Ultrasound diagnostic device and electrocardiogram waveform processing method

Abstract

To enable the end-diastole and the end-systole to be detected automatically in a stable section in an electrocardiographic waveform.SOLUTION: A setter 42 sets a plurality of heartbeat sections for an electrocardiographic waveform. A primary determination unit 44 determines a section that satisfies a primary determination condition in the plurality of heartbeat sections as a temporary stable section. A secondary determination unit 46 determines the temporary stable section as a stable section if the temporary stable section satisfies a secondary determination condition. An end-diastole detector 48 and an end-systole detector 50 detect the end-diastole and the end-systole in an attention section. A selection control part 33 controls selection of the attention section when changing the attention section so that the attention section after the change is the stable section.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an ultrasound diagnostic apparatus and an electrocardiogram waveform processing method, and in particular to a technique for detecting end diastole and end systole. [Background technology]

[0002] Ultrasound diagnostic devices used in cardiac ultrasound examinations generally have a function for acquiring electrocardiogram signals (ECG signals). In such ultrasound diagnostic devices, a waveform (electrocardiogram waveform) representing an electrocardiogram signal is displayed together with an ultrasound image. The electrocardiogram waveform is composed of a series of multiple heartbeat waveforms on the time axis. In a frozen state after real-time operation, an ultrasound image corresponding to a time phase (time phase of interest) designated or selected by the user on the electrocardiogram waveform is displayed on the display.

[0003] Various measurements are performed to evaluate cardiac function. Ejection fraction (EF) is known as a representative measurement value (cardiac function evaluation value). The ejection fraction is generally calculated from the left ventricular volume at end diastole and the left ventricular volume at end systole. Each volume is found, for example, from the left ventricular area calculated on a tomographic image. If the accuracy of identifying the end diastole and the end systole is low, the reliability of the calculated ejection fraction decreases.

[0004] Patent documents 1 and 2 disclose an ultrasonic diagnostic device having a function of determining a stable heartbeat among multiple heartbeats as a stable period. Patent document 3 discloses an ultrasonic diagnostic device having a function of detecting end systole and end diastole. None of the patent documents disclose a technique for linking the function of determining a stable period with the function of detecting end systole and end diastole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2012 / 029616 [Patent Document 2] International Publication No. 2013 / 105568 [Patent Document 3] International Publication No. 2012 / 023399 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide an ultrasound diagnostic device and an electrocardiogram waveform processing method capable of detecting end diastole and end systole within an appropriate heartbeat interval. [Means for solving the problem]

[0007] The ultrasound diagnostic device according to the present invention includes an image forming unit that forms an ultrasound image based on received data acquired from a subject; a setting unit that defines multiple intervals, in units of heartbeats, for an electrocardiogram waveform representing an electrocardiogram signal acquired from the subject; a detection unit that detects end diastole and end systole within a target interval among the multiple intervals based on the electrocardiogram waveform; and a display processing unit that displays an end diastole marker representing the end diastole within the target interval and an end systole marker representing the end systole within the target interval when the electrocardiogram waveform is displayed together with the ultrasound image.The ultrasound diagnostic device further includes a determination unit that determines each interval among the multiple intervals that satisfies a stability condition as a stable interval, and a selection control unit that, when an operation to change the target interval is performed, controls selection of the changed target interval so that the changed target interval is selected from the multiple stable intervals determined by the determination unit, and is characterized in that, when an operation to change the target interval is performed, the detection unit detects end diastole and end systole within a specific stable interval that is the changed target interval.

[0008] The electrocardiogram waveform processing method according to the present disclosure includes a step of defining a plurality of intervals, in units of heartbeats, for an electrocardiogram waveform representing an electrocardiogram signal obtained from a subject; a step of detecting end diastole and end systole within an interval of interest among the plurality of intervals based on the electrocardiogram waveform; and a step of displaying an end diastole marker representing the end diastole within the interval of interest and an end systole marker representing the end systole within the interval of interest when the electrocardiogram waveform is displayed together with an ultrasound image, and further includes a step of determining each interval among the plurality of intervals that satisfies a stability condition as a stable interval, and a step of controlling selection of the changed interval of interest so that, when an operation to change the interval of interest is performed, the changed interval of interest is selected from the determined plurality of stable intervals, characterized in that, when an operation to change the interval of interest is performed, end diastole and end systole are detected within a specific stable interval that is the changed interval of interest. Effect of the Invention

