)
Japanese (ja)
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一男 浜田
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日本メジフィジックス株式会社
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computerised tomographs
    • A61B6/037—Emission tomography
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/50—Clinical applications
    • A61B6/503—Clinical applications involving diagnosis of heart
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/52—Devices using data or image processing specially adapted for radiation diagnosis
    • A61B6/5211—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data
    • A61B6/5217—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data extracting a diagnostic or physiological parameter from medical diagnostic data
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/10—Segmentation; Edge detection
    • G06T7/12—Edge-based segmentation
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H50/00—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
    • G16H50/30—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for calculating health indices; for individual health risk assessment
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10072—Tomographic images
    • G06T2207/10108—Single photon emission computed tomography [SPECT]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/30—Subject of image; Context of image processing
    • G06T2207/30004—Biomedical image processing
    • G06T2207/30048—Heart; Cardiac

Definitions

  • the matter disclosed in this specification relates to a technique for determining a myocardial contour point in myocardial image data obtained by nuclear medicine imaging.
  • Nuclear medicine imaging technologies such as SPECT (Single Photon Emission Tomography) and PET (Positron Emission Tomography), administer drugs containing radionuclides into the body, and the nuclides
  • SPECT Single Photon Emission Tomography
  • PET PET
  • This is a technology that captures and images the gamma rays emitted due to the decay of the light.
  • CT and MRI which are other biological imaging technologies, are mainly used to examine abnormalities in the morphology of biological tissues
  • nuclear medicine imaging technology is based on the distribution and accumulation amount of administered radiopharmaceuticals, It is used to evaluate not only the form of organs and tissues, but also the function and metabolic state from information on changes.
  • myocardial imaging When 201 TlCl (thallium chloride) or 99 mTc-tetrofosmin (tetrofosmin) is administered as a radioactive tracer, these are taken into the myocardial cells in proportion to the blood flow of the coronary arteries. Thus, the ischemic site (defect site) in the myocardium can be searched. The search for ischemic sites in the myocardium is very useful for diagnosis of myocardial infarction and angina pectoris, differentiation of ischemic lesions, and the like.
  • gamma rays are typically collected by gating on an electrocardiogram. For this reason, myocardial imaging technology using SPECT is often referred to as ECG-synchronized myocardial SPECT. In ECG-synchronized myocardial SPECT, the left ventricular myocardium is usually imaged in many cases.
  • One of the technical problems in electrocardiogram-synchronized myocardial SPECT relates to how the myocardial part is specified in the image obtained by SPECT.
  • One method is to manually mark a portion considered to be a myocardial portion in each image slice by visual observation.
  • QGS Quadratative Gated SPECT
  • QGS creates a profile of pixel value changes radially from the central point of the 3D image data, and approximates each profile with a Gaussian on the myocardial intima side and epicardial side to maximize the pixel value.
  • the position of 65% of the standard deviation around the point is determined as the intima point and the epicardial point, respectively.
  • the determination of the central point of the heart lumen is based on obtaining an ellipsoid that best approximates the maximum pixel value point. First, a temporary center point and a long axis are determined, and changes in pixel values are examined radially from the center point to obtain an ellipsoid that approximates the maximum pixel value point in each direction.
  • the change in the pixel value is checked again radially from the center of the ellipsoid, and the ellipsoid that approximates the maximum pixel value point is recalculated. This is repeated until the angle of the major axis converges, and the center of the ellipsoid when it converges is determined as the central point of the heart lumen.
  • This software tries to improve the accuracy of the determination of the myocardial endocardial point by manually setting the central point of the heart lumen and the myocardial extraction range.
  • these existing software may not be able to perform good determination of myocardial intima and epicardial points due to problems such as radiopharmaceutical uptake due to myocardial blood flow, resolution of the SPECT device, and small heart. is there.
  • the present invention has been made to develop a technique for automatically and satisfactorily extracting myocardial intima and epicardial points from image data obtained by electrocardiogram-gated myocardial SPECT. is there.
  • the embodiments disclosed herein may be applied not only to ECG-gated myocardial SPECT, but also to image data in general obtained by nuclear medicine imaging of an organ or tissue having a lumen. Should.
  • An example of an embodiment of the present invention is a method for determining a myocardial contour point in myocardial nuclear medicine image data: examining a change in pixel value of the image data from a point in the ventricle radially in a spherical shape. Obtaining a first ellipsoid that approximates a set of pixel value maximum points in each direction; setting a plurality of trace directions based on the first ellipsoid; and in each of the plurality of trace directions Determining myocardial contour points from image data.
  • the trace direction is from a point on the long axis of the first ellipsoid to a direction perpendicular to the surface of the first ellipsoid.
  • the trace direction is from a point on the long axis toward a direction perpendicular to the long axis. It is set radially around the long axis.
  • determining the myocardial contour point includes creating a profile of pixel values for each of the set trace directions; and for each of the profiles, on the long axis side as viewed from the maximum pixel value point Of the points where the profile intersects the determination line, the point closest to the pixel value maximum point or its vicinity is determined as the myocardial intima point in the profile; for each profile, from the pixel value maximum point The point closest to the pixel value maximum point or the vicinity thereof among the points where the profile intersects the determination line on the opposite side of the major axis as viewed, is determined as the epicardial point of the myocardium in the profile; Including at least one of them.
  • the method includes determining the determination line based on a difference between a maximum value and a minimum value of pixel values in the profile multiplied by a predetermined search threshold; In the case of determining both outer membrane points, if the distance between the determined inner membrane point and the outer membrane point does not fall within a predetermined range, the search threshold is changed and the determination line is updated, Re-execution of the determination of the intima point and the epicardial point by the updated determination line;
  • the judgment line which is the judgment standard for intima and epicardial points
  • it can flexibly respond to various myocardial blood flow states and myocardial shapes, etc.
  • the contour point of the myocardium can be determined satisfactorily.
  • Another example of the embodiment of the present invention is a method for determining the center of the ventricle in the cross-sectional image along the short axis in the nuclear medicine image data of the myocardium.
  • a threshold value relating to a pixel value is set for the cross-sectional image, and a hole structure relating to the pixel value is searched under the set threshold value; and the hole structure is found in the search.
  • the threshold value is gradually increased in a predetermined step from the first value; and when the hole structure is not found even if the threshold value is increased to a second value higher than the first value, Repeating the search until the hole structure is found while gradually lowering the threshold value in a predetermined step from a third value lower than the first value; if the hole structure is found, it is found Identifying the center of the hole structure as the center of the ventricle.
  • the hole structure is tried to be found while gradually increasing the threshold value from the first value. However, if the hole structure cannot be found even if the threshold value is increased to some extent, the first threshold value is too high. In view of this, it is possible to improve the success rate of ventricular center identification by providing a processing configuration that attempts to find a hole structure while gradually lowering the threshold value starting from a value lower than the first value.
  • Another example of the embodiment of the present invention is the following method for determining myocardial contour points in myocardial nuclear medicine image data.
  • the method includes: creating a profile of pixel values on a straight line extending from a start point in the ventricle to outside the ventricle in the image data; identifying a maximum pixel value point in the profile; Of the points where the profile intersects the determination line on the start point side when viewed from the maximum point, the point closest to the pixel value maximum point or the vicinity thereof is determined as the intimal point of the myocardium in the profile; Of the points where the profile intersects the determination line on the opposite side of the starting point from the pixel value maximum point, the point closest to the pixel value maximum point or its vicinity is determined as the epicardial point of the myocardium in the profile And including; However, the determination line is determined based on a difference between the maximum value and the minimum value of the pixel values in the profile multiplied by a predetermined search threshold value, and is determined between the determined intima point
  • the judgment line which is the judgment standard for intima and epicardial points
  • it can flexibly respond to various myocardial blood flow states and myocardial shapes, etc.
  • the contour point of the myocardium can be determined satisfactorily.
  • Some embodiments of the present invention include a method of determining the apex of cardiac muscle nuclear medicine image data.
  • the method examines a change in the pixel value of the image data from a point in the ventricle in a spherical shape, and obtains a first ellipsoid that approximates a set of maximum pixel value points in each examined direction;
  • a profile of the pixel value of the image data is created again in a spherical shape from the center of one ellipsoid at least in the apex direction, and each of the profiles is opposite to the center when viewed from the maximum pixel value point of the profile.
  • a point closest to or near the pixel value maximum point among points where the profile intersects with the determination line is determined as an epicardial point of the myocardium in the profile; Determining a second ellipsoid that approximates a set; and determining a tip on the apex side of the second ellipsoid as a tip of the apex of the myocardium.
  • the apex of the apex can be specified with high accuracy by constructing the approximate ellipsoid twice using the estimated contour point of the epicardium.
  • Some of the embodiments of the present invention include a method for determining a heart base in nuclear medicine image data of the myocardium.
