Ultrasound diagnostic device and control method for ultrasound diagnostic device

Abstract

This invention provides an ultrasound diagnostic device and a control method for the ultrasound diagnostic device that can accurately measure cardiac function using ultrasound images representing multiple types of cross-sections. [Solution] The ultrasound diagnostic device includes an image acquisition unit (32) that uses an ultrasound probe (1) to send and receive an ultrasound beam to acquire a first ultrasound image and a second ultrasound image of the heart; a feature extraction unit (26) that extracts anatomical structural features from the first ultrasound image and the second ultrasound image, respectively; a consistency calculation unit (27) that calculates the consistency between the anatomical structural features in the first ultrasound image and the second ultrasound image; an appropriateness calculation unit (25) that calculates the appropriateness of the first ultrasound image and the second ultrasound image; and a measurement instruction unit (28) that starts measurement when the consistency is equal to or greater than a consistency threshold and the appropriateness of both the first ultrasound image and the second ultrasound image is equal to or greater than an appropriateness threshold.

Description

Technical Field

[0001] The present invention relates to an ultrasonic diagnostic apparatus for capturing ultrasonic images 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, etc. may be measured.

[0003] The user usually determines whether a cross-section suitable for measuring the target cardiac function has been captured by checking the captured ultrasonic image, but this determination may be difficult depending on the user's proficiency. Therefore, for example, as disclosed in Patent Document 1, a technique for automatically determining the type of cross-section represented by the captured ultrasonic image has been developed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when measuring left ventricular ejection fraction as a measure of cardiac function, it is common to use two types of ultrasound images: one representing the so-called apical four-chamber section and another representing the apical two-chamber section. When measuring cardiac function using multiple ultrasound images representing multiple types of sections in this way, even if the type of section represented by each ultrasound image is automatically determined by the technology described in Patent Document 1, if, for example, the position or tilt angle of the ultrasound probe shifts when acquiring ultrasound images representing different types of sections, it may not be possible to accurately measure cardiac function.

[0006] 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 accurately measure cardiac function using ultrasound images representing multiple types of cross-sections. [Means for solving the problem]

[0007] The above objective can be achieved with the following configuration. [1] An ultrasound probe and Monitor and, An image acquisition unit that acquires a first ultrasound image and a second ultrasound image, each capturing different cross-sections of the subject's heart, by transmitting and receiving an ultrasound beam using an ultrasound probe. A feature extraction unit extracts the anatomical features of the heart from the first ultrasound image and the second ultrasound image acquired by the image acquisition unit, A consistency calculation unit calculates the consistency between the anatomical structure features in the first ultrasound image extracted by the feature extraction unit and the anatomical structure features in the second ultrasound image extracted by the feature extraction unit. An appropriateness calculation unit calculates the suitability of each of the first and second ultrasound images as a measurement target, A measurement unit that measures the cardiac function of a subject based on a first ultrasound image and a second ultrasound image, A measurement instruction unit instructs the measurement unit to perform a measurement if the consistency calculated by the consistency calculation unit between the first ultrasound image and the second ultrasound image is equal to or greater than a defined consistency threshold, and the appropriateness calculated by the appropriateness calculation unit for each of the first and second ultrasound images is equal to or greater than a defined appropriateness threshold. An ultrasound diagnostic device equipped with the following features. [2] The ultrasound diagnostic apparatus described in [1], wherein the first and second ultrasound images are images taken of two of the following cross-sections of the apical two-chamber, apical three-chamber, apical four-chamber, and apical five-chamber sections. [3] The ultrasound diagnostic device described in [1] or [2], wherein the measurement unit measures the left ventricular ejection fraction or cardiac output as the cardiac function of the subject. [4] The image acquisition unit acquires a third ultrasound image in which a cross-section of the heart different from both the first ultrasound image and the second ultrasound image is captured. The feature extraction unit extracts the anatomical features of the heart from the third ultrasound image. The consistency calculation unit calculates the consistency between the anatomical structural features in the first ultrasound image and the anatomical structural features in the second ultrasound image and the anatomical structural features in the third ultrasound image. The suitability calculation unit calculates the suitability of the third ultrasound image as a measurement target. The ultrasound diagnostic apparatus according to any one of [1] to [3], wherein the measurement instruction unit starts further measurement of cardiac function by the measurement unit when the consistency between the anatomical structural features in the first ultrasound image, the anatomical structural features in the second ultrasound image, and the anatomical structural features in the third ultrasound image is above a defined consistency threshold, and the appropriateness calculated by the appropriateness calculation unit for the third ultrasound image is above a defined appropriateness threshold. [5] The feature extraction unit extracts the length of the long axis of the left ventricle as a feature of the anatomical structure of the heart. This is an ultrasound diagnostic device as described in any of [1] to [4]. [6] The ultrasound diagnostic apparatus described in [5], wherein the consistency threshold is 90%. [7] The feature extraction unit extracts the position of the cardiac apex as a feature of the anatomical structure of the heart. This is an ultrasound diagnostic device as described in any of [1] to [4]. [8] The ultrasound diagnostic apparatus described in [7], wherein the consistency threshold is 90%. [9] An ultrasound diagnostic apparatus according to any one of [1] to [8], further comprising an adjustment instruction unit that instructs the user to adjust at least one of the scanning position of the ultrasound probe, the posture of the subject, and the breathing method of the subject if, over a specified period of time, the consistency calculated by the consistency calculation unit between the first ultrasound image and the second ultrasound image is less than a specified consistency threshold, or if the appropriateness calculated by the appropriateness calculation unit for each of the first ultrasound image and the second ultrasound image is less than a specified appropriateness threshold.