[0009] According to the present disclosure, end diastole and end systole can be detected within an appropriate heartbeat interval. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an example of the configuration of an ultrasound diagnostic apparatus according to an embodiment. [Diagram 2] FIG. 4 illustrates an example of the configuration of a waveform analysis unit. [Diagram 3] 13A and 13B are diagrams showing changes in a waveform image when a section of interest is changed. [Figure 4] FIG. 13 is a diagram showing some tentative stable zone determination methods. [Diagram 5] FIG. 11 is a diagram illustrating a first example of tentative stable zone determination. [Figure 6] FIG. 11 is a diagram illustrating a second example of tentative stable zone determination. [Figure 7] FIG. 13 illustrates detection of end-diastole and end-systole within a stable period. [Figure 8] FIG. 13 is a schematic diagram showing a stable zone determination method. [Figure 9]FIG. 13 is a diagram illustrating multiple selectable options. [Figure 10] 13A and 13B are diagrams illustrating an example of operation according to option 2 and an example of operation according to option 3. [Figure 11] 4 is a flowchart showing an example of the operation of the ultrasound diagnostic apparatus. [Figure 12] FIG. 13 is a diagram showing an example of a two-screen display. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0012] (1) Overview of the embodiment An ultrasound diagnostic device according to an embodiment includes an image forming unit, a setting unit, a detection unit, a display processing unit, a determination unit, and a selection control unit. The image forming unit forms an ultrasound image based on received data acquired from a subject. The setting unit determines a plurality of sections (a plurality of heartbeat sections) in units of heartbeats for an electrocardiogram waveform representing an electrocardiogram signal acquired from the subject. The detection unit detects end diastole and end systole in a section of interest among the plurality of sections based on the electrocardiogram waveform. When the display processing unit displays the electrocardiogram waveform together with an ultrasound image, it displays an end diastole marker representing end diastole in the section of interest and an end systole marker representing the end systole in the section of interest. The determination unit determines each section that satisfies a stability condition among the plurality of sections as a stable section. When an operation to change the section of interest is performed, the selection control unit controls selection of the changed section of interest so that the changed section of interest is selected from the plurality of stable sections determined by the determination unit. When an operation to change the section of interest is performed, the detection unit detects end diastole and end systole in a specific stable section that is the changed section of interest.

[0013] According to the above configuration, the detection of the end diastole and the end systole within the stable section is guaranteed after the section of interest is changed. Even if the section of interest is repeatedly changed, the end diastole and the end systole are always detected within the stable section. This increases the reliability of the detected end diastole and the end systole.

[0014] In addition, if the time phase detection function is automatically activated during freezing, the end diastole and end systole may be detected in the latest section as the section of interest, regardless of whether the latest section is a stable section or not. If an instruction to start execution of the time phase detection function is given in the frozen state, the end diastole and end systole may be detected in the current section of interest, regardless of whether the current section of interest is a stable section or not. In either case, if the time phase detection function is on, after the section of interest is changed, a stable section is selected as the new section of interest. The frozen state is a state in which transmission and reception are stopped, and in the frozen state, the stored tomographic image is displayed, and the stored electrocardiogram waveform is also displayed.

[0015] In an embodiment, when a rewind operation is performed, the selection control unit selects the closest stable section before the section of interest as the new section of interest. On the other hand, when a forward operation is performed, the selection control unit selects the closest stable section after the section of interest as the new section of interest. For example, when the section of interest is repeatedly changed, the section of interest jumps sequentially. Each time the section of interest is changed, the end diastole and end systole are redetected.

[0016] According to the above configuration, since the user does not need to specify or select a stable interval, the burden on the user can be reduced. Also, according to the above configuration, cardiac function measurement based on the end diastolic and end systolic periods detected in an inappropriate interval can be avoided.

[0017] In an embodiment, during real-time operation and in a frozen state, when the electrocardiogram waveform is displayed, each stable section is distinguishably displayed. For example, each stable section is displayed in a specific color. In addition to an end-diastolic marker and an end-systolic marker, a time phase marker of interest indicating a time phase of interest is displayed on the electrocardiogram waveform. An ultrasound image corresponding to the time phase of interest is displayed.

[0018] In an embodiment, the selection control unit has a function of identifying a best stable section from among a plurality of stable sections, and selecting the best stable section as the initial section of interest or the changed section of interest. This function allows cardiac function measurement to be performed based on highly reliable end diastolic and end systolic periods. The best stable section is the section determined to be the most stable of the plurality of stable sections. For example, an evaluation value may be calculated for each stable section, and the stable section corresponding to the best evaluation value may be determined to be the best stable section.

[0019] In the embodiment, the selection control unit has a function of identifying the nearest stable section from among the multiple stable sections that is closest to the current phase of interest, and selecting the nearest stable section as the initial period of interest or the changed period of interest. This function allows a section that is close to the phase of interest of the user and is appropriate from the viewpoint of cardiac function measurement to be set as the detection target for the end diastole and the end systole. In other words, it is possible to avoid selecting a stable section that is far away in time from the phase of interest of the user. The current phase of interest is generally the phase indicated by the phase of interest marker on the time axis. For example, immediately after freezing, the latest phase is the current phase of interest. When the user moves (shifts) the phase of interest marker, the phase of interest moves along the time axis accordingly.

[0020] In an embodiment, the determination unit determines a plurality of stable intervals during real-time operation. The detection unit detects end diastole and end systole in a frozen state after real-time operation. By continuously determining the stable periods during real-time operation, each stable period can be recognized during real-time operation and can be immediately identified after real-time operation. Furthermore, end diastole and end systole can be quickly detected in a frozen state after real-time operation.

