Ultrasonic image retrieval apparatus and program of the same

Abstract

To simply acquire an ultrasonic image suitable for diagnosis of echo examination.SOLUTION: An ultrasonic image retrieval apparatus 13 is capable of retrieving an object image visualizing a desired examination cross section for a cardiac echo examination, out of a plurality of cardiac ultrasonic images obtained while varying the position and posture of an ultrasonic probe P in contact with the chest surface of an analyte. The retrieval apparatus 13 comprises an image analysis part 16 which performs image analysis of each ultrasonic image, thereby estimates a proper arrangement made of a desired position and desired posture of the ultrasonic probe P capable of obtaining the object image, and extracts as the object image the ultrasonic image obtained in the proper arrangement. The image analysis part 16 comprises a probe arrangement identification part 19 which performs image analysis of acquiring detection information including an inference value expressing the presence probability of a predetermined portion within the heart needing visualization in the object image, with respect to each ultrasonic image, and identifies the proper arrangement of the ultrasonic probe P on the surface of the cardiac apex of the analyte.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and a program for searching for ultrasound images suitable for diagnosis in ultrasound examination. [Background technology]

[0002] In recent years, cardiac ultrasound examination (echocardiography), which supports doctors' diagnosis non-invasively and with high accuracy, has been attracting attention for cardiac diseases, which are one of the leading causes of mortality in Japan. The echocardiography is performed to evaluate the morphology and movement of the subject's heart by applying ultrasound to the subject's heart and converting the reflected sound waves into electrical signals to depict them as images. In this echocardiography, for proper diagnosis, advanced techniques are required to accurately and clearly depict two-dimensional ultrasound images of the heart, which are examination cross sections, and therefore examiners such as doctors and technicians who perform the examination are required to have appropriate knowledge and experience. However, there are only a limited number of hospitals that employ experienced examiners, and many medical institutions currently lack examiners for echocardiography. Furthermore, in echocardiography, the ultrasound probe held by the examiner is applied to the body surface of the subject, such as a patient, at various angles, and the subject is forced to maintain an unnatural posture, so that the burden on the subject increases as the examination time increases. Therefore, the present inventors have developed an ultrasound examination robot that automates echocardiography, which has previously required an examiner to manually operate an ultrasound probe to search for an appropriate ultrasound image (see Patent Document 1). In this ultrasound examination robot, an ultrasound probe placed relative to the examinee's chest is automatically moved along the surface of the examinee's chest while rotating the examinee in a seated position to the side and in the front-back direction. This eliminates the need for the examiner to perform the complicated manual operation of the ultrasound probe as was previously required, and allows the examinee to undergo an echocardiography with a reduced burden on the examinee.

[0003] In the ultrasound examination robot, when controlling the operation of the ultrasound probe by the robot, it is necessary to specify the position and posture of the ultrasound probe that can obtain an ultrasound image of an appropriate examination section for determining the presence or absence of heart disease by echocardiography. Here, as examination sections for determining the presence or absence of heart disease, it is necessary to depict basic sections called the left parasternal left ventricular long axis section, the left parasternal left ventricular short axis section, and the apical four-chamber section. For the left parasternal left ventricular long axis section, the inventors have already proposed an algorithm that automatically specifies the position information and posture information of the ultrasound probe that can obtain a desired ultrasound image (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-70607 A [Patent Document 2] Patent Publication No. 2023-70601 Summary of the Invention [Problem to be solved by the invention]

[0005] As a result of further research by the inventors, for the ultrasound image of the apical four-chamber view among the basic views, an algorithm was created that utilizes information identified when acquiring an ultrasound image of the left ventricular long axis view using the algorithm of Patent Document 2, and identifies the position and posture of the ultrasound probe that can obtain an ultrasound image of the apical four-chamber view that is suitable for diagnosis through efficient operation of the ultrasound probe.

[0006] The present invention has been devised based on the research of the inventors, and its purpose is to provide an ultrasound image searching device and a program therefor that can easily obtain ultrasound images of the apical four-chamber cross section that are suitable for diagnosis through efficient operation of an ultrasound probe. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention is primarily an apparatus for searching for a target image depicting a desired examination cross-section for echocardiography from a plurality of cardiac ultrasound images obtained while changing the position and posture of an ultrasound probe in contact with a subject's chest surface, the apparatus comprising an image analysis unit that estimates an appropriate positioning consisting of a desired position and desired posture of the ultrasound probe at which the target image is obtained by image analysis of each of the ultrasound images, and extracts the ultrasound image obtained at the appropriate positioning as the target image, the image analysis unit performs image analysis on each of the ultrasound images to obtain detection information including an inference value representing the probability of the existence of a specific part in the heart that needs to be depicted in the target image, and a probe positioning identification unit that identifies the appropriate positioning of the ultrasound probe on the surface of the apex of the heart of the subject.

