Ultrasound diagnostic apparatus and method of controlling ultrasound diagnostic apparatus

Abstract

To provide an ultrasonic diagnostic apparatus which enables a user to easily photograph a cross section of an organ suitable for measurement, and a control method of the ultrasonic diagnostic apparatus.SOLUTION: An ultrasound diagnostic apparatus includes an image acquisition unit (31) that acquires ultrasound images of a plurality of frames in which a measurement target organ is imaged by transmitting and receiving an ultrasound beam using an ultrasound probe (1), a feature amount calculation unit (24) that calculates a feature amount of the measurement target organ in each of the ultrasound images of the plurality of frames by performing image analysis on the ultrasound images of the plurality of frames, a probe operation direction calculation unit (27) that calculates a target operation direction of the ultrasound probe (1) for imaging an optimum measurement cross section suitable for measurement of the measurement target organ based on a time-series change in a plurality of feature amounts calculated in the ultrasound images of the plurality of frames, and a notification unit (28) that notifies a user of the target operation direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic diagnostic apparatus for imaging an organ of a subject and a method for controlling the ultrasonic diagnostic apparatus. [Background technology]

[0002] Conventionally, measurements of organs in a subject have been performed by capturing ultrasound images showing cross sections of the subject using a so-called ultrasound diagnostic device. Generally, organs in a subject vary in shape, size, position, tilt angle, etc. from person to person. Therefore, in order to capture a cross section suitable for measuring the target organ, it is necessary to adjust the position, tilt angle, etc. of the ultrasound probe to suit the subject. In particular, when capturing a cross section suitable for measuring an organ with a complex structure such as the heart, delicate adjustments are required for the position, tilt angle, etc. of the ultrasound probe.

[0003] Therefore, an ultrasound diagnostic device such as that disclosed in Patent Document 1 has been developed to allow a user of the ultrasound diagnostic device to easily capture a cross section that allows appropriate measurement of a measurement target organ. The ultrasound diagnostic device of Patent Document 1 displays to the user information regarding the time-series increase and decrease in the long-axis diameter of the left ventricle calculated from a plurality of consecutive frames of ultrasound images of the left ventricle of the subject's heart. While checking the information regarding the time-series increase and decrease in the calculated value of the long-axis diameter of the left ventricle, the user adjusts the position, tilt angle, etc. of the ultrasound probe to capture a cross section of the left ventricle that is suitable for measuring the left ventricular ejection fraction (LVEF) of the heart. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-214393 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if the technology of Patent Document 1 is used to check information regarding the time-series increase and decrease in the calculated value of the long-axis diameter of the left ventricle, depending on the user's level of skill, it may be difficult to determine in which direction the ultrasound probe should actually be moved or how it should be tilted in order to capture a cross section suitable for measuring the left ventricle, and the desired cross section may not be captured easily.

[0006] The present invention has been made to solve these conventional problems, and an object of the present invention is to provide an ultrasound diagnostic apparatus and a control method for an ultrasound diagnostic apparatus that allow a user to easily capture cross sections of organs suitable for measurement. [Means for solving the problem]

[0007] The above object can be achieved by the following configuration. [1] An ultrasonic probe; an image acquisition unit that acquires a plurality of frames of ultrasound images of a measurement target organ of a subject by transmitting and receiving ultrasound beams using an ultrasound probe; a feature calculation unit that calculates a feature of the measurement target organ in each of the multiple frames of ultrasound images by image analysis of the multiple frames of ultrasound images acquired by the image acquisition unit; a probe operation direction calculation unit that calculates a target operation direction of the ultrasound probe for capturing an optimal measurement cross section suitable for measurement of the measurement target organ based on time-series changes in the plurality of feature amounts calculated by the feature amount calculation unit in the ultrasound images of the plurality of frames; a notification unit that notifies a user of the target operation direction calculated by the probe operation direction calculation unit; An ultrasound diagnostic device equipped with: [2] The ultrasound diagnostic device according to [1], wherein the probe operation direction calculation unit starts calculating the target operation direction when a predetermined time has elapsed since the image acquisition unit started acquiring ultrasound images. [3] An optimal feature quantity selection unit that selects one of the plurality of feature quantities calculated by the feature quantity calculation unit as an optimal feature quantity corresponding to the optimal measurement cross section, The ultrasound diagnostic device according to [1] or [2], wherein the notification unit notifies the user of the optimal feature selected by the optimal feature selection unit. [4] The ultrasound diagnostic device according to [3], wherein the notification unit notifies the user to acquire multiple frames of ultrasound images while moving the ultrasound probe. [5] The ultrasound diagnostic apparatus according to [3], further comprising a feature memory that stores optimal features in association with the subject. [6] The ultrasound diagnostic device according to any one of [3] to [5], wherein the organ to be measured is the heart. [7] The feature calculation unit calculates the depth of the upper end of the cardiac cavity in the multiple frames of ultrasound images as a feature; The probe operation direction calculation unit When the depth calculated by the feature amount calculation unit is changing to become shallower in time series, the current moving direction of the ultrasound probe by the user along the body surface of the subject is calculated as a target operation direction; The ultrasound diagnostic device according to [6], wherein when the depth calculated by the feature calculation unit is changing to become deeper over time, the target operation direction is calculated to be the opposite direction to the current direction of movement of the ultrasound probe along the body surface of the subject by the user. [8] The feature calculation unit calculates the length of the long axis of the cardiac chamber as a feature; The probe operation direction calculation unit When the length calculated by the feature amount calculation unit is changing so as to become longer in time series, the current tilt direction of the ultrasound probe by the user is calculated as the target operation direction; An ultrasound diagnostic device according to [6] or [7], wherein when the length calculated by the feature calculation unit is changing to become shorter over time, a direction opposite to the current tilt direction of the ultrasound probe by the user is calculated as the target operation direction. [9] The feature calculation unit calculates the area of ​​the cardiac cavity as the feature; The probe operation direction calculation unit When the area calculated by the feature amount calculation unit is changing so as to increase over time, the current tilt direction of the ultrasound probe by the user is calculated as the target operation direction; An ultrasound diagnostic device according to [6] or [7], which calculates, as a target operation direction, a direction opposite to the current tilt direction of the ultrasound probe by the user when the area calculated by the feature calculation unit is changing to become smaller over time.

[10] The plurality of feature quantities change in time series due to heartbeats to have a plurality of maximum values ​​and a plurality of minimum values; The ultrasonic diagnostic device according to any one of [6] to [9], wherein the probe operation direction calculation unit calculates a target operation direction based on changes in a time series of a plurality of maximum values ​​or a plurality of minimum values.

[11] The image acquisition unit acquires a plurality of frames of ultrasound images in sequence for each of the apical four-chamber and two-chamber views of the heart; the feature calculation unit calculates a plurality of feature amounts for a first cross section from which a plurality of frames of ultrasound images have been acquired first by the image acquisition unit, among the apical four-chamber cross section and the apical two-chamber cross section; the optimal feature quantity selection unit selects an optimal feature quantity from the plurality of feature quantities calculated for the first cross section; The ultrasound diagnostic device according to any one of [6] to

[10] , wherein the notification unit notifies the user of the optimal feature quantity selected for the first cross section while the image acquisition unit is acquiring multiple frames of ultrasound images of a second cross section different from the first cross section, among the apical four-chamber cross section and the apical two-chamber cross section.