[0021] In an embodiment, the stability condition includes a primary judgment condition for judging a provisionally stable section based on a plurality of time lengths of a plurality of sections consecutive in time, and a secondary judgment condition for judging that the duration of a provisionally stable section satisfying the primary judgment condition does not correspond to tachycardia / bradycardia. The judgment unit includes a primary judgment unit that applies the primary judgment condition to each section, and a secondary judgment unit that applies the secondary judgment condition to the provisionally judged section that satisfies the primary judgment condition.

[0022] According to this configuration, it is possible to prevent a section that is recognized as stable but corresponds to tachycardia, or a section that is recognized as stable but corresponds to bradycardia from being determined as a section of interest. Other determination conditions, such as a tertiary determination condition, may be added.

[0023] The electrocardiogram waveform processing method according to the embodiment includes a setting step, a detection step, a display processing step, a determination step, and a selection control step. In the setting step, a plurality of sections are defined in units of heartbeats for an electrocardiogram waveform representing an electrocardiogram signal acquired from a subject. In the detection step, an end diastole and an end systole are detected in a section of interest among the plurality of sections based on the electrocardiogram waveform. In the display processing step, when the electrocardiogram waveform is displayed together with an ultrasound image, an end diastole marker representing an end diastole in the section of interest and an end systole marker representing an end systole in the section of interest are displayed. In the determination step, each section that satisfies a stability condition among the plurality of sections is determined as a stable section. In the selection control step, when an operation to change the section of interest is performed, selection of the changed section of interest is controlled so that the changed section of interest is selected from the determined plurality of stable sections. When an operation to change the section of interest is performed, an end diastole and an end systole are detected in a specific stable section that is the changed section of interest.

[0024] The above method is realized as a hardware function or a software function. A program for executing the above method may be installed in an information processing device via a network or a portable storage medium. The information processing device includes an ultrasound diagnostic device. The information processing device includes a non-transitory storage medium for storing the program.

[0025] (2) Details of the embodiment An example of the configuration of an ultrasonic diagnostic apparatus according to an embodiment is shown in Fig. 1. This ultrasonic diagnostic apparatus is a medical apparatus used in medical institutions such as hospitals.

[0026] 1, the ultrasound diagnostic device has a probe 10. A transmitting / receiving surface of the probe 10 is brought into contact with the surface of a subject. In this state, ultrasonic waves are transmitted from the probe 10 into a living body, and reflected waves from the living body are received by the probe 10.

[0027] Specifically, the probe 10 has a transducer element array consisting of a plurality of transducer elements. An ultrasonic beam is formed by the transducer element array, and the ultrasonic beam is electronically scanned. Known electronic scanning methods include an electronic linear scanning method and an electronic sector scanning method. A beam scan plane is formed by electronically scanning the ultrasonic beam. A two-dimensional transducer element array may be provided in the probe 10, and volume data may be acquired from within a living body using the two-dimensional transducer element array.

[0028] The transmitter 12 is an electronic circuit that functions as a transmit beamformer, and the receiver 14 is an electronic circuit that functions as a receive beamformer. During transmission, multiple transmit signals are supplied in parallel from the transmitter 12 to the transducer array. This forms a transmit beam. During reception, multiple receive signals are output in parallel from the transducer array to the receiver 14. The receiver 14 applies phasing addition (delay addition) to the multiple receive signals. This generates receive beam data.

[0029] Receive frame data is composed of multiple receive beam data aligned in the electronic scanning direction. Each receive beam data is composed of multiple echo data aligned in the depth direction. Each receive frame data corresponds to a tomographic image. In addition, in color flow mapping (CFM) mode, receive frame data for forming a tomographic image and receive frame data set for forming a blood flow image are generally acquired alternately.

[0030] The image forming unit 16 generates a display frame data string based on the input received frame data string, and outputs the display frame data string. The display frame data string corresponds to a tomographic image as a moving image. Each display frame data corresponds to a tomographic image as a still image. The image forming unit 16 has a digital scan converter (DSC), which has a coordinate conversion function, an interpolation function, a frame rate conversion function, and the like. The display frame data string is sent to the display processing unit 20.

[0031] The memory 18 is a so-called cine memory, and a display frame data string for a certain period of time is stored in the memory 18. In the freeze state, the display frame data read from the memory 18 is sent to the display processing unit 20 and the measurement unit 30. The memory 18 may be disposed in front of the image forming unit 16.

[0032] The display processing unit 20 has a graphic image generating function, an image synthesis function, a color calculation function, etc. An image to be displayed on the display 21 is generated in the display processing unit 20. In the embodiment, the display processing unit 20 has a function of generating a waveform image including an electrocardiogram waveform (a waveform image generator to be described later).

[0033] The electrocardiograph 22 has a plurality of electrodes attached to the subject. An electrocardiogram signal (ECG signal) is acquired from the subject by the electrocardiograph 22. The electrocardiogram signal is sent to a waveform analyzer 26 via a signal processing circuit 24.