[0008] In the claims and the present specification, the directions of the position and posture of the ultrasonic probe are the directions shown in FIG. 1 unless otherwise specified. That is, the "x-axis direction" in the coordinate system of three orthogonal axes representing the position of the ultrasonic probe P is the head-tail direction of the subject, the "y-axis direction" is the lateral (left-right) direction of the subject, and the "z-axis direction" is the normal direction of the body surface of the subject. In addition, when the center part of the lower end of the ultrasonic probe P in the direction shown in the figure is the center of rotation, the "roll direction" representing the posture of the ultrasonic probe P is the rotation direction φ around the axis (the x-axis) perpendicular to the beam scanning plane F, the "pitch direction" is the rotation direction θ in the direction (around the y-axis) in which the beam scanning plane F is swung back and forth, and the "yaw direction" is the rotation direction ψ around the z-axis. Effect of the Invention

[0009] In the present invention, when searching for a target image depicting the apical four-chamber section for echocardiography from a plurality of cardiac ultrasound images obtained by the operation of a predetermined ultrasound probe, the appropriate position of the ultrasound probe on the apical surface for obtaining the target image is automatically identified. That is, the appropriate position is automatically identified by analyzing the ultrasound images obtained by the minimum necessary operation of the ultrasound probe from information on the left parasternal border left ventricular long axis section obtained separately and the target image is extracted. Therefore, by using an ultrasound examination robot in combination, efficient operation of the ultrasound probe for automatically obtaining the target image is possible, which can significantly reduce the time required for echocardiography compared to the past and contribute to reducing the burden on the subject, and is also expected to solve the social problem of a shortage of echocardiography cases due to a shortage of examiners. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a schematic configuration of an echocardiography system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a conceptual diagram of an apical four-chamber cross-section for explaining a specific part of the heart. [Diagram 3] 13(A) to 13(C) are conceptual diagrams of an apical four-chamber cross section for explaining the relationship between the beam scanning plane and changes in posture of an ultrasound probe in the yaw and roll directions in a desired posture estimation unit. [Figure 4] 13A and 13B are conceptual diagrams of an apical four-chamber cross section for explaining the relationship between a change in posture in the pitch direction of an ultrasound probe in a desired posture estimation unit and a beam scanning plane. [Diagram 5] 1 is a flowchart illustrating a procedure in a first step. [Figure 6] 13 is a flowchart illustrating a procedure in a modified example of the first step. [Figure 7] 13 is a flowchart illustrating a procedure in a second step. [Figure 8] 13 is a flowchart illustrating a procedure in a third step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 shows a block diagram showing a schematic configuration of an echocardiography system including a searching device for an ultrasonic image according to the present embodiment. In this figure, the echocardiography system 10 is a system that enables a doctor to perform an ultrasonic cardiac examination (echocardiography) on a subject at a location remote from the doctor. Specifically, the echocardiography system 10 includes an ultrasonic imaging device 11 that captures ultrasonic images depicting an examination cross section of the heart by contacting an ultrasonic probe P with the chest surface of the subject, a probe operating device 12 that operates the ultrasonic probe P so as to be able to change its position and posture relative to the subject, and a searching device 13 that searches for an ultrasonic image (hereinafter referred to as a "target image") depicting an apical four-chamber cross section, which is one of the basic cross sections for echocardiography, from a plurality of ultrasonic cardiac images obtained while changing the position and posture of the ultrasonic probe P in contact with the chest surface of the subject.

[0013] A known ultrasonic diagnostic device capable of acquiring ultrasonic images for performing various ultrasonic examinations is applied as the ultrasonic imaging device 11. That is, in this ultrasonic imaging device 11, a two-dimensional tomographic image in the same cross section as the beam scanning plane F is acquired as an ultrasonic image by beam scanning using an ultrasonic probe P.