  • the method includes: examining a change in pixel value of the image data from a point in the ventricle in a spherical shape, and obtaining a first ellipsoid that approximates a set of maximum pixel value points in each direction examined; Positioned on the long axis of one ellipsoid from the first short-axis cross-sectional tomogram located on the heart base side from the center of the first ellipsoid, and further on the heart-base side than the first short-axis cross-sectional tomogram Checking whether or not there is a continuous discontinuity of a predetermined angle or more in the septal side heart wall until the second short-axis transverse tomographic image, and in the second short-axis transverse tomographic image, When the transverse cross-sectional tomographic image in which there exists is continuous, the short-axis
  • the discontinuity exists in the second transverse cross-sectional tomogram If short-axis cross tomograms that are not contiguous: -If there is another short-axis cross-sectional tomogram in which the discontinuity exists in the second short-axis cross-sectional tomographic image or a short-axis cross-sectional tomographic image located closer to the apex than the second short-axis cross-sectional tomographic image, Identifying the short-axis cross-sectional tomographic image closest to the heart base side among the other short-axis cross-sectional tomographic images as a cross-sectional tomographic image representing the start of the heart base; When there is no other short-axis transverse tomogram in which the discontinuity exists on the apex side of the second short-axis transverse tomogram or the second short-axis transverse tomogram, the second short-axis transverse tomogram Identifying a short-axis cross-sectional tomographic image closer to the heart base than the image
  • a short-distance cross-sectional tomographic image in a predetermined range that is considered to be located on the base side that is, a short-axis cross-sectional tomographic image from the first short-axis cross-sectional tomographic image to the proximal side
  • Another example of an embodiment of the present invention is a method for determining a myocardial contour point in nuclear medicine image data of a myocardium, and examines a change in pixel value of the image data radially from a point in the ventricle, Obtaining a first ellipsoid approximating a set of pixel value maximum points in each direction examined; extracting a plurality of trace planes based on the first ellipsoid; and at each of the plurality of trace planes Determining myocardial contour points from the image data.
  • the trace plane has a point on the long axis of the first ellipsoid as a vertex and is perpendicular to the plane of the first ellipsoid.
  • the trace surface is extracted in a plane shape perpendicular to the long axis at least at a part of the first ellipsoid on the central side.
  • the determination of the myocardial contour point is to set a trace center for each of the trace surfaces, provided that when the trace surface is conical, the trace surface is defined as a coordinate in the major axis direction. Ignoring and setting the trace center as if it were a two-dimensional surface; and for each of the trace surfaces, creating a profile of pixel values radially from the set trace center, wherein If the trace plane is conical, the trace plane is treated as if it is a two-dimensional plane ignoring the coordinate in the major axis direction, and the profile of the pixel value is created.
  • a point closest to the pixel value maximum point or its vicinity among points where the profile intersects with the determination line on the trace center side when viewed from the pixel value maximum point is the profile. Determining the intima point of the myocardium at the point; for each of the created profiles, the pixel value maximum among the points where the profile intersects the determination line on the opposite side of the trace center as seen from the pixel value maximum point Determining the point closest to or near the point as the epicardial point of the myocardium in the profile.
  • a trace surface for performing intramyocardial / outer membrane determination is set in a direction perpendicular to the surface of a previously created ellipsoid (first ellipsoid). For this reason, the shape of the trace can be adapted to the shape and direction of the actual myocardium, and the determination of the intima and outer membrane points of the myocardium can be performed better than in the prior art.
  • any of the above-described methods can be implemented as an operation method of the computer apparatus. That is, the present invention can be implemented as a method in which a computer device including a processor is operated by executing a program stored in the storage device by the processor.
  • the embodiment of the present invention includes a computer program including a program code that is executed by a processor of a computer device to cause the computer device to perform any of the above-described methods.
  • a computer apparatus including a processor and a storage device, the computer program including a program code executed by the processor to cause the computer to perform any one of the above methods.
  • a computer device is included for storing in the device.
  • FIG. 1 is a diagram depicting a main configuration of an apparatus or system 100 for performing various processes disclosed in this specification.
  • FIG. It is a flowchart for demonstrating the flow of the myocardial outline extraction process in the Example introduce
  • 5 is a flowchart for explaining a modification of the processing example illustrated in FIG. 2.
  • It is a flowchart for demonstrating the process example for determining the ventricle center automatically.
  • FIG. 10 is a diagram for illustrating a state of determination point valid / invalid processing in step 636; It is a figure for demonstrating the process for pinpointing an apex part. It is a figure for showing a mode of processing for specifying a tip part of an apex part.
  • FIG. 1 is a diagram depicting a main configuration of an apparatus or system 100 for executing various processes disclosed in this specification.
  • the device or system 100 is a general computer including a CPU 102, a main storage device 104, and an auxiliary storage device 106.
  • a high-speed RAM Random Access Memory
  • an inexpensive, large-capacity hard disk, flash memory, SSD, or the like is used as the auxiliary storage device 106.
  • the most basic functions of the device 100 are provided by the CPU 102 reading and executing the operating system 110 stored in the auxiliary storage device 106.
  • various programs stored in the auxiliary storage device 106 are read into the CPU 102 and executed, thereby providing functions other than those provided by the operating system 110.
  • the apparatus or system 100 in the present embodiment preferably includes at least three of the DICOM support program 111, the slice operation program 112, and the myocardial contour extraction program 113 as the various programs.
  • the DICOM support program 111 is a program for supporting DICOM, which is a de facto standard for the file format of medical image data and communication standards.
  • the myocardial nuclear medicine image data to be subjected to myocardial contour extraction processing may also have a file format conforming to DICOM, and the DICOM support program 111 can input / output myocardial nuclear medicine image data. Supported.
  • the DICOM specification is open to the public, and it is easy to create a program having such a function, and there are many programs that can be used.
  • the slice operation program 112 is a program that provides a so-called reslice function that creates a two-dimensional slice by cutting out three-dimensional myocardial nuclear medicine image data with a free cross section. Programs having such functions are also widely available and are installed in many workstations for handling medical images. Therefore, also in this embodiment, the DICOM support program 111 and the slice operation program 112 can be easily implemented by appropriately using existing appropriate programs.
  • the myocardial contour extraction program 113 is a central element for realizing the automatic myocardial contour extraction function provided by this embodiment.
  • Various processes disclosed in the present specification can be implemented by reading and executing all or a part of the code of the myocardial contour extraction program 113 by the CPU 102 unless otherwise specified.
  • the CPU 102 reads out data from the storage device according to an instruction such as the myocardial contour extraction program 113 and performs calculations, and stores the resulting data mainly in the main storage device 104.
  • the stored data is used for another process or stored in the auxiliary storage device 106 in accordance with a command such as the myocardial contour extraction program 113.
  • data and calculation results are similarly exchanged between the CPU 102 and the storage devices 104 and 106 in all the processes described below.
  • the myocardial contour extraction program 113 may be implemented as a single executable file, or may be implemented as a program set including a plurality of executable files. Further, the myocardial contour extraction program 113 may be configured to call and use the DICOM support program 111 as necessary. For example, it may be configured such that the DICOM support program 111 is called and used to read cardiomyocardial medicine image data and to store the processing result in the DICOM format. Similarly, the myocardial contour extraction program 113 may be configured to call and use the slice operation program 112 as necessary. For example, the slice operation program 112 may be called to obtain two-dimensional image data of a short-axis transverse tomogram or to obtain two-dimensional image data of a long-axis tomogram. . Depending on the embodiment, the myocardial contour extraction program 113 may be a program including the functions of the DICOM support program 111 and the slice operation program 112.
  • At least a part of the operating system 110 and the programs 111 to 113 are not directly read into the CPU 102 from the auxiliary storage device 106 but are once copied or moved to the main storage device 104 and then read into the CPU 102 and executed. .
  • a part of the processing by these programs may be implemented by a dedicated hardware circuit or programmable logic.
  • the apparatus 100 is provided with a function of automatically extracting the outline of the myocardium from the image data of the myocardium acquired by the nuclear medicine imaging technique such as PET or SPECT.
  • the auxiliary storage device 106 can store original image data 114 to be processed, data 116 being processed, data 118 having been processed, and the like.
  • the main storage device 104 can also be used as a storage area for temporarily storing data to be processed.
  • the device 100 communicates with a user interface such as a keyboard and mouse for receiving input from a user, a display for displaying various information, and other computer devices.
  • a user interface such as a keyboard and mouse for receiving input from a user
  • a display for displaying various information
  • other computer devices such as keyboard and mouse
  • a network interface or the like can be provided.
  • the hardware configuration of the apparatus 100 is similar to that of a general computer and is already well known, further description is omitted.
  • the myocardial contour extraction program 113 may be stored in a remote storage device connected via a network, instead of being stored in the auxiliary storage device 106 that exists locally in the device 100.
  • the myocardial contour extraction program 113 is not stored in a single storage device (for example, a hard disk or an SSD) in terms of hardware, but is distributed to a plurality of storage devices using a known technique such as striping. And may be stored. Even in such an embodiment, in many cases, at the time of executing the program, all or a part of the code of the myocardial contour extraction program 113 is (temporarily) stored in the main memory 104 and then stored in the CPU 102. Is read.
  • the processing means for executing the myocardial contour extraction program 113 may be composed of a plurality of CPUs instead of the single CPU 102.
  • the plurality of CPUs may be distributed and installed in physically separated computer devices. That is, depending on the embodiment, a system composed of a plurality of physically different computer devices is physically or from a single or a plurality of storage devices provided in the system or connected to the system via a network.
  • the present invention is configured to (1) be executed by a processing unit to cause an apparatus or system including the processing unit to perform various processes described in this specification.
  • FIG. 2 is a flowchart showing the basic flow of this automatic extraction process.
  • the processing blocks in FIG. 2 may be executed in an order different from the order depicted in FIG. 2 or may be executed in parallel. Further, a part of the processing executed in each processing block may be executed in parallel with another processing block or processing executed in the processing block or in a different order from FIG. Sometimes. Accordingly, the order of the processing blocks depicted in FIG. 2 is merely an example of an embodiment of the present invention and should not be understood as an order that should apply to all of the various embodiments of the present invention.