[0034] The waveform analysis unit 26 analyzes the waveform of the electrocardiogram signal (electrocardiogram waveform), and in an embodiment, the waveform analysis unit 26 has a function of determining multiple heartbeat intervals for the electrocardiogram waveform, a function of determining each heartbeat interval that satisfies a stability condition among the multiple heartbeat intervals as a stable interval, a function of detecting end diastole and end systole within a selected heartbeat interval (interval of interest), and the like.

[0035] The waveform analysis unit 26 has a waveform memory 28. An electrocardiogram waveform over a certain period of time is stored in the waveform memory 28. The time phase of each waveform element in the electrocardiogram waveform stored in the waveform memory is associated with the time phase of each display frame data stored in the memory 18.

[0036] The measurement unit 30 measures and calculates evaluation values ​​for evaluating cardiac function. The evaluation values ​​include, for example, ejection fraction (EF). The ejection fraction is calculated from the left ventricular volume at end diastole and the left ventricular volume at end systole. In order to obtain a reliable ejection fraction, it is necessary to increase the reliability of the detected end diastole and end systole, in other words, it is necessary to detect the end diastole and end systole in a stable heartbeat section, not in an inappropriate heartbeat section.

[0037] The control unit 32 controls the operation of each component shown in Fig. 1. The control unit 32 functions as a selection control unit 33. The selection control unit 33 controls the selection of a section of interest so that a stable section is selected as the section of interest. The section of interest is a heartbeat section including a phase of interest. The phase of interest is a phase indicated by a phase of interest marker displayed on the screen. End diastole and end systole are detected within the section of interest. In an embodiment, under the control of the selection control unit 33, a stable section is selected as the section of interest when the section of interest is changed.

[0038] The control unit 32 is, for example, configured with a processor that executes a program, such as a CPU. As indicated by the reference numeral 36, the control unit 32, the waveform analysis unit 26, and the measurement unit 30 may all be realized by one processor. Furthermore, the processor may function as the display processing unit 20.

[0039] The operation panel 34 includes a plurality of switches, a trackball, a keyboard, etc. In the embodiment, the operation panel 34 includes a back button and a forward button, which will be described later, as well as a button for executing a stable zone determination function and a button for executing a time phase detection function, etc. The display 21 is configured by an organic EL device, a liquid crystal display, etc.

[0040] Fig. 2 shows an example of the configuration of the waveform analysis unit 26. Fig. 2 also shows a selection control unit 33 in the control unit and a waveform image generator 52 in the display processing unit 20. Electrocardiographic waveforms are stored in the waveform memory 28. During real-time operation, the input electrocardiographic waveform is stored in the memory 28 and supplied in parallel to the R-wave detector 38, the calculation unit 40, the end-diastolic detector 48, and the end-systolic detector 50.

[0041] The R wave detector 38 detects each R wave (specifically, the peak of each R wave) included in the electrocardiogram waveform. The calculation unit 40 has a setter 42, a primary determiner 44, and a secondary determiner 46. The setter 42 functions as a setting unit or setting means, and divides or segments the electrocardiogram waveform based on the detected R waves, thereby setting multiple heartbeat sections for the electrocardiogram waveform.

[0042] The primary determinator 44 and the secondary determinator 46 function as a whole as a determination section or determination means. The primary determinator 44 determines whether or not each heartbeat section satisfies a primary determination condition (stable condition). A heartbeat section that satisfies the primary determination condition is determined to be a tentative stable section. In the primary determinator 44, for example, multiple time lengths of multiple consecutive heartbeat sections on the time axis are compared with each other. The primary determination condition will be described in detail later.

[0043] The secondary determiner 46 determines whether the tentative stable section satisfies the secondary determination conditions (non-tachycardia condition, non-bradycardia condition). The tentative stable section that satisfies the secondary determination conditions is determined as a stable section. The secondary determiner 46 functions as a tachycardia filter and a bradycardia filter. For example, the secondary determiner 46 refers to the time length of the tentative determination section. The second determination conditions will be described in detail later.

[0044] In the embodiment, the calculation unit 40 has a function of determining whether each heartbeat section is a stable section during real-time operation. When this function is activated, end-diastole and end-systole can be detected quickly in a frozen state after real-time operation. Note that the determination of a stable section may be performed in the frozen state.

[0045] The end-diastolic detector 48 and the end-systolic detector 50 together function as a detection unit or detection means. Each time the interval of interest is changed, the end-diastolic detector 48 and the end-systolic detector 50 detect the end-diastolic and end-systolic periods within the new interval of interest. The detection method will be described later. The selection control unit 33 controls the operation of the end-diastolic detector 48 and the end-systolic detector 50.

[0046] When an operation to change the section of interest is performed, the selection control unit 33 restricts the selection of the section of interest so that a stable section becomes the new section of interest after the change, that is, so that a section that is not a stable section does not become the new section of interest after the change. Section information, stable section information, etc. are sent from the calculation unit 40 to the selection control unit 33.