[0014] The probe operation device 12 is a robot that operates a holding part (not shown) that holds the ultrasonic probe P, thereby enabling six-degree-of-freedom motion control of the ultrasonic probe P, consisting of translational motion in three orthogonal axial directions and rotational motion around three orthogonal axes. Although not particularly limited, in this embodiment, an ultrasonic examination robot already proposed by the present inventors is applied (see JP 2023-70607 A). This ultrasonic examination robot is configured to be able to change the position and posture of the ultrasonic probe P arranged relative to the chest of the subject while rotating the subject in a seated posture in the lateral direction and the front-back direction. In addition, the ultrasonic examination robot is equipped with a mechanism for contacting the ultrasonic probe P with the chest surface with a predetermined pressing force in accordance with the unevenness of the chest surface of the subject. Note that the configuration of the ultrasonic examination robot is not an essential element of the present invention, so detailed description will be omitted. The above-mentioned operation control in the probe operation device 12 is performed by simple remote operation by an examiner such as a doctor, as well as by operation commands from a search device 13 required in the process of image search described later.

[0015] The ultrasonic probe P is provided with a known sensor (not shown) capable of detecting its position and orientation. This sensor is capable of acquiring the coordinate position of three orthogonal axes with a preset predetermined point as the origin, and the orientation, which is the rotation angle around the three axes. Although not particularly limited, the coordinate system of this embodiment is a probe coordinate system in the direction of the ultrasonic probe P shown in FIG. 1. Note that as the sensor here, various devices, systems, etc., such as an acceleration sensor, a magnetic sensor, an optical sensor, etc., can be adopted as long as the position and orientation of the ultrasonic probe P can be acquired.

[0016] The searching device 13 is configured by a computer including a processor such as a CPU and storage devices such as a memory and a hard disk, and functions as the following units. The searching device 13 searches for a target image by estimating an appropriate arrangement consisting of a desired position and a desired posture of the ultrasound probe P that can obtain a target image depicting a desired apical four-chamber cross section.

[0017] This searching device 13 is equipped with a memory unit 15 that stores image data including ultrasound images acquired by the ultrasound imaging device 11, and an image analysis unit 16 that analyzes multiple ultrasound images of the heart acquired while changing the position and posture of the ultrasound probe P to estimate the proper positioning of the ultrasound probe P at which a target image is obtained, and extracts the ultrasound image acquired at the proper positioning as the target image.

[0018] The image data is data corresponding to the ultrasonic image, including detection information acquired by image analysis, described later, regarding the position and posture of the ultrasonic probe P when the ultrasonic image was acquired from the detection result of the sensor attached to the ultrasonic probe P, together with the acquisition time. The image data is sequentially stored in the storage unit 15 at each predetermined timing when the ultrasonic probe P moves or rotates.

[0019] In the image analysis unit 16, the position and posture of the ultrasound probe P capable of acquiring an ultrasound image of the left parasternal border left ventricular long axis section among the examination sections used for diagnosing a disease condition in echocardiography is set as the starting point of the search operation, and image analysis processing of the ultrasound image acquired with the subsequent operation of the ultrasound probe P is performed, and a target image is specified from among the acquired multiple ultrasound images. That is, here, a desired position that is estimated to be the subject's chest surface directly above the apex of the heart (hereinafter simply referred to as the "apex surface") is specified while translating the ultrasound probe P by the operation of the probe operation device 12. Then, the translation movement of the ultrasound probe P is stopped at the apex surface, and the desired posture at which the target image is obtained is specified while changing the posture of the ultrasound probe P by the operation of the probe operation device 12. These desired positions and postures are the appropriate arrangement of the ultrasound probe P at which the target image is obtained.

[0020] This image analysis unit 16 comprises a starting point identification unit 18 that identifies the position and posture of the ultrasonic probe P at the starting point of the search operation, and a probe placement identification unit 19 that identifies the appropriate placement of the ultrasonic probe P while changing the position and posture of the ultrasonic probe P from the starting point.

[0021] In the origin identification unit 18, the position and posture of the ultrasound probe P that obtains the optimal parasternal left edge left ventricular long axis cross section is identified based on the ultrasound image acquired from the ultrasound probe P scanned along a predetermined range of the subject's chest surface by the operation of the probe operation device 12 using the method already proposed by the present inventors in JP 2023-70601 A. In other words, according to this method, as shown in FIG. 2, the position and posture of the ultrasound probe P that captures the mitral valve M in the cross section of the heart H at the center of the image are obtained, and this part is set as the origin S, and the position of the left ventricular long axis LL, which is a straight line connecting the apex A at the tip of the left ventricle H1 and the center of the mitral valve M, is obtained.