  • Step 200 indicates the start of processing.
  • Step 204 is a step of inputting image data to be processed into the apparatus 100. Details of the image data will be described later. This image data may be created inside the apparatus or system 100 of FIG. 1 or created by another apparatus or system and transferred via an optical storage device such as a CD-ROM or DVD-ROM or a network. Or the like may be input to the apparatus or system 100. In step 204, the image data is stored in the auxiliary storage device 106 as original image data 114.
  • the original image data 114 is examined to determine the position of the ventricle center.
  • the center of the ventricle may be determined manually while displaying the original image data 114 on the display, in a preferred embodiment, the CPU 102 analyzes the original image data 114 according to the instructions of the myocardial contour extraction program 113. , Do it automatically. An example of a process for automatically determining the center of the ventricle will be introduced in detail later.
  • step 212 the ventricle is approximated by an ellipsoid using the result of the ventricular center determination process in step 208.
  • This approximate ellipsoid is used as the basis for the extraction of the myocardial contour in the next step 216.
  • an approximate ellipsoid may be obtained based on the intraventricular cavity point determined by another method.
  • step 216 a plurality of trace directions are set in the original image data 114 based on the approximate ellipsoid obtained in step 212, and myocardial contour points (intimal points and epicardial points) are determined in each trace direction. . Examples of these processes will also be introduced in detail later.
  • the image data input to the apparatus or system 100 in step 204 and stored in the auxiliary storage device 106 as the original image data 114 can be image data obtained by a nuclear medicine imaging technique such as PET or SPECT.
  • the file format of the image data is preferably a format that complies with DICOM, which is a de facto standard for medical image data.
  • DICOM is a de facto standard for medical image data.
  • radionuclides tracers
  • gamma rays generated due to the decay of these nuclides are detected by a detector installed around the subject.
  • By processing the detected gamma ray count by an image reconstruction algorithm it is possible to obtain image data in which each pixel has a pixel value related to the gamma ray count.
  • the pixel value of each pixel of the image data may be referred to as a count value, a count number, or a count.
  • the pixel value of each pixel is not the actual gamma ray count.
  • the count value of each pixel is a value estimated from actually measured data, and various conversion processing and noise reduction are performed on the raw data. This is obtained by performing processing, interpolation processing, and the like.
  • the pixel value of each pixel is subjected to a normalization process or the like in the middle of the calculation, and even becomes an integer.
  • the pixel value of each pixel may be referred to as “tracer amount” or a similar name. From these circumstances, those who read the specification, drawings, and claims of this application use the term “pixel value” in the present application, but in other documents, “count value”, “count number”, “tracer amount”. Note that it may have the same meaning as ".”
  • the original image data 114 in the present embodiment is, in particular, image data of the left ventricular myocardium obtained by the electrocardiogram synchronous myocardial SPECT described in the background art section.
  • the purpose is to specify a ventricular center point (cardiac lumen center point) or extract a point corresponding to the outline of the myocardium from the image data.
  • the image data input to the apparatus or system 100 does not have to be data itself collected by a PET apparatus or a SPECT apparatus and reconstructed. Rather, since the data collection resolution and slice interval naturally differ from device to device, in order to use the same processing myocardial contour extraction program 113 for image data from various imaging devices, the image data is: It is preferable that the resolution and the size are set in advance by processing such as interpolation.
  • the image data 114 in the present embodiment has a pixel size of 2 mm in all directions, and the original data is obtained by triple linear interpolation so that both the short-axis transverse tomogram and the sagittal tomogram are 128 ⁇ 128 pixels.
  • the data can be shaped.
  • a pixel having a pixel value greater than or equal to a predetermined threshold value may be rounded to a predetermined value.
  • the pixel value of a pixel that has a value of 0 or less as a result of interpolation may be set to 0.
  • Other preliminary image processing may be performed.
  • These interpolation / shaping processes are performed by software processing, and the program code for that may be included in the myocardial contour extraction program 113 or different from the myocardial contour extraction program 113. A program may be included.
  • These interpolation / shaping processes may be performed by another apparatus or system before being input to the apparatus or system 100, or may be performed by the apparatus or system 100 after being input to the apparatus or system 100. Implementations of the invention include all these embodiments. [Determination of ventricular center]
  • FIG. 3 is a flowchart showing details of the process shown in step 208 of FIG. 2, and is one specific example of the process for automatically determining the ventricular center.
  • This process automatically determines the ventricular center in the three-dimensional cardiac ventricle data input to the apparatus 100 in step 204 of FIG.
  • the center of the ventricle is specified for each of the short-axis transverse tomographic slices in a predetermined range, and the specified ventricular center of the slice that has been successfully specified is determined as the entire left ventricle. Is considered the center of
  • Step 300 indicates the start of processing.
  • a search start slice is determined.
  • the slice here is a short-axis cross-sectional tomogram slice, that is, a short-axis cross-sectional tomogram slice constructed from the image data 114 described with reference to FIG. 1.
  • the CPU 102 slices according to the command of the myocardial contour extraction program 113. It may be a short-axis transverse tomogram slice created by calling the operation program 112 and the CPU 102 operating the image data 114 in accordance with an instruction of the slice operation program 112.
  • tomographic image data may be obtained in the same manner.
  • the “short axis” may be an axis perpendicular to the Z coordinate in the coordinate system used to represent the position of each pixel in the image data 114.
  • the search start slice is determined as follows.
  • Sub-step 2 The average coordinates of all pixels having a pixel value equal to or greater than a predetermined ratio of the maximum pixel value are calculated. What is calculated is not the average coordinates of the pixels included in a specific transverse cross-sectional tomogram slice, but pixel values included in the short-axis cross-sectional tomographic image slice, regardless of which pixel is included in the short-axis transverse tomogram slice. Is the average coordinate of all pixels having. In this embodiment, 50% is adopted as the predetermined ratio, but it is natural that a user may adopt a favorite ratio other than 50%.
  • sub-steps 1 and 2 may be performed using only pixel data existing in the upper half of the slice. This is because the body orientation in the transversal tomographic slice is effectively standardized, and it is likely that only the myocardium is present in the upper half of the slice, while the myocardium is present in the lower half of the slice. In addition, there is a possibility that image data of the liver and intestinal tract may be included. Therefore, in order to obtain the threshold value relating to the myocardial part, it is preferable to perform the processing using only the upper half data in the slice, which is likely to include only the myocardial data.
  • an initial threshold value for searching the ventricular center is set for the search target slice determined in step 304.
  • the initial threshold is set to 30% of the maximum pixel value of the search target slice.
  • Step 312 is a step of executing a search for the center of the ventricle.
  • the search for the center of the ventricle is performed by the following process.
  • labeling is performed on an area having a pixel value exceeding the set threshold value (in this case, the initial threshold value set in step 308). Also, the label with the largest size is specified.
  • labeling is a term often used in the field of image processing, and refers to a process of assigning the same number to consecutive pixels.
  • the label having the maximum size means a label having a large number of pixels having the same number (label), not the size of the number used for the label. For example, in the case where 1 to 3 are assigned as labels, there are 10 pixels to which label 1 is assigned, 30 pixels to which label 2 is assigned, and 5 pixels to which label 3 is assigned. In this case, the label having the maximum size is label 2.
  • Sub-step 2 Calculate the center of the label area identified in sub-step 1 and having the maximum size. In the present specification or claims, this center may be referred to as the “maximum label center”.
  • (Sub-step 3) Labeling is performed on pixels having a pixel value lower than the set threshold in the label area having the maximum size identified in sub-step 1.
  • the label used at this time is referred to as a hole label in order to distinguish it from the label used for labeling performed in substep 1.
  • Sub-step 4 Among the assigned hole labels, labels satisfying at least one of the following conditions are excluded from the subsequent processing. That is, it is not used in later processing. A hole label centered in the area near the edge of the slice. This is because there seems to be no ventricular center at the end of the slice. For example, a hole label having a center within 40 mm from the edge of the slice is excluded. • A hole label centered in the septal region. However, the septal region must be estimated by appropriate means. For example, there are the following methods.
  • a pixel having a pixel value equal to or greater than 50% of the maximum pixel value is labeled, and a septum region is located above the average coordinate of the label having the largest size and to the left of the label coordinate located on the leftmost side.
  • the orientation of the ventricle (heart) in the PET and SPECT short-axis transverse tomographic images is effectively standardized, and the pixel data is displayed so that the front wall side is the upper side and the septal region side is the left side when displaying the display. It is common that they are arranged.
  • a hole label whose label size is less than 1 cm 2 .
  • Sub-step 5 In the processing up to sub-step 4, when the number of remaining hole labels is only one, the center of the hole label is determined as the ventricular center. If a plurality of hole labels remain after processing up to sub-step 4, among the remaining hole labels, the center of the hole label having the center closest to the maximum label center calculated in sub-step 2 is determined as the ventricular center. And decide.
  • the determined coordinate data of the center of the ventricle is stored in the main storage device 104 or the auxiliary storage device 106 by the CPU 102 in accordance with an instruction related to the program 113 and used for subsequent processing. In various processes described in this specification, the calculation results obtained by the cooperation of the programs 111 to 113 and the CPU 102 are stored in the main storage device 104 or the auxiliary storage device 106 and used for subsequent processing. .
  • Step 316 determines whether or not the center of the ventricle has been determined in Step 312. If the ventricular center has been determined, the ventricular center search process ends without further processing (step 336). However, if the ventricular center has not been determined, the process proceeds to step 320, the threshold used in step 312 is changed, and a search for the ventricular center is performed again (steps 324 and 312).