[0047] The waveform image generator 52 generates a waveform image as a graphic image. The waveform image includes an electrocardiogram waveform, a marker set, and the like. When a stable section is determined, each stable section is distinguishably displayed in the electrocardiogram waveform. For example, when the electrocardiogram waveform is displayed in a first hue, each stable section is displayed in a second hue different from the first hue. The marker set is displayed in a frozen state, and includes a target time phase marker, an end diastolic marker, an end systolic marker, and the like. In the frozen state, a tomographic image (still image) corresponding to the target time phase is displayed. In the frozen state, a stored moving image may be played back.

[0048] 3 shows the freeze state. A cross-sectional image 58 is displayed as a still image on the display screen 54, and a waveform image 60 including an electrocardiogram waveform 62 is displayed. The operation panel 56 includes a button 74 for instructing the start of execution of a function for determining a stable section, a button 76 for instructing the start of execution of a function for detecting end diastole and end systole, a back button 78, a forward button 80, a freeze button 82, etc. Each button may be configured as a virtual button displayed on a touch screen panel.

[0049] When button 74 is operated during real-time operation, each stable section is determined in sequence while real-time operation is being performed. In the embodiment, operation of button 76 is not permitted during real-time operation. When button 82 is operated, the real-time operation state transitions to a frozen state. In the frozen state, buttons 74 and 76 may be operated. If button 74 has already been operated during real-time operation or if button 74 is operated in the frozen state, button 76 may be automatically turned on. It may be possible to operate button 76 during real-time operation, i.e., to instruct execution of the time phase detection function.

[0050] In the electrocardiogram waveform 62, each heartbeat section represented by a thick line 64 is a stable section. Reference numeral 63 indicates the first time phase of interest (initial time phase of interest) at the time of freezing. In the illustrated example, a time phase of interest marker 66 corresponding to a cursor indicates a time phase of interest currently being focused on, which belongs to a central heartbeat section (stable section) on the time axis (horizontal axis) in FIG. 3. End diastole and end systole have already been detected in that heartbeat section, and an end diastole marker 68 and an end systole marker 70 are displayed within that heartbeat section. When the time phase of interest marker 66 is shifted along the time axis using a trackball or the like, the content of the tomographic image changes. That is, the content of the tomographic image changes according to the changing time phase of interest. When the time phase of interest marker 66 is aligned with the end diastole marker 68, a tomographic image corresponding to the end diastole is displayed. When the time phase of interest marker 66 is aligned with the end systole marker 70, a tomographic image corresponding to the end systole is displayed. A restriction may be imposed on the movement of the noted phase marker 66 so that the movement can only occur within any stable section, or the noted phase marker 66 may be allowed to move freely.

[0051] In the state shown in FIG. 3, when the back button 78 is operated, the section of interest jumps to the closest preceding stable section on the time axis (see reference numeral 84). In the example shown in FIG. 3, the stable section on the left becomes the new section of interest. In this case, the time phase of interest marker 66A jumps to the beginning of the new section of interest. A tomographic image corresponding to the time phase at the beginning is displayed. In the new section of interest, the end diastole and end systole are automatically detected, and the end diastole marker 68A and end systole marker 70A representing them are immediately displayed.

[0052] When the forward button 80 is operated in the state shown in FIG. 3, the section of interest jumps to the closest stable section that exists after it on the time axis (see reference symbol 86). In the example shown in FIG. 3, the stable section on the right becomes the new section of interest. In this case, the focused phase marker 66B jumps to the beginning of the new section of interest. A tomographic image corresponding to the time phase at the beginning is displayed. In the new section of interest, the end diastole and end systole are automatically detected, and the end diastole marker 68B and end systole marker 70B representing them are immediately displayed. The above operations are automatically performed each time the back button 78 and the forward button 80 are operated.

[0053] According to the embodiment, when the attention section is changed, the stable section becomes the attention section after the change, that is, the attention section target is limited to the stable section, so that it is possible to ensure detection of the end diastole and the end systole within the stable section without the user having to determine whether each heart rate section is a stable section or not. In other words, it is possible to optimize the preparation or premise for cardiac function measurement.

[0054] Some primary judgment conditions are shown in Fig. 4. An electrocardiogram waveform 90 includes three consecutive heartbeat intervals n, n-1, and n-2 on the time axis. Among them, the heartbeat interval n is the interval to be evaluated.

[0055] The first primary judgment condition 94 is a condition for judging whether the evaluation target section n is a stable section (tentative stable section) or not based on the duration Tn-1 of the heartbeat section n-1 immediately before the evaluation target section n and the duration Tn-2 of the heartbeat section n-2 immediately before the evaluation target section n. Specifically, when Tn-1 / Tn-2 is smaller than a threshold value Th1, the evaluation target section n is judged to be a stable section. This means that when there is little difference between the durations of two temporally consecutive heartbeat sections, the heartbeat section that arrives immediately after them is presumed to be the stable section. According to the first primary judgment condition, it is possible to evaluate the evaluation target section n even before the end of the evaluation target section n has arrived.