[12] The feature calculation unit calculates a similarity between the ultrasound images of the plurality of frames and a reference image corresponding to the optimal measurement cross section as a feature; The probe operation direction calculation unit When the plurality of similarities calculated by the feature amount calculation unit change so as to increase in time series, the current rotation direction of the ultrasound probe by the user is calculated as a target operation direction; The ultrasound diagnostic device according to any one of [6] to

[11] , wherein when the multiple similarities calculated by the feature calculation unit change so as to become smaller over time, a target operation direction is calculated as a direction opposite to the current rotation direction of the ultrasound probe by the user.

[13] A position and orientation sensor is provided to detect the position and tilt angle of the ultrasonic probe; The ultrasonic diagnostic device according to any one of [1] to

[12] , wherein the probe operation direction calculation unit calculates a target operation direction by further taking into account the position and tilt angle of the ultrasonic probe detected by a position and orientation sensor.

[14] Equipped with a monitor, 14. The ultrasonic diagnostic device according to claim 1, wherein the notification unit notifies the user of the target operation direction by displaying the target operation direction on a monitor.

[15] Acquiring multiple frames of ultrasound images of the subject's organ to be measured by transmitting and receiving ultrasound beams using an ultrasound probe; By performing image analysis on the acquired ultrasound images of the plurality of frames, a feature amount of the measurement target organ is calculated for each of the ultrasound images of the plurality of frames; calculating a target operation direction of the ultrasound probe for capturing an optimal measurement cross section suitable for measurement of the measurement target organ based on time-series changes in the plurality of feature amounts calculated in the plurality of frames of ultrasound images; The calculated target operation direction is notified to the user. A method for controlling an ultrasound diagnostic device. [Effects of the Invention]

[0008] The present invention provides an ultrasound diagnostic device comprising: an ultrasound probe; an image acquisition unit that acquires a plurality of frames of ultrasound images of a measurement target organ of a subject by transmitting and receiving ultrasound beams using the ultrasound probe; a feature calculation unit that calculates feature amounts of the measurement target organ in each of the plurality of frames of ultrasound image by image analysis of the plurality of frames of ultrasound image acquired by the image acquisition unit; a probe operation direction calculation unit that calculates a target operation direction of the ultrasound probe for capturing an optimal measurement cross section suitable for measurement of the measurement target organ based on time-series changes in the plurality of feature amounts calculated by the feature calculation unit in the plurality of frames of ultrasound image; and a notification unit that notifies the user of the target operation direction calculated by the probe operation direction calculation unit, thereby enabling the user to easily capture a cross section of the organ suitable for measurement. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing the configuration of an ultrasound diagnostic apparatus according to an embodiment of the present invention; [Figure 2] 1 is a block diagram showing a configuration of a transmission / reception circuit according to an embodiment of the present invention; [Figure 3] FIG. 2 is a block diagram showing a configuration of an image generating unit according to the embodiment of the present invention. [Figure 4] FIG. 1 is a diagram schematically illustrating an ultrasound image showing an apical four-chamber cross section of the heart. [Figure 5] FIG. 1 is a diagram schematically showing an optimum measurement cross section suitable for measuring the left ventricular ejection fraction of a subject's heart. [Figure 6] FIG. 10 is a diagram schematically illustrating a cross section of the heart when an ultrasound probe is placed at a position different from the position corresponding to the optimal measurement cross section. [Figure 7] 10A and 10B are diagrams illustrating an example of a display of a target operation direction of an ultrasound probe according to an embodiment of the present invention. [Figure 8] 4 is a flowchart showing the operation of the ultrasound diagnostic apparatus according to the embodiment of the present invention. [Figure 9] 10 is a graph showing an example of a feature whose value changes periodically due to the heart beating of a subject. [Figure 10] FIG. 1 is a diagram schematically illustrating an ultrasound image showing an apical two-chamber cross section of the heart. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following description of the components will be given based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the terms "same" and "identical" include a margin of error generally accepted in the technical field.

[0011] Embodiment 1 shows the configuration of an ultrasound diagnostic apparatus according to an embodiment of the present invention. The ultrasound diagnostic apparatus comprises an ultrasound probe 1 and a device main body 2 connected to the ultrasound probe 1. The ultrasound probe 1 and the device main body 2 are connected to each other via so-called wired communication or so-called wireless communication.

[0012] The ultrasonic probe 1 has a transducer array 11. A transmitting / receiving circuit 12 is connected to the transducer array 11.

[0013] The device main body 2 has an image generation unit 21 connected to the transmission / reception circuit 12 of the ultrasound probe 1. A display control unit 22 and a monitor 23 are connected to the image generation unit 21, in that order. A feature amount calculation unit 24 is connected to the image generation unit 21. An optimal feature amount selection unit 25 and a feature amount memory 26 are connected to the feature amount calculation unit 24, in that order. Furthermore, a probe operation direction calculation unit 27 is connected to the feature amount calculation unit 24. A notification unit 28 is connected to the feature amount memory 26 and the probe operation direction calculation unit 27. The notification unit 28 is connected to the display control unit 22. Furthermore, a main body control unit 29 is connected to the transmission / reception circuit 12, the image generation unit 21, the display control unit 22, the feature amount calculation unit 24, the optimal feature amount selection unit 25, the feature amount memory 26, the probe operation direction calculation unit 27, and the notification unit 28. An input device 30 is connected to the main body control unit 29.

[0014] The transmitting / receiving circuit 12 and the image generating unit 21 form an image acquiring unit 31. The image generating unit 21, the display control unit 22, the feature calculating unit 24, the optimal feature selecting unit 25, the probe operation direction calculating unit 27, the notifying unit 28, and the main body control unit 29 form a processor 32 for the device main body 2.

[0015] The transducer array 11 of the ultrasonic probe 1 has a plurality of ultrasonic transducers arranged one-dimensionally or two-dimensionally. These ultrasonic transducers transmit ultrasonic waves in accordance with drive signals supplied from the transmission / reception circuit 12, receive ultrasonic echoes from the subject, and output signals based on the ultrasonic echoes. Each ultrasonic transducer is configured by forming electrodes on both ends of a piezoelectric element made of, for example, a piezoelectric ceramic typified by PZT (Lead Zirconate Titanate), a polymer piezoelectric element typified by PVDF (Poly Vinylidene Di Fluoride), or a piezoelectric single crystal typified by PMN-PT (Lead Magnesium Niobate-Lead Titanate).

[0016] The image acquisition unit 31, which is composed of the transmission / reception circuit 12 and the image generation unit 21, transmits and receives ultrasonic beams using the ultrasonic probe 1 to acquire an ultrasonic image of the inside of the subject.

[0017] The transmission / reception circuit 12, under the control of the main body control unit 29, transmits ultrasonic waves from the transducer array 11 and generates sound ray signals based on reception signals acquired by the transducer array 11. As shown in Fig. 2, the transmission / reception 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, which are connected in series from the transducer array 11 in this order.

[0018] The pulser 41 includes, for example, a plurality of pulse generators, and adjusts the delay amount of each drive signal and supplies it to the plurality of ultrasonic transducers of the transducer array 11 so that the ultrasonic waves transmitted from the plurality of ultrasonic transducers form an ultrasonic beam based on a transmission delay pattern selected in response to a control signal from the main body control unit 29. 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, and pulsed or continuous wave ultrasonic waves are generated from each ultrasonic transducer, and an ultrasonic beam is formed from the composite wave of these ultrasonic waves.