  • the threshold value change performed in step 320 is performed as follows.
  • the threshold value is raised in a predetermined step.
  • the initial threshold is set to 30% of the maximum pixel value of the search target slice, but this is increased by 5% each time the processing loop returns to step 320.
  • the threshold Even if the threshold reaches a predetermined value, for example, 50%, if the center of the ventricle has not yet been determined, the threshold is set to a value lower than the initial threshold. For example, it is set to 28% lower than the initial threshold value 30%. Thereafter, each time the processing loop returns to step 320, the threshold value is decreased by a predetermined rate. For example, decrease by 2%.
  • the reason for changing the search threshold as described above is as follows. That is, the reason why the center of the ventricle cannot be determined up to a certain value (for example, 50%) is assumed to be that the threshold value is too low and the pixel value exceeds the threshold value even at the center of the ventricle. However, if the center of the ventricle cannot be determined even if it is set to a certain value (for example, 50%), the threshold value is too high in the first place, and even the myocardium is expected to be slice data having only a pixel value below the threshold value. Change and lower the threshold to try to make the myocardial pixel value exceed the threshold. Due to such a flexible threshold change scheme, the possibility of automatically specifying the center of the ventricle is greatly increased compared to the prior art.
  • a certain value for example, 50%
  • Fig. 3a shows the state of a label (that is, a continuous pixel) that is identified according to a change in the search threshold.
  • Each slice is a cross-sectional tomographic image obtained from the SPECT apparatus, and a region surrounded by a white line is a region in which pixels are identified (ie, a label region) identified according to a search threshold.
  • the numerical value of% described in the figure is the search threshold value. In this example, it can be seen that when the threshold is 40%, a hole structure appears at the center of the label having the maximum area.
  • step 324 it is checked whether or not the search threshold value changed as described above is less than the search end threshold value.
  • This search end threshold can be set to 10% of the maximum pixel value of the search target slice, for example.
  • the process proceeds to step 328, and the search target slice is changed.
  • a predetermined number for example, one
  • the process is terminated without performing the ventricular center specifying process for the other slices (step 336).
  • Steps 308 to 332 are repeated, and if the search threshold value is changed after reaching the search end slice, the ventricle center cannot be specified, an error is output (step 340).
  • the search end slice can be arbitrarily set. For example, a slice having a pixel value equal to or less than a predetermined ratio with respect to the maximum pixel value in all short-axis transverse tomogram slices may be set as the search end slice. . This predetermined ratio may be 30%, for example.
  • FIG. 4 is a flowchart illustrating details of the process in step 212 of FIG. Details of the processing in step 212 in FIG. 2 will be described with reference to FIG. In this step, an ellipsoid used as a basis for extracting the myocardial contour in the next step 216 is obtained.
  • Step 400 indicates the start of processing.
  • a center point serving as a reference for sampling a point serving as a basis for obtaining an approximate ellipsoid is determined.
  • this center point may be the ventricular center determined by step 208 of FIG.
  • the sampling center point may be determined as follows.
  • Sub-step 1 In the short-axis transverse tomographic image to which the ventricular center obtained in step 208 of FIG. 2 belongs, the change in pixel value is examined radially from the ventricular center. That is, a pixel value (change) profile (count profile) is created. In addition, the point where the pixel value is maximum is specified in each examined direction.
  • the coordinates of the center of the ventricle in the original image data are stored in the main storage device 104 or the auxiliary storage device 106 as a result of the previous step 208.
  • the axis direction may be in accordance with the coordinate system used in the original image data.
  • the short-axis transverse tomographic image including the ventricular center is created by the CPU 102 operating the image data 114 according to the command of the slice operation program 112 called according to the command of the myocardial contour extraction program 113 as described above. It may be a cross-axis tomographic slice.
  • Sub-step 2 A circle approximating the set of pixel value maximum points obtained in sub-step 1 is obtained.
  • Approximation circle can be derived by various methods. For example, a circle having an average value of coordinates of all the pixel value maximum points as the center coordinate and a radius of the average value of the distance from the center coordinate to each pixel value maximum point may be used as the approximate circle. Alternatively, the center coordinates and radius of the approximate circle may be changed little by little, and the sum of squares of the residuals may be calculated, and the circle having the smallest value may be used as the final approximate circle.
  • the following maximum pixel value point may be excluded from the process of calculating the approximate circle in sub-step 2.
  • a point where the distance from the origin (the center of the ventricle obtained in step 208 in FIG. 2) to the maximum pixel value point deviates by 2 ⁇ or more from the average of similar distances in other pixel value profiles.
  • the pixel value is below a predetermined ratio of the maximum value of all the maximum pixel values.
  • variations of the embodiment of the present invention include manually determining the sampling center point and using the ventricular center point determined using a commercially available program as the sampling center point.
  • Some variations of the myocardial contour extraction program 113 may be configured to instruct the CPU 102 to execute step 408 and subsequent steps using a sampling center point acquired by an arbitrary method.
  • step 408 the image data 114 (that is, the image data to be processed input to the apparatus 100) is sampled in a spherical shape from the sampling center point determined in the previous step, that is, three-dimensionally in all directions. Examine changes. Further, the point having the maximum pixel value is specified in each examined direction (step 410). In step 412, an ellipsoid that approximates the obtained set of maximum pixel value points is calculated.
  • steps 408 to 412 can be performed more specifically as follows.
  • the axis passing from the sampling center point and extending from the base to the apex is the Z axis, and in the cross section including this, the apex is 0 °, the base is 180 °, and the sampling center is the origin.
  • the sampling direction is set over the entire circumference at 10 ° intervals, and the image data 114 is sampled in each direction to examine the change in the pixel value. That is, a pixel value profile (count profile) is created.
  • the pixel value profile is not created.
  • the point where the pixel value is maximum is specified in each examined direction.
  • the sampling center point, sampling direction, and the appearance of the approximate ellipse created are shown in FIG. 4a.
  • the Z-axis can be actually determined as an axis perpendicular to the short-axis transverse tomographic image in the image data 114.
  • This axis may be slightly deviated from the actual apex direction or the base direction.
  • the center point and axis used in this step are the center point and axis for obtaining an ellipsoid for performing a tracing trace of the subsequent myocardial endocardial and epicardial points. Since it is not used, there may be some errors.
  • Substep 2 An ellipse that approximates the set of pixel value maximum points obtained in substep 1 is obtained.
  • Sub-step 4 The average of 18 approximate ellipse parameters (center coordinate, long side, short side, etc.) obtained by sub-step 1-3 (when the rotation interval in sub-step 3 is 10 °) , And approximate ellipsoid parameters (center coordinates, long side, short side, etc.). Therefore, the obtained approximate ellipsoid is a spheroid, that is, an ellipsoid that is circularly symmetric about the major axis.
  • sampling and ellipse approximation for a specific cross section instead of sampling and ellipse approximation for a specific cross section after the sampling and ellipse approximation for a specific cross section as in the example above, sampling for all cross sections and then elliptic approximation for each cross section Processing may be performed in the flow of performing.
  • the derivation of the approximate ellipse can be performed in various ways.
  • an ellipse with the average value of the coordinates of all the pixel value maximum points as the center coordinate, the maximum value of the distance from the center coordinate to each pixel value maximum point as the long side length, and the minimum value as the short side length May be an approximate ellipse.
  • the center coordinates and radius of the approximate ellipse may be changed little by little, and the sum of squares of the residuals with the actual maximum pixel value may be calculated, and the ellipse with the minimum may be used as the final approximate ellipse.
  • step 216 in FIG. 2 the details of the processing in step 216 in FIG. 2 will be described with reference to FIGS. 5a and 5b.
  • myocardial contour points are extracted from the image data to be processed (that is, the image data 114 drawn in FIG. 1) based on the ellipsoid obtained in the previous step 212.
  • Step 500 indicates the start of processing.
  • one cross section including the major axis of the ellipsoid obtained in step 212 of FIG. 2 is determined.
  • This cross section may be set arbitrarily. For example, when the long axis is the Z axis and the X axis and the Y axis are set perpendicularly to the Z axis, the cross section can be perpendicular to the Y axis. This cross section is naturally an ellipse.
  • step 504 and subsequent steps the ellipse obtained in step 502 is used to set the trace direction for extracting myocardial contour points.
  • the search angle is set by setting the apex direction to 0 ° and the base direction in the Z axis to 180 °, and in step 506, the intersection of the straight line extending from the ellipse center to the set search angle direction and the ellipse Ask for.
  • the initial search angle is set to 10 °, and each time the processing loop returns to step 504 through step 524, the angle is increased by 5 °.
  • the search angle reaches 170 °, the search angle is further increased. It is supposed to end without increasing the number. That is, the “search end angle” described in step 524 of FIG.
  • these numerical values are merely examples, and it goes without saying that other numerical values may be adopted for the initial search angle, the search end angle, and the angle increment step.
  • step 508 it is determined whether or not the search angle set in step 504 is less than 90 °. If the search angle is less than 90 °, the process proceeds to step 510 where the normal at the intersection calculated in step 506 is obtained. That is, a straight line perpendicular to the tangent at the intersection is obtained. In step 512, the intersection of this normal and the Z-axis (ie, the long axis of the ellipse) is calculated, and this intersection is determined as the trace center for myocardial contour point extraction in the current processing loop. That is, it is determined as the sampling starting point for extracting the myocardial contour point.
