Ultrasound diagnostic device and control method for ultrasound diagnostic device

Abstract

The present invention provides an ultrasound diagnostic device and a control method for the ultrasound diagnostic device that can easily and accurately correct the contour lines of the intracardiac chambers. [Solution] The ultrasound diagnostic device includes an intracardiac cavity extraction unit (25) that extracts intracardiac cavities from ultrasound images of the subject's heart, a correction possibility estimation unit (26) that estimates the possibility of correction in each part of the contour by analyzing the contour of the extracted intracardiac cavities, a control point identification unit (27) that identifies control points on the contour based on the estimated correction possibilities, an input device (32) for the user to perform input operations, a correction operation reception unit (28) that receives correction operations performed by the user on the identified control points via the input device (32), and a contour line correction unit (29) that corrects the contour based on the received correction operations.

Description

Technical Field

[0001] The present invention relates to an ultrasonic diagnostic apparatus for imaging an ultrasonic image of a subject's heart and a control method for the ultrasonic diagnostic apparatus.

Background Art

[0002] Conventionally, an ultrasonic image representing a tomographic plane of a subject's heart has been captured using a so-called ultrasonic diagnostic apparatus, and using this ultrasonic image, so-called left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular regional wall motion, GLS (Global Longitudinal Strain), MAPSE (Mitral Annular Plane Systolic Excursion), TAPSE (Tricuspid Annular Plane Systolic Excursion), cardiac output, stroke volume, and other cardiac functions may be measured.

[0003] Measurement of cardiac function may be performed based on the contour line of the cardiac cavity in the ultrasonic image. Although it is known that the contour line of the cardiac cavity can be automatically extracted by analyzing the ultrasonic image, if the automatically extracted contour line of the cardiac cavity is erroneously extracted, or if the automatically extracted contour line is different from the contour line recognized by a user such as a doctor when viewing the ultrasonic image, accurate or desired measurement values of cardiac function may not be obtained with the extracted contour line.

[0004] Therefore, for example, as disclosed in Patent Document 1, a technique for correcting the automatically extracted contour line of the cardiac cavity has been developed. Patent Document 1 discloses that a user manually places control points on the extracted contour line of the cardiac cavity, manually moves the placed control points, and corrects the contour line according to the positions of the moved control points.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Special Publication No. 2018-507738 [Overview of the initiative] [Problems that the invention aims to solve]

[0006] However, in Patent Document 1, the user manually places the control points, making it difficult to place the control points in the appropriate positions to correct the contour line to the desired shape and size, which can result in time-consuming contour line correction. Cardiac function measurements are sometimes performed in emergency medical settings where rapid treatment of the subject is required. If contour line correction takes time, it may become impossible to quickly measure the subject's cardiac function and evaluate the cardiac function using those measurements, potentially hindering rapid treatment of the subject.

[0007] This invention was made to solve the problems of the conventional methods, and aims to provide an ultrasound diagnostic device and a control method for the ultrasound diagnostic device that can easily and accurately correct the contour lines of the intracardiac chambers. [Means for solving the problem]

[0008] The above objective can be achieved with the following configuration. [1] An intracardiac cavity extraction unit that extracts intracardiac chambers from ultrasound images of the subject's heart, The system includes a modification possibility estimation unit that analyzes the contour lines of the intracardiac chambers extracted by the intracardiac chamber extraction unit to estimate the possibility of modification in each part of the contour line in order to evaluate cardiac function, and A control point identification unit identifies control points on the contour line based on the possibility of modification predicted by the modification possibility prediction unit, An input device for the user to perform input operations, A correction operation receiving unit receives correction operations performed by the user via an input device on the control points identified by the control point identification unit, The contour line correction unit corrects the contour lines based on the correction operations received by the correction operation reception unit. An ultrasound diagnostic device equipped with the following features. [2] The ultrasound diagnostic apparatus according to [1], wherein the correction possibility estimation unit estimates the possibility of correction in each part of the contour line based on changes in the shape of the contour line over multiple heartbeats. [3] The ultrasound diagnostic apparatus according to [2], wherein the control point identification unit identifies control points in the portion where the amount of change in the shape of the contour line over multiple heartbeats is greater than or equal to a first threshold. [4] The intracardiac chamber extraction unit calculates the confidence level of the extracted intracardiac chamber region. The ultrasound diagnostic apparatus described in [1], wherein the correction possibility estimation unit estimates the possibility of correction in each part of the contour line based on the confidence level calculated by the intracardiac cavity extraction unit. [5] The ultrasound diagnostic apparatus according to [4], wherein the control point identification unit identifies a control point in the region of the intracardiac chamber where the change in confidence is less than or equal to a second threshold. [6] The ultrasound diagnostic apparatus according to [1], wherein the correction possibility estimation unit estimates the possibility of correction in each part of the contour line based on changes in brightness values ​​along the contour line. [7] The ultrasonic diagnostic apparatus according to [6], wherein the control point identification unit identifies control points in the portion of the contour line where the change in brightness value is greater than or equal to a third threshold. [8] Extract the intracardiac chambers from the ultrasound images taken of the subject's heart. By analyzing the extracted intracardiac cavity contour lines, we can infer the possibility of modifications in each part of the contour line in order to evaluate cardiac function. Based on the suspected possibility of modifications, identify control points on the contour line. It accepts modification operations performed by the user on the control points. Modify the contour lines based on the correction operation. A method for controlling an ultrasound diagnostic device. [Effects of the Invention]

