JP2010088943A - Doppler ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide Doppler ultrasonic diagnostic apparatus which automates the operation of a velocity range and a baseline shift of a Doppler spectrum image. <P>SOLUTION: Doppler ultrasonic diagnostic apparatus operates as a tracing step which traces at least either a maximum flow velocity or mean flow velocity in the frequency direction of a spectrum signal in the direction of time and implements the processing for outputting the trace waveform in real time, as a velocity range adjustment step which adjusts a Doppler velocity range at prescribed observation time intervals based on the statistics for the distribution of at least either the maximum flow velocity or the mean flow velocity, as an adjustment step which adjusts the Doppler velocity range at prescribed observation time intervals based on the statistics for the distribution of at least either the maximum flow velocity or the mean flow velocity, and as a setting step which sets the multiple number of how many times the estimate value of the upper limit and lower limit of the velocity range is set at a display range as parameter variably in order to change the parameter used in the processing of the adjustment step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a Doppler ultrasonic diagnostic apparatus capable of displaying a Doppler spectrum, and more particularly, to a Doppler ultrasonic diagnostic apparatus capable of automatically adjusting a speed range and a baseline of a Doppler spectrum image.

  Conventionally, the ultrasonic pulse reflection method and the ultrasonic Doppler method are used together to obtain a tomographic image of the diagnostic region and blood flow information by ultrasonic scanning using one ultrasonic probe, and at least display the blood flow information in real time A Doppler ultrasound diagnostic apparatus is known. In this device, the reception frequency slightly shifts with respect to the transmission frequency due to the Doppler effect of ultrasonic waves transmitted and received toward a diagnostic site with a flow such as blood flow in the body, and the shift frequency (Doppler frequency) The frequency analysis of the Doppler frequency is performed based on the principle of the ultrasonic Doppler method that is proportional to the blood flow velocity, and blood flow information is obtained from the result.

  In the above Doppler ultrasonic diagnostic apparatus, the result of the fast Fourier transform (FFT) frequency analysis on the obtained Doppler signal, the frequency f on the vertical axis, the time t on the horizontal axis, and the power (strength) of each frequency component. Measurement processing of items (parameters) used in diagnosis is performed on a spectrum image of the Doppler frequency displayed as a spectrum of luminance (gradation).

That is, according to this measurement process, as shown in FIG.
1) On the spectrum image of the Doppler frequency, the position of the maximum flow velocity Vp (Vpeak) corresponding to the maximum frequency in the frequency distribution in the frequency f-axis direction and the average flow velocity Vm (Vmean) corresponding to the average frequency are obtained (see FIG. 24 (a)),
2) Trace the time change of the position of the maximum flow velocity Vp and the average flow velocity Vm in the direction of the time axis t (trace waveform detection processing: see FIG. 24B),
3) On the trace waveform showing the temporal position change curves of Vp and Vm, the systolic waveform peak PS (Peak of Systolic) and the diastolic waveform peak ED (End) for each cardiac cycle (one heartbeat) of Diastolic) (peak detection processing: see FIG. 24C),
4) Various parameters related to diagnosis such as HR (Heart Rate), PI (Pulsatility Index) and RI (Resistance Index) of blood flow and pulsatile flow in the blood vessel based on the PS / ED information ( A process (parameter measurement process) of measuring the index) and displaying the measured value is executed.

  The above-described Vp, Vm trace waveform detection processing, PS / ED peak detection processing, parameter measurement processing such as PI, RI, etc. are performed on the basis of manual operation for freeze images, but in recent years, Devices that perform automatic operations on real-time images have also become widespread.

  By the way, in the pulse Doppler (PW) method, when the sampling frequency fs for frequency analysis is lower than the Dobra shift frequency, an aliasing phenomenon (folding) occurs. Therefore, in order to prevent this, it is necessary to increase the pulse repetition frequency (PRF: Pu1se Repetition Frequency) and shorten the observation time interval every time. In this case, when the location position to be measured is designated, the maximum PRF is inevitably determined. When the PRF is determined, the maximum blood flow rate that can be measured is also determined. This maximum blood flow rate that can be measured is called the speed range.

