Ultrasonic diagnostic apparatus and electrocardiogram waveform processing method

Abstract

The present application relates to an ultrasonic diagnostic apparatus and an electrocardiogram waveform processing method. A setter (42) sets a plurality of heart rate intervals for an electrocardiogram waveform. A primary determiner (44) determines an interval satisfying a primary determination condition as a temporary stable interval within the plurality of heart rate intervals. A secondary determiner (46) determines the temporary stable interval as a stable interval in a case where the temporary stable interval satisfies a secondary determination condition. An end-diastole detector (48) and an end-systole detector (50) detect an end-diastole and an end-systole within a focus interval. A selection control section (33) controls selection of the focus interval at a time of change of the focus interval so that the changed focus interval becomes the stable interval.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an ultrasonic diagnostic apparatus and an electrocardiogram waveform processing method, and particularly relates to a technique for detecting end-diastole and end-systole. BACKGROUND

[0002] An ultrasonic diagnostic apparatus used in ultrasonic examination of a heart generally has a function of acquiring an electrocardiogram signal (ECG signal). In such an ultrasonic diagnostic apparatus, a waveform (electrocardiogram waveform) representing the electrocardiogram signal is displayed together with an ultrasonic image. The electrocardiogram waveform is constituted by a plurality of heart rate waveforms connected on a time axis. In a frozen state after real-time operation, an ultrasonic image corresponding to a time phase (time phase of interest) specified or selected by a user on the electrocardiogram waveform is displayed on a display.

[0003] Various measurements are performed in order to evaluate the function of a heart. As a representative measurement value (cardiac function evaluation value), ejection fraction (EF) is known. The ejection fraction is generally calculated from a left ventricular volume at end-diastole and a left ventricular volume at end-systole. Each volume is obtained, for example, from a left ventricular area calculated on a tomographic image. In a case where the determination accuracy of end-diastole and end-systole is low, the reliability of the calculated ejection fraction decreases.

[0004] An ultrasonic diagnostic apparatus having a function of determining a stable heart rate as a stable range among a plurality of heart rates is disclosed in Document 1 (International Publication No. 2012 / 029616) and Document 2 (International Publication No. 2013 / 105568). An ultrasonic diagnostic apparatus having a function of detecting end-systole and end-diastole is disclosed in Document 3 (International Publication No. 2012 / 023399). Document 1, Document 2, and Document 3 do not describe a technique for cooperating the function of determining a stable range and the function of detecting end-systole / end-diastole. SUMMARY

[0005] An object of the present disclosure is to provide an ultrasonic diagnostic apparatus and an electrocardiogram waveform processing method capable of detecting end-diastole and end-systole in a suitable heart rate range.

[0006] The ultrasound diagnostic apparatus according to the present disclosure includes an image forming unit that forms an ultrasound image based on reception data acquired from a subject; a setting unit that determines a plurality of intervals in units of heart rates for an electrocardiogram waveform that represents an electrocardio signal acquired from the subject; a detection unit that detects an end diastole and an end systole within a focus interval among the plurality of intervals based on the electrocardiogram waveform; and a display processing unit that displays an end diastole marker that represents the end diastole within the focus interval and an end systole marker that represents the end systole within the focus interval in a case where the electrocardiogram waveform is displayed together with the ultrasound image, further includes a determination unit that determines each interval that satisfies a stable condition as a stable interval among the plurality of intervals; and a selection control unit that controls selection of the focus interval after a change in a case where there is an operation to change the focus interval so that the focus interval after the change is selected from among a plurality of stable intervals determined by the determination unit, and the detection unit detects an end diastole and an end systole within the focus interval after the change, that is, a specific stable interval in a case where there is an operation to change the focus interval.

[0007] The electrocardiogram waveform processing method according to the present disclosure includes a process of determining a plurality of intervals in units of heart rates for an electrocardiogram waveform that represents an electrocardio signal acquired from a subject; a process of detecting an end diastole and an end systole within a focus interval among the plurality of intervals based on the electrocardiogram waveform; and a process of displaying an end diastole marker that represents the end diastole within the focus interval and an end systole marker that represents the end systole within the focus interval in a case where the electrocardiogram waveform is displayed together with an ultrasound image, further includes a process of determining each interval that satisfies a stable condition as a stable interval among the plurality of intervals; a process of controlling selection of the focus interval after a change in a case where there is an operation to change the focus interval so that the focus interval after the change is selected from among the plurality of stable intervals determined, and a process of detecting an end diastole and an end systole within the focus interval after the change, that is, a specific stable interval in a case where there is an operation to change the focus interval. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a block diagram that shows a configuration example of an ultrasound diagnostic apparatus according to an embodiment.

[0009] Figure 2 is a diagram that shows a configuration example of a waveform analysis unit.

[0010] Figure 3 is a diagram that shows a change in a waveform image at the time of a focus interval change.

[0011] Figure 4 is a diagram that shows several temporary stable interval determination methods.

[0012] Figure 5is a diagram showing a first temporary stable interval determination example.

[0013] Figure 6 is a diagram showing a second temporary stable interval determination example.

[0014] Figure 7 is a diagram showing detection of end diastole and end systole within a stable interval.

[0015] Figure 8 is a diagram showing a stable interval determination method.