[0009] The present invention provides an ultrasound diagnostic device comprising: an intracardiac cavity extraction unit that extracts intracardiac cavities from ultrasound images of a subject's heart; a modification possibility estimation unit that analyzes the contour lines of the intracardiac cavities extracted by the intracardiac cavity extraction unit to estimate the possibility of modification in each part of the contour line in order to evaluate the functionality of the heart; a control point identification unit that identifies control points on the contour line based on the modification possibilities estimated by the modification possibility estimation unit; an input device for the user to perform input operations; a modification operation reception unit that receives modification operations performed by the user via the input device on the control points identified by the control point identification unit; and a contour line modification unit that modifies the contour line based on the modification operations received by the modification operation reception unit. As a result, the contour lines of the intracardiac cavities can be easily and accurately modified. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing the configuration of an ultrasound diagnostic device according to an embodiment of the present invention. [Figure 2] This is a block diagram showing the internal configuration of the transmitting and receiving circuit in an embodiment of the present invention. [Figure 3] This is a block diagram showing the internal configuration of the image generation unit in an embodiment of the present invention. [Figure 4] This diagram schematically shows an example of an ultrasound image representing a two-chamber cross-section of the cardiac apex. [Figure 5] This is an example of a graph showing the time-series changes in the area of ​​the cardiac cavity in ultrasound images. [Figure 6] This diagram shows multiple contours of the cardiac chambers corresponding to different stages of end-diastole, superimposed on each other. [Figure 7] This diagram schematically shows an example of a heat map illustrating the confidence level of intracardiac chambers. [Figure 8] This is an example of a graph showing the change in brightness values ​​in an ultrasound image along the contour lines of the intracardiac cavity. [Figure 9] This diagram schematically shows an example of a control point identified on the contour line of the intracardiac cavity. [Figure 10] This flowchart shows the operation of an ultrasound diagnostic device according to an embodiment of the present invention.

Best Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. The description of the constituent elements described below is based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In this specification, "identical" and "the same" shall include the error range generally allowed in the technical field.

[0012] Embodiment FIG. 1 shows the configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. The ultrasonic diagnostic apparatus includes an ultrasonic probe 1 and a device main body 2 connected to each other by so-called wired communication or so-called wireless communication.

[0013] The ultrasonic probe 1 includes a transducer array 11 and a transmission / reception circuit 12 connected thereto.

[0014] The device main body 2 includes an image generation unit 21 connected to the transmission / reception circuit 12. In the device main body 2, a display control unit 22 and a monitor 23 are sequentially connected to the image generation unit 21. A memory 24 is connected to the image generation unit 21. A cardiac cavity extraction unit 25 is connected to the memory 24. A modification possibility estimation unit 26, a control point identification unit 27, a modification operation reception unit 28, a contour line modification unit 29, and a cardiac function measurement unit 30 are sequentially connected to the cardiac cavity extraction unit 25. The memory 24, the modification possibility estimation unit 26, the control point identification unit 27, the contour line modification unit 29, and the cardiac function measurement unit 30 are connected to the display control unit 22. Further, a main body control unit 31 is connected to the transmission / reception circuit 12, the image generation unit 21, the display control unit 22, the memory 24, the cardiac cavity extraction unit 25, the modification possibility estimation unit 26, the control point identification unit 27, the modification operation reception unit 28, the contour line modification unit 20, and the cardiac function measurement unit 30. An input device 32 is connected to the main body control unit 31.

[0015] Furthermore, the image acquisition unit 33 is comprised of the transmitting / receiving circuit 12 and the image generation unit 21. In addition, the processor 34 for the main unit 2 is comprised of the image generation unit 21, the display control unit 22, the intracardiac chamber extraction unit 25, the correction possibility estimation unit 26, the control point identification unit 27, the correction operation reception unit 28, the contour line correction unit 29, the cardiac function measurement unit 30, and the main unit control unit 31.

[0016] The transducer array 11 of the ultrasonic probe 1 has a plurality of ultrasonic transducers arranged in one or two dimensions. Each of these ultrasonic transducers transmits ultrasound according to a drive signal supplied from the transmitting / receiving circuit 12, and also receives ultrasonic echoes from the subject and outputs a signal based on the ultrasonic echoes. Each ultrasonic transducer is constructed by forming electrodes at both ends of a piezoelectric body made of, for example, a piezoelectric ceramic represented by PZT (Lead Zirconate Titanate), a polymer piezoelectric element represented by PVDF (Poly Vinylidene Di Fluoride), or a piezoelectric single crystal represented by PMN-PT (Lead Magnesium Niobate-Lead Titanate).

[0017] The image acquisition unit 33, which consists of a transmitting / receiving circuit 12 and an image generation unit 21, acquires an ultrasound image of the subject's heart by transmitting and receiving an ultrasound beam using the ultrasound probe 1.

[0018] The transmitting / receiving circuit 12 transmits ultrasonic waves from the transducer array 11 and generates a sound line signal based on the received signal acquired by the transducer array 11, under the control of the main unit control 31. As shown in Figure 2, the transmitting / receiving circuit 12 has a pulser 41 connected to the transducer array 11, and an amplifier 42, an AD (Analog to Digital) converter 43, and a beamformer 44 connected sequentially in series from the transducer array 11.