[0019] The transmitted ultrasonic beam is reflected by an object 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 in this manner is received by each ultrasonic transducer constituting the transducer array 11. At this time, each ultrasonic transducer constituting the transducer array 11 expands and contracts upon receiving the propagating ultrasonic echo, generating received signals which are electrical signals, and outputs these received signals to the amplifier 42.

[0020] The amplifier 42 amplifies the signals input from each ultrasonic transducer constituting the transducer array 11 and transmits the amplified signals to the AD converter 43. The AD converter 43 converts the signals transmitted from the amplifier 42 into digital reception data. The beamformer 44 performs so-called reception focusing processing by delaying and adding each piece of reception data received from the AD converter 43. This reception focusing processing causes the reception data converted by the AD converter 43 to be phased and added, and a sound ray signal in which the focus of the ultrasonic echo is narrowed is acquired.

[0021] As shown in FIG. 3, the image generating 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.

[0022] The signal processing unit 45 corrects the sound ray signals received from the transmission / reception circuit 12 for attenuation due to distance in accordance with the depth of the ultrasonic reflection position using the sound velocity value set by the main body control unit 29, and then performs envelope detection processing to generate a B-mode image signal, which is tomographic image information regarding the tissue within the subject.

[0023] The DSC 46 converts (raster converts) the B-mode image signal generated by the signal processing unit 45 into an image signal that conforms to the scanning method of a normal television signal. 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 optimum feature selection unit 25. Hereinafter, the B-mode image signal that has been subjected to image processing by the image processing unit 47 will be referred to as an ultrasound image.

[0024] The feature calculation unit 24 calculates feature values ​​of the subject's measurement target organ in each of the multiple frames of ultrasound images by performing image analysis on multiple frames of ultrasound images acquired by the image acquisition unit 31. The subject's measurement target organ is an organ within the subject that is the subject of a specific measurement. For example, measurement of the so-called left ventricular ejection fraction (LVEF) can be set as the specific measurement, and the heart, which is the subject of measurement of the LVEF, can be set as the measurement target organ. The LVEF is usually calculated as the ratio of the left ventricular volume at end systole to the left ventricular volume at end diastole.

[0025] The feature values ​​of the measurement target organ are measurement values ​​related to the cross-sectional structure of the measurement target organ, which are used as index values ​​for determining whether the captured ultrasound image represents the optimal measurement cross section, i.e., a cross section suitable for performing a specific measurement of the measurement target organ. For example, when determining the optimal measurement cross section for measuring the left ventricular ejection fraction of a heart H as shown in Figure 4, the feature values ​​can be set as follows: the depth D of the upper end E of the lumen of the left ventricle A in the ultrasound image U, and the length of the major axis B of the lumen of the left ventricle A in the ultrasound image U, i.e., the major axis diameter L. The upper end E of the lumen of the left ventricle A in the ultrasound image U refers to the shallowest part of the boundary of the lumen of the left ventricle A that appears in the ultrasound image U. The major axis B of the lumen of the left ventricle A in the ultrasound image U can be defined as the longest line segment connecting the upper end E of the lumen of the left ventricle A to another position on the boundary of the lumen of the left ventricle A.

[0026] When calculating the depth D of the upper end E of the left ventricle A as a feature, the feature calculation unit 24 can extract the contour of the cavity of the left ventricle A from the ultrasound image U by a so-called segmentation method using, for example, a trained model in machine learning that has learned the relationship between an ultrasound image U showing the left ventricle A and the contour of the cavity of the left ventricle A shown therein, and identify the shallowest position of the extracted contour or the position of the extracted contour with the greatest curvature as the position of the upper end E. The feature calculation unit 24 can calculate the depth D by measuring the distance between the identified position of the upper end E and the upper end of the ultrasound image U.

[0027] The feature amount calculation unit 24 can also extract the upper end E of the lumen of the left ventricle A and calculate its depth D using an algorithm that extracts characteristic points, i.e., so-called key points, in an image, such as SIFT (Scale Invariant Feature Transform) and SVM (Support Vector Machine). In this case, the feature amount calculation unit 24 can extract the positions of the roots of a pair of mitral valves at the lower end of the left ventricle A using, for example, the above-mentioned algorithm, identify the line segment connecting the midpoint of the roots of the extracted pair of mitral valves and the upper end E as the long axis B of the lumen of the left ventricle A, and calculate the long axis diameter L by measuring the length of the identified long axis B.

[0028] In this way, the feature amount calculation unit 24 can perform image analysis of the ultrasound image using a segmentation method based on machine learning or an algorithm for extracting key points in the ultrasound image U, and calculate the feature amount.

[0029] Figure 5 shows a schematic diagram of the ideal positional relationship between the cavity of the left ventricle A and the ultrasound probe 1, which allows imaging of the optimal measurement cross section for measuring the left ventricular ejection fraction. In this figure, the ultrasound probe 1 and the cavity of the left ventricle A are viewed from the direction along the scan plane P1 of the ultrasound probe 1, which extends in a direction perpendicular to the paper surface.

[0030] When the ultrasound probe 1 is placed on the surface of the subject's body at an ideal position and tilt angle to capture the optimal measurement cross section for left ventricular ejection fraction, the scan plane P1 of the ultrasound probe 1 passes through the apex C of the left ventricle A, and the long-axis diameter L1 of the lumen of the left ventricle A in the ultrasound image U corresponding to the scan plane P1 is longer than when the ultrasound probe 1 is at any other position and tilt angle. The apex C corresponds to the upper end E of the lumen of the left ventricle A, which has the shallowest depth D1 in the ultrasound image U.

[0031] Therefore, for example, in a plurality of ultrasound images U acquired corresponding to a plurality of positions and tilt angles of the ultrasound probe 1, when a plurality of depths D of the upper end E of the cavity of the left ventricle A and a plurality of long axis diameters L of the cavity of the left ventricle A are calculated as feature quantities, the minimum depth D1 and the maximum long axis diameter L1 can be determined as optimal feature quantities corresponding to the optimal measurement cross section for the left ventricular ejection fraction.

[0032] The optimal feature quantity selection unit 25 selects one of the multiple feature quantities calculated by the feature quantity calculation unit 24 as the optimal feature quantity corresponding to the optimal measurement cross-section, for example, based on such criteria. If the feature quantity calculation unit 24 sequentially calculates feature quantities and calculates a more preferable feature quantity corresponding to the optimal measurement cross-section, for example, if a smaller value of depth D or a larger value of major axis diameter L is calculated, the optimal feature quantity selection unit 25 updates the value of the optimal feature quantity by selecting the calculated more preferable feature quantity as the optimal feature quantity. The optimal feature quantity selection unit 25 sends the optimal feature quantity selected in this way to the feature quantity memory 26.

[0033] The feature memory 26 is a memory that stores the optimal feature selected by the optimal feature selection unit 25. Since it is expected that the depth D1 of the apex C of the cavity of the left ventricle A and the value of the maximum major axis diameter L1 of the cavity of the left ventricle A will not change significantly between examinations for the same subject, the feature memory 26 can store the optimal feature in association with the subject, for example, by associating the optimal feature with an identifier (ID) of the subject.

[0034] The feature memory 26 may be, for example, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), an FD (Flexible Disk), an MO disk (Magneto-Optical disk), an MT (Magnetic Tape), a RAM (Random Access Memory), a CD (Compact Disc), a DVD (Digital Versatile Disc), an SD card (Secure Digital card), or a USB memory (Universal Serial Bus memory).