  For example, when it is desired to measure the blood flow velocity of about 30 cm, the blood flow cannot be measured if the velocity range is about 10 cm. The speed range needs to be set to about 50 cm.

  When Doppler spectrum display is performed, if the speed range is too small, a folded portion (portion (A) in FIG. 25) occurs as shown in FIG. In such a case, the operator operates the speed range switch to increase the speed range of the Doppler spectrum image. When the speed range is increased in this way, as shown in FIG. 25 (c), the folded portion (a) is within the Nyquist frequency, and a Doppler spectrum that is well connected for display is obtained.

  On the other hand, if the speed range is too large, the spectrum waveform becomes small and difficult to observe, as shown in FIG. In such a case, the operator operates the speed range switch to reduce the speed range of the Doppler spectrum image, and it is easy to observe by effectively using the top and bottom of the display screen as shown in FIG. Get the Doppler spectrum.

  In the Doppler method, a sign that the direction of the blood flow is positive with respect to the blood flow toward the ultrasonic probe and negative with respect to the blood flow moving away. When an ultrasonic probe is applied to a certain blood vessel, if the blood vessel is an artery, the speed of blood flow varies depending on the pulsation, but it rarely changes between positive and negative, and is usually biased to either positive or negative.

  For example, when a Doppler spectrum display is performed, as shown in FIG. 25A, when a folded portion occurs, the user operates the baseline shift switch to change the baseline BL ( BL = 0) may be shifted. This is called a baseline shift (BLS). By shifting the base line BL by -0.25 (that is, the base line shift amount BLS = -0.25), the folded portion (a) exceeds the Nyquist frequency as shown in FIG. It moves and a Doppler spectrum with good connection is obtained.

  When measuring blood flow velocity, etc. with a Doppler ultrasound diagnostic device, the blood to be measured according to the disease and physical condition of the subject, how to apply the probe (angle), and the range gate position and width in the blood vessel in PW Doppler The flow velocity varies greatly. For this reason, the user has conventionally performed optimization such as adjusting the speed range of the apparatus or shifting the base line every time, and has measured HR, PI, and RI from the expanded waveform. However, it is troublesome to adjust the speed range and the baseline shift function each time the blood flow state to be diagnosed changes.

  Therefore, what adjusts automatically is proposed (for example, refer patent documents 1-4).

JP 2000-197634 A US Pat. No. 5,628,321 US Pat. No. 5,871,447 US Pat. No. 5,647,366

  However, these proposed processing algorithms have many problems. For example, when determining the speed near the Nyquist frequency, or when the trace direction crosses both signs (when the DC line is crossed), the trace waveform lacks stability, cannot be restored, or oscillates at all. It is a technical problem that a strange process occurs and a state of confusion occurs.

  Such inconveniences are thought to occur because these prior proposals use a Doppler spectrum image and perform calculation using an algorithm that sequentially discriminates based on the boundary between the noise region and the signal region. Also, with this method, a baseline shift cannot be performed after freezing.

  Such a problem can be solved by calculating using the spectrum data itself, but in this case, the calculation amount becomes enormous and a problem arises in real-time followability.

  The present invention has been made in consideration of the above-described circumstances. The speed range and baseline shift operation of the Doppler spectrum image is automated, the operability of blood flow measurement is improved, and the user cares about the device settings. It is an object of the present invention to provide a Doppler ultrasonic diagnostic apparatus capable of making a diagnosis.

  Another object of the present invention is to provide a Doppler ultrasonic diagnostic apparatus that performs the automatic adjustment with particularly high stability and quick response processing.