[0019] The pulser 41 includes, for example, multiple pulse generators, and based on a transmission delay pattern selected according to a control signal from the main unit control 31, it supplies each drive signal to the multiple ultrasonic transducers of the transducer array 11, adjusting the delay amount, so that the ultrasonic waves transmitted from the transducers form an ultrasonic beam. In this way, when a pulsed or continuous wave voltage is applied to the electrodes of the ultrasonic transducers of the transducer array 11, the piezoelectric material expands and contracts, generating pulsed or continuous wave ultrasonic waves from each ultrasonic transducer, and an ultrasonic beam is formed from the combined wave of these ultrasonic waves.

[0020] The transmitted ultrasonic beam is reflected from a target, such as a part of the subject, and propagates toward the transducer array 11 of the ultrasonic probe 1. The ultrasonic echo propagating toward the transducer array 11 is received by each ultrasonic transducer that makes up the transducer array 11. At this time, each ultrasonic transducer that makes up the transducer array 11 expands and contracts upon receiving the propagating ultrasonic echo, generating a received signal which is an electrical signal, and outputs these received signals to the amplification unit 42.

[0021] The amplification unit 42 amplifies the signals input from each ultrasonic transducer constituting the transducer array 11 and transmits the amplified signals to the AD conversion unit 43. The AD conversion unit 43 converts the signals transmitted from the amplification unit 42 into digital received data. The beamformer 44 performs so-called receive focus processing by adding each received data received from the AD conversion unit 43 with a corresponding delay. Through this receive focus processing, each received data converted by the AD conversion unit 43 is phase-corrected and added together, and a sound ray signal with a focused ultrasonic echo is obtained.

[0022] As shown in Figure 3, the image generation unit 21 has a configuration in which a signal processing unit 45, a DSC (Digital Scan Converter) 46, and an image processing unit 47 are connected in series in sequence.

[0023] The signal processing unit 45 receives the sound line signal from the transmitting / receiving circuit 12, and after correcting for attenuation due to distance according to the depth of the ultrasonic reflection position using the sound velocity value set by the main unit control unit 31, it performs envelope detection processing to generate a B-mode image signal, which is tomographic image information of the tissue within the subject.

[0024] The DSC46 converts the B-mode image signal generated by the signal processing unit 45 into an image signal that follows the scanning method of a normal television signal (raster conversion). The image processing unit 47 performs various necessary image processing, such as gradation processing, on the B-mode image signal input from the DSC 46, and then sends the B-mode image signal to the display control unit 22 and the memory 24. Hereafter, the B-mode image signal processed by the image processing unit 47 will be referred to as the ultrasound image.

[0025] The ultrasound diagnostic device according to the embodiment of the present invention is used to evaluate cardiac function by measuring cardiac function parameters such as left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular local wall motion, global longitudinal strain (GLS), mitral annular plane systolic excursion (MAPSE), tricuspid annular plane systolic excursion (TAPSE), cardiac output, and stroke volume.

[0026] For measuring cardiac function, the image acquisition unit 33 acquires ultrasound images U representing cross-sections of intracardiac chambers A, such as the so-called apical two-chamber section 2C of the heart H, as shown in Figure 4. Intracardiac chambers A refer to any of the left ventricle, left atrium, right ventricle, or right atrium. In addition to the apical two-chamber section 2C, other cross-sections of intracardiac chambers A passing through the apex can be captured, such as the so-called apical four-chamber section, apical three-chamber section, and apical five-chamber section.

[0027] The display control unit 22, under the control of the main unit control unit 31, performs predetermined processing on the ultrasound image U acquired by the image acquisition unit 33 and displays it on the monitor 23.

[0028] The monitor 23 displays ultrasound images U, etc., under the control of the display control unit 22, and has a display device such as an LCD (Liquid Crystal Display) or an organic EL display (Organic Electroluminescence Display).

[0029] The main unit control unit 31 controls each part of the main unit 2 and the transmitting / receiving circuit 12 of the ultrasonic probe 1 based on a control program or the like that is stored in advance.

[0030] The input device 32 is for the user to perform input operations and consists of devices such as a keyboard, mouse, trackball, touchpad, and touch sensor placed on top of the monitor 23.

[0031] The memory 24 stores the ultrasound image U acquired by the image acquisition unit 33 under the control of the main unit control unit 31.

[0032] For memory 24, for example, recording media such as flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), FD (Flexible Disk), MO disk (Magneto-Optical disk), MT (Magnetic Tape), RAM (Random Access Memory), CD (Compact Disc), DVD (Digital Versatile Disc), SD card (Secure Digital card), or USB memory (Universal Serial Bus memory) can be used.

[0033] The intracardiac cavity extraction unit 25 performs image analysis on the ultrasound image U acquired by the image acquisition unit 33 and stored in the memory 24, thereby extracting intracardiac cavity A from the ultrasound image U, as shown in Figure 4. In Figure 4, the left ventricle of heart H is shown as an example of intracardiac cavity A.

[0034] The intracardiac cavity extraction unit 25 has a pre-trained model in machine learning, which has been trained on a large number of ultrasound images U in which intracardiac cavity A is captured, and can output the extraction result of intracardiac cavity A by inputting the ultrasound images U into the pre-trained model.

[0035] Furthermore, the intracardiac cavity extraction unit 25 can also extract intracardiac cavity A from the ultrasound image U by a so-called template matching method, which involves pre-storing a template image of intracardiac cavity A and searching within the ultrasound image U using that template image. In this way, the intracardiac cavity extraction unit 25 can extract intracardiac cavity A from the ultrasound image U using various known methods.