[0016] Figure 9 is a diagram for explaining a plurality of options that can be selected.

[0017] Figure 10 is a diagram showing an action example related to option 2 and an action example related to option 3.

[0018] Figure 11 is a flowchart showing an action example of an ultrasonic diagnostic apparatus.

[0019] Figure 12 is a diagram showing an example of 2-screen display. DETAILED DESCRIPTION

[0020] Embodiments will be described below based on the drawings.

[0021] (1) Outline of Embodiments

[0022] An ultrasonic diagnostic apparatus according to an embodiment determines a plurality of intervals (a plurality of heart rate intervals) in heart rate units from an electrocardiogram waveform that characterizes an electrocardiogram signal acquired from a subject. The ultrasonic diagnostic apparatus detects end diastole and end systole within a focus interval among the plurality of intervals based on the electrocardiogram waveform. The ultrasonic diagnostic apparatus displays an end diastole marker that characterizes the end diastole within the focus interval and an end systole marker that characterizes the end systole within the focus interval in a case where the electrocardiogram waveform is displayed together with an ultrasonic image. The ultrasonic diagnostic apparatus determines each interval that satisfies a stable condition as a stable interval among the plurality of intervals. The ultrasonic diagnostic apparatus controls selection of a changed focus interval in a case where there is an operation to change the focus interval, so that the changed focus interval is selected from among the plurality of stable intervals determined by the determination section. The ultrasonic diagnostic apparatus detects the end diastole and the end systole within the changed focus interval, i.e., a specific stable interval in a case where there is an operation to change the focus interval.

[0023] The ultrasound diagnostic apparatus according to the embodiment has a processor. The processor functions as the image forming section, the setting section, the detecting section, the display processing section, the determining section, and the selection control section described above. The processor can be constituted by one or a plurality of physical processors.

[0024] According to the above structure, after the change of the attention interval, the detection of the end-diastole and the end-systole in the stable interval is ensured. Even if the change of the attention interval is repeated, the end-diastole and the end-systole are detected in the stable interval all the time. Thus, the reliability of the detected end-diastole and end-systole is improved.

[0025] In addition, in the case where the phase detection function is automatically started at the time of freezing, the end-diastole and the end-systole can be detected in the latest interval as the attention interval, regardless of whether the latest interval is a stable interval. In the case where the execution start of the phase detection function is instructed in the frozen state, the end-diastole and the end-systole can be detected in the current attention interval, regardless of whether the current attention interval is a stable interval. In either case, after the change of the attention interval, the stable interval is selected as the attention interval after the change, as long as the phase detection function is on. The frozen state is a state where the transmission and reception are stopped, and in the frozen state, the stored tomographic image is displayed, and in addition, the stored electrocardiogram waveform is displayed.

[0026] In the embodiment, the selection control section selects, as the attention interval after the change, the closest stable interval located before the attention interval, in the case where the backward operation is performed. On the other hand, the selection control section selects, as the attention interval after the change, the closest stable interval located after the attention interval, in the case where the forward operation is performed. For example, in the case where the change of the attention interval is repeated, the attention interval is sequentially shifted. The end-diastole and the end-systole are detected again each time the attention interval is changed.

[0027] According to the above structure, since the stable interval does not need to be specified or selected on the user side, the burden on the user can be reduced. In addition, according to the above structure, the cardiac function measurement based on the end-diastole and the end-systole detected in an inappropriate interval can be avoided.

[0028] In the embodiment, in the real-time operation and in the frozen state, each stable interval is identified and displayed at the time of displaying the electrocardiogram waveform. For example, each stable interval is displayed in a specific color tone. In addition to the display of the end-diastole marker and the end-systole marker, an attention phase marker indicating the attention phase is displayed on the electrocardiogram waveform. The ultrasound image corresponding to the attention phase is displayed. In the real-time operation, the ultrasound image is displayed in real time while the transmission and reception of the ultrasound are performed.

[0029] In the embodiment, the selection control section has a function of determining an optimum stable section from among the plurality of stable sections, and selecting the optimum stable section as the initial attention section or the changed attention section. According to this function, the cardiac function measurement can be performed based on the diastasis and the systasis, which are highly reliable. The optimum stable section is a section that is judged to be the most stable among the plurality of stable sections. For example, an evaluation value can be calculated for each of the stable sections, and the stable section corresponding to the optimum evaluation value can be determined as the optimum stable section.

[0030] In the embodiment, the selection control section has a function of determining a nearest stable section that is closest to a current attention phase from among the plurality of stable sections, and selecting the nearest stable section as the initial attention section or the changed attention section. According to this function, a section that is close to a phase of interest of a user and is appropriate from the viewpoint of the cardiac function measurement can be selected as the detection target of the diastasis and the systasis. In other words, a stable section that is considerably distant in time from the phase of interest of the user can be avoided. The current attention phase is generally a phase indicated by the attention phase marker on the time axis. For example, immediately after freezing, the latest phase is the current attention phase. In a case where the user moves (shifts) the attention phase marker, the attention phase moves along the time axis in conjunction therewith.