[0056] The second primary judgment condition 96 and the third primary judgment condition 98 judge whether the evaluation target section n is a stable section (tentative stable section) or not based on the duration of three heartbeat sections including the evaluation target section n. When the second primary judgment condition 96 is applied, a maximum value Tmax and a minimum value Tmin are identified from the duration of the three heartbeat sections. When the ratio Tmax / Tmin between them is smaller than a threshold value Th2, the evaluation target section n is judged to be a stable section. When the third primary judgment condition 98 is applied, when |Tn-|Tn-1-Tn-2|| is smaller than a threshold value Th3, the evaluation target section n is judged to be a stable section.

[0057] When the second primary judgment condition 96 and the third primary judgment condition are adopted, the evaluation can be performed only after the end of the evaluation section n has arrived. On the other hand, since the time length of the evaluation section n can be taken into consideration, it is possible to more accurately judge whether the evaluation section n is a stable section or not.

[0058] 5, when the first primary judgment condition is adopted, during real-time operation, for each of three cardiac periods that are consecutive in time, including the latest cardiac period, in an electrocardiogram waveform 100, it is judged whether or not the first cardiac period is a stable period (provisional stable period) based on the durations of the two cardiac periods other than the first cardiac period (see reference numerals 103 and 104). Reference numeral 102 indicates the current time phase.

[0059] 6, when the second or third primary judgment condition is adopted, during real-time operation, for each of three cardiac periods consecutive in time, not including the latest cardiac period, in the electrocardiogram waveform 108, it is judged whether or not the first cardiac period is a stable period based on the three time lengths of the three cardiac periods (see reference numerals 111 and 112). Reference numeral 110 indicates the current time phase.

[0060] The secondary judgment condition applied in the above secondary judgment is a condition for excluding a heartbeat section corresponding to tachycardia and a heartbeat section corresponding to bradycardia. In the embodiment, the secondary judgment condition is satisfied when the time length of the provisional stable section is greater than threshold value Th4 and less than threshold value Th5. That is, in this case, the provisional judgment section satisfying the primary judgment condition is judged as the judgment section. Instead of the time length of the provisional stable section, a secondary judgment condition for evaluating the heart rate corresponding thereto may be used. In any case, by evaluating the size of the provisional stable section, it is possible to avoid an inappropriate heartbeat section being judged as a stable section.

[0061] A method for detecting the end diastole and the end systole is shown in Fig. 7. Fig. 7 shows a frozen state. An electrocardiogram waveform 118 is shown in the lower part of Fig. 7, and a tomographic image sequence 116 is shown in the upper part of Fig. 7.

[0062] The section of interest 120 including the time phase of interest marker 122 is a stable section. The section of interest 120 is identified and displayed (see reference numeral 121). A tomographic image 130 corresponding to the time phase of interest is displayed. The section of interest 120 is a section between two R waves adjacent in time. The end diastole is estimated as the timing after a certain time 126 from the R wave at the beginning of the section of interest 120, and an end diastolic marker 123 is displayed at a position corresponding to that phase. Meanwhile, the end systole is estimated by analyzing the T wave in the section of interest 120 (see reference numeral 128), and an end systolic marker 124 is displayed at a position corresponding to that phase. For example, the time phase at which the slope becomes zero in the last part of the T wave is determined to be the end systole. The end diastole and the end systole may be detected by a method other than the above-mentioned methods.

[0063] When the time phase marker of interest 122 is aligned with the end diastolic marker 123, a sectional image corresponding to the end diastolic period is selected from the sectional image sequence 116 and displayed (see reference numeral 132). When the time phase marker of interest 122 is aligned with the end systolic marker 124, a sectional image corresponding to the end systolic period is selected from the sectional image sequence 116 and displayed (see reference numeral 134).

[0064] 8 shows the operation of determining a stable section, that is, the operation of the primary and secondary determiners. A heartbeat section in which both the primary and secondary determination conditions 136 and 138 are satisfied is determined to be a stable section 140. A heartbeat section in which neither the primary and secondary determination conditions 136 and 138 are satisfied is determined to be an unstable section.

[0065] FIG. 9 shows several options related to the function for detecting end diastole and end systole (phase detection function). When the phase detection function is turned on, the option that has already been selected is executed. For example, if the automatic detection function is automatically turned on during freezing, the initial interval of interest is selected according to the option that has already been selected. Also, if the automatic detection function is manually turned on during freezing and an operation to change the interval of interest is performed, the jump destination of the time phase marker of interest, that is, the new interval of interest, is selected according to the option that has already been selected.

[0066] When option 2 indicated by reference numeral 146 is selected, the best stable section becomes the initial section of interest or the jump destination. An evaluation value indicating the stability of each stable section is calculated, and the stable section corresponding to the best evaluation value is determined to be the best stable section. As the evaluation value, those shown in FIG. 4 (the left side of each formula) may be used. According to option 2, it is possible to measure the most reliable stable section.