[0036] In this way, intracardiac cavity A extracted by the intracardiac cavity extraction unit 25 may not be accurately extracted depending on factors such as the clarity of the ultrasound image U. Furthermore, it may not necessarily coincide with the area of ​​intracardiac cavity A that the user determines by visually inspecting the ultrasound image U.

[0037] The modification possibility estimation unit 26 analyzes the contour lines of intracardiac chamber A extracted by the intracardiac chamber extraction unit 25 to estimate the possibility of modification in each part of the contour line in order to evaluate the functionality of the heart H. Here, the possibility of modification estimated by the modification possibility estimation unit 26 includes positions on the contour line of intracardiac chamber A that may be modified by a user such as a physician. The modification possibility estimation unit 26 also estimates the possibility of modification for the contour line of intracardiac chamber A in the ultrasound image U of a measurement frame used for measuring cardiac function, for example, a frame selected by the user.

[0038] The correction possibility estimation unit 26 can estimate the possibility of correction in each part of the contour line of the ultrasound image U of the measurement frame, for example, based on changes in the shape of the contour line of the intracardiac chamber A over multiple heartbeats. In this case, the correction possibility estimation unit 26 can estimate, for example, that the portion where the amount of change in the shape of the contour line over multiple heartbeats is greater than or equal to a first threshold is a portion that may be corrected. A specific example of this method is described below.

[0039] The correction possibility estimation unit 26 first calculates the area of ​​multiple intracardiac chambers A extracted by the intracardiac chamber extraction unit 25 in the ultrasound image U of multiple consecutive frames U acquired by the image acquisition unit 33, and creates information representing the correspondence between the calculated area values ​​and the time when the ultrasound image U corresponding to each area value was acquired. This information representing the correspondence can be created in the form of a graph, as shown in Figure 5, or in the form of a table. By referring to the information representing the correspondence thus created, the correction possibility estimation unit 26 selects intracardiac chamber A in the ultrasound image U of the measurement frame and in the ultrasound image U of a frame at the same time phase in a different heartbeat.

[0040] Furthermore, the correction possibility estimation unit 26 can calculate the total number of pixels present in the extracted intracardiac cavity A region as the area of ​​intracardiac cavity A. In addition, as the ultrasound image U of the measurement frame, for example, an ultrasound image U corresponding to the so-called end-diastolic or end-systolic phase of the heart H can be selected. Typically, the area of ​​intracardiac cavity A in the ultrasound image U is maximum during end-diastolic phase, and minimum during end-systolic phase.

[0041] The correction possibility estimation unit 26 further superimposes, for example, the contour line C1 of the intracardiac cavity A in the ultrasound image U of the measurement frame and the contour lines C2 and C3 of the intracardiac cavity A in the ultrasound image U of a frame that is a different heartbeat but in the same time phase, onto each other, as shown in Figure 6, and sets a reference point RP1 inside the multiple contour lines C1, C2 and C3. As the reference point RP1, for example, the centroid of the intracardiac cavity A in the ultrasound image U of the measurement frame can be set. The correction possibility estimation unit 26 sets multiple reference lines RL1, which are half-lines extending radially from the reference point RP1, and calculates the distance L1 between the reference point RP1 and contour line C1, the distance L2 between the reference point RP1 and contour line C2, and the distance L3 between the reference point RP1 and contour line C3 along each reference line RL1.

[0042] The correction possibility estimation unit 26 calculates the distance [L2-L1] between contour lines C1 and C2, and the distance [L3-L1] between contour lines C1 and C3, in the direction along the reference line RL1. The correction possibility estimation unit 26 determines that the portion where the amount of change in the shape of contour lines C1, C2, and C3 over multiple heartbeats, i.e., the distance [L2-L1] or the distance [L3-L1], is greater than or equal to a first threshold, is a portion where the amount of change in the shape of contour lines C1, C2, and C3 is large, and can estimate it as a portion where correction is possible.

[0043] Furthermore, the intracardiac cavity extraction unit 25 can calculate the confidence level of the extracted intracardiac cavity A region when extracting intracardiac cavity A from the ultrasound image U. The confidence level represents the likelihood that the extracted region is indeed intracardiac cavity A, and is calculated for each pixel of the ultrasound image U. The intracardiac cavity extraction unit 25 can, for example, calculate the confidence level in the form of a so-called heatmap HM in the ultrasound image U, as schematically shown in Figure 7, by using a pre-trained machine learning model that has previously learned the relationship between a large number of ultrasound images U showing intracardiac cavity A and the confidence level for each pixel. A heatmap HM is a diagram in which the ultrasound image U is colored according to the magnitude of the confidence level, and can include contour lines of the confidence level, as shown in Figure 7.

[0044] When the confidence level of the region of intracardiac chamber A is calculated by the intracardiac chamber extraction unit 25, the correction possibility estimation unit 26 can also estimate the possibility of correction in each part of the contour line of intracardiac chamber A based on the confidence level calculated by the intracardiac chamber extraction unit 25 for the ultrasound image U of the measurement frame. In this case, the correction possibility estimation unit 26 can estimate the portion of the region of intracardiac chamber A where the change in confidence level is less than or equal to a second threshold as a portion that may be corrected. A specific example of this method is described below.

[0045] The correction possibility estimation unit 26 sets a reference point RP2 at the position with the highest confidence value in the heatmap HM, as shown in Figure 7, for example, and sets multiple reference lines RL2, which are half-lines extending radially from the reference point RP2. The correction possibility estimation unit 26 calculates the amount of change in confidence, i.e., the slope, in the heatmap HM along each of the reference lines RL2.