[10] By transmitting and receiving an ultrasound beam using an ultrasound probe, a first ultrasound image and a second ultrasound image are obtained, each capturing a different cross-section of the subject's heart. The anatomical features of the heart were extracted from the first and second ultrasound images, respectively. The consistency between the anatomical structural features in the first extracted ultrasound image and the anatomical structural features in the second extracted ultrasound image is calculated. The suitability of each of the first and second ultrasound images as a measurement target is calculated. The subject's cardiac function will be measured if the consistency calculated between the first and second ultrasound images is equal to or greater than a defined consistency threshold, and the appropriateness calculated for each of the first and second ultrasound images is equal to or greater than a defined appropriateness threshold. A method for controlling an ultrasound diagnostic device. [Effects of the Invention]

[0008] The present invention relates to an ultrasound diagnostic apparatus comprising: an ultrasound probe; a monitor; an image acquisition unit that acquires first and second ultrasound images of different cross-sections of the subject's heart by transmitting and receiving ultrasound beams using the ultrasound probe; a feature extraction unit that extracts anatomical structural features of the heart from the first and second ultrasound images acquired by the image acquisition unit; a consistency calculation unit that calculates the consistency between the anatomical structural features in the first ultrasound image extracted by the feature extraction unit and the anatomical structural features in the second ultrasound image extracted by the feature extraction unit; and the first and second ultrasound images The system includes an appropriateness calculation unit that calculates the appropriateness of each ultrasound image as a measurement target, a measurement unit that measures the cardiac function of a subject based on a first ultrasound image and a second ultrasound image, and a measurement instruction unit that instructs the measurement unit to perform the measurement when the consistency calculated by the consistency calculation unit between the first ultrasound image and the second ultrasound image is equal to or greater than a defined consistency threshold, and the appropriateness calculated by the appropriateness calculation unit for each of the first and second ultrasound images is equal to or greater than a defined appropriateness threshold. Therefore, it is possible to accurately measure cardiac function using ultrasound images representing multiple types of cross-sections. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the configuration of an ultrasound diagnostic device according to Embodiment 1 of the present invention. [Figure 2] This is a block diagram showing the internal configuration of the transmitting and receiving circuit in Embodiment 1 of the present invention. [Figure 3] This is a block diagram showing the internal configuration of the image generation unit in Embodiment 1 of the present invention. [Figure 4] This figure schematically shows an example of the first ultrasound image representing a four-chamber view of the apical region of the heart. [Figure 5] This figure schematically shows an example of a second ultrasound image representing a two-chamber view of the cardiac apex. [Figure 6] This figure shows an example of the display of appropriateness calculated for the first ultrasound image. [Figure 7]It is a diagram showing an example of display of appropriateness and consistency calculated for a second ultrasonic image. [Figure 8] It is a flowchart showing the operation of the ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention. [Figure 9] It is a flowchart showing the operation of acquiring a first ultrasonic image of a measurement target in Embodiment 1 of the present invention. [Figure 10] It is a flowchart showing the operation of acquiring a second ultrasonic image of a measurement target in Embodiment 1 of the present invention. [Figure 11] It is a block diagram showing the configuration of the ultrasonic diagnostic apparatus according to Embodiment 2 of the present invention. Embodiments of the Invention

[0010] Hereinafter, embodiments of this invention will be described based on the accompanying drawings. The description of the constituent elements described below is based on typical 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" include an error range generally acceptable in the technical field.

[0011] Embodiment 1 Fig. 1 shows the configuration of the ultrasonic diagnostic apparatus according to an embodiment of the present invention. The ultrasonic diagnostic apparatus includes an ultrasonic probe 1 and a device body 2 connected to each other by so-called wired communication or so-called wireless communication.

[0012] The ultrasonic probe 1 includes a vibrator array 11 and a transmission / reception circuit 12 connected thereto.

[0013] The main unit 2 of the device includes an image generation unit 21 connected to the transmitting / receiving circuit 12. In the main unit 2, the display control unit 22 and the monitor 23 are sequentially connected to the image generation unit 21. A memory 24 and an appropriateness calculation unit 25 are connected to the image generation unit 21. A feature extraction unit 26 is also connected to the image generation unit 21. The feature extraction unit 26 is connected to the memory 24 and an consistency calculation unit 27. The consistency calculation unit 27 is connected to the memory 24. The appropriateness calculation unit 25 and the consistency calculation unit 27 are connected to the measurement instruction unit 28. The measurement instruction unit 28 is connected to the measurement unit 29. The memory 24, appropriateness calculation unit 25, consistency calculation unit 27, and measurement unit 29 are connected to the display control unit 22. The main unit control unit 30 is connected to the transmitting / receiving circuit 12, the image generation unit 21, the display control unit 22, the memory 24, the appropriateness calculation unit 25, the feature extraction unit 26, the consistency calculation unit 27, the measurement instruction unit 28, and the measurement unit 29. The input device 31 is connected to the main control unit 30.

[0014] The image acquisition unit 32 is composed of a transmitting / receiving circuit 12 and an image generation unit 21. Furthermore, the processor 33 for the main unit 2 is composed of the image generation unit 21, display control unit 22, appropriateness calculation unit 25, feature extraction unit 26, consistency calculation unit 27, measurement instruction unit 28, measurement unit 29, and main unit control unit 30.

[0015] 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).

[0016] The image acquisition unit 32, which consists of a transmitting / receiving circuit 12 and an image generation unit 21, acquires multiple frames of ultrasound images as moving images of the subject's heart by transmitting and receiving an ultrasound beam using an ultrasound probe 1.

[0017] 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 30. As shown in Figure 2, the transmitting / receiving circuit 12 includes 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.

[0018] 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 30, 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 30, it performs envelope detection processing to generate a B-mode image signal, which is tomographic image information of the tissue within the subject.

[0023] 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, memory 24, appropriateness calculation unit 25, and feature extraction unit 26. Hereafter, the B-mode image signal processed by the image processing unit 47 will be referred to as an ultrasonic image.

[0024] The ultrasound diagnostic device according to the embodiment of the present invention is used to measure cardiac functions such as left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular regional wall motion, global longitudinal strain (GLS), mitral annular plane systolic excursion (MAPSE), tricuspid annular plane systolic excursion (TAPSE), cardiac output, and stroke volume.

[0025] For measuring cardiac function, the image acquisition unit 32 acquires, for example, a first ultrasound image U1 consisting of multiple frames representing a so-called apical four-chamber section 4C of the heart H, and a second ultrasound image U2 consisting of multiple frames representing a so-called apical two-chamber section 2C, as shown in Figures 4 and 5. The first ultrasound image U1 and the second ultrasound image U2 capture the same cardiac chamber A and represent different cross-sections of cardiac chamber A. Here, cardiac chamber A refers to one of the left ventricle, left atrium, right ventricle, or right atrium. In addition to the apical four-chamber section 4C and the apical two-chamber section 2C, cross-sections of cardiac chamber A passing through the apex, such as the so-called apical three-chamber section and the apical five-chamber section, can also be captured.

[0026] The display control unit 22, under the control of the main unit control unit 30, performs predetermined processing on the first ultrasound image U1 and the second ultrasound image U2 acquired by the image acquisition unit 32 and displays them on the monitor 23.

[0027] The monitor 23 displays the first ultrasound image U1 and the second ultrasound image U2, 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).

[0028] The memory 24 stores the first ultrasound image U1 and the second ultrasound image U2, etc., acquired by the image acquisition unit 32 under the control of the main unit control unit 30.