  • step 508 determines that the search angle is 90 ° or more. If it is determined in step 508 that the search angle is 90 ° or more, the process proceeds to step 514, and the position of the Z coordinate of the intersection calculated in step 506 on the Z axis is determined as the myocardial contour in the current processing loop. Determine the trace center for point extraction. That is, the intersection point between the perpendicular line drawn down from the intersection calculated in step 506 on the Z axis and the Z axis is determined as the trace center.
  • step 516 the initial trace direction (ie, sampling direction) for performing myocardial contour point extraction is determined. This is determined to be the direction from the trace center determined in step 512 or 514 to the intersection calculated in step 506. A vector pointing in this direction (trace direction vector) is calculated for subsequent processing.
  • 5C and 5D show the relationship between the search angle, the intersection of the straight line and the ellipse extending in the search angle direction, the normal of the intersection, the intersection of the normal and the Z axis, the trace direction vector, and the like.
  • the case where the search angle is less than 90 ° is shown in FIG. 5c, and the case where the search angle is 90 ° or more is shown in FIG. 5d.
  • step 518 a rotation angle for rotating the trace direction vector around the Z axis (that is, the long axis of the ellipse) is set.
  • the rotation angle is increased in steps of 10 ° from 0 ° to 350 °. That is, the initial direction vector is made to make a round around the Z axis.
  • the angle increment step may be other values, for example 5 °.
  • myocardial contour point extraction processing of image data is performed in the direction set in step 518, that is, the direction of the rotated direction vector. This process will be described later in detail with reference to FIG.
  • step 522 it is determined whether or not the rotation angle around the Z axis of the trace direction vector is the rotation end angle. As described above, in the present embodiment, this is set to 350 °. If the rotation end angle is reached, the process proceeds to step 524, where it is determined whether or not the current search angle set in step 504 is the search end angle. As described above, in the present embodiment, this is set to 170 °. If the search end angle is reached, the process ends (step 526).
  • the trace direction for extracting the myocardial contour point is the length of the ellipsoid obtained in step 212. It is set radially from a point on the axis in a direction perpendicular to the ellipsoid of the ellipsoid.
  • the image data 114 is sampled in a conical shape with a point on the ellipsoidal long axis as a vertex.
  • the trace direction for extracting the myocardial contour point is from a point on the ellipsoidal long axis to a direction perpendicular to the long axis. It is set radially around the long axis.
  • the image data 114 is sampled radially within a cross section perpendicular to a point on the ellipsoidal long axis. This is to reflect in the contour point extraction process that the shape of the ventricle is different between the apex side and the base side.
  • the shape of the ventricle has a tapered shape as it goes to the tip like an egg, whereas on the base side, the diameter does not change so much even if it reaches the end of the base. It has a shape.
  • the reason for changing the method of setting the trace direction with the search angle of 90 ° as a boundary is that the shape of the ventricle is reflected in the contour point extraction process to improve the accuracy of contour point extraction. It is.
  • the angle for changing the method of setting the trace direction may be other than 90 °, for example, 80 °.
  • Step 530 indicates the start of processing.
  • image data to be processed image data indicated as original image data 114 in FIG. 1 is scanned from the trace center set in step 512 or 514 in the direction of the trace direction vector set in step 522.
  • a profile of pixel values is created. That is, the change in the pixel value according to the position is examined.
  • a threshold value may be provided for effective pixel values. For example, the pixel value may be invalid or 0 for a pixel value of 30% or less of the maximum pixel value in this profile. This is to exclude pixels that may contain noise from processing.
  • the point (pixel) having the maximum pixel value in this profile is identified.
  • step 540 determination lines serving as a reference for determining the intima and epicardium points of the myocardium in step 540 are set.
  • step 540 the vicinity of the point where the pixel value profile intersects the determination line is determined as an intima point or an epicardial point of the myocardium.
  • the point closest to the maximum pixel value point or the vicinity thereof is determined as the inside of the myocardium in the profile. Determined as a film point.
  • the point (pixel) where the profile first falls below the determination line is determined as the myocardial intima point in the profile.
  • the point closest to the pixel value maximum point or the vicinity thereof among the points where the profile intersects the determination line on the opposite side of the trace center when viewed from the pixel value maximum point in the profile is the profile. It is determined as the outer membrane point of the myocardium.
  • the point (pixel) where the profile first falls below the judgment line is determined as the myocardial epicardial point in the profile To do.
  • the determination threshold is set in steps 536 and 544 and is variable. The reason for making the decision threshold variable will be explained later in connection with step 542.
  • the initial determination threshold value set in step 536 is 75% in this embodiment.
  • FIG. 5e shows the relationship between the trace plane of the image data, the trace center, the trace direction, the pixel value profile, the judgment line, the pixel value maximum point, the intima judgment point, the epicardial judgment point, etc., as seen from the Z-axis direction. Please refer to it.
  • the search angle set in step 504 is less than 90 °, the image data trace surface is actually angled in the Z-axis direction, and represents the cone-shaped trace surface from the top. Note that there are.
  • step 542 the distance between the intima point and the epicardium point determined in step 540 is calculated, and it is determined whether or not this distance is within a predetermined range.
  • the distance between the intima point and the epicardium point is considered to reflect the thickness of the myocardium.
  • the aforementioned predetermined range can be, for example, 8 mm or more and 32 mm or less. This range is an example, but according to the inventor's research, even for those who have no abnormality in the myocardium, those who have some abnormality, for example, those who have a disease where the myocardium becomes thin This is the range in which the myocardial contour point extraction is best performed.
  • step 542 If it is determined in step 542 that the distance between the intima determination point and the adventitia determination point is not within the predetermined range, the process proceeds to step 544 and the determination threshold is changed.
  • the threshold changing step can be set to 5%, for example. For example, when the distance between the intima determination point and the adventitia determination point is 8 mm or less, the determination threshold value may be increased by 5%. Further, for example, when the distance between the intima determination point and the adventitia determination point is 32 mm or more, the determination threshold may be decreased by 5%. If the distance between the intima determination point and the adventitia determination point is within a predetermined range, the intima and outer film determination points are determined, and the process is terminated (step 548).
  • an error is output (step 550), and in the profile, the intima point and / or It is shown that the epicardial point could not be specified. Even when the process ends with an error output (step 550), it is preferable to include, for example, an intima point and / or an epicardial point determined based on a determination line based on an initial determination threshold, for example.
  • the contour point determination trace region (that is, the conical region set in steps 504 to 522) may enter or approach too close to the myocardial membrane, and the myocardial intimal point cannot be specified. is there. Therefore, in the trace region that seems to be the apex, only the epicardial point may be determined and the intimal point may not be determined. In that case, since it is not necessary to change the determination line, for example, based on the determination line based on the initial determination threshold set in step 536, the epicardial point is determined as described above, and the determination point is answered. It may be determined as an outer membrane determination point in the profile.
  • Whether or not the trace area is located at the apex can be determined, for example, when the search angle is within a predetermined range, for example, within 15 ° in step 504. Further, the apex may be specified based on the apex specifying method described later with reference to FIG. [Removal of deviation judgment points]
  • step 220 of FIG. 2 details of the process shown in step 220 of FIG. 2 will be described.
  • points that deviate from the tendency of other determination points and are not determined normally among the determination points of the myocardial intima and outer membrane obtained in step 216 are removed.
  • the determination of the departure determination point can be performed as follows, for example.
  • “Outer side” is the outer side with reference to the major axis of the ellipsoid created in step 212, and the direction away from the major axis is called “outer side”.
  • “Adjacent to the profile” means adjacent to the Z-axis direction, that is, adjacent to the cross section including the long axis, and adjacent to the longitudinal direction around the Z-axis (ellipsoidal long axis). Including both.
  • the deviation determination process in (c) may not be executed.
  • the departure determination process of (c) may not be executed.
  • the deviation determination process of (c) and (d) may not be applied to the profile located at the base.
  • the determination as to whether or not a certain profile is located at the base may be, for example, a case where the search angle is not less than a predetermined range in step 504, for example, not less than 135 °.
  • the heart base may be specified based on the heart base specifying method described later with reference to FIG. [Interpolation / Shaping]
  • step 224 of FIG. 2 details of the process shown in step 224 of FIG. 2 will be described with reference to FIG.
  • the determination points are invalid or do not exist based on the points that are not invalidated in step 220 (that is, points that are not determined to be deviations). Interpolate points or correct the position of decision points.
  • Step 600 indicates the start of processing.
  • the processing for interpolation and shaping differs depending on whether the determination point is located at the apex, the base, or between them. Therefore, in step 604, first, the location of the apex is specified.
  • the apex of the apex may be determined uniformly in step 504, for example, when the search angle is within a predetermined range, for example, within 15 °.
  • the apex is automatically specified based on the specification of the epicardial points in the individual image data.
  • Step 608 identifies where the heart base is.
  • the base of the heart may be uniformly determined, for example, in step 504 such that the search angle is a predetermined range or more, for example, 135 ° or more.
  • the base is automatically specified based on the specification of the intima and epicardium points in the individual image data. . Details of the processing will be described later.
  • a surface including all profiles created from the same trace center may be referred to as a slice.
  • this slice is not necessarily two-dimensionally planar.
  • each slice has a conical shape near the apex from the center of the ellipsoid obtained in step 212 in FIG.
  • near the base it is a two-dimensional plane and parallel to the cross section in the anatomical direction.