[0035] The probe operation direction calculation unit 27 calculates a target operation direction of the ultrasound probe 1 for capturing an optimum measurement cross section suitable for measuring the measurement target organ, based on the time-series changes in the plurality of feature amounts calculated by the feature amount calculation unit 24 in the plurality of frames of ultrasound image U. The target operation direction of the ultrasound probe 1 is the direction in which the ultrasound probe 1 should be operated to capture the optimum measurement cross section, and includes the direction in which the ultrasound probe 1 is translated along the body surface of the subject, the tilt direction of the ultrasound probe 1, etc.

[0036] Figure 6 shows a schematic diagram of the positional relationship between the ultrasound probe 1 and the cavity of the left ventricle A when the ultrasound probe 1 is placed away from the ideal position for capturing the optimal measurement cross section for measuring the left ventricular ejection fraction. In this figure, as in Figure 5, the ultrasound probe 1 and the cavity of the left ventricle A are viewed from the direction along the scan plane P2 of the ultrasound probe 1.

[0037] When the ultrasonic probe 1 is positioned away from the ideal position for capturing the optimal measurement cross section for measuring the left ventricular ejection fraction, even if the tilt angle of the ultrasonic probe 1 can be adjusted to capture a cross section in which the long-axis diameter L2 of the lumen of the left ventricle A in the ultrasonic image U is maximized, the long-axis diameter L1 of the lumen of the left ventricle A in the optimal measurement cross section cannot be obtained unless the scan plane P2 of the ultrasonic probe 1 passes through the apex C of the lumen of the left ventricle A. In order for the scan plane P2 to pass through the apex C and maximize the long-axis diameter L2 of the lumen of the left ventricle A, the ultrasonic probe 1 must be translated along the body surface of the subject. As the ultrasonic probe 1 is translated along the body surface of the subject toward the ideal position, the value of the depth D2 of the upper end E of the lumen of the left ventricle A gradually decreases over time, and as the ultrasonic probe 1 is translated along the body surface of the subject away from the ideal position, the value of the depth D2 of the upper end E of the lumen of the left ventricle A gradually increases over time.

[0038] Therefore, when the value of the depth D2 of the upper end E of the cavity of the left ventricle A changes so as to gradually decrease in time series from an arbitrary time in the past to the current time, the probe operation direction calculation unit 27 can calculate the current (parallel) movement direction of the ultrasound probe 1 along the body surface of the subject as the target operation direction. Also, when the value of the depth D2 of the upper end E of the cavity of the left ventricle A changes so as to gradually increase in time series from an arbitrary time in the past to the current time, the probe operation direction calculation unit 27 can calculate the opposite direction to the current (parallel) movement direction of the ultrasound probe 1 along the body surface of the subject as the target operation direction.

[0039] Furthermore, for example, when attempting to obtain the maximum major axis diameter L2 of the lumen of the left ventricle A while keeping the position of the ultrasound probe 1 on the body surface of the subject fixed, it is necessary to adjust the tilt angle of the ultrasound probe 1. Therefore, when the value of the major axis diameter L2 of the lumen of the left ventricle A changes so as to gradually increase in time series from an arbitrary time in the past to the current time, the probe operation direction calculation unit 27 can calculate the current tilt direction of the ultrasound probe 1 as the target operation direction. When the value of the major axis diameter L2 of the lumen of the left ventricle A changes so as to gradually decrease in time series from an arbitrary time in the past to the current time, the probe operation direction calculation unit 27 can calculate the opposite direction to the current tilt direction of the ultrasound probe 1 as the target operation direction.

[0040] In order to accurately determine the time-series changes of the plurality of feature amounts, the probe operation direction calculation unit 27 can start calculating the target operation direction when a predetermined time has elapsed since the image acquisition unit 31 started acquiring the ultrasound images U, or when a predetermined number of frames of the ultrasound images U have been acquired by the image acquisition unit 31.

[0041] The notification unit 28 notifies the user of the ultrasound diagnostic device of the target operation direction calculated by the probe operation direction calculation unit 27 and the optimal feature selected by the optimal feature selection unit 25 and stored in the feature memory 26. The notification unit 28 can display a message M on the monitor 23 to notify the user of the target operation direction, as shown in, for example, FIG. 7. In the example of FIG. 7, the message M "Please move the probe in the opposite direction" is displayed on the monitor 23, indicating that the ultrasound probe 1 should be moved parallel to the subject in the opposite direction to the current movement direction along the body surface of the subject. Although not shown, the notification unit 28 can also display, for example, a message M "Please tilt the probe in the opposite direction" on the monitor 23, indicating that the ultrasound probe 1 should be tilted in the opposite direction to the current tilt direction.

[0042] Furthermore, the notification unit 28 can display, for example, a depth indication line G1 indicating the depth D3 of the upper end E of the lumen of the left ventricle A having the smallest calculated value, and a long axis indication line G2 indicating the depth position of the long axis B of the lumen of the left ventricle A having the largest calculated long axis diameter L3, as optimal features on the monitor 23. The notification unit 28 can also tilt the long axis indication line G2 in accordance with the tilt of the long axis B.

[0043] By checking the target operation direction notified by the notifying unit 28, the user can easily capture the optimal measurement cross section by translating and tilting the ultrasound probe 1 toward the ideal position and ideal tilt angle of the ultrasound probe 1 for capturing the optimal measurement cross section. Furthermore, by checking the optimal feature amount notified by the notifying unit 28, the user can easily determine whether the current ultrasound image U displayed on the monitor 23 represents the optimal measurement cross section.

[0044] Under the control of the main body control unit 29, the display control unit 22 performs predetermined processing on the ultrasound image U sent from the image generation unit 21, information representing the content of the notification to the user by the notification unit 28, etc., and displays them on the monitor 23.

[0045] The monitor 23 displays the ultrasound image U and instructions to the user 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).

[0046] The main body control unit 29 controls each part of the device main body 2 and the transmitting / receiving circuit 12 of the ultrasonic probe 1 based on a control program stored in advance.

[0047] The input device 30 is used by the user to perform input operations, and is configured by devices such as a keyboard, a mouse, a trackball, a touchpad, and a touch sensor placed over the monitor 23, for example.

[0048] The processor 32, which includes the image generation unit 21, the display control unit 22, the feature calculation unit 24, the optimal feature selection unit 25, the probe operation direction calculation unit 27, the notification unit 28, and the main body control unit 29, may be configured with one or more pieces of hardware, and the type of hardware is not limited. For example, the processor may be configured with hardware such as a programmable logic device such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), an FPGA (Field Programmable Gate Array), a dedicated circuit for executing specific processes such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). The processor also has various units or means for executing various processes in this embodiment. The type of hardware may also be a combination of different types of hardware. When multiple pieces of hardware are configured to execute one or more processes of a certain processor, the multiple pieces of hardware may be located in physically separate devices or may be located in the same device. In any embodiment, the order of the processes performed by the processor is not limited to the order described above and may be changed as appropriate. Note that the hardware is configured by an electric circuit or the like that combines circuit elements such as semiconductor elements.

[0049] Furthermore, the present invention may be implemented by hardware, software, firmware, microcode, or a combination thereof. Software, firmware, and microcode may be configured by a program. A program may also be, for example, a group of program modules, each function of which may be implemented by a processor configured to execute the respective function. The program may be program code or multiple code segments stored in one or more non-transitory computer-readable media (e.g., storage media or other storages). The program may be stored in multiple non-transitory computer-readable media that reside in physically separate devices. Program code or a code segment may represent a procedure, a function, a subprogram, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. Program code or a code segment may be connected to another code segment or a hardware circuit by sending or receiving information, data, arguments, parameters, or memory contents.