  Still another object of the present invention is to provide a Doppler ultrasonic diagnostic apparatus capable of shifting the baseline not only in real time but also after freezing.

  In order to solve the above-described problem, a Doppler ultrasonic diagnostic apparatus according to the present invention is obtained by transmitting and receiving ultrasonic waves toward a diagnostic site including a kinetic fluid in a subject, as described in claim 1. In a Doppler ultrasonic diagnostic apparatus that displays a spectrum image based on a spectrum signal of a Doppler frequency that carries information related to the flow velocity of the diagnostic part, at least one of the maximum flow velocity and the average flow velocity in the frequency direction of the spectrum signal is traced in the time direction. A tracing means for executing processing for outputting a trace waveform in real time; a speed range adjusting means for adjusting a Doppler speed range based on a statistical value for at least one of the maximum flow velocity and the average flow velocity every predetermined observation time; In order to change the parameters used in the processing of the speed range adjusting means, A multiple of either set the display range many times the upper limit and the lower limit estimate of the one in which and a setting unit that variably sets as said parameter.

  Further, in order to solve the above-described problem, the Doppler ultrasonic diagnostic apparatus according to the present invention transmits and receives ultrasonic waves toward a diagnostic site including a kinetic fluid in a subject as described in claim 2. In a Doppler ultrasonic diagnostic apparatus that displays a spectrum image based on a spectrum signal of a Doppler frequency that bears information on the flow velocity of the obtained diagnostic site, traces at least one of the maximum velocity and the average velocity in the frequency direction of the spectrum signal in the time direction. And a tracing means for executing processing for outputting the trace waveform in real time, and a speed range adjusting means for adjusting a Doppler velocity range based on a statistical value for at least one distribution of the maximum flow velocity and the average flow velocity every predetermined observation time. And calculating the positive side maximum value and the negative side maximum value of the maximum flow velocity, In order to change the parameters used in the processing of the baseline adjustment means for adjusting the baseline and the speed range adjustment means and the baseline adjustment means, Setting means for variably setting, as the parameter, a multiple of how many times the lower limit estimated value is set in the display range.

  More preferably, the setting means is a color Doppler mode preceding the calculation as an initial value of the calculation for adjusting the Doppler speed range executed by the speed range adjustment means. It is possible to select either the adopted speed range or a predetermined value set in advance for each diagnosis part.

  Further, as set forth in claim 4, the setting means updates the calculation result of the predetermined time by the speed range adjustment means once every image scrolling in synchronization with scrolling of the spectrum image. In addition, as described in claim 5, update of the calculation result by the speed range adjusting means is performed at an arbitrary time during scrolling of the spectrum image. It is also possible to update with the scrolling of the spectrum image.

  In order to solve the above-described problem, the Doppler ultrasonic diagnostic apparatus according to claim 6 further includes a trace waveform storage unit that stores a trace waveform of at least one of the maximum flow velocity and the average flow velocity, and after freezing, Based on the trace waveform stored in the trace waveform storage means, the baseline adjustment means calculates the positive maximum value and the negative maximum value of the maximum flow velocity, and the shift amount of the baseline in the display of the spectrum image To adjust the baseline.

  Furthermore, in order to solve the above-described problem, the speed range adjusting means according to claim 7 compares a predetermined control target value with a transfer function value fed back from the speed range adjusting means, and according to the difference. Thus, the parameters of the control system elements P, I, and D are variably determined.

  As described above, according to the Doppler ultrasound diagnostic apparatus according to the present invention, the speed range and baseline shift operation of the Doppler spectrum image is automated, the operability of blood flow measurement is improved, and the user can set the device It is possible to provide a Doppler ultrasound diagnostic apparatus that can diagnose without worrying about the above.

  In addition, the present invention can provide an effect capable of providing a Doppler ultrasonic diagnostic apparatus that performs the automatic adjustment with particularly high stability and quick response processing.