[0067] When option 3 indicated by reference numeral 148 is selected, the nearest stable section becomes the initial section of interest or the jump destination. The nearest stable section is the stable section closest to the phase of interest or section of interest before or after the current phase of interest. At the time of freezing, the latest phase becomes the current phase of interest, so the newest stable section based on that is determined as the nearest stable section. When the phase of interest marker is in an arbitrary position in the frozen state, the nearest stable section is determined based on the phase of interest or section of interest. Option 3 makes it possible to measure the nearest stable section at the time of freezing, or to measure the stable section closest to the current phase of interest.

[0068] Fig. 10 shows an example of operation related to option 2 and an example of operation related to option 3. In an electrocardiogram waveform 150, the latest phase 152 is the phase at the time of freezing. In Fig. 10, the current phase of interest is the phase specified by a phase of interest marker 154. If the automatic detection function is turned ON while option 2 is currently selected, the best stable section n-4 becomes a new phase of interest as indicated by reference numeral 156, and its leading edge 158 becomes a new phase of interest. A phase of interest marker is displayed at the leading edge.

[0069] On the other hand, if option 3 is currently selected and the automatic detection function is turned on, the nearest stable section n-2 becomes a new section of interest, and its beginning becomes a new phase of interest, as indicated by reference numeral 164. A phase of interest marker is displayed at its beginning 166.

[0070] 11 shows an example of the operation of the ultrasound diagnostic apparatus according to the embodiment, particularly an example of the operation after freezing. In S10, it is determined whether or not a stable zone determination has been performed during real-time operation. If not, in S12, it is determined whether or not each heartbeat zone constituting an electrocardiogram waveform is a stable zone. Prior to this, if necessary, a button for executing a stable zone determination function is operated, and also a button for executing a function for automatically detecting end diastole and end systole is operated.

[0071] In S14, the first section and the first phase of interest are determined according to the selected option. If option 0 is selected, the first phase of interest is the latest phase at the time of freezing, and the first section of interest is the heart rate section including the latest phase. If option 1 is selected, the best stable section becomes the section of interest, and its beginning becomes the phase of interest. If option 2 is selected, the closest stable section based on the latest phase becomes the section of interest, and its beginning becomes the phase of interest.

[0072] In S18, the end diastole and the end systole are detected in the section of interest. Then, a marker set, i.e., a marker for a time phase of interest, a marker for end diastole, and a marker for end systole are displayed in the section of interest. In S20, it is determined whether or not to continue this process.

[0073] In S22, it is determined whether or not an operation to shift the time phase marker of interest has been performed. If such an operation has been performed, in S24, the waveform image is updated, and at the same time, the tomographic image is updated. If the time phase marker of interest has entered an adjacent heartbeat interval, the end diastole and the end systole are detected in the new interval of interest.

[0074] In S26, it is determined whether the back button or the forward button has been operated. If it is determined in S26 that the back button has been operated, then in S28, the closest stable period before the current section of interest becomes the new period of interest after the change. In other words, the period of interest jumps toward the past. Then, in S24, the waveform image and the tomographic image are updated. On the other hand, if it is determined in S28 that the forward button has been operated, then in S30, the closest stable period after the current section of interest becomes the new period of interest after the change. In other words, the period of interest jumps toward the future. Then, in S24, the waveform image and the tomographic image are updated.

[0075] As described above, according to the operation of the embodiment, when a backward or forward operation is performed, a stable section is set as a new section of interest, so that the detection of the end diastole and the end systole within the stable section is guaranteed. This has the advantage that the user does not need to determine whether or not the section is stable. In addition, it is possible to prevent the end diastole and the end systole detected in an inappropriate heartbeat section from being used in cardiac function measurement.

[0076] In FIG. 12, two cross-sectional images 182 and 184 are displayed in the display screen 172, and a waveform image 174 is also displayed. A specific stable section in the electrocardiogram waveform included in the waveform image 174 is the section of interest. A time phase marker 176 of interest, a terminal diastolic marker 178, and a terminal systolic marker 180 are displayed in the section of interest. The cross-sectional image 182 is a cross-sectional image corresponding to the terminal diastolic period indicated by the terminal diastolic marker 178, and the cross-sectional image 184 is a cross-sectional image corresponding to the terminal systolic period indicated by the terminal systolic marker 180. Measurement is performed based on these cross-sectional images 182 and 184 to obtain an evaluation value. Since the terminal diastolic period and the terminal systolic period are detected in the stable section, it is possible to calculate an evaluation value based on two appropriate cross-sectional images. A waveform image may be displayed for each cross-sectional image 182 and 184. [Explanation of symbols]

[0077] 22 electrocardiograph, 26 waveform analysis unit, 30 measurement unit, 38 R wave detector, 40 calculation unit, 42 setting unit, 44 primary judgment unit, 46 secondary judgment unit, 48 end diastolic detector, 50 end systolic detector, 52 waveform image generator.