[0031] In the embodiment, the determination section determines the plurality of stable sections in the real-time operation. The detection section detects the diastasis and the systasis in the frozen state after the real-time operation. If the determination of the stable period is continuously performed in the real-time operation, the respective stable periods can be recognized in the real-time operation, and in addition, the respective stable periods can be recognized immediately after the real-time operation. Furthermore, the detection of the diastasis and the systasis can be rapidly performed in the frozen state after the real-time operation.

[0032] In the embodiment, the stable condition includes a first determination condition for determining a temporary stable section based on a plurality of time lengths possessed by a plurality of sections that are connected in time, and a second determination condition for determining that a time length of the temporary stable section that satisfies the first determination condition does not correspond to tachycardia or bradycardia. The determination section includes a first determination section that applies the first determination condition to each section, and a second determination section that applies the second determination condition to the temporary stable section that satisfies the first determination condition. The above-described processor functions as the first determination section and the second determination section.

[0033] According to this structure, it is possible to prevent a section that is determined to be stable but corresponds to tachycardia or a section that is determined to be stable but corresponds to bradycardia from being set as the attention section. Other determination conditions such as a third determination condition can be added.

[0034] 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 intervals are determined for an electrocardiogram representing a cardiac electrical signal acquired from a subject, in units of heart rate. In the detection step, based on the electrocardiogram, diastasis and systasis are detected within a focus interval among the plurality of intervals. In the display processing step, in a case where the electrocardiogram is displayed together with an ultrasonic image, a diastasis marker representing diastasis within the focus interval and a systasis marker representing systasis within the focus interval are displayed. In the determination step, each interval satisfying a stability condition among the plurality of intervals is determined as a stable interval. In the selection control step, in a case where there is an operation to change the focus interval, selection of the changed focus interval is controlled so that the changed focus interval is selected from among the plurality of stable intervals determined. In a case where there is an operation to change the focus interval, diastasis and systasis are detected within the changed focus interval, that is, a specific stable interval.

[0035] The above-described method is implemented as a function of hardware or as a function of software. A program for executing the above-described method can be installed in an information processing apparatus via a network or a removable storage medium. An ultrasonic diagnostic apparatus is included in the information processing apparatus. A non-transitory storage medium storing the program is included in the information processing apparatus.

[0036] (2) Details of the Embodiment

[0037] A structure example of an ultrasonic diagnostic apparatus according to the embodiment is shown in Figure 1 The ultrasonic diagnostic apparatus is provided in a medical institution such as a hospital, and is a medical apparatus used in ultrasonic examination of a subject.

[0038] In Figure 1 The ultrasonic diagnostic apparatus has a probe 10. A wave transmitting / receiving surface of the probe 10 abuts against a surface of a subject. In this state, an ultrasonic wave is transmitted from the probe 10 into a living body, and a reflected wave from the living body is received at the probe 10.

[0039] Specifically, the probe 10 has a transducer array including a plurality of transducers. An ultrasonic beam is formed by the transducer array, and the ultrasonic beam is electronically scanned. As an electronic scanning method, an electronic linear scanning method, an electronic sector scanning method, or the like is known. A beam scanning surface is formed by the electronic scanning of the ultrasonic beam. A two-dimensional transducer array can also be provided in the probe 10, and a volume data is acquired from the living body using the two-dimensional transducer array.

[0040] The transmission section 12 is an electronic circuit functioning as a transmission beamformer, and the reception section 14 is an electronic circuit functioning as a reception beamformer. At the time of transmission, a plurality of transmission signals are supplied in parallel from the transmission section 12 to the vibration element array. Thereby, a transmission beam is formed. At the time of reception, a plurality of reception signals are output in parallel from the vibration element array to the reception section 14. In the reception section 14, a phase-summing addition operation (delay-summing addition operation) is performed on the plurality of reception signals. Thereby, reception beam data is generated.

[0041] A reception frame data set is constituted by a plurality of reception beam data sets arranged in an electronic scanning direction. Each reception beam data set is constituted by a plurality of echo data sets arranged in a depth direction. Each reception frame data set corresponds to a tomographic image. In addition, in a color flow mapping (CFM) mode, reception frame data sets for tomographic image formation and reception frame data sets for flow image formation are generally acquired alternately.

[0042] The image formation section 16 generates a display frame data string based on the input reception frame data string, and outputs the display frame data string. The display frame data string corresponds to a tomographic image as a dynamic image. Each display frame data corresponds to a tomographic image as a still image. The image formation section 16 has a digital scan converter (DSC). The DSC is a kind of processor. The DSC 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 section 20.

[0043] The memory 18 is a so-called video memory, and stores the display frame data string over a certain time in the memory 18. In a freeze state, the display frame data read out from the memory 18 is sent to the display processing section 20 and the measurement section 30. The memory 18 can be arranged at a stage prior to the image formation section 16.

[0044] The display processing section 20 is constituted by a processor. The display processing section 20 has a graphic image generation function, an image combining function, a color calculation function, and the like. An image displayed on the display 21 is generated in the display processing section 20. In the embodiment, the display processing section 20 has a function of generating a waveform image including an electrocardiograph waveform (waveform image generator described later).

[0045] The electrocardiograph 22 has a plurality of electrodes attached to the subject. An electrocardiograph signal (ECG signal) is acquired from the subject by the electrocardiograph 22. The electrocardiograph signal is sent to the waveform analysis section 26 via the signal processing circuit 24.