[0050] Next, the operation of the ultrasound diagnostic apparatus according to the embodiment will be described with reference to the flowchart shown in FIG.

[0051] In step S1, the image acquisition unit 31 acquires an ultrasound image U of an organ to be measured. At this time, under the control of the main body control unit 29, transmission and reception of ultrasound waves is started from the multiple transducers of the transducer array 11 in accordance with a drive signal from the pulser 41 of the transmission and reception circuit 12 of the ultrasound probe 1, ultrasound echoes from inside the subject are received by the multiple transducers of the transducer array 11, and the received signals, which are analog signals, are output to the amplifier 42 and amplified, and then AD converted by the AD conversion unit 43 to acquire received data.

[0052] The beam former 44 performs reception focus processing on this reception data, and the sound ray signals generated thereby are sent to the image generator 21 of the device main body 2, which generates an ultrasound image U representing tomographic image information of the subject. At this time, the signal processor 45 of the image generator 21 performs attenuation correction and envelope detection processing on the sound ray signals according to the depth of the reflection position of the ultrasound, and the DSC 46 converts them into image signals in accordance with the scanning method of ordinary television signals, and the image processor 47 performs various necessary image processing such as gradation processing. The ultrasound image U generated in this way in step S2 is displayed on the monitor 23 via the display controller 22 and sent to the feature calculator 24.

[0053] In step S2, the feature calculation unit 24 calculates feature amounts of the measurement target organ of the subject by performing image analysis on the ultrasound image U acquired in step S1. For example, the feature calculation unit 24 can calculate the depth D of the upper end E of the lumen of the left ventricle A and the long axis diameter L of the lumen of the left ventricle A in the ultrasound image U as feature amounts of the left ventricle A, which is the measurement target for the left ventricular ejection fraction of the subject's heart H, using a segmentation method using machine learning or an algorithm for extracting key points in the ultrasound image U.

[0054] In step S3, the optimum feature quantity selection unit 25 selects, from the feature quantities calculated in step S2, the feature quantity that is most preferable as the feature quantity that corresponds to the optimum measurement cross section of the measurement target organ, as the optimum feature quantity. At this point, only one feature quantity has been calculated for each type of feature quantity in step S2, so the optimum feature quantity selection unit 25 selects the feature quantity calculated in step S2 as the optimum feature quantity. The feature quantity memory 26 stores the optimum feature quantities selected by the optimum feature quantity selection unit 25 in this manner.

[0055] In step S4, the probe operation direction calculation unit 27 determines whether a sufficient number of feature amounts have been obtained to calculate the target operation direction of the ultrasound probe 1, i.e., whether a sufficient number of ultrasound images U have been obtained. The probe operation direction calculation unit 27 can determine that a sufficient number of ultrasound images U have been obtained when, for example, a predetermined time, such as five seconds, has elapsed since the ultrasound image U was acquired, or when a predetermined number of frames of ultrasound images U corresponding to that time have been acquired. Furthermore, the probe operation direction calculation unit 27 can determine that a sufficient number of ultrasound images U have not been obtained when a predetermined time, such as five seconds, has not elapsed since the ultrasound image U was acquired, or when a predetermined number of frames of ultrasound images U have not been acquired.

[0056] If it is determined in step S4 that a sufficient number of ultrasound images U have not been obtained, the process returns to step S1 to acquire a new frame of ultrasound image U. In the following step S2, the feature amount of the measurement target organ in the ultrasound image U acquired in the immediately preceding step S1 is calculated.

[0057] In step S3, the optimum feature quantity selection unit 25 selects one of the feature quantity calculated and selected as the optimum feature quantity in the first step S2 and the feature quantity calculated in the second step S2 as the optimum feature quantity. For example, if the depth D of the upper end E of the lumen of the left ventricle A is calculated as the feature quantity, the optimum feature quantity selection unit 25 selects the shallower depth D between the depth D calculated in the first step S2 and the depth D calculated in the second step S2 as the optimum feature quantity.

[0058] When the feature calculated in step S2 for the first time is selected as the optimum feature, the feature memory 26 maintains the optimum feature that has already been stored, and when the feature calculated in step S2 for the second time is selected as the optimum feature, the feature memory 26 updates the stored optimum feature to the feature calculated in step S2 for the second time.

[0059] In this way, as long as it is determined in step S4 that a sufficient number of ultrasound images U have not been obtained, the processing of steps S1 to S4 is repeated to calculate multiple feature amounts from multiple frames of ultrasound images U, and the most preferable feature amount among the calculated multiple feature amounts as the feature amount corresponding to the optimal measurement cross section is selected as the optimal feature amount and stored in feature amount memory 26.

[0060] If it is determined in step S4 that a sufficient number of ultrasound images U have been obtained, the process proceeds to step S5. In step S5, the probe operation direction calculation unit 27 calculates a target operation direction of the ultrasound probe 1 for capturing an optimal measurement cross section based on the time-series changes in the multiple feature amounts calculated by repeating steps S1 to S4.

[0061] For example, when the value of the depth D of the upper end E of the lumen of the left ventricle A calculated as a feature amount has gradually decreased from an arbitrary time in the past to the present, the probe operation direction calculation unit 27 can calculate the current movement direction of the ultrasound probe 1 along the body surface of the subject as the target operation direction, and when the value of the depth D of the upper end E of the lumen of the left ventricle A has gradually increased from an arbitrary time in the past to the present, the probe operation direction calculation unit 27 can calculate the opposite direction of the current movement direction of the ultrasound probe 1 along the body surface of the subject as the target operation direction. Furthermore, when the value of the major axis diameter L of the lumen of the left ventricle A calculated as a feature amount has gradually increased from an arbitrary time in the past to the present, the probe operation direction calculation unit 27 can calculate the current tilt direction of the ultrasound probe 1 as the target operation direction, and when the value of the major axis diameter L of the lumen of the left ventricle A has gradually decreased from an arbitrary time in the past to the present, the probe operation direction calculation unit 27 can calculate the opposite direction of the current tilt direction of the ultrasound probe 1 as the target operation direction.

[0062] In step S6, the notification unit 28 notifies the user of the target operation direction calculated in step S5 and the optimal feature finally selected in step S3 and stored in the feature memory 26. The notification unit 28 can notify the user of the target operation direction and the optimal feature by displaying, on the monitor 23, a message M indicating the target operation direction, a depth indication line G1 indicating the depth D3 having the smallest value as the optimal feature, and a long axis indication line G2 indicating the depth position of the long axis B having the largest long axis diameter L3 as the optimal feature, as shown in Fig. 7, for example. The notification unit 28 can also tilt the long axis indication line G2 in accordance with the tilt of the long axis B.

[0063] In step S7, the main body control unit 29 determines whether or not to terminate the acquisition of the ultrasound image U. For example, the main body control unit 29 can determine to terminate the acquisition of the ultrasound image U when it determines that the user has successfully captured the optimal measurement cross section and has input an instruction to terminate the acquisition of the ultrasound image U via the input device 30. Furthermore, the main body control unit 29 can determine to continue the acquisition of the ultrasound image U when it determines that the user has not yet successfully captured the optimal measurement cross section and has not specifically input an instruction to terminate the acquisition of the ultrasound image U via the input device 30.