[0022] In the probe placement determination unit 19, when the ultrasonic probe P is translated and its posture is changed by the operation control of the probe operating device 12, the ultrasonic images obtained successively are analyzed, and the proper placement of the ultrasonic probe P in the desired posture with the desired position on the surface of the apex of the subject's heart is determined.

[0023] In the analysis of this ultrasound image, detection information is obtained within the image of a predetermined part of the heart (mitral valve M, tricuspid valve T, ventricular septum VS) shown in FIG. 2. That is, as the detection information here, an inference value indicating the probability of the presence (certainty) of the predetermined part, its position within the image, etc. are appropriately obtained. For this image analysis, a known object detection model such as YOLO that utilizes deep learning or the like to recognize a predetermined object based on trained image data is used. Note that for this image analysis, various other systems and devices can be adopted as long as the detection information can be obtained based on the acquired ultrasound image.

[0024] This probe placement identification unit 19 includes a desired position estimation unit 21 that estimates the desired position of the ultrasound probe P that will be in contact with the apex surface, and a desired posture estimation unit 22 that estimates the desired posture of the ultrasound probe P that will obtain a target image at the desired position.

[0025] In the desired position estimation unit 21, the ultrasonic probe P moves from the origin S along the left ventricular long axis L in the posture specified by the origin specification unit 18 while contacting the chest surface according to the procedure described below, and the vertical and horizontal (xy-axis) positions of the apical surface, which is the target position, are estimated by analyzing the ultrasonic images acquired sequentially during the movement. In the image analysis here, the object detection model is used to obtain detection information such as an inferred value of the mitral valve M in each acquired ultrasonic image, and the vertical and horizontal positions of the apical surface are specified based on the detection information. The position of the apical surface in the internal and external directions (z-axis) is automatically specified because the probe operation device 12 has a mechanism for contacting the ultrasonic probe P by following the unevenness of the subject. The ultrasonic probe P located above the apical surface acquires an ultrasonic image depicting the apical left ventricular long axis cross section.

[0026] The desired posture estimation unit 22 analyzes ultrasonic images acquired sequentially while changing the posture of the ultrasonic probe P at a desired position on the apical surface of the heart, and estimates a desired posture of the ultrasonic probe P in which the mitral valve M, ventricular septum VS, and tricuspid valve T, which are the conditions for depicting the apical four-chamber cross-section, are on the same plane, and the four chambers H1 to H4 of the heart H are best balanced around the ventricular septum VS.

[0027] The desired posture estimation unit 22 includes a yawing information acquisition unit 24 that identifies the desired posture in the yaw direction ψ by analyzing each of the ultrasound images obtained sequentially in accordance with the rotational movement in the yaw direction ψ of the ultrasound probe P contacting the surface of the apex of the heart, a rolling information acquisition unit 25 that identifies the desired posture in the roll direction φ by analyzing each of the ultrasound images obtained sequentially in accordance with the rotational movement in the roll direction φ, and a pitching information acquisition unit 26 that identifies the desired posture in the pitch direction θ by analyzing each of the ultrasound images obtained sequentially in accordance with the rotational movement in the pitch direction θ.

[0028] The yawing information acquisition unit 24 analyzes ultrasonic images sequentially obtained when the ultrasonic probe P is rotated in the yaw direction ψ from the initial posture of the ultrasonic probe P on the apex A shown in Fig. 3(A). That is, here, the object detection model specifies a desired posture of the ultrasonic probe P in the yaw direction ψ in which the mitral valve M and the ventricular septum VS are included more in the beam scanning plane F as shown in Fig. 3(B) from each acquired ultrasonic image.

[0029] The rolling information acquisition unit 25 analyzes the ultrasonic images obtained sequentially when the ultrasonic probe P is rotated in the roll direction φ from the state of Fig. 3(B) in which the attitude in the yaw direction ψ specified by the yawing information acquisition unit 24 is fixed. That is, here, for each acquired ultrasonic image, as shown in Fig. 3(C), in order to visualize more of the tricuspid valve T that appears symmetrically with the mitral valve M centered on the ventricular septum VS, a desired attitude in the roll direction φ of the ultrasonic probe P is identified, in which the position of the ventricular septum VS becomes the beam scanning plane F that visualizes the position of the ventricular septum VS near the center of the image.