  The present invention is further advantageous in that it provides a Doppler ultrasound diagnostic apparatus that can shift the baseline not only in real time but also after freezing.

1 is a schematic block diagram showing the overall configuration of a Doppler ultrasound diagnostic apparatus according to an embodiment of the present invention. 1 is a schematic functional block diagram showing a main configuration of a Doppler ultrasound diagnostic apparatus according to an embodiment. The flowchart which shows the flow of a calculation of a speed range and baseline shift automatic optimal adjustment. The figure explaining extraction of a Doppler trace waveform. The figure which plotted the spectrum distribution of Vp and Vm for ± 3 Nyquist frequency. The figure which shows the spectrum distribution of Vp which added the weight. The figure which shows an example of the statistical value calculation process by a normal distribution model for estimating the upper limit and lower limit of a speed range. The figure which shows an example of the statistical value calculation process by the threshold value processing model after smoothing for estimating the upper limit and lower limit of a speed range. It is a figure which superimposes and displays the upper limit and lower limit of a speed range on the time-dependent change of weighted Vp and Vm distribution, (a) is a figure about Vp, (b) is a figure about Vm. The figure which shows the time-dependent fluctuation | variation of a speed range. It is a figure which superimposes and displays the upper and lower limits of a speed range, and BLS on the time-dependent change of weighted Vp and Vm distribution, (a) is a figure about Vp, (b) is a figure about Vm. The figure which shows the time-dependent fluctuation | variation of a speed range and a baseline. The schematic block diagram which shows the function of a PID control part. It is a figure explaining the response by PID control, (a) is a case by P control, (b) is a figure by the case by PID control. The figure explaining EOS. The figure which shows an example of an EOS table. The flowchart which shows the flow of a process in case both automatic speed range update and BLS update are performed continuously during observation in real time. The time chart explaining an example of the processing result of FIG. 17 in time series. The flowchart which shows the flow of the process which performs both automatic speed range update and BLS update only once at arbitrary times during observation in real time. The time chart explaining an example of the processing result of FIG. 19 in time series. The flowchart which shows the flow of the process which performs BLS update only once at arbitrary times after image freeze. The example which observed the carotid artery system is shown, (a) is a figure which shows an example of the statistical value calculation process by the threshold value processing model after smoothing, (b) displays the time-dependent change of weighted Vp and Vm distribution. (C) is a figure which shows a time-dependent fluctuation | variation of a speed range and a baseline. The example which performed the LV measurement between ridges, (a) is a figure which shows an example of the statistical value calculation process by the threshold value processing model after smoothing, (b) is a time-dependent change of weighted Vp and Vm distribution. The figure to display, (c) is a figure which shows the time-dependent fluctuation | variation of a speed range and a baseline. It is a figure explaining the outline | summary of a measurement of a spectrum signal, (a) is a Doppler spectrum image, (b) is a trace image of Vp, Vm, (c) is a figure which shows the synchronous detection image of PS / ED. It is a screen figure explaining the speed range in Doppler spectrum display, (a) is a state where folding occurs, (b) is a state where the speed range is too large, (c) is a state where the speed range is adjusted, ( FIG. 4D is a diagram showing a state where the baseline is shifted.

  Hereinafter, embodiments of a Doppler ultrasonic diagnostic apparatus according to the present invention will be described with reference to the accompanying drawings.

(Device configuration)
FIG. 1 is a block diagram showing an overall outline of the Doppler ultrasound diagnostic apparatus according to the present embodiment. This Doppler ultrasound diagnostic apparatus displays a B mode for displaying an ultrasonic tomogram (B mode tomogram), an M mode for displaying a temporal position change of a reflection source in the ultrasonic beam direction as a motion curve, and blood flow information. Various known modes such as Doppler mode (pulse Doppler (PW) / continuous wave Doppler (CW)) and CFM (color flow mapping or color Doppler) mode for displaying blood flow information two-dimensionally. It can be operated accordingly.