  • step 616 For slices located immediately before the base of the heart from the inside of the apex, go to step 616. In this step, for each slice, effective intima-determination points and outer-membrane determination points belonging to the slice are respectively circularly approximated.
  • the effective intima / outer membrane determination points are the intima and outer membrane points that can be identified in step 540 of FIG. 5B, and the distance between them (that is, the film thickness) in step 542. Is determined within the predetermined range, and is a determination point that was not invalidated in the departure determination process of step 220 in FIG.
  • an interpolation point of the intima or / and outer membrane determination point is inserted into a profile in which the intima or / and outer membrane determination point does not exist or is invalid.
  • the intima point and the epicardium point are determined for all profiles belonging to the slice subjected to the interpolation process.
  • the Z coordinate (that is, the position in the long axis direction) of each determination point is disjoint. However, in the above circle approximation process, the Z coordinate is ignored.
  • an effective intima-determination point or average Z-coordinate of the epicardial determination point is used depending on whether the interpolated point is an intima point or an epicardial point.
  • the Z coordinate of each point is later smoothed by the smoothing process in step 228.
  • step 616 is performed for all slices located immediately before the base of the heart from the inside of the apex. Although no loop is described in FIG. 6, it should be understood that processing is performed for all these slices. However, when there are few effective judgment points of the intima of a slice, for example, when it is 25% or less of the entire circumference, the circular approximation interpolation process of step 616 is not performed for the intima of the slice. Similarly, when the valid judgment point of the outer membrane of a certain slice is 25% or less of the entire circumference, the circular approximation interpolation process of step 616 is not performed on the outer membrane of the slice. For the inner membrane or outer membrane of such a slice, the interpolation processing by the adjacent slice in step 620 is applied.
  • the state of the interpolation processing by the approximate circle in step 616 is shown in FIG. 6a.
  • the image is a slice viewed from the Z-axis direction, and if the search angle set in step 504 is less than 90 °, the actual slice plane is angled in the Z-axis direction.
  • the outer side is the outer membrane determination point and the inner side is the intima determination point.
  • the figure also shows a circle that approximates these. Also shown are interpolation points for profiles that do not exist or are invalid.
  • step 620 the process of step 620 is applied to a slice with a small number of valid judgment points for the intima or epicardium.
  • the valid judgment point is 25% or less of the entire circumference in the intima of a slice A.
  • slice B adjacent to slice A the average of the distance between the trace center or Z axis and each intima decision point is obtained.
  • the slice B is preferably a slice adjacent to the center side of the slice A (that is, the center side of the ellipsoid obtained in step 212).
  • difference used in sub-step 4 is an average calculated in the same manner from slice B and another slice adjacent thereto when the number of effective intima determination points of slice A is very small, for example, 10% or less. A difference in distance may be used.
  • the outer membrane can be treated in the same manner as the inner membrane.
  • step 624 The processing of step 624 is performed only for slices immediately inside the apex, and each inner diameter is such that the diameter of a circle that approximates the intima decision point for these slices decreases at a predetermined rate toward the apex. The position of the film judgment point is corrected.
  • the position of the intima determination point may be corrected.
  • the intima approximate circle refers to a circle approximating the intima decision point. The same as that obtained in step 616.) By performing such correction, the intima contour becomes smoother and more natural. be able to.
  • Step 628 the decision point is approximated by a circle, and the center and radius of the obtained approximate circle are used to interpolate the profile where the decision point does not exist or is invalid. Add judgment points.
  • circle approximation and interpolation are performed only for the epicardium determination points.
  • the interpolation process of the adjacent slice of step 632 is performed without performing the interpolation process of step 628.
  • step 632 interpolation is performed using the second ellipsoid obtained in step 716 described later.
  • the second ellipsoid see FIG. 7 and the description of steps 704-720.
  • an average distance between all valid outer membrane judgment points included in a slice whose effective judgment points are 50% or less of the entire circumference (hereinafter referred to as slice P) and the central axis of the second ellipsoid is obtained. calculate. Further, the average distance between the outer membrane determination point included in the slice adjacent to the slice P (hereinafter referred to as slice Q) and the central axis of the second ellipsoid is calculated. Then, the difference between these average distances is obtained, and the point obtained by moving the outer membrane determination point of slice Q by the amount of the difference is set as the outer membrane determination point of slice P.
  • step 636 processing including the following substeps is performed.
  • Slice A a slice representing the start of the heart base
  • slice A for each of the outer membrane and the inner membrane, using a technique such as labeling, the effective area that is the maximum continuous effective decision point Identify the area.
  • Valid decision points may mean decision points that are not marked invalid.
  • slice B In a slice adjacent to the basal terminus end side with respect to slice A (hereinafter referred to as slice B), it corresponds to an effective region related to the outer membrane of slice A among the outer membrane determination points included in the slice. Decision points not included in the area are invalidated.
  • the region of slice B corresponding to the effective region related to the outer membrane of slice A refers to a region that overlaps the effective region of slice A in the region of slice B in the Z-axis direction.
  • the determination point not included in the region corresponding to the effective region related to the intima of the slice A that is, the region overlapping in the long axis direction
  • Sub-step 4 The same processing as that of sub-step 3 is performed on a slice (hereinafter referred to as slice C) that is further adjacent to the base end side of slice B. That is, assuming that slice B is slice A and slice C is slice B, the same processing as in sub-step 3 is performed.
  • slice C a slice
  • slice C the same processing as in sub-step 3 is performed.
  • Sub-step 5 the angular width of the effective area is calculated around the trace center of the slice. When the angle width of the effective area of a certain slice is equal to or smaller than a predetermined angle, all determination points in the slice and the slice on the basal end side are invalidated. This predetermined angle can be set to 120 °, for example.
  • step 636 is a process performed for a plurality of slices in the same manner as the process in each step of FIG. Although a loop is not drawn in FIG. 6, it should be noted that the processing of step 636 actually includes a loop, as can be understood from the description of sub-step 4 above.
  • step 640 for each slice having valid intima and adventitia determination points, circular approximation is performed individually for the intima and adventitia. Further, the position of each determination point is corrected so that each determination point is positioned on the circumference of the approximate circle obtained.
  • Step 644 indicates the end of the process. [Identification of apical region]
  • a second ellipsoid different from the ellipsoid obtained in step 212 in FIG. 2 is obtained, and the tip is determined as the tip of the apex.
  • the average film thickness of the myocardium is calculated by using the short-axis transverse tomographic image slice near the center of the obtained ellipsoid, and this is also used as the film thickness of the apex.
  • Step 700 indicates the start of processing.
  • Steps 704 to 720 are processing for determining the most distal portion of the apex.
  • a center point for performing tracing for obtaining the second ellipsoid is set. In one embodiment, this center point is the center of the ellipsoid obtained in step 212 (hereinafter, this ellipsoid may be referred to as a first ellipsoid).
  • the image data to be processed that is, the image data described as the original image data 114 with respect to FIG. 1 is traced radially from the set center point, and the change in the pixel value is examined. That is, a pixel value profile is created.
  • this tracing may be performed only on the apex side.
  • tracing is performed only in the range of 0 to 80 ° and 180 to 100 ° from the center of the ellipsoid (trace center). (See FIG. 7a).
  • an outer membrane point is specified by the same processing as in step 540 in FIG. 5b. That is, on the side opposite to the trace center when viewed from the maximum pixel value point of the profile, the point closest to or near the maximum pixel value point among the points where the profile intersects the determination line is the outer membrane point of the myocardium in the profile. Is identified. For example, the point where the pixel value profile first falls below the determination line on the opposite side of the trace center from the pixel value maximum point is determined as the outer membrane point of the profile.
  • an ellipsoid ie, the second ellipsoid described above
  • the calculation for obtaining the second ellipsoid can be performed in the same manner as the calculation in step 412. That is, for example, for each of the cross sections including the major axis of the first ellipsoid and having the outer membrane determination point, the sum of squares of the residuals with the outer membrane determination point included in the cross section is minimized.
  • the ellipse is obtained, and the average value of these ellipse centers and the average value of the long side and short side may be used as the center, long side, and short side of the second approximate ellipsoid to be obtained.
  • the following decision points are excluded from the calculation for obtaining the approximate ellipsoid as invalid. May be. -The distance from the trace center to the judgment point is farther than the specified value.
  • a determination point for example, the relevant point
  • the distance ratio is 30% or more.
  • the major axis position is the major axis.
  • step 720 the leading edge of the apex is determined.
  • the most distal portion on the apex side of the obtained second approximate ellipsoid may be the most distal portion of the apex of the heart ventricle included in the image data.
  • FIG. 7a shows the start point and direction of image data sampling for examining the change of the trace center and direction of the image data, that is, the pixel value using a certain long-axis cross section, the determined epicardial point, and the epicardial determination. It is the figure on which the state of the ellipse which approximated the point was drawn. This figure also depicts a transverse tomographic image slice that touches the tip of the apex determined at step 720, that is, the outside of the apex. In FIG. 7a, the apex outer slice is drawn so as to touch the long side of the two-dimensional ellipse, but this is only for convenience of explanation, and in practice it is obtained in step 716. The slice is in contact with the long side of the three-dimensional approximate ellipsoid.
  • Step 724 and subsequent steps are processing for determining the thickness of the apex.
  • step 724 several short-axis transverse tomographic images near the sampling center set in step 704 are extracted.
  • the minor axis transverse direction can be, for example, a direction perpendicular to the major axis of the first ellipsoid.
  • 10 short-axis cross-sectional tomographic images including the center of the first ellipsoid as the sampling center and 10 short-axis cross-sectional tomographic images adjacent thereto in the apex direction and the base direction are extracted. Also good.