[0046] The waveform analysis section 26 is configured by a processor and a waveform memory 28. The waveform analysis section 26 analyzes the waveform of the electrocardio signal (electrocardio waveform), and in the embodiment, has functions such as a function of determining a plurality of heart rate intervals from the electrocardio waveform, a function of determining each heart rate interval that satisfies a stability condition as a stable interval among the plurality of heart rate intervals, and a function of detecting the end of diastole and the end of systole within the selected heart rate interval (focus interval).

[0047] The electrocardio waveform over a certain time is stored in the waveform memory 28 described above. The timing of each waveform element in the electrocardio waveform stored in the waveform memory and the timing of each display frame data stored in the memory 18 are made to correspond.

[0048] The measurement section 30 is configured by a processor. The measurement section 30 measures and calculates an evaluation value for evaluating the cardiac function. The evaluation value includes, for example, the ejection fraction (EF). The ejection fraction is calculated from the left ventricular volume at the end of diastole and the left ventricular volume at the end of systole. In order to obtain the ejection fraction with reliability, it is necessary to improve the reliability of the detected end of diastole and end of systole, in other words, it is necessary to detect the end of diastole and end of systole within a stable heart rate interval, rather than within an inappropriate heart rate interval.

[0049] The control section 32 controls Figure 1 the operation of each structure shown. The control section 32 functions as a selection control section 33. The selection control section 33 controls the selection of the focus interval so that the stable interval is selected as the focus interval. The focus interval is a heart rate interval that includes a focus timing. The focus timing is the timing indicated by the focus timing mark displayed on the screen. The end of diastole and the end of systole are detected within the focus interval. In the embodiment, the stable interval is selected as the focus interval at the time of change of the focus interval by the control of the selection control section 33.

[0050] The control section 32 is configured by, for example, a processor that executes a program, such as a CPU. As shown by reference numeral 36, the entire control section 32, waveform analysis section 26, and measurement section 30 can be implemented by one processor. Further, the processor can function as the display processing section 20.

[0051] A plurality of switches, trackballs, keyboards, and the like are included in the operation panel 34. In the operation panel 34, in the embodiment, the back button and the forward button described later are included, and in addition, a button that causes the stable interval determination function to be executed, a button that causes the timing detection function to be executed, and the like are included. The display 21 is configured by an organic EL device, a liquid crystal display, or the like.

[0052] In Figure 2 An example of the configuration of the waveform analysis section 26 is illustrated. In Figure 2Also shown are the selection control section 33 within the control section and the waveform image generator 52 within the display processing section 20. The electrocardiograph waveform is stored in the waveform memory 28. In real-time operation, the input electrocardiograph waveform is stored in the memory 28 and supplied to the R-wave detector 38, the arithmetic section 40, the end-diastole detector 48, and the end-systole detector 50 in parallel.

[0053] The R-wave detector 38 detects each R wave (specifically, the peak of each R wave) contained in the electrocardiograph waveform. The arithmetic section 40 has a setter 42, a primary determiner 44, and a secondary determiner 46. The setter 42 functions as a setting section or a setting unit, divides or distinguishes the electrocardiograph waveform on the basis of the detected R waves, thereby setting a plurality of heart rate intervals for the electrocardiograph waveform.

[0054] The primary determiner 44 and the secondary determiner 46 function as a determination section or a determination unit as a whole. The primary determiner 44 determines whether each heart rate interval satisfies a primary determination condition (a stability condition). A heart rate interval that satisfies the primary determination condition is determined to be a temporary stable interval. In the primary determiner 44, for example, a plurality of time lengths possessed by a plurality of heart rate intervals connected in the time axis are compared with each other. The primary determination condition will be described later.

[0055] The secondary determiner 46 determines whether the temporary stable interval satisfies a secondary determination condition (a non-tachyarrhythmia condition, a non-bradycardia condition). A temporary stable interval that satisfies the secondary determination condition is determined to be a stable interval. The secondary determiner 46 functions as a tachyarrhythmia filter and a bradycardia filter. In the secondary determiner 46, for example, the time length of the temporary stable interval is referred to. The second determination condition will be described later.

[0056] In the embodiment, the arithmetic section 40 has a function of determining whether each heart rate interval is a stable interval in real-time operation. In a case where this function is operated, the detection of the end-diastole and the end-systole can be promptly performed in the frozen state after the real-time operation. In addition, the determination of the stable interval can also be performed in the frozen state.

[0057] The end-diastole detector 48 and the end-systole detector 50 function as a detection section or a detection unit as a whole. The end-diastole detector 48 and the end-systole detector 50 detect the end-diastole and the end-systole in the new focus interval every time the focus interval is changed. The detection methods will be described later. The selection control section 33 controls the operation of the end-diastole detector 48 and the end-systole detector 50.

[0058] When there is an operation that changes the range of interest, the selection control unit 33 restricts the selection of the range of interest so that stable ranges become the new range of interest after the change. That is, it prevents non-stable ranges from becoming the new range of interest after the change. The calculation unit 40 sends range information, stable range information, etc. to the selection control unit 33.