  The Doppler ultrasonic diagnostic apparatus shown in FIG. 1 transmits a plurality of piezoelectric vibrations that transmit ultrasonic waves to a diagnostic site including a blood flow BF in a subject P, convert the ultrasonic echoes into corresponding voltage signals, and receive the ultrasonic signals. An electronic scanning ultrasonic probe 1 having a child and an apparatus main body 2 connected to the ultrasonic probe 1 are provided. An ECG module 3 that measures an electrocardiographic waveform (ECG waveform) of the subject P is connected to the apparatus main body 2.

  In addition to the overall controller 11 serving as a control center for the entire apparatus, the apparatus body 2 includes various units (described later) whose operations can be controlled based on control signals from the overall controller 11. That is, the apparatus main body 2 includes a transmission / reception unit 21 connected to the ultrasonic probe 1. The transmission / reception unit 21 includes, as components on the transmission side (not shown), a pulser that is connected to the ultrasonic probe 1 and excites each piezoelectric vibrator, and a delay line that supplies a drive signal that delays the pulser (when receiving) And a reference oscillator for supplying a reference clock to the delay line, and a preamplifier connected to each piezoelectric vibrator of the ultrasonic probe 1 as a receiving side component (not shown), and the preamplifier A delay line for delaying the output signal and an adder for phasing and adding the output signal giving the delay from the delay line are incorporated.

  Further, the apparatus main body 2 has an envelope detector 22 for adding logarithmic amplification and envelope detection of the adder output to the output side of the transmission / reception unit 21, and the detection output of the B-mode tomogram and M-mode image. A digital scan converter (DSC) 23 that converts an ultrasonic scanning signal into a standard TV scanning signal as an image signal, and the like, and displays the converted signal of the DSC 23 as a B-mode tomographic image or the like via a D / A converter 24 Display 25.

  In the apparatus body 2, the reference signal from the reference transmitter and its phase difference of 90 degrees are provided on the output side of the transmission / reception unit 21 as a signal processing system related to the Doppler mode (CW / PW) or the like in a two-channel configuration. And a quadrature phase detector 26 for phase detection that mixes the output of the adder of the transmitter / receiver 21 and a Doppler signal consisting only of the Doppler shift frequency component by removing the high frequency component of the mixed signal. Among them, a range gate (RG) processing unit 27 having a low-pass filter and a sample hold circuit for extracting a Doppler signal at a desired depth position (position designated by the range gate corresponding to ROI) in the subject P; In an after-mentioned DSP (Digital Signal Processor) 31, unnecessary low-frequency Doppler signals such as blood vessels walls and heart walls that are relatively slow are removed from the output of the RG processor 27. A spectrum Doppler processing block 28 is provided that extracts a Doppler signal of a blood flow BF to be output, performs frequency analysis on the output of the Doppler signal, obtains a Doppler spectrum signal as an analysis result, and outputs the Doppler spectrum signal to the DSC 23 described above. The Thereby, a Doppler spectrum image is displayed on the display device 25 together with, for example, a B-mode tomographic image.

  Further, in the apparatus main body 2, as a signal processing system related to the CFM mode, an MTI filter that removes unnecessary fixed reflection signals such as a heart wall from the output of the quadrature detector 26 is provided on the output side of the mixer 25, and the output is self- Using the correlation method, average velocity calculation, variance calculation, and power calculation of each point are performed, and two-dimensional blood flow information (velocity, direction, and variance of blood flow BF) as the calculation result is output to the DSC 23 described above. A CFM mode processing block 30 is connected. Thereby, on the display device 25, for example, blood flow information is two-dimensionally displayed on a B-mode tomographic image, for example, the velocity of the blood flow BF is luminance, the direction is red and blue, and the dispersion is green hue. Displayed as color information.