  • an average film thickness is obtained for each short-axis transverse tomogram extracted in step 724, and an average film thickness is obtained for all the extracted short-axis transverse tomograms.
  • a method for obtaining the film thickness in each short-axis transverse tomographic image the same method as that described in Steps 512 to 522 of FIG. 5a can be used. That is, a profile of change in pixel value is created in each angular direction from a trace center in a predetermined angular range within a predetermined angular range, and each of the inner membranes near a point that intersects the judgment line near the maximum pixel value.
  • the film thickness can be defined as a point and an outer film point, and a distance between them. As described in connection with FIG. 5b, the decision line can be variable.
  • the angle range for obtaining the film thickness in each short-axis cross-sectional tomographic image is centered on the ventricular center of the short-axis cross-sectional tomographic image and the upward direction of each short-axis cross-sectional tomographic image is 0 °. ⁇ 60 °. This is because only the film thickness in the front wall direction is extracted. In addition, it is common in the field of nuclear medicine imaging that this angle range is a front wall direction in a short-axis transverse tomogram.
  • the center of the ventricle may be the trace center obtained in step 512, that is, the position of the major axis of the first ellipsoid, or the center of the ventricle obtained individually in the short-axis transverse tomographic image.
  • the ventricular center obtained by the method described with reference to FIG. 9b described later may be used.
  • step 732 the film thickness of the apex is determined by averaging the average film thicknesses of the respective transverse cross-sectional tomographic images extracted in step 724.
  • step 736 the position obtained by subtracting the apex film thickness determined in step 732 from the apex most distal part determined in step 720 is determined as the apex inner end.
  • Step 740 represents the completion of processing.
  • step 7b the range for checking the average film thickness set in step 724, the angle range for wall thickness search in step 728, and the apex inner end determined in step 732 are determined in step 720 of FIG. This is illustrated together with the outer apex outer end. [Identification of the heart region]
  • step 608 of FIG. 6 the details of the processing for specifying the heart region shown in step 608 of FIG. 6 will be described with reference to FIG.
  • the heart base portion is determined. Specify the start position.
  • Step 800 indicates the start of processing.
  • Step 804 sets the first short-axis transverse tomographic image slice (determination start slice) for determining the heart wall discontinuity in the image data 114 to be examined.
  • This slice can be set using, for example, the ellipsoid obtained in step 212 in FIG. 2, and can be set as a slice corresponding to the predetermined angle set in step 504 in FIG. 5a, for example.
  • This predetermined angle can be set to 110 °, for example.
  • step 808 the intima point and the epicardial point are determined for the slice to be determined. This process is exactly the same as steps 518-522 in FIG. 5a. Further, the process for invalidating the deviation determination point described in relation to step 220 in FIG. 2 may be applied to the determination point of the intima point and the epicardial point. Accordingly, by reusing the processing results of steps 518-522 of FIG. 5a (and processing associated with step 220 of FIG. 2 in some embodiments), the required processing results can be obtained at step 808.
  • step 812 it is checked from the processing result in step 808 whether or not there is a break of a predetermined angle or more in the septal heart wall in the slice to be determined.
  • the presence of a heart wall break can be determined by the absence of valid intimal and / or epicardial points in a particular pixel value profile. In such a case, the angular region corresponding to the pixel value profile can be determined to have a broken heart wall.
  • the left direction of the screen is generally the septal side.
  • a range of 150 to 210 ° is set as the septum side. Can do.
  • this range is merely an example, and another range may be used.
  • FIG. 8a shows the state of the angle range to be searched in this example.
  • step 812 it is checked whether or not there is a continuous heart wall break of a predetermined angle (for example, 20 °) or more in this angle range.
  • steps 808 and 812 is sequentially performed from the determination start slice to a slice called “investigation slice” located on the heart base side (steps 816 and 818). Thereby, for each slice, it is examined whether or not there is a break of a predetermined angle or more on the septal side heart wall.
  • step 822 an attempt is made to determine the starting slice of the heart base. This is done as follows.
  • step 824 it is determined whether or not the start slice of the heart base has been determined in step 822. If it has been determined, the process proceeds to step 848 and the process ends. If not, the process proceeds to step 828.
  • step 828 and subsequent steps the slices are moved one by one to the base side from the investigation slice, and it is determined whether or not the heart wall is interrupted as described above by the same processing as in steps 808 and 812, respectively.
  • Step 832 it is determined whether or not a heart wall break is found in the slice. If so, the slice is determined as the heart base start slice (step 840). If not found, the slices are moved one by one to the determination end slice, and a slice having a heart wall break is searched (steps 844 and 828). If a slice having a heart wall break as described above is not found even after searching for a processing range end slice, an error is output and the processing ends (step 852).
  • the “investigation slice” can be, for example, a slice when set to 135 ° in step 504 of FIG. 5A.
  • the “processing range end slice” can be a slice when the search angle is set to 150 ° in step 504 of FIG. 5A.
  • these angles are exemplary, and other angles may be reused depending on the embodiment.
  • FIG. 8 b shows an example of the relationship between the base portion determination start slice, the investigation slice, the determination target slice range, and the processing range end slice.
  • steps 504 to 524 in FIG. 5a when a plane including all profiles created from the same trace center is called a slice, smoothing processing is individually performed for each slice. Specifically, this is performed as follows. -Fitting by Fourier series approximation is performed for the distance from the ventricular center of each slice to the effective judgment point, and the result is reflected in the judgment point. As the center of the ventricle, the trace center determined in step 512 of FIG. 5a can be adopted. ⁇ In the range from the apex inside to the base start slice, the intima and epicardium determination points are individually fitted. For the apex, only the epicardial decision point is fitted. For the base, fitting is performed by connecting the inner and outer membrane points. The approximate interval is 2 except for the base and 4 is the base. (The smaller this value, the duller the shape.)
  • Fig. 9a shows an example of fitting.
  • Intima or epicardial decision points are plotted with the trace angle (rotation angle of the trace direction vector set in step 58) as the horizontal axis and the distance from the ventricular center (trace center) as the vertical axis.
  • trace angle rotation angle of the trace direction vector set in step 58
  • trace center the distance from the ventricular center
  • points after fitting are also shown. It can be seen that the position of the contour point of the intima or epicardium has been modified to change smoothly.
  • the ventricular center may be obtained again by image analysis for each slice.
  • the ventricle center of each slice may be obtained by performing the same processing as in FIG. 3 for each slice. Even if the slice is a cone having an angle with respect to the Z axis, the processing of FIG. 3 can be applied by performing image analysis on a two-dimensional plane ignoring the Z axis.
  • the center of the approximate circle of the intima or epicardium obtained in steps 616 and 628 of FIG. 6 may be used as the ventricular center of the slice.
  • the center of the intima approximate circle obtained in step 640 of FIG. 6 may be the ventricular center of the slice.
  • the ventricular center of each slice obtained as described above may be corrected by a technique such as linear interpolation.
  • FIG. 9b shows an example of the correction of the ventricular center.
  • the center position (slice including the center of the ventricle determined in the processing of FIG. 3) is the base point, and the center position is constant in both the apex direction and the base direction. Linear interpolation is performed to correct the center of the heart of each slice. (Sub-step 2) Smoothing in the long axis direction
  • step 504 to 524 in FIG. 5A determination points are fitted to each surface including profiles having the same rotation angle set in step 518.
  • This plane includes the major axis of the ellipsoid created in step 212 in FIG. 2, and the plane determined in step 502 in FIG. 5a is rotated around the major axis by the rotation angle set in step 518. It becomes a rotated surface.
  • Curve fitting is performed with respect to the distance of each determination point from the center of the ellipsoid, and the result is reflected on the determination point. Specifically, this is performed as follows. ⁇ For the judgment point near the ellipsoid center from the outside of the apex, fitting by Gaussian approximation is performed. -Fitting by moving average approximation (average interval: 4) is performed on the determination points from the vicinity of the center of the ellipsoid to the end of the base.
  • FIG. 9c shows an example of how to set a range for fitting by Gaussian approximation and a range for fitting by moving average approximation.
  • the fitting is performed separately for the apex and the base, but it is preferable to perform the fitting so that the determination points on the base side and the apex side are slightly included from the center. This is to make the change of the position of the contour point smooth in the vicinity of the center. [Determination of contour line]
  • FIG. 10 illustrates the state of connection between the heart apex and the heart apex from the apex, from the inside of the apex to immediately before the base. Since there is only an epicardial decision point for the apex, this is connected by linear interpolation to create a closed curve. From the inside of the apex to immediately before the base of the heart, a closed curve is created by individually connecting the intima decision point and the epicardium decision point by linear interpolation.
  • an intimal point and an epicardial point are connected to create one closed curve. That is, one closed curve is created by connecting the intima point and the epicardium point by linear interpolation. These closed curves are output from the CPU 102 as myocardial contours.
  • the device 100 may be a computer device including a plurality of CPUs, or may be a system including a plurality of physically computer devices each including a CPU. be able to.
  • the auxiliary storage device 106 for storing the original image data 114 and the myocardial contour extraction program 113 may be housed in the same housing as the device or the system 100, or via an interface such as USB or SAS. It may be connected to the device or system 100.
  • the auxiliary storage device 106 is not limited to a single hard disk or flash memory, but may be composed of a plurality of hard disks or flash memory. A stored hard disk, flash memory, or the like may be virtually configured as one storage device.