[0046] When the slope of confidence is greater than a certain value, that is, when the confidence level changes abruptly, for example, the portion on the reference line RL2A shown in Figure 7 where the confidence level begins to change abruptly can be determined to be the contour of intracardiac chamber A. On the other hand, when the slope of confidence is less than or equal to a certain value, that is, when the confidence level changes smoothly, for example, it is difficult to determine which portion on the reference line RL2B shown in Figure 7 is the contour of intracardiac chamber A. Therefore, the correction possibility estimation unit 26 can estimate the portion along the reference line RL2 where the slope of confidence is less than or equal to the second threshold as a portion that may be corrected.

[0047] Furthermore, the correction possibility estimation unit 26 can also estimate the possibility of correction in each part of the contour line of intracardiac cavity A, based on the change in brightness value along the contour line of intracardiac cavity A extracted by the intracardiac cavity extraction unit 25. In this case, the correction possibility estimation unit 26 can estimate the portion where the change in brightness value along the contour line of intracardiac cavity A in the ultrasound image U of the measurement frame is greater than or equal to a third threshold as a portion that may require correction. A specific example of this method is described below.

[0048] The correction possibility estimation unit 26 detects the brightness values ​​on the contour line of intracardiac cavity A in the ultrasound image U of the measurement frame and creates information representing the correspondence between the detected brightness values ​​and their positions on the contour line of intracardiac cavity A. This information representing the correspondence can be created in the form of a graph, as shown in Figure 8, or in the form of a table. The position on the contour line can be represented, for example, by the distance along the contour line from a reference point to any point on the contour line, when one point on the contour line of intracardiac cavity A is set as the reference point.

[0049] Since the ultrasound image U represents structures within the subject by changes in brightness values, users such as physicians typically visually inspect the ultrasound image U to determine the contour of intracardiac cavity A, making their judgment based on the brightness values ​​of the pixels in the ultrasound image U. It is expected that the brightness values ​​on the contour of intracardiac cavity A determined by the user in this way will be roughly the same. Therefore, if the amount of change in brightness values ​​on the contour of intracardiac cavity A exceeds a certain value, it can be determined that the contour is being detected on a structure that is not the contour of intracardiac cavity A. Accordingly, as shown in Figure 8, the correction possibility estimation unit 26 can estimate that the portion R1 where the amount of change in brightness values ​​relative to the position on the contour is greater than or equal to the third threshold is a portion that may require correction.

[0050] The control point identification unit 27 identifies control points on the contour line based on the possibility of modification predicted by the modification possibility prediction unit 26. The control points are used to deform the contour line, and when the user moves the control points via the input device 32, the contour line can be deformed accordingly. For example, as shown in Figure 9, the control point identification unit 27 can identify a plurality of first control points P1 at a plurality of characteristic positions such as inflection points or at a plurality of equally spaced positions on the contour line C, and then identify a second control point P2 at any position in the portion where modification is possible as predicted by the modification possibility prediction unit 26.

[0051] The control point identification unit 27 can identify a second control point P2 in the portion where the amount of change in the shape of contour line C in multiple heartbeats is greater than or equal to a first threshold, in accordance with the method of estimating the possibility of correction by the correction possibility estimation unit 26, in the portion where the amount of change in the confidence level in the region of intracardiac chamber A is less than or equal to a second threshold, and in the portion where the amount of change in the brightness value on contour line C is greater than or equal to a third threshold.

[0052] The contour line C, the first control point P1, and the second control point P2 are displayed on the monitor 23 via the display control unit 22, for example, together with the ultrasound image U.

[0053] The correction operation reception unit 28 receives correction operations performed by the user via the input device 32 on the control points identified by the control point identification unit 27. Specifically, a correction operation refers to an operation to move a control point. The user moves the second control point P2 while checking the ultrasound image U, the contour lines C of the intracardiac chamber A, the first control point P1, and the second control point P2 displayed on the monitor 23. At this time, the user can fine-tune the shape of the contour line C, which has been deformed by the movement of the second control point P2, by moving the first control point P1.

[0054] The display control unit 22 can highlight the second control point P2 by displaying it in a different color from the first control point P1, so that the user can distinguish between the first control point P1 and the second control point P2. The display control unit 22 can also highlight the portion of the contour line C of the intracardiac chamber A that the modification possibility prediction unit 26 has predicted may require modification by displaying it in a different color from the other portions of the contour line C.

[0055] The contour line correction unit 29 corrects the contour line C of the intracardiac chamber A based on the correction operation received by the correction operation reception unit 28, that is, corresponding to the positions of the first control point P1 and the second control point P2 moved by the user. The corrected contour line C is displayed on the monitor 23 via the display control unit 22.

[0056] The modification possibility prediction unit 26 automatically identifies a second control point P2 for deforming the portion that may need modification, and the user can modify the contour line C of the intracardiac chamber A by moving the second control point P2. Therefore, the user can easily and quickly obtain the accurate contour line C of the intracardiac chamber A or the contour line C desired by the user.

[0057] The cardiac function measurement unit 30 measures the subject's cardiac function based on the intracardiac chamber A, whose contour line C has been corrected by the contour line correction unit 29. The cardiac function measurement unit 30 can measure cardiac function parameters such as left ventricular ejection fraction, left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular local wall motion, GLS, MAPSE, TAPSE, cardiac output, stroke volume, etc.