[0059] Waveform image generator 52 generates a waveform image as a graphic image. The waveform image includes an electrocardiogram (ECG) waveform, a set of markers, etc. When a stable interval is determined, each stable interval is identified and displayed in the ECG waveform. For example, if the ECG waveform is displayed in a first hue, each stable interval is displayed in a second hue, different from the first hue. The marker set is displayed in a frozen state and includes markers for the phase of attention, end-diastolic markers, end-systolic markers, etc. In the frozen state, a tomographic image (still image) corresponding to the phase of attention is displayed. Furthermore, in the frozen state, stored dynamic images can be reproduced.

[0060] exist Figure 3 The image shows a frozen state. A tomographic image 58, displayed as a still image, and a waveform image 60 containing an electrocardiogram waveform 62 are displayed on the display screen 54. The operation panel 56 includes a button 74 indicating the start of execution of the function for determining the stable interval, a button 76 indicating the start of execution of the function for detecting end-diastolic / end-systolic phase, a back button 78, a forward button 80, a freeze button 82, etc. These buttons can be configured as virtual buttons displayed on the touchscreen panel.

[0061] In real-time operation, when button 74 is operated, each stable interval is determined sequentially while the real-time operation is being performed. In this implementation, operation of button 76 is not allowed during real-time operation. At the point when button 82 is operated, the system transitions from the real-time operation state to the frozen state. In the frozen state, both button 74 and button 76 can be operated. Alternatively, button 76 can be automatically activated if button 74 has been operated during real-time operation or if button 74 has been operated in the frozen state. During real-time operation, the operation of button 76 can be indicated by the execution of the phase detection function.

[0062] In the ECG waveform 62, the heart rate intervals represented by the thick line 64 are stable intervals. The reference numeral 63 indicates the initial phase of focus (initial phase of focus) at the frozen time point. In the illustrated example, the phase of focus marker 66, equivalent to a cursor, indicates the currently focused phase of focus. Figure 3In the center, a central heart rate interval (stable interval) on the time axis (horizontal axis) is shown. In this heart rate interval, the end diastole and the end systole have been detected, and the end diastole marker 68 and the end systole marker 70 are displayed within this heart rate interval. If the attention phase marker 66 is displaced 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 in accordance with the changed attention phase. If the attention phase marker 66 is made to coincide with the end diastole marker 68, the tomographic image corresponding to the end diastole is displayed. If the attention phase marker 66 is made to coincide with the end systole marker 70, the tomographic image corresponding to the end systole is displayed. The movement of the attention phase marker 66 can be restricted so that the movement is made only within an arbitrary stable interval, or the movement of the attention phase marker 66 can be made freely.

[0063] In the state shown in FIG. 8, the attention interval is shifted to the nearest stable interval existing before on the time axis (refer to reference numeral 84). In the state shown in FIG. 9, the attention interval is shifted to the nearest stable interval existing after on the time axis (refer to reference numeral 86). Figure 3 In the case where the backward button 78 is operated in the state shown in FIG. 8, the attention interval is shifted to the nearest stable interval existing before on the time axis (refer to reference numeral 84). In the case where the forward button 80 is operated in the state shown in FIG. 9, the attention interval is shifted to the nearest stable interval existing after on the time axis (refer to reference numeral 86). Figure 3 In the example shown in FIG. 10, the stable interval on the left becomes the new attention interval. In this case, the attention phase marker 66A is shifted to the front of the new attention interval. The tomographic image corresponding to the foremost phase is displayed. The end diastole and the end systole are automatically detected within the new attention interval, and the end diastole marker 68A and the end systole marker 70A representing them are immediately displayed.

[0064] In the case where the backward button 78 is operated in the state shown in FIG. 8, the attention interval is shifted to the nearest stable interval existing before on the time axis (refer to reference numeral 84). In the case where the forward button 80 is operated in the state shown in FIG. 9, the attention interval is shifted to the nearest stable interval existing after on the time axis (refer to reference numeral 86). Figure 3 In the case where the backward button 78 is operated in the state shown in FIG. 8, the attention interval is shifted to the nearest stable interval existing before on the time axis (refer to reference numeral 84). In the case where the forward button 80 is operated in the state shown in FIG. 9, the attention interval is shifted to the nearest stable interval existing after on the time axis (refer to reference numeral 86). Figure 3 In the example shown in FIG. 11, the stable interval on the right becomes the new attention interval. In this case, the attention phase marker 66B is shifted to the front of the new attention interval. The tomographic image corresponding to the foremost phase is displayed. The end diastole and the end systole are automatically detected within the new attention interval, and the end diastole marker 68B and the end systole marker 70B representing them are immediately displayed. The above-described actions are automatically performed every time the backward button 78 and the forward button 80 are operated.

[0065] According to the embodiment, since the stable interval becomes the changed attention interval at the time of the change of the attention interval, that is, since the attention interval object is restricted to the stable interval, the user can ensure the detection of the end diastole and the end systole within the stable interval without determining whether each heart rate interval is a stable interval. That is, the preparation or premise of the cardiac function measurement can be adapted.

[0066] In the case where the backward button 78 is operated in the state shown in FIG. 8, the attention interval is shifted to the nearest stable interval existing before on the time axis (refer to reference numeral 84). In the case where the forward button 80 is operated in the state shown in FIG. 9, the attention interval is shifted to the nearest stable interval existing after on the time axis (refer to reference numeral 86). Figure 4Several initial judgment conditions are shown. The ECG waveform 90 contains three consecutive heart rate intervals n, n-1, and n-2 on the time axis. Among them, heart rate interval n is the evaluation interval.