[0029] 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.

[0030] The main unit control unit 30 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.

[0031] The input device 31 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.

[0032] The appropriateness calculation unit 25 calculates the appropriateness of each of the first ultrasound image U1 and the second ultrasound image U2 as targets for measuring cardiac function. The appropriateness of each of the first ultrasound image U1 and the second ultrasound image U2 as targets for measuring cardiac function refers to the degree to which the cross-sections represented by the first ultrasound image U1 and the cross-sections represented by the second ultrasound image U2 appropriately represent the defined cross-sections corresponding to the measurement of a specific cardiac function.

[0033] Specifically, as criteria for suitability, the similarity between the cross-section represented by the first ultrasound image U1 and the first cross-section suitable for measuring a specific cardiac function, and the similarity between the cross-section represented by the second ultrasound image U2 and the second cross-section suitable for measuring a specific cardiac function can be used. As cross-sections suitable for measuring cardiac function, for example, cross-sections of cardiac chamber A passing through the apex, such as the apical four-chamber cross-section 4C, the apical two-chamber cross-section 2C, the apical three-chamber cross-section, and the apical five-chamber cross-section, are used, and the cross-section in which the long axis of cardiac chamber A is maximized is used. The long axis of cardiac chamber A refers to the longest line segment that passes through the apex and connects the apex to a point on the contour of cardiac chamber A.

[0034] The appropriateness calculation unit 25 stores, for example, multiple measurement items of cardiac function such as left ventricular ejection fraction and cardiac output, and the type of cross-section suitable for each of the multiple measurement items of cardiac function, and can calculate the appropriateness of the first ultrasound image U1 and the second ultrasound image U2 for the measurement items selected by the user via the input device 31. For example, when left ventricular ejection fraction is selected as a measurement item, the appropriateness calculation unit 25 can calculate the appropriateness of the first ultrasound image U1 for the apical four-chamber cross-section 4C and the appropriateness of the second ultrasound image U2 for the apical two-chamber cross-section 2C.

[0035] Furthermore, when cardiac output is measured, ultrasound images representing the so-called parasternal left ventricular long-axis section and ultrasound images representing the apical five-chamber section are often used for measurement. However, if the ultrasound image representing the apical five-chamber section includes areas of interventricular septum protrusion or calcification, cardiac output may not be measured correctly. In this case, an ultrasound image representing the apical three-chamber section may be used instead of the ultrasound image representing the apical five-chamber section. Therefore, when cardiac output is selected as the measurement item, the appropriateness calculation unit 25 can calculate, for example, the appropriateness of the first ultrasound image U1 for the apical five-chamber section and the appropriateness of the second ultrasound image U2 representing the apical three-chamber section.

[0036] The appropriateness calculation unit 25 can, for example, pre-store template images representing typical image patterns of multiple cross-sections corresponding to multiple measurement items of cardiac function, and calculate the appropriateness of the first ultrasound image U1 based on the similarity between the first ultrasound image U1 and the corresponding first template image, and calculate the appropriateness of the first ultrasound image U1 based on the similarity between the second ultrasound image U2 and the corresponding second template image. Furthermore, the appropriateness calculation unit 25 can also calculate the appropriateness of the first ultrasound image U1 and the second ultrasound image U2 using a learning model in so-called machine learning, which has learned the relationship between the cross-sections represented by numerous ultrasound images taken of cardiac chamber A, the multiple cross-sections corresponding to multiple measurement items of cardiac function, and their similarity, i.e., the appropriateness of each ultrasound image for each cross-section.

[0037] The display control unit 22 can sequentially display the appropriateness values ​​on the monitor 23, as shown in Figures 6 and 7, each time the appropriateness of the first ultrasound image U1 is calculated by the appropriateness calculation unit 25, and each time the appropriateness of the second ultrasound image U2 is calculated. The user can adjust the position and tilt angle of the ultrasound probe 1 while checking the appropriateness values ​​displayed on the monitor 23 to capture the first ultrasound image U1 and the second ultrasound image U2.

[0038] The feature extraction unit 26 extracts anatomical structural features of the heart H from the first ultrasound image U1 and the second ultrasound image U2, respectively, acquired by the image acquisition unit 32. For example, in cross-sections of the cardiac chambers A passing through the apex, such as the apical four-chamber section 4C, the apical two-chamber section 2C, the apical three-chamber section, and the apical five-chamber section, the feature extraction unit 26 can extract parameters such as the depth position of the cardiac chamber and the length of the long axis of cardiac chamber A, which ideally have constant values ​​between cross-sections and do not fluctuate with heartbeats, as anatomical structural features of the heart H in the first ultrasound image U1 and the second ultrasound image U2.

[0039] The consistency calculation unit 27 calculates the consistency between the anatomical structure features of heart H in the first ultrasound image U1 extracted by the feature extraction unit 26 and the anatomical structure features of heart H in the second ultrasound image U2 extracted by the feature extraction unit 26. This consistency can be calculated, for example, as a value obtained by subtracting the rate of change of the anatomical structure in the second ultrasound image U2 from 100% relative to the anatomical structure features in the first ultrasound image U1.

[0040] For example, if the anatomical features of heart H in the first ultrasound image U1 and the apical depth position P1 in the first ultrasound image U1 and the apical depth position P2 in the second ultrasound image U2 are extracted as anatomical features of heart H in the first ultrasound image U1 and the apical depth position P2 in the second ultrasound image U2, the consistency calculation unit 27 can calculate consistency using [100% - (P1 - P2) / P1 × 100%] = P2 / P1 × 100%. Also, if the anatomical features of heart H in the first ultrasound image U1 and the long axis length L1 of cardiac chamber A in the first ultrasound image U1 and the long axis length L2 of cardiac chamber A in the second ultrasound image U2 are extracted as anatomical features of heart H in the first ultrasound image U1 and the apical depth position L2 in the second ultrasound image U2, the consistency calculation unit 27 can calculate consistency using [100% - (L1 - L2) / L1 × 100%] = L2 / L1 × 100%.

[0041] Here, two different cross-sections of cardiac chamber A passing through the apex can be acquired by rotating the ultrasound probe 1 around an axis aligned with the direction in which the ultrasound probe 1 is pressed against the subject's body surface. Ideally, the anatomical features of the heart H extracted by the feature extraction unit 26 remain unchanged with respect to such rotation of the ultrasound probe 1, and the consistency calculated by the consistency calculation unit 27 is ideally 100%. If the position or tilt angle of the ultrasound probe 1 changes when rotating it to acquire a different cross-section from a state in which a specific cross-section is being acquired, the depth position of the cardiac apex and the length of the long axis of cardiac chamber A change, and the consistency decreases from 100%. Thus, consistency can be understood as an indicator of the degree of agreement between the position and tilt angle of the ultrasound probe 1 between the acquisition of the first ultrasound image U1 and the acquisition of the second ultrasound image U2.