[0030] The pitching information acquisition unit 26 analyzes the ultrasonic images sequentially obtained when the ultrasonic probe P on the apex A is rotated in the pitch direction θ in the desired posture in the yaw direction ψ and roll direction φ specified by the yawing information acquisition unit 24 and the rolling information acquisition unit 25. That is, here, for each acquired ultrasonic image, a desired posture in the pitch direction θ of the ultrasonic probe P is specified, which is a beam scanning plane F that can depict the four cavities H1 to H4 of the heart H in the best balance, as shown in FIG. 4(B) from the state shown in FIG. 4(A).

[0031] In the above-described probe arrangement specifying unit 19, an ultrasound image obtained by properly placing the ultrasound probe P is extracted as a target image.

[0032] Next, a procedure for searching for a target image while operating the ultrasonic probe P will be described with reference to the flowcharts of FIGS.

[0033] The following search procedure is executed in the following order: a first step of identifying the desired position of the ultrasonic probe P by image analysis processing in the desired position estimation unit 21; a second step of identifying the desired attitudes of the ultrasonic probe P in the yaw direction ψ and roll direction φ by image analysis processing in the yawing information acquisition unit 24 and the rolling information acquisition unit 25; and a third step of identifying the desired attitude of the ultrasonic probe P in the pitch direction θ by image analysis processing in the pitching information acquisition unit 26.

[0034] In the first step, the desired location of the apical surface is identified using the procedure shown in FIG.

[0035] First, the origin identifying unit 18 identifies an origin S, which is the position of the ultrasound probe P in a posture that allows an appropriate left parasternal border left ventricular long axis cross section to be obtained (step S101). The ultrasound probe P moves in the same posture from the origin S along the left ventricular long axis LL (see FIG. 2) determined by the origin identifying unit 18 while contacting the subject's chest surface (step S102) by the operation of the probe operating device 12. At this time, ultrasound images are acquired at predetermined time intervals (step S103). For each acquired ultrasound image, an inference value of the mitral valve M is calculated by the object detection model, and the presence or absence of detection of the mitral valve M is determined (step S104). Here, when the inference value is equal to or greater than zero or equal to or greater than a predetermined value, it is determined that the mitral valve M is present in the acquired ultrasound image. At this time, the position of the mitral valve M in the image is obtained, and it is determined whether or not the position in the image is near the center of the image, that is, within a predetermined allowable range (hereinafter referred to as the "image center range") from the center of the image (step S105). Therefore, when the position of the mitral valve M in the image does not exist within the image central range, the posture of the ultrasonic probe P is adjusted while rotating in the roll direction φ by the operation control of the probe operation device 12 so as to eliminate the positional deviation depending on the distance in the left or right direction from the image central range in the image (step S106). The ultrasonic image acquired after this posture adjustment is stored in the storage unit 15 as image data corresponding to the position, posture, etc. of the ultrasonic probe P at that time (step S107). On the other hand, when the position of the mitral valve M in the image exists within the image central range, the ultrasonic image at that time is stored in the storage unit 15 as image data corresponding to the position, posture, etc. of the ultrasonic probe P (step S107). Then, it is determined whether the movement distance of the ultrasonic probe P from the starting point S has reached a preset distance (step S108). When the preset distance is reached, a position corresponding to the ultrasound image at the last timing when the inferred value of the mitral valve M is equal to or greater than a predetermined value, i.e., a preset threshold value, and when the mitral valve M was detected consecutively, is identified as the desired position on the apical surface from among the image data stored in the memory unit 15, and the ultrasound probe P is moved to the apical surface in this posture by the operation control of the probe operating device 12 (step S109).Here, when the mitral valve M is not detected multiple times in succession, the position where the inferred value of the mitral valve M is equal to or greater than the predetermined value and corresponds to the ultrasonic image where the mitral valve M was last detected is specified as the desired position. Note that the threshold value here is not particularly limited, and may be an arbitrary value set in advance or an average value of the inferred values ​​in each ultrasonic image.

[0036] As the first step, instead of the procedure of FIG. 5, the procedure shown in FIG. 6 can be used to identify the desired position on the apex surface.

[0037] 5 described above, but instead of the determination based on the moving distance of the ultrasonic probe P in step S108, it is determined whether the non-detection state of the mitral valve M in step S104 continues a predetermined number of times (step S110). Then, when the non-detection state of the mitral valve M continues, the same process as step S109 is performed.