[0064] As long as it is determined in step S7 that acquisition of the ultrasound image U should be continued, the processes of steps S1 to S7 are repeated. By checking the target operation direction notified sequentially in step S7, the user can translate and tilt the ultrasound probe 1 toward the ideal position and ideal tilt angle of the ultrasound probe 1 for capturing the optimal measurement cross section, thereby easily capturing the optimal measurement cross section. Furthermore, by checking the optimal feature amount notified in step S7, the user can easily determine whether the current ultrasound image U displayed on the monitor 23 represents the optimal measurement cross section.

[0065] When it is determined in step S7 that acquisition of the ultrasound image U is to be terminated, the operation of the ultrasound diagnostic apparatus shown in the flowchart of Fig. 8 is terminated. Using the ultrasound image U representing the optimal measurement cross section obtained by this operation, the user performs measurements of the measurement target organ, such as the left ventricular ejection fraction of the subject's heart H.

[0066] As described above, according to the ultrasound diagnostic apparatus of the embodiment of the present invention, the probe operation direction calculation unit 27 calculates the target operation direction of the ultrasound probe 1 for capturing an optimum measurement cross section based on the time-series changes in the plurality of feature amounts calculated by the feature amount calculation unit 24 in the ultrasound image U of the plurality of frames, and the notification unit 28 notifies the user of the calculated target operation direction, so that the user can easily capture an optimum measurement cross section of the organ to be measured.

[0067] Although the transmitting and receiving circuit 12 has been described as being provided in the ultrasonic probe 1, the transmitting and receiving circuit 12 may be provided in the device main body 2. Furthermore, although the image generating unit 21 has been described as being provided in the device main body 2, the image generating unit 21 may be provided in the ultrasound probe 1.

[0068] The device main body 2 may be a so-called stationary type, a portable type that is easy to carry, or a so-called handheld type that is configured by, for example, a smartphone or a tablet computer. In this way, the type of device that configures the device main body 2 is not particularly limited.

[0069] The notification unit 28 can notify the user that multiple frames of ultrasound images U will be acquired while moving the ultrasound probe 1 so as to capture a wide range in order to accurately acquire preferred feature amounts corresponding to the optimal measurement cross section. By moving the ultrasound probe 1 in accordance with this notification, the user can acquire multiple frames of ultrasound images U corresponding to various positions and tilt angles of the ultrasound probe 1, making it easier to acquire feature amounts corresponding to the optimal measurement cross section.

[0070] Although it has been described that the notification unit 28 notifies the user by displaying a message M or the like on the monitor 23, the notification method by the notification unit 28 is not limited to this. For example, if the ultrasound diagnostic apparatus is equipped with a speaker (not shown), the notification unit 28 can notify the user by emitting a voice or a warning sound from the speaker. Furthermore, if the ultrasound diagnostic apparatus is equipped with a lamp (not shown), the notification unit 28 can notify the user by changing the blinking pattern of the lamp, for example. Furthermore, if the ultrasound probe 1 is equipped with a vibration device such as a so-called small vibration motor, the notification unit 28 can notify the user by vibrating the ultrasound probe 1, for example.

[0071] Although it is described that the user determines whether the current ultrasound image U displayed on the monitor 23 represents the optimal measurement cross section by checking the optimal feature value notified by the notification unit 28, the main body control unit 29 can, for example, automatically determine this. In this case, the main body control unit 29 can determine that the current ultrasound image U represents the optimal measurement cross section, for example, when the value of the optimal feature value stored in the feature value memory 26 has not been updated for a certain period of time or more and the difference between the feature value calculated for the current ultrasound image U displayed on the monitor 23 and the value of the optimal feature value is within a certain range. For example, when the depth D of the upper end E of the lumen of the left ventricle A and the long-axis diameter L of the lumen of the left ventricle A are calculated as the feature values, the main body control unit 29 can determine that the current ultrasound image U represents the optimal measurement cross section, if both the difference between the depth D and the optimal feature value and the difference between the long-axis diameter L and the optimal feature value are within certain ranges.

[0072] Furthermore, in this case, the notification unit 28 can notify the user that the optimum measurement cross section has been captured by, for example, displaying a message M on the monitor 23. This allows even a less skilled user to easily understand that the optimum measurement cross section has been captured.

[0073] Here, it is explained that in order to determine whether an ultrasound image U representing an optimal measurement cross section for calculating the left ventricular ejection fraction has been acquired, it is determined whether both the depth D of the upper end E of the lumen of the left ventricle A and the long axis diameter L of the lumen of the left ventricle A generally match the corresponding optimal feature amounts. In this way, in order to determine whether an ultrasound image U representing an optimal measurement cross section for a specific measurement has been acquired, it is necessary to determine whether one or more types of feature amounts defined corresponding to the optimal measurement cross section generally match the respective optimal feature amounts.

[0074] Therefore, the main body control unit 29 can identify problematic features, i.e., feature quantities that do not generally match the optimal feature quantities, by determining whether one or more types of feature quantities defined corresponding to the optimal measurement cross section generally match the respective optimal feature quantities, i.e., whether the difference is within a certain range. In this case, the notification unit 28 can notify the user of the problematic feature quantities. For example, if the depth D of the upper end E of the lumen of the left ventricle A does not generally match the depth D1 of the apex C, the notification unit 28 can display a message M, such as "The apex is not being properly depicted," on the monitor 23. Furthermore, if the major axis diameter L of the lumen of the left ventricle A does not generally match the maximum major axis diameter L1, the notification unit 28 can display a message M, such as "The maximum diameter plane is not being depicted," on the monitor 23. This allows the user to easily grasp the target for capturing the optimal measurement cross section and appropriately move the ultrasound probe 1.

[0075] Although it has been described that the feature amount calculation unit 24 calculates the long-axis diameter L of the lumen of the left ventricle A as a feature amount, it is also possible to calculate the area of ​​the lumen of the left ventricle A in the ultrasound image U instead of the long-axis diameter L of the lumen of the left ventricle A. In this case, the probe operation direction calculation unit 27 can calculate the current tilt direction of the ultrasound probe 1 as the target operation direction when the value of the area of ​​the lumen of the left ventricle A has gradually increased from an arbitrary time in the past to the present, and can calculate the opposite direction to the current tilt direction of the ultrasound probe 1 as the target operation direction when the value of the area of ​​the lumen of the left ventricle A has gradually decreased from an arbitrary time in the past to the present.

[0076] Feature quantities represented by the depth D of the upper end E of the lumen of the left ventricle A, the long-axis diameter L of the lumen of the left ventricle A, the area of ​​the lumen of the left ventricle A, etc., change to have multiple maximum values ​​and multiple minimum values ​​in a time series due to the pulsation of the heart H, as shown in Fig. 9. In this figure, three maximum values ​​and two minimum values ​​are shown as an example. In order to accurately obtain the time series changes in these feature quantities due to the position or tilt angle of the ultrasound probe 1, the probe operation direction calculation unit 27 can calculate the target operation direction based on the time series changes in the multiple maximum values ​​of these feature quantities or the time series changes in the multiple minimum values ​​of these feature quantities.

[0077] Known cross sections of the heart H that can be imaged by an ultrasound diagnostic device include the so-called apical four-chamber cross section, which includes the left ventricle A, right ventricle, left atrium, and right atrium, as shown in Figures 4 and 7, and the so-called apical two-chamber cross section, which includes the left ventricle A and the left atrium, or the right atrium and right ventricle, as shown in Figure 10. When the user is imaging one of the apical four-chamber cross section or the apical two-chamber cross section, and then rotates the ultrasound probe 1 by 90 degrees around the axis of the direction in which the ultrasound probe 1 is pressed against the body surface of the subject, the other of the apical four-chamber cross section or the apical two-chamber cross section can be imaged.