[0042] The measurement instruction unit 28 has a predetermined consistency threshold, such as 90%, for consistency, and determines whether the consistency calculated by the consistency calculation unit 27 between the first ultrasound image U1 and the second ultrasound image U2 is equal to or greater than the consistency threshold. The measurement instruction unit 28 also has a predetermined appropriateness threshold for appropriateness, and determines whether the appropriateness of the first ultrasound image U1 and the second ultrasound image U2 is equal to or greater than the appropriateness threshold. The measurement instruction unit 28 instructs the measurement unit 29 to perform cardiac function measurement when the consistency calculated between the first ultrasound image U1 and the second ultrasound image U2 is equal to or greater than the consistency threshold, and the appropriateness calculated for the first ultrasound image U1 and the second ultrasound image U2 is equal to or greater than the appropriateness threshold. This allows the measurement to be performed using the first ultrasound image U1 and the second ultrasound image U2 which are suitable for measuring cardiac function, thus enabling accurate measurement of cardiac function.

[0043] The measurement unit 29 measures the cardiac function of the subject based on the first ultrasound image U1 and the second ultrasound image U2. When measuring left ventricular ejection fraction as a cardiac function, for example, the measurement unit 29 extracts the left ventricle shown in the first ultrasound image U1, which represents the apical four-chamber view 4C, by image analysis, and calculates the volume of the extracted left ventricle in the first ultrasound image U1. Similarly, the measurement unit 29 extracts the left ventricle shown in the second ultrasound image U2, which represents the apical two-chamber view 2C, and calculates its volume. Based on the left ventricular volume in the first ultrasound image U1 and the left ventricular volume in the second ultrasound image U2 calculated in this way, the measurement unit 29 can measure the left ventricular ejection fraction. In this process, the measurement unit 29 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.

[0044] Furthermore, the measurement unit 29 can extract the left ventricle from the first ultrasound image U1 and the second ultrasound image U2 by a so-called template matching method, which involves searching within the first ultrasound image U1 and the second ultrasound image U2 using a template image representing a typical image pattern of the left ventricle. Alternatively, the measurement unit 29 can also extract the left ventricle from the first ultrasound image U1 and the second ultrasound image U2 by using a trained model in machine learning that has learned the relationship between a large number of ultrasound images and the left ventricle depicted in them.

[0045] When measuring cardiac function, for example, cardiac output, the measurement unit 29 analyzes an ultrasound image representing the parasternal left ventricular long-axis section to extract the aorta visible in the ultrasound image and calculates the diameter of the extracted aorta. The measurement unit 29 analyzes a first ultrasound image U1 representing the five-chamber section of the cardiac apex to extract the aorta visible in the first ultrasound image U1, and places a so-called Doppler gate on the aorta extracted in the first ultrasound image U1. The measurement unit 29 uses a so-called pulsed Doppler method to calculate the blood flow velocity in the aorta at the position of the Doppler gate. Furthermore, the measurement unit 29 can measure cardiac output based on the calculated aortic diameter and the calculated blood flow velocity in the aorta.

[0046] In the first ultrasound image U1 representing the five-chamber section of the apex, if the interventricular septum protrudes so as to overlap with the aorta, or if there are areas of calcification in the aorta, the blood flow velocity cannot be accurately measured. Therefore, the measurement unit 29 can calculate the blood flow velocity in the aorta using, for example, a second ultrasound image U2 representing a three-chamber section of the apex, instead of the first ultrasound image U1 representing the five-chamber section of the apex.

[0047] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor as hardware, a program as software, or a combination thereof. In that case, the processor is configured to work in cooperation with the program to execute the various processes in this embodiment, and can function as one of the units or means in this embodiment. Also, the execution order of the processes by the processor 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.

[0048] The processor 33, which includes an image generation unit 21, a display control unit 22, an appropriateness calculation unit 25, a feature extraction unit 26, an consistency calculation unit 27, a measurement instruction unit 28, a measurement unit 29, and a main unit control unit 30, may be composed of one or more hardware components, and the type of hardware is not limited. For example, the processor 33 can be composed of hardware such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a programmable logic device such as an FPGA (Field Programmable Gate Array), a dedicated circuit for executing a specific process such as an ASIC (Application Specific Integrated Circuit), 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 a given processor, 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 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.

[0049] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a set of program modules, each function of which may be implemented by a processor 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 can 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.

[0050] Next, the operation of the ultrasound diagnostic device according to the embodiment will be described with reference to the flowchart shown in Figure 8. Here, an example of calculating left ventricular ejection fraction as a cardiac function will be described, but the present invention is not limited to the case of calculating left ventricular ejection fraction as a cardiac function, and can also be applied to the calculation of other cardiac functions based on ultrasound images representing a cross-section of the heart H passing through the apex, such as cardiac output.

[0051] In step S1, a first scan is performed to acquire a first ultrasound image U1 consisting of multiple frames. In this first scan, the volume of the left ventricle in the first ultrasound image U1 at end-diastolic cardiac motion and the volume of the left ventricle in the first ultrasound image U1 at end-systolic cardiac motion are acquired from the first ultrasound image U1 suitable for measuring the left ventricular ejection fraction, as indicators necessary for measuring the left ventricular ejection fraction. Here, the first ultrasound image U1 suitable for measuring the left ventricular ejection fraction refers to the first ultrasound image U1 that represents the apical four-chamber section 4C as shown in Figure 4 and in which the length of the long axis of the left ventricle is maximized. The processing in step S1 consists of multiple steps in the flowchart shown in Figure 9.

[0052] First, in step S11, the user positions the ultrasound probe 1 to acquire a first ultrasound image U1 representing a four-chamber cross-section 4C of the apex of the heart, as shown in Figure 4. The image acquisition unit 32 acquires the first ultrasound image U1 representing a cross-section of the left ventricle. At this time, under the control of the main unit control unit 30, 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.

[0053] The beamformer 44 performs reception focus processing on this received data, and the resulting sound ray signal is sent to the image generation unit 21 of the main unit 2, where the image generation unit 21 generates the first ultrasonic image U1. 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 ray signal, and the DSC 46 converts it into an image signal that follows the scanning method of a normal television signal, and the image processing unit 47 performs various necessary image processing such as gradation processing. The first ultrasonic image U1 generated in step S11 in this way is sent to the display control unit 22, memory 24, appropriateness calculation unit 25, and feature extraction unit 26.