  Furthermore, the apparatus main body 2 receives the Doppler spectrum signal from the spectrum Doppler processing block 28 and the RG processing unit 27 described above, and sets the position of the maximum velocity Vp and the average velocity Vm in the frequency direction of the spectrum in the time direction. A DSP (Digital Signal Processor) 31 having a function of tracing and detecting the trace waveform in real time, and a function of detecting the above-mentioned PS / ED peak position from the Vp and Vm trace waveforms from the DSP 31 in real time or after freezing. The PS / ED detector 32 and the PS / ED information detected by the PS / DS detector 32 based on the blood flow rate in the blood vessel, the HR, PI, and RI (Resistance Index) of the pulsatile flow A measuring unit 33 having a function of measuring various parameters related to diagnosis, and a main part of the Doppler ultrasonic diagnostic apparatus of the present invention An auto range / auto BLS processing unit 49 having a speed range adjustment function and a baseline adjustment function as a configuration is provided. Among these, the PS / ED detection unit 32, the measurement unit 33, and the auto range / auto BLS processing unit 49 are mounted as application software constituting software components executed by a computer mounted on the apparatus main body 2, for example.

  Each output of the DSP 31 and the measurement unit 33 is supplied to the DSC 23 via the video I / F 34. Thereby, on the display 25, PS / ED and each measurement result are displayed on the trace waveform image of Vp and Vm in real time. The trace waveform data of Vp and Vm of the DSP 31 is held in the image storage unit 35 and can be supplied to the PS / ED detection unit 32 after freezing.

  In the example shown in FIG. 2, the DSP 31 is functionally connected to a relatively slow moving blood vessel wall, heart wall, etc. from a Doppler signal at a desired position in the subject P designated by the range gate from the range gate processing unit 27. A wall filter 41 as a Doppler filter that extracts the Doppler signal of the blood flow BF to be detected by removing the unnecessary low-frequency Doppler signal, and the extracted Doppler signal is input via the cine memory buffer 42. Then, an FFT spectrum processing unit 43 that performs frequency analysis on the output of the Doppler signal, obtains a Doppler spectrum signal as a result of the analysis, and outputs the Doppler spectrum signal to the DSC 23 is provided. These wall filter 41, cine memory buffer 42 and DSC 23 constitute the spectrum Doppler processing block 28 described above.

  Further, the DSP 31 obtains Vp and Vm trace waveforms from the spectrum signal output from the FFT spectrum processing unit 43, Vp and Vm trace waveform detection processing unit 44, and a display audio input unit for inputting the Vp and Vm trace waveforms. And a video buffer 45.

  Further, the DSP 31 converts the Doppler spectrum signal from the FFT spectrum processing unit 43 into an audio signal (Doppler sound) and outputs it to the display audio / video buffer 45, and the ECG module 3 An ECG waveform processing unit 54 that performs predetermined waveform processing on the ECG waveform data and outputs the result to the display audio / video buffer 45; a detection output of an M mode image from the envelope detector 22; and a CFM mode processing block 30 An M / M color processing unit 55 that performs predetermined color processing on the two-dimensional blood flow information and outputs the processed information to the display audio / video buffer 45.

  Thus, the trace waveform data from the Vp, Vm trace waveform detection processing unit 44 is supplied from the display audio / video buffer 45 to the video interface 34 via the ping-pong buffer 34a, and Vp, Vm is displayed on the display 25. The auto trace waveform is displayed in real time. The audio signal of the Doppler signal from the audio processing unit 46 is supplied from the display audio / video buffer 45 to the audio interface 38 via the ping-pong buffer 34a, and is output as audio from an audio output device (speaker).