[0058] The cardiac function measurement unit 30, when measuring cardiac function, for example, left ventricular ejection fraction, calculates the volume of the left ventricle in the ultrasound image U extracted from the ultrasound image U representing the apical four-chamber section. Similarly, the cardiac function measurement unit 30 calculates the volume of the left ventricle extracted from the ultrasound image U representing the apical two-chamber section 2C. The cardiac function measurement unit 30 can measure the left ventricular ejection fraction based on the volume of the left ventricle in the ultrasound image U calculated for each section. In this case, the cardiac function measurement unit 30 can calculate the volume and then calculate the left ventricular ejection fraction using methods such as the so-called modified-Simpson method, the stacked-disk method, or the area-length method.

[0059] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor 34 as hardware, a program as software, or a combination thereof. In this case, the processor 34 is configured to cooperate with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor 34 is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0060] The processor 34 may be composed of one or more hardware components, and the type of hardware is not limited. For example, the processor 34 may be composed of hardware such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), FPGA (Field Programmable Gate Array) or other programmable logic devices, an ASIC (Application Specific Integrated Circuit) or other dedicated circuit for executing specific processing, a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of the processor 34, these multiple hardware components may reside in physically separate devices or in the same device. Also, in any embodiment, the order of each process performed by the processor 34 is not limited to the order described above and may be changed as appropriate. The hardware is composed of electrical circuits (circuitry) that combine circuit elements such as semiconductor elements.

[0061] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a group of program modules, each function of which may be implemented by a processor 34 configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage). The program may be divided and stored on multiple non-temporary computer-readable media located in physically separate devices. Program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0062] Next, the operation of the ultrasound diagnostic apparatus according to the embodiment will be described with reference to the flowchart shown in Figure 10.

[0063] First, in step S1, the user positions the ultrasound probe 1 to capture an ultrasound image U representing a desired cross-section for measuring cardiac function. The image acquisition unit 33 acquires the ultrasound image U including the intracardiac chamber A. At this time, under the control of the main unit control unit 31, the transmission and reception of ultrasound is started from multiple transducers of the transducer array 11 according to the drive signal from the pulser 41 of the transmitting and receiving circuit 12 of the ultrasound probe 1. The ultrasound echo from within the subject is received by multiple transducers of the transducer array 11, the received signal, which is an analog signal, is output to the amplification unit 42 for amplification, and then converted to AD by the AD conversion unit 43 to acquire the received data.

[0064] The beamformer 44 performs reception focus processing on this received data, and the resulting sound line signal is sent to the image generation unit 21 of the main unit 2, where the image generation unit 21 generates an ultrasonic image U. At this time, the signal processing unit 45 of the image generation unit 21 performs attenuation correction according to the depth of the ultrasonic reflection position and envelope detection processing on the sound line signal, the DSC 46 converts it into an image signal following the scanning method of a normal television signal, and the image processing unit 47 performs various necessary image processing such as gradation processing. The ultrasonic image U generated in step S1 in this way is sent to the display control unit 22 and the memory 24.

[0065] In step S2, the main unit control 31 determines whether or not to terminate the acquisition of ultrasound images U. The main unit control 31 can determine to terminate the acquisition of ultrasound images U if, for example, the user inputs an instruction to terminate the acquisition of ultrasound images U via the input device 32. The main unit control 31 can also determine to continue acquiring ultrasound images U if, for example, the user does not input an instruction to terminate the acquisition of ultrasound images U via the input device 32. As long as it is determined that the acquisition of ultrasound images U will continue, the processing in steps S1 and S2 is repeated. As a result, multiple frames of ultrasound images U are stored in the memory 24. When an instruction is input via the input device 32, for example, because the user has determined that sufficient ultrasound images U have been acquired, and it is determined that the acquisition of ultrasound images U should be terminated, the process proceeds to step S3.

[0066] In step S3, the main control unit 31 selects an ultrasound image U for measurement to be used for measuring cardiac function from among the multiple ultrasound image U frames stored in the memory 24 in step S1. The main control unit 31 can select the ultrasound image U for measurement based on user instructions, for example, via the input device 32. At this time, the main control unit 31 can, for example, display the multiple ultrasound image U frames stored in the memory 24 on the monitor 23 based on the user's instructions, and the user can specify one ultrasound image U frame from among the multiple ultrasound image U frames displayed on the monitor 23 as the ultrasound image U for measurement.

[0067] In step S4, the intracardiac cavity extraction unit 25 extracts intracardiac cavity A from the ultrasound image U of the measurement frame selected in step S3 by performing image analysis on the ultrasound image U. The intracardiac cavity extraction unit 25 can extract intracardiac cavity A from the ultrasound image U by, for example, using a trained model in machine learning that has learned from a large number of ultrasound images U in which intracardiac cavity A is captured, or by a template matching method.

[0068] Depending on the processing method of the correction possibility estimation unit 26 in the next step S5, the intracardiac cavity extraction unit 25 can extract intracardiac cavity A from ultrasound images U of multiple frames other than the ultrasound image U of the measurement frame. Furthermore, depending on the processing method of the correction possibility estimation unit 26 in the next step S5, the intracardiac cavity extraction unit 25 can also calculate the confidence level of the extracted intracardiac cavity A. The confidence level is calculated for each pixel in the form of a heatmap HM, for example, as shown in Figure 7.

[0069] In step S5, the modification possibility estimation unit 26 analyzes the contour lines C of the intracardiac chamber A extracted in step S4 to estimate the possibility of modification in each part of the contour line C in order to evaluate the functionality of the heart H.