[0054] In step S12, the suitability calculation unit 25 calculates the suitability of the first ultrasound image U1 acquired in step S11 as a target for measuring left ventricular ejection fraction. The suitability calculation unit 25 can calculate the suitability of the first ultrasound image U1 as the similarity between the first ultrasound image U1 and a template image representing a four-chamber apical view 4C, as shown in Figure 4, where the length of the long axis of the left ventricle is maximized. Once the suitability is calculated in step S12, the display control unit 22 displays the calculated suitability value together with the first ultrasound image U1 on the monitor 23, as shown in Figure 6, for example.

[0055] In step S13, the measurement instruction unit 28 determines whether the appropriateness of the first ultrasound image U1 calculated in step S12 is equal to or greater than a defined appropriateness threshold. As long as the appropriateness is determined to be less than the appropriateness threshold in step S13, the processing in steps S11 to S13 is repeated. If the appropriateness is determined to be equal to or greater than the appropriateness threshold in step S13, this appropriateness is stored in the memory 24, and the process proceeds to step S14.

[0056] In step S14, the memory 24 stores the most recent first ultrasound image U1 acquired in step S11 under the control of the main unit control 30.

[0057] In step S15, the feature extraction unit 26 extracts anatomical features of the heart H from the first ultrasound image U1, which was acquired in step S11, by performing image analysis on the latest first ultrasound image U1. The feature extraction unit 26 can extract, for example, the depth position of the cardiac apex or the length of the long axis of the left ventricle in the first ultrasound image U1 as anatomical features of the heart H.

[0058] In step S16, the measurement unit 29 analyzes the first ultrasound image U1 stored in the memory 24 in step S14 to calculate the volume of the left ventricle in the first ultrasound image U1 at the end of diastole and the volume of the left ventricle in the first ultrasound image U1 at the end of systole of the heart H, as indicators necessary for measuring the left ventricular ejection fraction.

[0059] In this process, the measurement unit 29 performs image analysis on the first ultrasound image U1 stored in the memory 24 in step S14, such as a template matching method or a method using a trained model in machine learning, to extract the left ventricle visible in the first ultrasound image U1, calculates the area in the first ultrasound image U1 by counting the total number of pixels surrounded by the contour of the extracted left ventricle, and calculates the volume of the left ventricle from the calculated area.

[0060] The measurement unit 29 can determine, for example, whether the first ultrasound image U1 represents the left ventricle in end-diastolic or end-systolic state based on the change in left ventricular volume in multiple consecutive frames of the first ultrasound image U1 in a time series. Currently, this determination cannot be made because only one frame of the first ultrasound image U1 is stored in memory 24. In this case, if it is not possible to determine whether the first ultrasound image U1 represents the left ventricle in end-diastolic or end-systolic state, step S16 is skipped.

[0061] In step S17, the main unit control unit 30 determines whether or not to terminate the acquisition of the first ultrasound image U1. The main unit control unit 30 can determine to terminate the acquisition of the first ultrasound image U1 if, for example, the user gives an instruction to terminate the acquisition of the first ultrasound image U1 via the input device 31. The main unit control unit 30 can also determine to continue acquiring the first ultrasound image U1 if, for example, the user does not give an instruction to terminate the acquisition of the first ultrasound image U1 via the input device 31.

[0062] As long as it is determined in step S17 to continue acquiring the first ultrasound image U1, the processes in steps S11 to S17 are repeated. As a result, in step S14, multiple frames of the first ultrasound image U1 are saved in memory 24. Ideally, the anatomical features of heart H, such as the depth position of the apex and the length of the long axis of the left ventricle, should not change across multiple frames of the first ultrasound image U1. Therefore, in step S15, only the anatomical features of heart H extracted initially can be saved in memory 24, and subsequent processing can be skipped. Alternatively, in step S15, the average value of the anatomical features of heart H extracted from multiple frames of the first ultrasound image U1 can be calculated, and the calculated average value can be saved in memory 24 as the final anatomical features of heart H.

[0063] Furthermore, in step S16, each time the processes in steps S11 to S17 are repeated, the measurement unit 29 arranges the calculated left ventricular volume in the first ultrasound image U1 in chronological order to create and update time-series change data of the left ventricular volume. The maximum value in the updated time-series change data is obtained as the left ventricular volume at the end of diastole, and the minimum value in the time-series change data is obtained as the left ventricular volume at the end of systole.

[0064] If the user determines that the indicators necessary for measuring the left ventricular ejection fraction have been sufficiently calculated, and it is determined, based on the user's instructions, that the acquisition of the first ultrasound image U1 should be terminated in step S17, then the first scanning process in step S1, according to the flowchart in Figure 9, is completed.

[0065] In step S2, following step S1, a second scan is performed to acquire multiple second ultrasound images U2, and the left ventricular ejection fraction is measured during the second scan. In the second scan, the volume of the left ventricle in the second ultrasound image U2 at end-diastolic and the volume of the left ventricle in the second ultrasound image U2 at end-systolic are acquired from the second ultrasound image U2 suitable for measuring the left ventricular ejection fraction, as indicators necessary for measuring the left ventricular ejection fraction. Based on the indicators acquired in the first scan in step S1 and the indicators acquired in the second scan in step S2, the left ventricular ejection fraction is measured. Here, the second ultrasound image U2 suitable for measuring the left ventricular ejection fraction refers to the second ultrasound image U2 that shows the apical two-chamber section 2C as shown in Figure 5 and has the longest major axis length of the left ventricle. The process in step S2 consists of multiple steps in the flowchart shown in Figure 10.

[0066] First, in step S21, the user positions the ultrasound probe 1 to acquire a second ultrasound image U2 representing a two-chamber cross-section of the apex, as shown in Figure 5. The image acquisition unit 32 acquires a second ultrasound image U2 representing a cross-section of the left ventricle in the same manner as in step S11. The second ultrasound image U2 generated in step S11 is then sent to the display control unit 22, the memory 24, the appropriateness calculation unit 25, and the feature extraction unit 26. Once the processing in step S21 is completed, the processing in step S22, and the processing in steps S23 and S24 are performed in parallel.