[0038] In the above first step, the processing is based on the property that the entire ultrasound image suddenly turns black immediately after the ultrasound probe P, which moves along the left ventricular long axis LL with the mitral valve M as the starting point S, passes over the apex A due to the presence of an air layer between the ultrasound probe P and the heart H. In other words, based on the findings of the inventors' research results that the moment just before the ultrasound image turns black is the position of the ultrasound probe P on the apex A, the position where the mitral valve M was last detected in the ultrasound image during the movement of the ultrasound probe P along the left ventricular long axis LL from above the mitral valve M is estimated to be the position of the apex surface.

[0039] In the second step shown in FIG. 7, while appropriately changing the posture of the ultrasound probe P present on the surface of the apex of the heart, a desired posture in the yaw direction ψ and roll direction φ of the ultrasound probe P is specified by processing in the yawing information acquisition unit 24 and the rolling information acquisition unit 25, at which the mitral valve M, the tricuspid valve T, and the ventricular septum VS are depicted on the same plane of the ultrasound image.

[0040] First, the ultrasonic probe P moved to the apex surface in the first step is rotated in the yaw direction ψ by the operation of the probe operating device 12 (step S201), and ultrasonic images are acquired at predetermined time intervals (step S202). Then, the yawing information acquisition unit 24 performs the following process on the acquired ultrasonic images. That is, the object detection model calculates inference values ​​including the presence or absence of detection of the ventricular septum VS and the mitral valve M as detection information (steps S203 and S204). Here, when the inference value is equal to or greater than zero or equal to or greater than a predetermined value, it is determined that the ventricular septum VS and the mitral valve M are present in the acquired ultrasonic image. Then, an overall inference value is calculated by summing up the inference values ​​for the ventricular septum VS and the mitral valve M, and the image data at that time including the detection information including the overall inference value is stored in the storage unit 15 (step S205). This overall inference value is calculated by summing up the inference values ​​for the ventricular septum VS and the mitral valve M multiplied by a preset weighting constant. Then, when the rotation of the ultrasonic probe P in the yaw direction ψ exceeds a predetermined angle (e.g., 180 degrees) (step S206), the rotation angle in the yaw direction ψ with the higher overall inference value is specified as the desired posture (step S207). By comparing ultrasonic images within a preset angle range (predetermined range), the rotation angle in the yaw direction ψ with the higher overall inference value of the ventricular septum VS and the mitral valve M can be specified as the desired posture, and further, the highest rotation angle among the higher rotation angles within each range may be determined as the desired posture in the yaw direction ψ. Then, the probe operating device 12 rotates the ultrasonic probe P so as to achieve the desired posture in the yaw direction ψ.

[0041] Next, the ultrasonic probe P is rotated in the roll direction φ by the operation of the probe operation device 12 (step S208), and ultrasonic images are acquired at predetermined time intervals (step S209). Then, the following process is performed on the acquired ultrasonic images by the rolling information acquisition unit 24. That is, the object detection model determines whether the ventricular septum VS is detected in the acquired ultrasonic images from the detection information of the ventricular septum VS (step S210). Here, too, when the inference value is equal to or greater than zero or equal to or greater than a predetermined value, it is determined that the ventricular septum VS exists in the acquired ultrasonic images, and it is determined whether the position of the ventricular septum VS exists within the image center range (step S211). Therefore, when the position of the ventricular septum VS does not exist within the image center range, the attitude of the ultrasonic probe P is adjusted by rotating it in the roll direction φ by the operation control of the probe operation device 12 so that the ventricular septum VS is within the image center range (step S212). Then, in the process of rotating the ultrasonic probe P in the roll direction φ while the orientation in the yaw direction ψ is fixed at the position of the apex surface, the ultrasonic probe P at the rotation angle in the roll direction φ when the ventricular septum VS is initially present within the image center range is identified as the desired orientation in the roll direction φ (step S213). The probe operating device 12 rotates the ultrasonic probe P so that it assumes the desired orientation in the roll direction φ.