[0070] The correction possibility estimation unit 26 can, for example, estimate the possibility of correction in each part of the contour line C based on the change in the shape of the contour line C over multiple heartbeats, when intracardiac chambers A are extracted from multiple ultrasound images U in step S4. In this case, the correction possibility estimation unit 26 calculates the area of ​​the multiple extracted intracardiac chambers A, and creates information representing the correspondence between the calculated area values ​​and the acquisition time of the ultrasound image U containing each intracardiac chamber A, as shown in Figure 5. By referring to this information representing the correspondence, the correction possibility estimation unit 26 identifies the ultrasound image U of the measurement frame selected in step S3 and the ultrasound image U of a different heartbeat but in the same time phase.

[0071] The correction possibility estimation unit 26, for example as shown in Figure 6, superimposes the contours of the intracardiac cavity A in the ultrasound image U of the measurement frame and the ultrasound image U of the identified frame onto each other, and sets a reference point RP1 inside the intracardiac cavity A in the ultrasound image U of the measurement frame. The reference point RP1 can be set, for example, at the centroid position of the intracardiac cavity A in the ultrasound image U of the measurement frame.

[0072] The correction possibility estimation unit 26 sets multiple reference lines RL1, which are half-lines extending radially from a reference point RP1. It calculates the distances [L2-L1] and [L3-L1] between the contour line C1 of intracardiac cavity A in the ultrasound image U of the measurement frame along each reference line RL1 and the other multiple intracardiac cavity A. If the calculated distance [L2-L1] or [L3-L1] is greater than or equal to a first threshold, the unit can estimate the portion on the contour line C1 corresponding to that reference line RL1 as a portion that may be corrected. In this way, the correction possibility estimation unit 26 can estimate portions that may have been incorrectly extracted as the contour line C of intracardiac cavity A.

[0073] If, in step S4, the confidence level of the intracardiac chamber A extracted by the intracardiac chamber extraction unit 25 for the ultrasound image U of the measurement frame is calculated, the correction possibility estimation unit 26 can also estimate the possibility of correction in each part of the contour line C based on the confidence level.

[0074] The correction possibility estimation unit 26 sets a reference point RP2 at the position with the highest confidence level in the confidence level heatmap HM, for example, as shown in Figure 7, and sets multiple reference lines RL2, which are half-lines extending radially from the reference point RP2. The correction possibility estimation unit 26 calculates the amount of change in confidence level, i.e., the slope, along each reference line RL2, and can determine the portion where the calculated slope is below a second threshold as a portion that may be corrected. In this way, the correction possibility estimation unit 26 can estimate the portion that may have been incorrectly extracted as the contour line C of the intracardiac chamber A.

[0075] The correction possibility estimation unit 26 can also estimate the possibility of correction in each part of the contour line C based on the change in brightness value on the contour line C of intracardiac cavity A in the ultrasound image U of the measurement frame extracted in step S4. For example, the correction possibility estimation unit 26 can calculate as a part that may be corrected any part where the amount of change in brightness value relative to the position on the contour line C of intracardiac cavity A is greater than or equal to a third threshold. In this way, the correction possibility estimation unit 26 can estimate parts of the extracted contour line C of intracardiac cavity A that may differ from the contour line C determined by the user by visually inspecting the ultrasound image U.

[0076] In step S6, the control point identification unit 27 identifies multiple control points on the contour line C based on the possibility of modifying the contour line C inferred in step S5. The control point identification unit 27 can identify multiple first control points P1 at multiple characteristic locations such as inflection points of the contour line C or at multiple equally spaced locations on the contour line C, as shown in Figure 9, for example, and can identify second control points P2 at any of the potentially modifyable portions of the contour line C inferred in step S5.

[0077] In step S7, the correction operation reception unit 28 receives correction operations performed by the user via the input device 32 for the first control point P1 and the second control point P2 identified in step S6. At this time, the user can select either the first control point P1 or the second control point P2 via the input device 32 and move the selected first control point P1 or second control point P2 on the ultrasound image U. When either the first control point P1 or the second control point P2 moves, the contour line C deforms accordingly.

[0078] Furthermore, in this process, the display control unit 22 can highlight the second control point P2, which has been identified as a position where correction may be necessary, on the monitor 23 by changing its display color, etc., so that the user can distinguish it from the first control point P1. By moving the second control point P2, the user can obtain the accurate contour line C of the intracardiac chamber A or the contour line C desired by the user.

[0079] In step S8, the contour line correction unit 29 corrects the contour line C of the intracardiac chamber A based on the correction operation performed by the user in step S7.

[0080] Finally, in step S9, the cardiac function measurement unit 30 measures cardiac function, such as left ventricular ejection fraction, using the contour lines C of the cardiac chamber A corrected in step S8. The measured cardiac function values ​​obtained are displayed on, for example, the monitor 23 and used by a user such as a physician to evaluate the functionality of the heart H.

[0081] Once the process in step S9 is completed, the operation of the ultrasound diagnostic device, as shown in the flowchart in Figure 10, is complete.

[0082] As described above, according to the ultrasound diagnostic apparatus of the embodiment of the present invention, the intracardiac cavity extraction unit 25 extracts the intracardiac cavity A from the ultrasound image U of the subject's heart H, the correction possibility estimation unit 26 estimates the possibility of correction in each part of the contour line C by analyzing the contour line C of the extracted intracardiac cavity A, the control point identification unit 27 identifies control points on the contour line C of the intracardiac cavity A based on the estimated possibility of correction, the correction operation reception unit 28 receives correction operations performed by the user on the identified control points, and the contour line correction unit 29 corrects the contour line C based on the received correction operations, thereby enabling easy and accurate correction of the contour line C of the intracardiac cavity A.