[0067] In step S22, the suitability calculation unit 25 calculates the suitability of the second ultrasound image U2 acquired in step S21 as a target for measuring left ventricular ejection fraction, using the same method as in step S12. The suitability calculation unit 25 can calculate the suitability of the second ultrasound image U2 as the similarity between the second ultrasound image U2 and, for example, a template image representing a two-chamber apical section 2C, as shown in Figure 5, where the length of the long axis of the left ventricle is maximized.

[0068] In step S23, the feature extraction unit 26 performs image analysis on the second ultrasound image U2 acquired in step S21 to extract from the second ultrasound image U2 the same anatomical structural features as those of the heart H extracted from the first ultrasound image U1 in step S15.

[0069] In step S24, the consistency calculation unit 27 calculates the consistency between the anatomical structure features in the first ultrasound image U1, which was extracted in step S15 and stored in memory 24, and the anatomical structure features in the second ultrasound image U2, which was extracted in step S23. For example, the consistency calculation unit 27 can calculate the consistency as a value obtained by subtracting the rate of change of the anatomical structure features in the second ultrasound image U2 relative to the anatomical structure features in the first ultrasound image U1 from 100%.

[0070] In step S22, the appropriateness of the second ultrasound image U2 is calculated, and in step S24, the consistency is calculated. These values ​​are then displayed on the monitor 23 along with the second ultrasound image U2 acquired in step S21, as shown in Figure 7, for example.

[0071] In the subsequent step S25, the measurement instruction unit 28 determines whether the appropriateness of the second ultrasound image U2 calculated in step S22 is equal to or greater than a defined appropriateness threshold. As long as the appropriateness is determined to be less than the appropriateness threshold in step S25, the processing of steps S21 to S25 is repeated. If the appropriateness is determined to be equal to or greater than the appropriateness threshold in step S25, the process proceeds to step S26.

[0072] In step S26, the measurement instruction unit 28 determines whether the consistency calculated in step S24 is equal to or greater than the defined consistency threshold. As long as it is determined in step S26 that the consistency is less than the consistency threshold, the processes in steps S21 to S26 are repeated. If it is determined in step S26 that the consistency is equal to or greater than the consistency threshold, the process proceeds to step S27.

[0073] In step S27, the memory 24, under the control of the main unit control 30, saves the most recent second ultrasound image U2 acquired in step S21. In this way, the second ultrasound image U2, which represents the apical two-chamber section 2C appropriate for measuring the left ventricular ejection fraction and was acquired with the same position and tilt angle of the ultrasound probe 1 as when the first ultrasound image U1 was acquired, is automatically saved.

[0074] In step S28, the measurement instruction unit 28 instructs the measurement unit 29 to measure the left ventricular ejection fraction.

[0075] In step S29, the measurement unit 29 analyzes the second ultrasound image U2 stored in the memory 24 in step S27 to calculate the volume of the left ventricle in the second ultrasound image U2 of the heart H in end-diastolic state and the volume of the left ventricle in the second ultrasound image U2 of the heart H in end-systolic state, as indicators necessary for measuring the left ventricular ejection fraction.

[0076] In this process, the measurement unit 29 performs image analysis on the second ultrasound image U2 stored in the memory 24 in step S27, such as a template matching method or a method using a trained model in machine learning, to extract the left ventricle shown in the second ultrasound image U2, calculates the area in the second ultrasound image U2 by counting the total number of pixels surrounded by the contour of the extracted left ventricle, and calculates the volume of the left ventricle from the calculated area.

[0077] The measurement unit 29 can determine, for example, whether the second ultrasound image U2 represents the left ventricle in end-diastolic or end-systolic state based on the change in left ventricular volume in multiple consecutive frames of the second ultrasound image U2 in a time series. Currently, this determination cannot be made because only one frame of the second ultrasound image U2 is stored in memory 24. In this case, if it is not possible to determine whether the second ultrasound image U2 represents the left ventricle in end-diastolic or end-systolic state, step S28 is skipped.

[0078] In step S30, the measurement unit 29 measures the left ventricular ejection fraction using the indicators necessary for measurement calculated in step S1 and the indicators necessary for measurement calculated in step S29. At this point, since the processing in step S28 has been skipped, the processing in step S30 is also skipped.

[0079] In step S31, the main unit control 30 determines whether or not to terminate the acquisition of the second ultrasound image U2. The main unit control 30 can determine to terminate the acquisition of the second ultrasound image U2 if, for example, the user gives an instruction to terminate the acquisition of the second ultrasound image U2 via the input device 31. The main unit control 30 can also determine to continue acquiring the second ultrasound image U2 if, for example, the user does not give an instruction to terminate the acquisition of the second ultrasound image U2 via the input device 31.

[0080] As long as it is determined in step S31 to continue acquiring the second ultrasound image U2, the processing in steps S21 to S31 is repeated. As a result, in step S27, multiple frames of the second ultrasound image U2 are saved in memory 24. In step S29, each time the processing in steps S21 to S31 is repeated, the measurement unit 29 arranges the left ventricular volume in the calculated second ultrasound image U2 in chronological order to create and update time-series change data of the left ventricular volume. The maximum value in the updated time-series change data is obtained as the left ventricular volume at the end of diastole, and the minimum value in the time-series change data is obtained as the left ventricular volume at the end of systole.

[0081] In step S29, when the indicators necessary for measuring the left ventricular ejection fraction are obtained from the second ultrasound image U2, the measurement unit 29 calculates the left ventricular ejection fraction using these indicators and the indicators obtained from the first ultrasound image U1 in step S1. At this time, the measurement unit 29 can, for example, calculate the final volume of the left ventricle at end diastole based on the volume of the left ventricle in the first ultrasound image U1 and the second ultrasound image U2 corresponding to the end diastole of heart H, calculate the final volume of the left ventricle at end systole based on the volume of the left ventricle in the first ultrasound image U1 and the second ultrasound image U2 corresponding to the end systole of heart H, and then calculate the left ventricular ejection fraction based on the calculated final volume of the left ventricle at end diastole and the final volume of the left ventricle at end systole.

[0082] The measurement unit 29 displays the calculated left ventricular ejection fraction value on the monitor 23 via the display control unit 22. As the processing of steps S21 to S31 is repeated, if the maximum or minimum value of the left ventricular volume is updated in step S29, the left ventricular ejection fraction is measured again in step S30 using the updated maximum or minimum value of the left ventricular volume, and the resulting measurement value is displayed on the monitor 23. In this way, the left ventricular ejection fraction is measured in real time during the second scan, and the measurement value is displayed on the monitor 23 as it occurs.