Claims

1. an image forming unit that forms an ultrasound image based on reception data acquired from a subject; A setting unit that defines a plurality of sections in units of heartbeats for an electrocardiogram waveform representing an electrocardiogram signal acquired from the subject; a detection unit that detects a terminal diastole and a terminal systole within a target interval among the plurality of intervals based on the electrocardiogram waveform; a display processing unit that displays, when the electrocardiogram waveform is displayed together with the ultrasound image, an end-diastolic marker that indicates the end-diastolic period within the interval of interest and an end-systolic marker that indicates the end-systolic period within the interval of interest; and a determination unit that determines each section that satisfies a stability condition among the plurality of sections as a stable section; a selection control unit that, when a freeze operation is performed, controls selection of an initial section of interest in accordance with an option selected from among a plurality of options, and, when an operation to change the section of interest is performed, controls selection of the changed section of interest so that the changed section of interest is selected from among the plurality of stable sections determined by the determination unit; Including, the detection unit detects an end diastolic period and an end systolic period in the initial interval of interest when the freeze operation is performed, and detects an end diastolic period and an end systolic period in a specific stable interval that is the interval of interest after the change when an operation to change the interval of interest is performed; The selection control unit is When the freeze operation has been performed and option 1 has been selected, select, as the first interval of interest, the latest interval including the latest time phase at the time of the freeze operation, regardless of whether the latest interval is a stable interval or not; When the freeze operation has been performed and option 2 has been selected, a best stable section corresponding to a best evaluation value among a plurality of evaluation values ​​calculated for the plurality of stable sections is selected as the first target section from among the plurality of stable sections; When the freeze operation has been performed and option 3 has been selected, a nearest stable interval that is closest to the latest time phase or the latest interval is selected from among the plurality of stable intervals as the first interval of interest.

1. An ultrasonic diagnostic apparatus comprising:

2. 2. The ultrasonic diagnostic apparatus according to claim 1, The selection control unit is When a back operation is performed as an operation for changing the section of interest, a closest stable section that is located before the section of interest is selected as the section of interest after the change; when a forward operation is performed as an operation for changing the section of interest, a closest stable section subsequent to the section of interest is selected as the section of interest after the change; 1. An ultrasonic diagnostic apparatus comprising:

3. 2. The ultrasonic diagnostic apparatus according to claim 1, the selection control unit has a function of, when an operation for changing the attention section is performed, identifying a best stable section from among the plurality of stable sections, and selecting the best stable section as the attention section after the change.

1. An ultrasonic diagnostic apparatus comprising:

4. 2. The ultrasonic diagnostic apparatus according to claim 1, the selection control unit has a function of, when an operation for changing the section of interest is performed, identifying a nearest stable section from the plurality of stable sections that is nearest to a current phase of interest or a section including the current phase of interest, and selecting the nearest stable section as the section of interest after the change.

1. An ultrasonic diagnostic apparatus comprising:

5. 2. The ultrasonic diagnostic apparatus according to claim 1, The determination unit determines the plurality of stable periods during real-time operation, the detection unit detects the end diastole and the end systole in a frozen state after the real-time operation.

1. An ultrasonic diagnostic apparatus comprising:

6. 2. The ultrasonic diagnostic apparatus according to claim 1, The stability condition is a first determination condition for determining a provisional stable section based on a plurality of time lengths of a plurality of sections that are consecutive in time; a secondary judgment condition for judging that the time length of the provisional stable section satisfying the primary judgment condition does not correspond to tachycardia or bradycardia; Including, The determination unit is a primary determination unit that applies the primary determination condition to each of the sections; a secondary judgment unit that applies the secondary judgment condition to a tentative judgment section that satisfies the primary judgment condition; 1. An ultrasonic diagnostic apparatus comprising:

7. defining a plurality of sections, each section being a unit of heartbeat, for an electrocardiogram waveform representing an electrocardiogram signal acquired from a subject; detecting a terminal diastole and a terminal systole within a section of interest among the plurality of sections based on the electrocardiogram waveform; displaying an end-diastolic marker representing the end-diastolic period within the interval of interest and an end-systolic marker representing the end-systolic period within the interval of interest when displaying an ultrasound image and the electrocardiogram waveform; and determining each of the plurality of sections that satisfy a stability condition as a stable section; a step of controlling selection of an initial section of interest in accordance with a selected option from among a plurality of options when a freeze operation is performed, and controlling selection of a new section of interest in accordance with an operation to change the section of interest such that the new section of interest is selected from the plurality of determined stable sections; Including, When the freeze operation is performed, a terminal diastole and a terminal systole are detected in the initial interval of interest, and when an operation to change the interval of interest is performed, a terminal diastole and a terminal systole are detected in a specific stable interval that is the interval of interest after the change, When the freeze operation is performed and option 1 is selected, the latest section including the latest time phase at the time of the freeze operation is selected as the first section of interest, regardless of whether it is a stable section or not; When the freeze operation has been performed and option 2 has been selected, a best stable section corresponding to a best evaluation value among a plurality of evaluation values ​​calculated for the plurality of stable sections is selected as the first attention section from among the plurality of stable sections; When the freeze operation is performed and option 3 is selected, a nearest stable interval to the latest time phase or the latest interval is selected from the plurality of stable intervals as the first interval of interest. Electrocardiogram waveform processing method.

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