[0067] The first judgment condition 94 is used to determine whether the evaluation interval n is a stable interval (temporarily stable interval) based on the time length Tn-1 of the preceding heart rate interval n-1 and the time length Tn-2 of the preceding heart rate interval n-2. Specifically, if Tn-1 / Tn-2 is less than the threshold Th1, the evaluation interval n is determined to be a stable interval. If the time lengths of two consecutive heart rate intervals are not significantly different, the heart rate interval immediately following them is presumed to be a stable interval. According to the first judgment condition, the evaluation interval n can also be evaluated at time points before its end.

[0068] The second and third judgment conditions 96 and 98 are used to determine whether the evaluation interval n is a stable interval (temporarily stable interval) based on the time length of the three heart rate intervals containing the evaluation interval n. When using the second judgment condition 96, the maximum value Tmax and the minimum value Tmin are determined from the time lengths of the three heart rate intervals. If their ratio Tmax / Tmin is less than the threshold Th2, the evaluation interval n is determined to be a stable interval. When using the third judgment condition 98, if |Tn-|Tn-1-Tn-2|| is less than the threshold Th3, the evaluation interval n is determined to be a stable interval.

[0069] When using the second and third judgment conditions, the evaluation of the evaluation interval n is only performed after the end of the evaluation period has arrived. On the other hand, since the time length of the evaluation interval n can be considered, it is possible to more accurately determine whether the evaluation interval n is a stable interval.

[0070] like Figure 5 As shown, when using the first determination condition, in real-time operation, for each of the three consecutive heart rate periods in the ECG waveform 100 that contain the latest heart rate interval, it is determined whether the foremost heart rate period is a stable interval (temporary stable interval) based on the duration of the two heart rate periods other than the foremost heart rate period (refer to reference numerals 103 and 104). Additionally, reference numeral 102 indicates the current phase.

[0071] like Figure 6As shown, in the case where the second or third determination condition is adopted, in the real-time operation, in each of the three heart rate periods connected in time without the latest heart rate interval in the electrocardiograph 108, it is determined whether the foremost heart rate period is a stable interval based on the three time lengths they have (refer to reference numeral 111 and reference numeral 112). In addition, reference numeral 110 indicates the current time phase.

[0072] The second determination condition used in the above-described second determination is a condition for excluding the heart rate interval corresponding to tachycardia and the heart rate interval corresponding to bradycardia. In the embodiment, the second determination condition is satisfied in the case where the time length of the provisional stable interval is greater than the threshold value Th4 and less than the threshold value Th5. That is, in this case, the provisional stable interval satisfying the first determination condition is determined as a determination interval. Instead of using the time length of the provisional stable interval, a second determination condition evaluating the number of heartbeats corresponding thereto can be used. In either case, by evaluating the size of the provisional stable interval, it is possible to avoid the case where an inappropriate heart rate interval is determined as a stable interval.

[0073] In Figure 7 A method of detecting the end diastole and the end systole is shown in Figure 7 Indicates a frozen state. In Figure 7 The electrocardiograph 118 is shown in the lower layer of Figure 7 The tomographic image column 116 is shown in the upper layer of

[0074] The attention interval 120 containing the attention time phase mark 122 is a stable interval. The attention interval 120 is identified (refer to reference numeral 121). The tomographic image 130 corresponding to the attention time phase is displayed. The attention interval 120 is an interval between two R waves adjacent in time. The end diastole is estimated as a timing after a certain time 126 from the foremost R wave in the attention interval 120, and the end diastole mark 123 is displayed at a position corresponding to the time phase. On the other hand, the end systole is estimated by analysis of the T wave within the attention interval 120 (refer to reference numeral 128), and the end systole mark 124 is displayed at a position corresponding to the time phase. For example, the time phase at which the inclination of the last portion of the T wave becomes zero is determined as the end systole. The end diastole and the end systole can be detected by a method other than the above-mentioned method.

[0075] If the attention time phase mark 122 coincides with the end diastole mark 123, the tomographic image corresponding to the end diastole is selected from the tomographic image column 116 and displayed (refer to reference numeral 132). If the attention time phase mark 122 coincides with the end systole mark 124, the tomographic image corresponding to the end systole is selected from the tomographic image column 116 and displayed (refer to reference numeral 134).

[0076] InFigure 8 The operation of determining the stable section, that is, the operation of the primary determiner and the operation of the secondary determiner are shown. The heart rate section satisfying both the primary determination condition 136 and the secondary determination condition 138 is determined as the stable section 140. The heart rate section not satisfying both the primary determination condition 136 and the secondary determination condition 138 is determined as the non-stable section.

[0077] In Figure 9 Several options related to the detection of the end diastole / end systole function (phase detection function) are shown. At the point in time when the phase detection function is turned on, the selected option is executed. For example, in the case where the phase detection function is automatically turned on at the freeze, the initial focus section is selected in accordance with the selected option. Further, in the case where the phase detection function is manually turned on and an operation of changing the focus section is performed in the freeze state, the jump destination of the focus phase marker, that is, the changed focus section is selected in accordance with the selected option.