[0078] Therefore, when the apical four-chamber view or the apical two-chamber view is set as the optimal measurement view, in order to determine the appropriate rotation direction of the ultrasound probe 1, the feature calculation unit 24 can calculate, as a feature, the similarity between multiple frames of ultrasound image U and a reference image corresponding to the apical four-chamber view or the apical two-chamber view set as the optimal measurement view. The feature calculation unit 24 can calculate the similarity by, for example, a so-called template matching method, a method using a trained model in machine learning that has learned the relationship between the similarity between a large number of ultrasound images U and the reference image, or the like.

[0079] In this case, when the multiple similarities calculated by the feature amount calculation unit 24 change so as to gradually increase in the time series from any time in the past to the present, the probe operation direction calculation unit 27 can calculate, as the target operation direction, the current rotation direction of the ultrasound probe 1 by the user. Also, when the multiple similarities calculated by the feature amount calculation unit 24 change so as to gradually decrease in the time series from any time in the past to the present, the probe operation direction calculation unit 27 can calculate, as the target operation direction, the opposite direction to the current rotation direction of the ultrasound probe 1 by the user. This allows the user to easily adjust the rotation direction to acquire an ultrasound image U that appropriately represents the apical four-chamber cross section or the apical two-chamber cross section.

[0080] Generally, when calculating the left ventricular ejection fraction of heart H, the long-axis diameter L and short-axis diameter of the lumen of left ventricle A at end-diastole and end-systole in the apical four-chamber cross section and the long-axis diameter L and short-axis diameter of the lumen of left ventricle A at end-diastole and end-systole in the apical two-chamber cross section are measured, and the left ventricular ejection fraction is often calculated using the long-axis diameter L and short-axis diameter of the lumen of left ventricle A in the apical four-chamber cross section and the long-axis diameter L and short-axis diameter of the lumen of left ventricle A in the apical two-chamber cross section. Here, the short-axis diameter of the lumen of left ventricle A refers to the length of the short axis defined by a line segment that is perpendicular to the long axis B of the lumen of left ventricle A and has the longest length.

[0081] When both the apical four-chamber view and the apical two-chamber view are to be photographed, by applying the present invention to both the apical four-chamber view and the apical two-chamber view, a message M or the like indicating the target operation direction for the apical four-chamber view and the apical two-chamber view is displayed on the monitor 23, as shown in, for example, Figures 4, 7, and 10, so that an ultrasound image U representing the optimal measurement view corresponding to the apical four-chamber view and an ultrasound image U representing the optimal measurement view corresponding to the apical two-chamber view can be easily obtained.

[0082] In this case, the image acquisition unit 31 can sequentially acquire multiple frames of ultrasound images U for each of the apical four-chamber and apical two-chamber views of the heart H. Because the value of the optimal feature is expected to remain the same for the apical four-chamber and apical two-chamber views, the feature calculation unit 24 calculates multiple feature amounts for a first cross section, of the apical four-chamber and apical two-chamber views, for which multiple frames of ultrasound images U have been acquired first by the image acquisition unit 31, and the optimal feature selection unit 25 selects an optimal feature amount from the multiple feature amounts calculated for the first cross section. After that, the notification unit 28 can notify the user of the optimal feature amount selected for the first cross section while the image acquisition unit 31 is acquiring multiple frames of ultrasound images U for a second cross section, of the apical four-chamber and apical two-chamber views, which is different from the first cross section. This omits the process of selecting and saving optimal feature amounts for the second cross section, which is captured after the first cross section, thereby reducing the calculation load imposed on the processor 32.

[0083] Although an example has been described in which the feature calculation unit 24 calculates feature amounts related to the left ventricle A, the target for calculating feature amounts is not limited to the left ventricle A. For example, when measuring the right ventricular ejection fraction of the heart H, the feature calculation unit 24 can calculate feature amounts related to the right ventricle, such as the depth of the upper end of the right ventricle lumen, the long-axis diameter of the right ventricle lumen, or the area of ​​the right ventricle lumen. Furthermore, depending on the type of measurement, the feature calculation unit 24 can also calculate feature amounts related to the left atrium or right atrium. In this way, the feature calculation unit 24 can calculate feature amounts related to any of the left ventricle A, the right ventricle, the left atrium, and the right atrium, i.e., the cardiac chambers.

[0084] Also, although an example has been described in which the measurement target organ is the heart H, the measurement target organ is not limited to the heart H, and for example, the subject's bladder can be set as the measurement target organ. In this case, feature calculation unit 24 can calculate, as feature amounts, the depth of the shallowest part of the contour of the bladder in ultrasound image U and the long axis diameter of the bladder in ultrasound image U. The long axis diameter of the bladder in ultrasound image U is calculated from the distance of the longest line segment between two points on the contour of the bladder.

[0085] The probe operation direction calculation unit 27 can calculate the current movement direction of the ultrasound probe 1 as the target operation direction when the depth value of the shallowest part of the bladder contour decreases in time series, just as when the measurement target organ is the heart H. Furthermore, the probe operation direction calculation unit 27 can calculate the current tilt direction of the ultrasound probe 1 as the target operation direction when the long-axis diameter value of the bladder increases in time series, just as when the measurement target organ is the heart H.

[0086] Furthermore, the measurement item or the type of optimal measurement cross section can be input by the user via the input device 30 before acquiring the ultrasound image U. In this case, the feature calculation unit 24 calculates the feature corresponding to the input measurement item or the type of optimal measurement cross section from the ultrasound image U.

[0087] Furthermore, for example, the main body control unit 29 can also estimate the measurement item or the type of optimal measurement cross section by analyzing the acquired ultrasound image U. The main body control unit 29 can estimate the measurement item or the type of optimal measurement cross section from the ultrasound image U by using, for example, a trained model in machine learning that has learned the relationship between a large number of ultrasound images U and parts of the subject, such as the left ventricle A, right ventricle, or bladder, and the relationship between parts of the subject and the measurement item or the type of optimal measurement cross section. In this case, the feature amount calculation unit 24 calculates, from the ultrasound image U, a feature amount corresponding to the estimated measurement item or the type of optimal measurement cross section.

[0088] The ultrasound diagnostic apparatus may also include a position and orientation sensor for detecting the position and tilt angle of the ultrasound probe 1. The position and orientation sensor may include, for example, at least one of an inertial sensor, a magnetic sensor, an optical sensor, or an optical camera. The inertial sensor may include, for example, at least one of an acceleration sensor and a gyro sensor. The position and orientation sensor may be built into the ultrasound probe 1 or attached to the housing of the ultrasound probe 1. When a sensor device that measures the ultrasound probe 1 from the outside, such as an optical sensor, is used as the position and orientation sensor, the position and orientation sensor may be located at a position away from the ultrasound probe 1. The position and orientation sensor may also be configured, for example, with a marker, such as an augmented reality (AR) marker, attached to the ultrasound probe 1, an optical camera that captures an optical image of the marker, and a marker recognition unit that recognizes the marker in the optical image and calculates the position and tilt angle of the ultrasound probe 1 from the size, tilt angle, etc. of the marker. The marker recognition unit may be incorporated into the processor 32, for example.