[0042] In the desired posture in the yaw direction ψ and roll direction φ specified in the second step, the mitral valve M is visualized with the ventricular septum VS at the center of the ultrasound image, and the tricuspid valve T, which is symmetrical to the mitral valve M across the ventricular septum VS, is also visualized on the same plane of the ultrasound image. Note that, as long as the position and posture of the ultrasound probe P at which there is always a moment when both the mitral valve M and the ventricular septum VS can be visualized when the ultrasound probe P is rotated fully around in the yaw direction ψ, are known, the processing in the first step may be omitted, and the second step may be started from the position and posture.

[0043] In the third step shown in FIG. 8, the posture of the ultrasound probe P present on the surface of the apex of the heart is appropriately changed in the pitch direction θ while maintaining the desired posture in the yaw direction ψ and roll direction φ specified in the second step, and the desired posture of the ultrasound probe P in the pitch direction θ is specified by processing in the pitching information acquisition unit 26 when an image in which the four cavities H1 to H4 of the heart H are depicted in a better balanced state is obtained.

[0044] First, the ultrasonic probe P is rotated in the pitch direction θ by the operation of the probe operating device 12 while maintaining the posture in the yaw direction ψ and roll direction φ specified in the second step at the position of the apex surface (step S301), and ultrasonic images are acquired at predetermined time intervals (step S302). The following process is performed on the acquired ultrasonic images by the pitching information acquisition unit 26. That is, the object detection model calculates inference values ​​including the presence or absence of detection of the mitral valve M and the tricuspid valve T as detection information (steps S303 and S304). Here, when the inference value is equal to or greater than zero or equal to or greater than a predetermined value, it is determined that the mitral valve M and the tricuspid valve T are present in the acquired ultrasonic image. After that, an overall inference value is calculated by integrating the inference values ​​for the mitral valve M and the tricuspid valve T, and the image data at that time including the detection information including the overall inference value is stored in the storage unit 15 (step S305). This overall inference value is calculated by summing values ​​obtained by multiplying each inference value of the mitral valve M and the tricuspid valve T by a preset weighting constant. Then, it is determined whether the rotation of the ultrasonic probe P in the pitch direction θ is greater than or equal to a predetermined angle range (for example, a range of ±40 degrees based on the posture at the time of determining the desired position in the first step) (step S306), and when the rotation within the predetermined angle range is completed, the rotation angle in the pitch direction θ with the highest overall inference value is specified as the desired posture (step S307). Note that, by comparing ultrasonic images within a preset angle range (predetermined range), the rotation angle in the pitch direction θ with the highest overall inference value of the mitral valve M and the tricuspid valve T can be specified as the desired posture. Furthermore, the highest rotation angle among the higher rotation angles within each range may be specified as the desired posture in the pitch direction θ.

[0045] The ultrasound image corresponding to the desired position and desired posture of the ultrasound probe P identified through the above first to third steps is extracted as a target image, which is an ultrasound image depicting an apical four-chamber cross section suitable for examination (step S308).

[0046] In the above embodiment, the ultrasonic probe P is moved and rotated by the operation of the probe operation device 12. However, the present invention is not limited to this. Under the guidance of the search device 13, the operator can manually move and rotate the ultrasonic probe P, while the search device 13 processes the ultrasonic probe P to identify a desired position and a desired posture of the ultrasonic probe P suitable for obtaining a target image.

[0047] Additionally, the configurations and processing procedures of the various parts of the device in the present invention are not limited to those described above, and various modifications are possible as long as they provide substantially the same effects. [Explanation of symbols]

[0048] 13 Search device 16 Image Analysis Section 19 Probe placement identification unit 21 Desired position estimation unit 22 Desired posture estimation section 24 Yaw information acquisition unit 25 Rolling Information Acquisition Department 26 Pitching information acquisition section A apex H1~H4 four chambers LL Left ventricular long axis M Mitral valve P Ultrasonic Probe T Tricuspid valve VS ventricular septum

Claims

1. An apparatus for searching for a target image depicting a desired examination cross section for echocardiography from a plurality of cardiac ultrasound images obtained while changing the position and orientation of an ultrasound probe in contact with a chest surface of a subject, comprising: an image analysis unit that estimates an appropriate arrangement of the ultrasound probe, which is a desired position and a desired posture, at which the target image is obtained, by image analysis of each of the ultrasound images, and extracts the ultrasound image obtained at the appropriate arrangement as the target image; The image analysis unit performs image analysis for each of the ultrasound images to obtain detection information including an inference value representing the probability of the presence of a specific site within the heart that needs to be depicted in the target image, and the ultrasound image exploration device is characterized in that it is equipped with a probe placement identification unit that identifies the appropriate placement of the ultrasound probe on the surface of the apex of the heart of the subject.