[0078] In the case where the option 2 indicated by the reference numeral 146 is selected, the best stable section becomes the initial focus section or the jump destination. The evaluation value indicating the stability is calculated for each stable section, and the stable section corresponding to the best evaluation value is determined as the best stable section. As the evaluation value, the evaluation value (left side of each mathematical expression) shown in the drawing can be used. According to the option 2, the stable section having the most reliability can be set as the measurement object. Figure 4

[0079] In the case where the option 3 indicated by the reference numeral 148 is selected, the nearest stable section becomes the initial focus section or the jump destination. The nearest stable section is the stable section closest to the focus phase or the focus section before or after the current focus phase. At the freeze point, since the latest phase becomes the current focus phase, the latest stable section is determined as the nearest stable section based thereon. In the case where the focus phase marker is located at an arbitrary position in the freeze state, the nearest stable section is determined based on the focus phase or the focus section. According to the option 3, the stable section closest to the freeze time or the stable section closest to the current focus phase can be set as the measurement object.

[0080] In Figure 10 Examples of the operation related to the option 2 and the operation related to the option 3 are shown. In the electrocardiogram waveform 150, the latest phase 152 is the phase at the freeze point. In Figure 10 the current focus phase is the phase determined by the focus phase marker 154. In the case where the phase detection function is turned on in the state where the option 2 is currently selected, as indicated by the reference numeral 156, the best stable section n-4 becomes the new focus section, and the foremost 158 thereof becomes the new focus phase. The focus phase marker is displayed at the foremost.​

[0081] On the other hand, in a case where the phase detection function is enabled in a state where Option 3 is currently selected, the most recent stable interval n-2 becomes a new attention interval, and the foremost thereof becomes a new attention phase as shown by reference numeral 164. The attention phase mark is displayed at the foremost 166.

[0082] In Figure 11 An operation example of the ultrasonic diagnostic apparatus according to the embodiment is shown, and a post-freeze operation example is particularly shown. In S10, it is determined whether or not the stable interval determination in real-time operation has been performed. In a case where it has not been performed, in S12, it is determined whether or not each heart rate interval constituting an electrocardiographic waveform is a stable interval. Before this, a button for causing the stable interval determination function to be executed is operated as necessary, and a button for causing the function of automatically detecting the end of diastole / end of systole to be executed is operated.

[0083] In S14, the initial attention interval and the initial attention phase are determined in accordance with the selected option. In a case where Option 0 is selected, the initial attention phase is the latest phase of the freeze time point, and the initial attention interval is the heart rate interval including the latest phase. In a case where Option 1 is selected, the best stable interval becomes the attention interval, and the foremost thereof becomes the attention phase. In a case where Option 2 is selected, the most recent stable interval becomes the attention interval with the latest phase as a reference, and the foremost thereof becomes the attention phase.

[0084] In S18, the end of diastole and the end of systole are detected within the attention interval. Subsequently, a set of marks, i.e., the attention phase mark, the end of diastole mark, and the end of systole mark are displayed within the attention interval. In S20, it is determined whether or not the present processing is continued.

[0085] In S22, it is determined whether or not there is an operation of shifting the attention phase mark. In a case where there is the operation, in S24, the waveform image is updated, and the tomographic image is updated. In a case where the attention phase mark enters a heart rate interval next to it, the end of diastole and the end of systole are detected within the new attention interval.

[0086] In S26, it is determined whether or not there is an operation of the back button or the forward button. In S26, in a case where the operation of the back button is determined, in S28, the closest stable interval before the current attention interval becomes a changed new attention interval. That is, the attention interval jumps in the past direction. Thereafter, in S24, the waveform image and the tomographic image are updated. On the other hand, in S28, in a case where the operation of the forward button is determined, in S30, the closest stable interval after the current attention interval becomes a changed new attention interval. That is, the attention interval jumps in the future direction. Thereafter, in S24, the waveform image and the tomographic image are updated.

[0087] As above, according to the operation involved in the embodiment, since the stable interval is set as the new interval of interest in the case where there is a retreat operation as well as a forward operation, detection of the end-systole and end-diastole within the stable interval is ensured. Thus, the advantage that the user does not need to determine whether or not it is a stable interval is obtained. Furthermore, it is possible to prevent the case where the end-systole and end-diastole detected within an inappropriate heart rate interval are used in cardiac function measurement.

[0088] In Figure 12 the display screen 172, in addition to displaying two tomographic images 182, 184, a waveform image 174 is displayed. In the electrocardiograph waveform included in the waveform image 174, a specific stable interval becomes an interval of interest. Within this interval of interest, an attention phase marker 176, an end-diastole marker 178, and an end-systole marker 180 are displayed. The tomographic image 182 is a tomographic image corresponding to the end-diastole indicated by the end-diastole marker 178, and the tomographic image 184 is a tomographic image corresponding to the end-systole indicated by the end-systole marker 180. Measurement is performed based on these tomographic images 182, 184 and an evaluation value is calculated. Since the end-systole and end-diastole are detected within the stable interval, it is possible to calculate the evaluation value based on appropriate two tomographic images. In addition, it is also possible to display a waveform image for each of the tomographic images 182, 184.