[0083] Since the multiple first ultrasound images U1 and the multiple second ultrasound images U2 all represent appropriate cross-sections for measurement and have sufficient consistency with each other, the first ultrasound images U1 and the second ultrasound images U2 of the measurement target extracted by the measurement unit 29 are all appropriate ultrasound images to be used for measurement. Therefore, the measurement unit 29 can accurately calculate the left ventricular ejection fraction based on the extracted first ultrasound images U1 and the second ultrasound images U2 of the measurement target.

[0084] If the user determines that the left ventricular ejection fraction has been sufficiently measured and, based on the user's instructions, it is determined that the acquisition of the second ultrasound image U2 should be terminated in step S31, the second scan in step S2 and the measurement of the left ventricular ejection fraction during the second scan are completed according to the flowchart in Figure 10.

[0085] Once the process in step S2 is completed, the operation of the ultrasound diagnostic apparatus of Embodiment 1, according to the flowchart in Figure 8, is complete.

[0086] As described above, according to the ultrasound diagnostic apparatus of Embodiment 1, the appropriateness calculation unit 25 calculates the appropriateness of the first ultrasound image U1 and the second ultrasound image U2 as measurement targets, the feature extraction unit 26 extracts the anatomical structure features of the heart H from each of the first ultrasound image U1 and the second ultrasound image U2, the consistency calculation unit 27 calculates the consistency between the anatomical structure features of the heart H in the first ultrasound image U1 and the second ultrasound image U2, and the measurement instruction unit 28 instructs the measurement unit 29 to perform cardiac function measurement when the calculated consistency is above a predetermined consistency threshold and the calculated appropriateness for each of the first ultrasound image U1 and the second ultrasound image U2 is above a predetermined appropriateness threshold, thereby enabling accurate measurement of cardiac function using the first ultrasound image U1 and the second ultrasound image U2.

[0087] 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.

[0088] 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.

[0089] Examples of cardiac function measurement items using two types of ultrasound images, the first ultrasound image U1 and the second ultrasound image U2, include left ventricular ejection fraction using an ultrasound image representing the apical two-chamber view 2C and an ultrasound image representing the apical four-chamber view 4C. Other examples include left ventricular end-diastolic volume using an ultrasound image representing the apical two-chamber view 2C and an ultrasound image representing the apical four-chamber view 4C, and left ventricular end-systolic volume using an ultrasound image representing the apical two-chamber view 2C and an ultrasound image representing the apical four-chamber view 4C.

[0090] Furthermore, the present invention can also be applied to the measurement of cardiac function using multiple types of ultrasound images representing three or more cross-sections. In this case, the appropriateness calculation unit 25 calculates the appropriateness of each of the multiple types of ultrasound images as a measurement target, the feature extraction unit 26 extracts anatomical structural features of the heart H from each of the multiple types of ultrasound images, and the consistency calculation unit 27 can calculate the consistency between the anatomical structural features of the heart H in the multiple types of ultrasound images. At this time, the consistency calculation unit 27 can, for example, calculate the consistency between either the anatomical structural features of the heart H extracted from the first ultrasound image U1 or the anatomical structural features of the heart H extracted from the second ultrasound image U2, and a third ultrasound image representing a different cross-section from the first ultrasound image U1 and the second ultrasound image U2. The measurement instruction unit 28 can instruct the measurement unit 29 to perform the measurement if the consistency calculated between the multiple types of ultrasound images is equal to or greater than a defined consistency threshold and the appropriateness calculated for each of the multiple types of ultrasound images is equal to or greater than a defined appropriateness threshold.

[0091] For example, examples of cardiac function measurement items that use ultrasound images representing three types of cross-sections include left ventricular regional wall motion, GLS, and MAPSE, all of which use ultrasound images representing the apical two-chamber section (2C), the apical three-chamber section (3C), and the apical four-chamber section (4C).

[0092] Furthermore, when measuring different cardiac function measurements consecutively, the consistency calculation unit 27 can calculate the consistency between the anatomical features of heart H in the ultrasound image used for the immediately preceding measurement item and the anatomical features of heart H in the first ultrasound image U1 used for the current measurement item. The measurement instruction unit 28 can save this first ultrasound image U1 as a candidate for the first ultrasound image U1 to be actually used for measurement in the memory 24 if the consistency calculated in this way is equal to or greater than a defined consistency threshold and the appropriateness calculated for the first ultrasound image U1 used for the current measurement item is equal to or greater than a defined appropriateness. In this way, by taking into account the consistency between the anatomical features of heart H in the ultrasound image used for the previous measurement item and the anatomical features of heart H in the first ultrasound image U1 used for the current measurement item, in addition to the appropriateness of the first ultrasound image U1 used for the current measurement item, it is possible to obtain a first ultrasound image U1 that more appropriately represents the cross-section of the object to be measured.

[0093] Embodiment 2 Depending on the scanning position of the ultrasound probe 1, the posture of the subject, and the respiratory state of the subject, the appropriateness of the first ultrasound image U1 and the second ultrasound image U2 may fall below the appropriateness threshold, or the consistency between the anatomical features of heart H in the first ultrasound image U1 and the anatomical features of heart H in the second ultrasound image U2 may fall below the consistency threshold. In such cases, the processor 33 may instruct the user to rectify the cause.

[0094] Figure 11 shows the configuration of the ultrasound diagnostic apparatus of Embodiment 2. The ultrasound diagnostic apparatus of Embodiment 2 is equipped with a device body 2A in place of the device body 2 shown in Figure 1. The device body 2A in Embodiment 2 is equipped with an adjustment instruction unit 51 in place of the device body 2 in Embodiment 1, and a main unit control unit 30A in place of the main unit control unit 30.

[0095] In the main unit 2A of the device, the adjustment instruction unit 51 is connected to the appropriateness calculation unit 25 and the consistency calculation unit 27. The adjustment instruction unit 51 is connected to the display control unit 22 and the main unit control unit 30A. Furthermore, the image generation unit 21, the display control unit 22, the appropriateness calculation unit 25, the feature extraction unit 26, the consistency calculation unit 27, the measurement instruction unit 28, the measurement unit 29, the main unit control unit 30A, and the adjustment instruction unit 51 constitute the processor 33A for the main unit 2A.

[0096] The adjustment instruction unit 51 instructs the user to adjust at least one of the following: the scanning position of the ultrasound probe 1, the posture of the subject, and the breathing method of the subject, if, over a predetermined period of time, the consistency calculated by the consistency calculation unit 27 between the first ultrasound image U1 and the second ultrasound image U2 is less than a predetermined consistency threshold, or if the appropriateness calculated by the appropriateness calculation unit 25 for each of the first ultrasound image U1 and the second ultrasound image U2 is less than a predetermined appropriateness threshold. The adjustment instruction unit 51 can, for example, display a message on the monitor 23 indicating that the user should adjust at least one of the following: the scanning position of the ultrasound probe 1, the posture of the subject, and the breathing method of the subject.