2. the probe placement specifying unit includes a desired position estimating unit that estimates the desired position where the ultrasound probe comes into contact with the surface of the apex of the heart, 2. The ultrasound image searching device according to claim 1, wherein the desired position estimation unit determines, for each of the ultrasound images sequentially obtained while the ultrasound probe moves on the chest surface along the left ventricular long axis starting from a mitral valve whose position has been estimated in advance, the desired position based on the detection information of the mitral valve as the position of the ultrasound probe at the last timing when the inference value is equal to or greater than a predetermined value and the mitral valve is detected multiple times in succession.

3. the probe placement specifying unit includes a desired posture estimating unit that estimates the desired posture of the ultrasound probe that is in contact with the apex surface, the desired posture estimation unit includes a yaw information acquisition unit that identifies the desired posture in a yaw direction by analyzing the ultrasound images sequentially obtained in accordance with a rotational movement of the ultrasound probe in the yaw direction, 3. The ultrasound image searching device according to claim 1, wherein the yawing information acquisition unit determines, for each of the ultrasound images, a yaw direction posture having a higher overall inference value, which is a combination of the inference values ​​of the mitral valve and the ventricular septum, based on the detection information of the mitral valve and the ventricular septum, as the desired posture.

4. the probe placement specifying unit includes a desired posture estimating unit that estimates the desired posture of the ultrasound probe that is in contact with the apex surface, the desired posture estimation unit includes a rolling information acquisition unit that identifies the desired posture in a roll direction by analyzing the ultrasound images sequentially obtained in association with a rotational movement of the ultrasound probe in the roll direction; 3. The ultrasound image searching device according to claim 1, wherein the rolling information acquisition unit determines, for each ultrasound image, a roll direction posture in which the ventricular septum is located near the center of the image as the desired posture based on the detection information of the ventricular septum.

5. the probe placement specifying unit includes a desired posture estimating unit that estimates the desired posture of the ultrasound probe that is in contact with the apex surface, the desired attitude estimation unit includes a pitching information acquisition unit that identifies the desired attitude in a pitch direction by analyzing the ultrasound images sequentially obtained in accordance with a rotational movement of the ultrasound probe in the pitch direction, 3. The ultrasonic image searching device according to claim 1, wherein the pitching information acquisition unit determines, for each of the ultrasonic images, a posture in the pitch direction having a higher overall inference value obtained by combining the inference values ​​of the mitral valve and the tricuspid valve based on the detection information of the mitral valve and the tricuspid valve as the desired posture.

6. the probe placement specifying unit includes a desired posture estimating unit that estimates the desired posture of the ultrasound probe that is in contact with a surface of the apex of the heart so that an apical four-chamber cross section is depicted as the target image; The desired posture estimation unit specifies the desired posture in the yaw direction and the roll direction in which the mitral valve, the tricuspid valve, and the ventricular septum can be visualized on the same plane of the ultrasound image and the four chambers can be visualized with the ventricular septum at the center, based on the detection information of the mitral valve and the ventricular septum obtained by analyzing each of the ultrasound images obtained sequentially in accordance with the rotational movement of the ultrasound probe in the yaw direction and the roll direction, and specifies the desired posture in the pitch direction in which the four chambers can be visualized in a more balanced state, based on the detection information of the mitral valve and the tricuspid valve obtained by analyzing each of the ultrasound images obtained sequentially in accordance with the rotational movement of the ultrasound probe in the pitch direction in the desired posture state in the yaw direction and the roll direction.

7. A program for an apparatus for searching for a target image depicting a desired examination cross section for an echocardiogram from a plurality of cardiac ultrasound images obtained while changing the position and orientation of an ultrasound probe in contact with a chest surface of a subject, the program comprising: by performing image analysis of each of the ultrasound images, a proper arrangement of the ultrasound probe, which is a desired position and a desired posture, at which the target image is obtained, is estimated, and the ultrasound image obtained at the proper arrangement is extracted as the target image; The image analysis unit performs image analysis for each of the ultrasound images to obtain detection information including an inference value representing the probability of the presence of a specific site within the heart that needs to be depicted in the target image, and the image analysis unit is further characterized by having a probe placement identification unit that identifies the appropriate placement of the ultrasound probe on the surface of the apex of the heart of the subject.

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