Claims

1. An ultrasonic diagnostic apparatus, characterized by comprising: comprising: an image forming section (16) that forms an ultrasonic image based on reception data acquired from a subject; a setting section (42) that determines a plurality of intervals in units of heart rates for an electrocardiograph waveform that represents an electrocardiograph signal acquired from the subject; a detection section (48, 50) that detects an end diastole and a systolic end within an attention interval among the plurality of intervals based on the electrocardiograph waveform; and a display processing section (20) that displays an end diastole mark that represents the end diastole within the attention interval and a systolic end mark that represents the systolic end within the attention interval when the electrocardiograph waveform is displayed together with the ultrasonic image, the ultrasonic diagnostic apparatus further comprising: a determination section (44, 46) that determines each interval that satisfies a stability condition as a stable interval among the plurality of intervals; and a selection control section (33) that controls selection of an attention interval after a change in a case where there is an operation to change the attention interval, so that the attention interval after the change is selected from among a plurality of stable intervals determined by the determination section (44, 46), the detection section (48, 50) detects an end diastole and a systolic end within a specific stable interval that is the attention interval after the change in a case where there is an operation to change the attention interval, in a case where a time length of an evaluation target interval n is set as Tn, a time length of a preceding heart rate interval n-1 of the evaluation target interval n is set as Tn-1, a time length of a preceding preceding heart rate interval n-2 of the evaluation target interval n is set as Tn-2, a maximum value among the three time lengths of Tn-1, Tn, and Tn-2 is set as Tmax, and a minimum value among the three time lengths of Tn-1, Tn, and Tn-2 is set as Tmin, the determination section (44, 46) determines that the evaluation target interval n is a stable interval in a case where Tn-1 / Tn-2 is smaller than a first threshold value, determines that the evaluation target interval n is a stable interval in a case where Tmax / Tmin is smaller than a second threshold value, and determines that the evaluation target interval n is a stable interval in a case where |Tn-|Tn-1-Tn-2|| is smaller than a third threshold value.

2. The ultrasonic diagnostic apparatus according to claim 1, characterized in that the selection control section (33) selects, in a case where there is a backward operation, a closest stable interval located before the attention interval as the attention interval after the change, and selects, in a case where there is a forward operation, a closest stable interval located after the attention interval as the attention interval after the change.

3. The ultrasonic diagnostic apparatus according to claim 1, characterized in that the selection control section (33) has a function of determining an optimal stable interval from among the plurality of stable intervals and selecting the optimal stable interval as the initial attention interval or the attention interval after the change.

4. The ultrasonic diagnostic apparatus according to claim 1, characterized in that The selection control section (33) has a function of determining a nearest stable section closest to a current interest phase from among the plurality of stable sections, and selecting the nearest stable section as an initial interest section or the changed interest section.

5. The ultrasonic diagnostic apparatus according to claim 1, wherein The determination section (44, 46) determines the plurality of stable sections in real time, The detection section (48, 50) detects the end diastole and the end systole in a frozen state after the real time.

6. The ultrasonic diagnostic apparatus according to claim 1, wherein The stable condition includes: a primary determination condition for determining a temporary stable section based on a plurality of time lengths possessed by a plurality of sections connected in time; and a secondary determination condition for determining that a time length of a temporary stable section satisfying the primary determination condition does not conform to tachycardia bradycardia, The determination section (44, 46) includes: a primary determination section (44) that applies the primary determination condition to the respective sections; and a secondary determination section (46) that applies the secondary determination condition to a temporary stable section satisfying the primary determination condition.

7. A method of electrocardiogram waveform processing, characterized by, includes: a step (42) of determining a plurality of sections in units of heart rates from an electrocardiogram waveform representing an electrocardiogram signal acquired from a subject; a step (S16, S24) of detecting an end diastole and an end systole in an interest section among the plurality of sections based on the electrocardiogram waveform; and a step (S18, S24) of displaying an end diastole marker representing the end diastole within the interest section and an end systole marker representing the end systole within the interest section, in a case where an ultrasonic image and the electrocardiogram waveform are displayed, The electrocardiogram waveform processing method further includes: a step (S12) of determining each section satisfying a stable condition as a stable section among the plurality of sections; and a step (S28, S30) of controlling selection of a changed interest section so that the changed interest section is selected from among the plurality of determined stable sections, in a case where there is an operation to change the interest section, The electrocardiogram waveform processing method detects an end diastole and an end systole in a changed interest section, which is a specific stable section, in a case where there is an operation to change the interest section, In a case where a time length of an evaluation target section n is set to Tn, a time length of a preceding heart rate section n-1 of the evaluation target section n is set to Tn-1, a time length of a still preceding heart rate section n-2 of the evaluation target section n is set to Tn-2, a maximum value among the three time lengths of Tn-1, Tn, and Tn-2 is set to Tmax, and a minimum value among the three time lengths of Tn-1, Tn, and Tn-2 is set to Tmin, ​ In the process (S12), in a case where Tn-1 / Tn-2 is smaller than a first threshold value, it is determined that the evaluation target interval n is a stable interval, in a case where Tmax / Tmin is smaller than a second threshold value, it is determined that the evaluation target interval n is a stable interval, and in a case where |Tn-1-Tn-2| is smaller than a third threshold value, it is determined that the evaluation target interval n is a stable interval.

Images