[0097] According to the ultrasound diagnostic apparatus of Embodiment 2, even if the user has low measurement skills, for example, by checking the instructions from the adjustment instruction unit 51, the user can easily obtain a first ultrasound image U1 that shows a cross-section appropriate for measurement, a second ultrasound image U2 that shows a cross-section appropriate for measurement, or a second ultrasound image U2 that shows anatomical features consistent with the anatomical features of the heart H in the first ultrasound image U1.

[0098] Although an example is described in which the adjustment instruction unit 51 gives instructions to the user by displaying a message on the monitor 23, the method of giving instructions by the adjustment instruction unit 51 is not particularly limited to this. If the ultrasound diagnostic device is equipped with a speaker (not shown), the adjustment instruction unit 51 can give instructions to the user, for example, by sound transmitted through the speaker. Also, if the ultrasound diagnostic device is equipped with a lamp (not shown), the adjustment instruction unit 51 can give instructions to the user, for example, by changing the light emission pattern of the lamp according to the content of the instruction. [Explanation of Symbols]

[0099] 1 Ultrasound probe, 2,2A Main unit, 11 Transducer array, 12 Transmit / receive circuit, 21 Image generation unit, 22 Display control unit, 23 Monitor, 24 Memory, 25 Appropriateness calculation unit, 26 Feature extraction unit, 27 Consistency calculation unit, 28 Measurement instruction unit, 29 Measurement unit, 30,30A Main unit control unit, 31 Input device, 32 Image acquisition unit, 33,33A Processor, 41 Pulsar, 42 Amplifier unit, 43 AD conversion unit, 44 Beamformer, 45 Signal processing unit, 46 DSC, 47 Image processing unit, 51 Adjustment instruction unit, 2C Apical two-chamber section, 4C Apical four-chamber section, A Cardiac chamber, H Heart, U1 First ultrasound image, U2 Second ultrasound image.

Claims

1. Ultrasound probe and Monitor and, An image acquisition unit that acquires a first ultrasound image and a second ultrasound image, each capturing different cross-sections of the subject's heart, by transmitting and receiving an ultrasound beam using the ultrasound probe. A feature extraction unit extracts the anatomical structure features of the heart from the first ultrasound image and the second ultrasound image acquired by the image acquisition unit, A consistency calculation unit calculates the consistency between the anatomical structure features in the first ultrasound image extracted by the feature extraction unit and the anatomical structure features in the second ultrasound image extracted by the feature extraction unit. An appropriateness calculation unit that calculates the suitability of each of the first and second ultrasound images as a measurement target, A measurement unit that measures the cardiac function of the subject based on the first ultrasound image and the second ultrasound image, A measurement instruction unit instructs the measurement unit to perform a measurement if the consistency calculated by the consistency calculation unit between the first ultrasound image and the second ultrasound image is equal to or greater than a defined consistency threshold, and the appropriateness calculated by the appropriateness calculation unit for each of the first ultrasound image and the second ultrasound image is equal to or greater than a defined appropriateness threshold. An ultrasound diagnostic device equipped with the following features.

2. The ultrasound diagnostic apparatus according to claim 1, wherein the first ultrasound image and the second ultrasound image are images taken of two cross-sections from among a two-chamber apical section, a three-chamber apical section, a four-chamber apical section, and a five-chamber apical section.

3. The ultrasound diagnostic apparatus according to claim 1, wherein the measurement unit measures the left ventricular ejection fraction or cardiac output as the cardiac function of the subject.

4. The image acquisition unit acquires a third ultrasound image in which a cross-section of the heart different from both the first ultrasound image and the second ultrasound image is captured. The feature extraction unit extracts the anatomical structure features of the heart from the third ultrasound image. The consistency calculation unit calculates the consistency between the characteristics of the anatomical structure in the first ultrasound image and the characteristics of the anatomical structure in the second ultrasound image and the characteristics of the anatomical structure in the third ultrasound image. The suitability calculation unit calculates the suitability of the third ultrasound image as a measurement target, The ultrasound diagnostic apparatus according to claim 1, wherein the measurement instruction unit initiates further measurement of cardiac function by the measurement unit when the consistency between the anatomical structure features in the first ultrasound image and the anatomical structure features in the second ultrasound image and the anatomical structure features in the third ultrasound image is equal to or greater than the predetermined consistency threshold, and the appropriateness calculated by the appropriateness calculation unit for the third ultrasound image is equal to or greater than the predetermined appropriateness threshold.

5. The ultrasound diagnostic apparatus according to claim 1, wherein the feature extraction unit extracts the length of the long axis of the left ventricle as a feature of the anatomical structure of the heart.

6. The ultrasound diagnostic apparatus according to claim 5, wherein the consistency threshold is 90%.

7. The ultrasound diagnostic apparatus according to claim 1, wherein the feature extraction unit extracts the position of the cardiac apex as a feature of the anatomical structure of the heart.

8. The ultrasound diagnostic apparatus according to claim 7, wherein the consistency threshold is 90%.

9. The ultrasound diagnostic apparatus according to claim 1, further comprising an adjustment instruction unit that instructs the user to adjust at least one of the scanning position of the ultrasound probe, the posture of the subject, and the breathing method of the subject if, over a predetermined period of time, the consistency calculated by the consistency calculation unit between the first ultrasound image and the second ultrasound image is less than the predetermined consistency threshold, or if the appropriateness calculated by the appropriateness calculation unit for each of the first ultrasound image and the second ultrasound image is less than the predetermined appropriateness threshold.

10. By transmitting and receiving ultrasound beams using an ultrasound probe, a first ultrasound image and a second ultrasound image are obtained, each capturing a different cross-section of the subject's heart. The anatomical features of the heart are extracted from the first ultrasound image and the second ultrasound image, The consistency between the anatomical structure features in the extracted first ultrasound image and the anatomical structure features in the extracted second ultrasound image is calculated. The suitability of each of the first and second ultrasound images as a measurement target is calculated. The cardiac function of the subject is measured if the consistency calculated between the first ultrasound image and the second ultrasound image is equal to or greater than a defined consistency threshold, and the appropriateness calculated for each of the first and second ultrasound images is equal to or greater than a defined appropriateness threshold. A method for controlling an ultrasound diagnostic device.

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