[0089] If the ultrasound diagnostic apparatus is equipped with a position and orientation sensor, the probe operation direction calculation unit 27 can calculate the target operation direction by further taking into account the position and tilt angle of the ultrasound probe 1 detected by the position and orientation sensor. For example, when the ultrasound probe 1 is translated along the body surface of the subject or tilted, both the depth D of the upper end E of the cavity of the left ventricle A and the major axis diameter L of the cavity of the left ventricle A change. However, by referring to the detection result of the position and orientation sensor, the probe operation direction calculation unit 27 can reliably determine whether the ultrasound probe 1 is translated along the body surface of the subject or tilted relative to the body surface, and can accurately calculate the target operation direction. [Explanation of symbols]

[0090] 1 ultrasound probe, 2 device main body, 11 transducer array, 12 transmission / reception circuit, 21 image generation unit, 22 display control unit, 23 monitor, 24 feature calculation unit, 25 optimal feature selection unit, 26 feature memory, 27 probe operation direction calculation unit, 28 notification unit, 29 main body control unit, 30 input device, 31 image acquisition unit, 32 processor, 41 pulser, 42 amplifier unit, 43 AD conversion unit, 44 beamformer, 45 signal processing unit, 46 DSC, 47 image processing unit, A left ventricle, B long axis, C apex, D, D1, D2, D3 depth, E upper end, G1 depth indicator line, G2 long axis indicator line, H heart, L, L1, L2, L3 long axis diameter, M message, P1, P2 scan plane, U ultrasound image.

Claims

1. an ultrasound probe; an image acquisition unit that acquires a plurality of frames of ultrasound images of a measurement target organ of a subject by transmitting and receiving ultrasound beams using the ultrasound probe; a feature calculation unit that calculates a feature of the measurement target organ in each of the plurality of frames of ultrasound images by image analysis of the plurality of frames of ultrasound images acquired by the image acquisition unit; a probe operation direction calculation unit that calculates a target operation direction of the ultrasound probe for capturing an optimum measurement cross section suitable for measurement of the measurement target organ, based on time-series changes in the plurality of feature amounts calculated by the feature amount calculation unit in the plurality of frames of ultrasound images; a notification unit that notifies a user of the target operation direction calculated by the probe operation direction calculation unit; An ultrasound diagnostic device equipped with:

2. 2. The ultrasound diagnostic apparatus according to claim 1, wherein the probe operation direction calculation unit starts calculating the target operation direction when a predetermined time has elapsed since the image acquisition unit started acquiring the ultrasound image.

3. an optimal feature amount selection unit that selects one of the plurality of feature amounts calculated by the feature amount calculation unit as an optimal feature amount corresponding to the optimal measurement cross section, The ultrasound diagnostic apparatus according to claim 1 , wherein the notification unit notifies the user of the optimum feature quantity selected by the optimum feature quantity selection unit.

4. The ultrasound diagnostic apparatus according to claim 3 , wherein the notification unit notifies the user to acquire the plurality of frames of ultrasound images while moving the ultrasound probe.

5. The ultrasonic diagnostic apparatus according to claim 3, further comprising a feature memory for storing the optimum feature in association with the subject.

6. The ultrasonic diagnostic apparatus according to claim 3, wherein the organ to be measured is a heart.

7. the feature amount calculation unit calculates a depth of an upper end of a cardiac cavity in the plurality of frames of ultrasound images as the feature amount; The probe operation direction calculation unit When the depth calculated by the feature amount calculation unit is changing to become shallower over time, a current moving direction of the ultrasound probe by the user along the body surface of the subject is calculated as the target operation direction, 7. The ultrasound diagnostic apparatus according to claim 6, wherein, when the depth calculated by the feature calculation unit is changing so as to become deeper over time, a direction opposite to a current direction of movement of the ultrasound probe by the user along the body surface of the subject is calculated as the target operation direction.

8. the feature calculation unit calculates a length of a long axis of a cardiac chamber as the feature; The probe operation direction calculation unit When the length calculated by the feature amount calculation unit is changing so as to become longer in time series, a current tilt direction of the ultrasound probe by the user is calculated as the target operation direction; 7. The ultrasound diagnostic apparatus according to claim 6, wherein, when the length calculated by the feature calculation unit changes so as to become shorter over time, a direction opposite to a current tilt direction of the ultrasound probe by the user is calculated as the target operation direction.

9. the feature amount calculation unit calculates an area of ​​a cardiac cavity as the feature amount; The probe operation direction calculation unit When the area calculated by the feature amount calculation unit is changing so as to increase over time, a current tilt direction of the ultrasound probe by the user is calculated as the target operation direction; 7. The ultrasound diagnostic apparatus according to claim 6, wherein, when the area calculated by the feature calculation unit changes so as to become smaller over time, a direction opposite to a current tilt direction of the ultrasound probe by the user is calculated as the target operation direction.

10. the plurality of feature amounts change in time series due to the beating of the heart so as to have a plurality of maximum values ​​and a plurality of minimum values; The ultrasonic diagnostic apparatus according to claim 6 , wherein the probe operation direction calculation unit calculates the target operation direction based on changes in the plurality of maximum values ​​or the plurality of minimum values ​​in time series.

11. the image acquisition unit acquires the plurality of frames of ultrasound images in turn for each of an apical four-chamber cross section and an apical two-chamber cross section of the heart; the feature amount calculation unit calculates the plurality of feature amounts for a first cross section from which the plurality of frames of ultrasound images have been acquired first by the image acquisition unit, among the apical four-chamber cross section and the apical two-chamber cross section; the optimum feature quantity selection unit selects the optimum feature quantity from the plurality of feature quantities calculated for the first cross section; 7. The ultrasound diagnostic device of claim 6, wherein the notification unit notifies the user of the optimal feature selected for the first cross section while the image acquisition unit is acquiring the plurality of frames of ultrasound images of a second cross section, which is different from the first cross section, among the apical four-chamber cross section and the apical two-chamber cross section.

12. the feature amount calculation unit calculates, as the feature amount, a similarity between the ultrasound images of the plurality of frames and a reference image corresponding to the optimal measurement cross section; The probe operation direction calculation unit When the plurality of similarities calculated by the feature amount calculation unit change so as to increase in time series, a current rotation direction of the ultrasound probe by the user is calculated as the target operation direction, 7. The ultrasound diagnostic apparatus according to claim 6, wherein, when the plurality of similarities calculated by the feature calculation unit change so as to decrease over time, a direction opposite to a current rotation direction of the ultrasound probe by the user is calculated as the target operation direction.

13. a position and orientation sensor for detecting the position and tilt angle of the ultrasonic probe; 13. The ultrasound diagnostic apparatus according to claim 1, wherein the probe operation direction calculation unit calculates the target operation direction by further taking into account the position and the tilt angle of the ultrasound probe detected by the position and orientation sensor.

14. Equipped with a monitor, 13. The ultrasound diagnostic apparatus according to claim 1, wherein the notification unit notifies the user of the target operation direction by displaying the target operation direction on the monitor.

15. Acquiring a plurality of frames of ultrasound images of the subject's organ to be measured by transmitting and receiving ultrasound beams using an ultrasound probe; calculating a feature amount of the measurement target organ in each of the plurality of frames of ultrasound images by performing image analysis on the acquired plurality of frames of ultrasound images; calculating a target operation direction of the ultrasound probe for capturing an optimum measurement cross section suitable for measurement of the measurement target organ based on time-series changes in the plurality of feature amounts calculated in the plurality of frames of ultrasound images; The calculated target operation direction is notified to the user. A method for controlling an ultrasound diagnostic device.

Images