  • the myocardial contour extraction program 113 and the image data 114 and data 116 and 118 may be configured to be stored in the physically same storage device, or may be stored in different storage devices. May be. Techniques for realizing these configurations are already well known and will not be described in detail here. However, various hardware configurations that implement at least a portion of the various functions provided by the implementation of the present invention can be included in variations of the embodiments of the present invention. They can also be claimed comprehensively or individually.
  • the myocardial contour extraction program 113 may include all of the instructions for causing the CPU 102 to perform the functions introduced so far as a single program, but causes the CPU 102 to perform a part of the functions. It can also be implemented as a set of element programs each having one or more instructions. These element programs may be individually moved, copied, and stored, and may be stored in physically different storage media or devices. Some of these element programs can be claimed as independent inventions.
  • the myocardial contour extraction program 113 or an element program constituting the myocardial contour extraction program 113 can be stored in a portable storage medium such as a CD-ROM or a removable memory and can be marketed. Such a storage medium is also an example of realization of the present invention. As described above, the embodiments of the present invention have many variations in terms of software configuration and implementation. These variations may also be claimed comprehensively or individually.
  • processing has been described using several flowcharts. However, the order of these processing is merely an example, and it is not necessarily that processing must be performed in the order illustrated. Note that there is no. As illustrated below, processing may be performed in a different order, or specific processing may be implemented as a subroutine, software function, dynamic link library, etc., and called and used in other processing steps. May be configured.
  • step 220 of FIG. 2 different processes are performed depending on the three parts of the heart base from the apex and the inner apex to immediately before the base as described above. Therefore, even if steps 604 and 608 in FIG. 6 (described in detail in FIGS. 7 and 8 respectively), which are processes for identifying the apex and base, are executed before step 220 in FIG. Good.
  • steps 604 and 608 in FIG. 6 which are processes for identifying the apex and base
  • steps 604 and 608 in FIG. 6 which are processes for identifying the apex and base
  • the determination line is dynamically changed, but since it is not performed at the apex, Preferably, the apex is identified. Therefore, the process of step 604 in FIG. 6 that is a process for identifying the apex may be configured to be performed before step 216 in FIG.
  • FIG. 2-1 shows the flowchart when processing is performed in this order. Steps 604 and 608 in FIG. 6 have moved to the front and back of the intima-media determination trace 216 as steps 604 ′ and 608 ′, respectively. Since the interpolation / shaping step 224 in FIG. 2 does not include the processing steps 604 and 608, it is indicated by reference numeral 224 ′ in FIG. 2-1. However, the process is the same as step 224 in FIG. 2 except that the process steps 604 and 608 are not included. In addition, the steps denoted by the same reference numerals as in FIG. 2 perform the same processing as in FIG.
  • step 220 for determining the validity / invalidity of the determination point and the steps 616 and 628 for performing the interpolation processing are performed in units of slices
  • the intima-media point for a specific slice You may comprise so that it may perform immediately after performing determination. That is, a part of the invalidity determination process and the interpolation process may be executed between steps 522 and 524 in FIG.
  • the image data is traced in a specific direction to check the change of the pixel value, and the process of obtaining the maximum value of the pixel value and the intersection with the determination line is performed.
  • step 408-410, step 520 (and step of FIG. 5b), step 708, step 728, and step 808-812. Therefore, processes such as execution of trace and creation of pixel value profile, specification of maximum value of pixel value and its position, specification of position of judgment point of intima and / or adventitia are implemented as software functions etc. You may comprise so that it may be called and used in the process step.
  • FIG. 5a and FIG. 5a-1 blocks having the same processing contents are denoted by the same reference numerals and description thereof is omitted.
  • steps 500 and 526 representing the start and end of the process are respectively represented as steps 500 ′ and 526 ′ in FIG.
  • steps 512 ′ and 514 ′ unlike the case of steps 512 and 514 in FIG. 5A, the extraction of the trace plane for performing the myocardial contour point extraction is performed. This is done as follows.
  • the trace plane for performing myocardial contour point extraction is determined in step 510. It is extracted in the shape of a conical surface with the intersection between the obtained normal and the Z axis (that is, the long axis of the ellipse obtained in step 502) as the apex, and the straight line extending in the normal direction as the generating line.
  • step 514 ′ that is, when it is determined (in step 508) that the search angle set in step 504 is 90 ° or more, the trace plane for performing myocardial contour point extraction is determined in step 506.
  • a plane that includes the calculated intersection and is perpendicular to the Z axis that is, the long axis of the ellipse obtained in step 502) is extracted.
  • a center for performing myocardial contour point extraction tracing that is, a trace center is set for the trace surface extracted in step 512 ′ or 514 ′.
  • the trace center is a point on the Z-axis, but in the case of the embodiment of FIG. 5a-1, this is individually set for each extracted trace plane.
  • the trace center can be obtained by various methods.
  • the trace center may be the ventricular center obtained by the same processing as in steps 308 to 340 in FIG.
  • the trace surface is elliptical, that is, the trace surface obtained in step 512 ′, the coordinates in the Z-axis direction are ignored and treated as a two-dimensional surface.
  • the search start threshold set in step 308 may be the threshold when the ventricular center is specified in step 208 in FIG. If the determined ventricular center position is far away from the position of the Z axis on the trace plane, that is, the position of the long axis of the ellipse obtained in step 502, the determined ventricular center is invalidated, The position of the long axis may be set as the trace center.
  • step 516 ′ the first trace direction (namely, sampling direction) for performing myocardial contour point extraction is determined from the trace center set in step 515 ′. It is the same as step 516 in FIG. 5a, but in step 516 ′, if the trace surface is elliptical, that is, if it is the trace surface obtained in step 512 ′, the coordinates in the Z-axis direction are ignored. Determine the trace direction.
  • the initial trace direction set in step 516 ′ may be in any direction on the plane perpendicular to the Z axis, and can be set arbitrarily.
  • step 518 ′ a rotation angle for rotating the trace direction vector set in step 516 ′ is set in the same manner as in step 518 in FIG. 5a. However, this rotation angle is set around the trace center set in step 515 ′ unlike step 518 in FIG. 5a.
  • a myocardial contour point extraction trace is performed in the direction of the trace direction vector set in step 518 ′, as in step 520 of FIG. 5A.
  • steps 516′-520 ′ the Z coordinate of the trace plane is ignored. That is, even when the trace surface is extracted in an elliptical shape, that is, in the case of the trace surface extracted in step 512 ′, the Z coordinate of the pixel belonging to the trace surface is ignored in a two-dimensional surface. Treat as if there is a myocardial contour point extraction trace.
  • the technique of the myocardial contour point extraction trace may be the same as the technique described with reference to FIG.
  • the inventor of the present application has actually made a program to confirm that the determination of the myocardial inner and outer membrane points can be satisfactorily performed even by the above-described processing illustrated in FIG. 5a-1.
  • the center of the ventricle corrected by the technique described with reference to FIG. 9b may be adopted as the center of the trace obtained in step 515 ′. It is actually confirmed by a program that the determination of the myocardial inner and outer membrane points can be satisfactorily performed by such processing.
  • the present invention can be embodied in various forms, and the embodiment of the present invention includes many variations other than those exemplified here.
  • the individual features included in the various described embodiments can only be used with the embodiments in which the features are directly described, and are not limited to the other embodiments and descriptions described herein. It can also be used in combination in various implementations that are not. All of these variations are within the scope of the present invention, and the applicant claims to have the right to obtain a patent regardless of whether the current claims are claimed. Please note that.

Abstract

La présente invention concerne un procédé d'évaluation du contour d'un myocarde dans des données d'image médicale nucléaire de myocarde. La modification de la valeur d'un pixel desdites données d'image est évaluée au moyen d'une bille radiale à partir d'un point se trouvant dans le ventricule et un premier ellipsoïde se rapprochant de l'ensemble de points de valeur maximale de pixel dans les diverses directions examinées est trouvé. Une pluralité de directions de trace est établie sur la base de ce premier ellipsoïde et le contour du myocarde est évalué à partir des données d'image dans ladite pluralité respective de directions de trace.
PCT/JP2012/074516 2011-09-27 2012-09-25 Technique d'évaluation du contour du myocarde WO2013047496A1 (fr)

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JP5669977B1 (ja) * 2013-08-29 2015-02-18 日本メジフィジックス株式会社 心筋輪郭抽出技術
EP2843620A2 (fr) 2013-08-29 2015-03-04 Nihon Medi-Physics Co., Ltd. L'éxtraction des points de contour myocardiques
JP2015064338A (ja) * 2013-08-29 2015-04-09 日本メジフィジックス株式会社 心筋輪郭抽出技術
US9424642B2 (en) 2013-08-29 2016-08-23 Nihon Medi-Physics Co., Ltd. Extraction of myocardial contour points
EP3254624A1 (fr) 2016-06-08 2017-12-13 Nihon Medi-Physics Co., Ltd. Procédé et appareil d'analyse d'image de médecine nucléaire de myocarde
EP3254625A1 (fr) 2016-06-10 2017-12-13 Nihon Medi-Physics Co., Ltd. Procédé et appareil d'analyse d'image de médecine nucléaire de myocarde
JP7121818B1 (ja) 2021-02-19 2022-08-18 Ｐｄｒファーマ株式会社 プログラム、画像処理装置及び画像処理方法
JP2022126995A (ja) * 2021-02-19 2022-08-31 Ｐｄｒファーマ株式会社 プログラム、画像処理装置及び画像処理方法

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