[0083] Although it is explained that the transmitting / receiving circuit 12 is provided in the ultrasonic probe 1, the transmitting / receiving circuit 12 may also be provided in the main body of the device 2. Furthermore, although it is explained that the image generation unit 21 is provided in the main body 2 of the device, the image generation unit 21 may also be provided in the ultrasonic probe 1.

[0084] The main unit 2 of the device may be a stationary type, a portable type that is easy to carry, or a handheld type, for example, composed of a smartphone or tablet computer. Thus, the type of equipment that makes up the main unit 2 is not particularly limited.

[0085] An example is described in which the control point identification unit 27 identifies multiple first control points P1 at multiple characteristic locations on the contour line C of the intracardiac chamber A, or at multiple locations equally spaced on the contour line C. However, the locations of the first control points P1 are not particularly limited. For example, the control point identification unit 27 may determine that the portion of the contour line C of the intracardiac chamber A, excluding the portion estimated by the modification possibility prediction unit 26 to be potentially modifiable, is likely to represent an accurate contour line C, and that deformation is undesirable. In this portion, it may identify even more first control points P1 at additional locations beyond the multiple characteristic locations on the contour line C.

[0086] Furthermore, although step S3 in the flowchart of Figure 10 describes an example in which the user manually selects the ultrasound image U of the measurement frame, the method of selecting the ultrasound image U of the measurement frame is not particularly limited to this. For example, after extracting intracardiac chambers A from multiple ultrasound image U frames stored in memory 24 in step S4, the main unit control 31 can calculate the area of ​​multiple intracardiac chambers A, create information representing the correspondence between the calculated area values ​​and the acquisition time of the corresponding ultrasound image U, and based on the created information representing the correspondence, select the ultrasound image U corresponding to a specific time phase, such as the end of diastole or end of systole of the heart H, as the ultrasound image U of the measurement frame. [Explanation of Symbols]

[0087] 1 Ultrasound probe, 2 Main unit, 11 Transducer array, 12 Transmit / receive circuit, 21 Image generation unit, 22 Display control unit, 23 Monitor, 24 Memory, 25 Intracardiac chamber extraction unit, 26 Correction possibility estimation unit, 27 Control point identification unit, 28 Correction operation reception unit, 29 Contour line correction unit, 30 Cardiac function measurement unit, 31 Main unit control unit, 32 Input device, 33 Image acquisition unit, 34 Processor, 41 Pulsar, 42 Amplifier unit, 43 AD conversion unit, 44 Beamformer, 45 Signal processing unit, 46 DSC, 47 Image processing unit, 2C Apical two-chamber section, A Intracardiac chamber, C, C1, C2, C3 Contour lines, L1, L2, L3 Distance, H Heart, HM Heatmap, P1 First control point, P2 Second control point, R1 Section, RL1, RL2, RL2A, RL2B Reference line, RP1, RP2 reference points, U ultrasound image.

Claims

1. A cardiac chamber extraction unit that extracts the intracardiac chambers from ultrasound images of the subject's heart, A modification possibility estimation unit analyzes the contour lines of the intracardiac chambers extracted by the intracardiac chamber extraction unit to estimate the possibility of modification in each part of the contour lines in order to evaluate the functionality of the heart. A control point identification unit identifies control points on the contour line based on the possibility of modification predicted by the modification possibility prediction unit, An input device for the user to perform input operations, A correction operation receiving unit that receives correction operations performed by the user via the input device on the control point identified by the control point identification unit, A contour line correction unit corrects the contour line based on the correction operation received by the correction operation reception unit. An ultrasound diagnostic device equipped with the following features.

2. The ultrasound diagnostic apparatus according to claim 1, wherein the correction possibility estimation unit estimates the possibility of correction in each part of the contour line based on changes in the shape of the contour line over multiple heartbeats.

3. The ultrasound diagnostic apparatus according to claim 2, wherein the control point identification unit identifies the control point in the portion where the amount of change in the shape of the contour line over multiple heartbeats is greater than or equal to a first threshold.

4. The intracardiac cavity extraction unit calculates the confidence level of the extracted intracardiac cavity region, The ultrasound diagnostic apparatus according to claim 1, wherein the modification possibility estimation unit estimates the possibility of modification in each portion of the contour line based on the degree of confidence calculated by the intracardiac cavity extraction unit.

5. The ultrasound diagnostic apparatus according to claim 4, wherein the control point identification unit identifies the control point in the region of the intracardiac cavity in which the change in confidence is less than or equal to a second threshold.

6. The ultrasonic diagnostic apparatus according to claim 1, wherein the correction possibility estimation unit estimates the possibility of correction in each part of the contour line based on the change in brightness value on the contour line.

7. The ultrasonic diagnostic apparatus according to claim 6, wherein the control point identification unit identifies the control point in the portion of the contour line where the amount of change in the brightness value is greater than or equal to a third threshold.

8. The intracardiac chambers were extracted from ultrasound images taken of the subject's heart. By analyzing the extracted contour lines of the cardiac chambers, the possibility of modification in each part of the contour lines is estimated in order to evaluate the functionality of the heart. Based on the hypothesized possibility of the above modification, control points are identified on the contour line, The control point accepts modification operations performed by the user. The contour line is modified based on the aforementioned modification operation. A method for controlling an ultrasound diagnostic device.

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