  In the example shown in FIG. 2, the trace waveform data from the Vp and Vm trace waveform detection processing unit 44 has a PS / ED detection unit 32 (in FIG. 2, the peak detection processing unit 32b is executed by the processing of the CPU 32a. ) And the measurement unit 33 (in FIG. 2, the real-time automatic measurement processing unit 33a and the re-measurement processing unit 33b after cine / freeze have respective functional units) are supplied to the video interface 34 and are displayed. 25, in addition to the auto trace waveforms of Vp and Vm, numerical values are displayed in real time as auto measurement values based on PS / ED information. After the freeze, the PS / ED information is supplied from the PS / ED buffer 29 to the video interface 34 via the cine-freeze re-measurement processing unit 33b in the measurement unit 33, and is displayed on the display 25. Thus, numerical values are displayed together with the auto trace waveforms of Vp and Vm from the image storage unit 35.

  As shown in FIG. 1, an auto range / auto BLS processing unit 49 is connected to the output side of the display audio / video buffer 45 and the PS / ED buffer 29 in the DSP 31. The auto range / auto BLS processing unit 49 adjusts the Vp and Vm auto-trace waveforms from the display audio / video buffer 45 in accordance with the synchronization information from the PS / ED buffer 29 for each observation time of Vp and Vm. A distribution is calculated, an optimum speed range and baseline shift amount are calculated from statistical values representing the distribution shape, and the speed range and baseline shift (BLS) are automatically optimally adjusted.

  As shown in FIG. 1, a parameter setting unit 36 is connected to or built in the DSP 31, the PS / ED detection unit 32, and the auto range / auto BLS processing unit 49. The parameter setting unit 36 operates according to the present invention. It is connected to a user interface 37 for operator operation that constitutes means.

  As shown in FIG. 1, an operation panel circuit 38 for inputting operation signals (parameter setting, etc.) from various operating devices (switches, joystick, keyboard, mouse, etc.) on the operation panel of the apparatus body 2 is input to the user interface 37. And a TCS circuit 39 for inputting an operation signal (parameter setting, etc.) from a TCS (Touch Command Screen) mounted on the operation panel, and an operation from a GUI (Graphical User Interface) on the display unit 23 And a GUI circuit 40 for inputting a signal (parameter setting or the like).

  An instruction necessary for operating the apparatus, for example, specification of the above-described range gate (ROI) can be operated by the user interface 37.

  Then, parameters of the automatic optimum adjustment algorithm for the speed range and baseline shift executed by the auto range / auto BLS processing unit 49, for example, whether only the speed range is automatically adjusted or whether the base line shift is performed, Range update timing and the like are set by the parameter setting unit 36 through the user interface 37.

  The parameter setting unit 36 includes a PID control circuit 50 therein so that the speed range and the base line shift can be automatically and optimally adjusted with fast responsiveness even when the speed range changes drastically with respect to the observation time.

(Calculation algorithm for automatic speed range adjustment)
Next, an algorithm for automatic optimum adjustment of the speed range and baseline shift executed by the auto range / auto BLS processing unit 49 will be described. FIG. 3 is a flowchart showing a schematic flow of a series of processes relating to this process.

  The auto range / auto BLS processing unit 49 first extracts the trace waveforms of Vp and / or Vm detected by the Vp, Vm trace waveform detection processing unit 44 for the observation time set by the parameter setting unit 36 (step). S2).

  FIG. 4 shows the speeds of Vp and Vm at each time, with time on the horizontal axis and speed on the vertical axis. In this case, if the observation time is set to 4 seconds (the portion surrounded by a bold line in the figure), 240 columns of data are collected for each of Vp and Vm, assuming that the column is divided into 60 columns per second. .

The velocity data of Vp and Vm collected in this way is plotted in the form of a histogram (step S4). FIG. 5 shows an example of this velocity distribution, with the horizontal axis representing frequency and the vertical axis representing frequency. As shown in FIG. 5, three distribution maps having the same shape are arranged. The distribution map actually obtained is located at the center, and the left and right ones are expanded to ± 3 Nyquist frequency (f _N ). That is, while the original distribution exists from -f _N between f _N, the left distribution is a copy between -f _N The original distribution from -3f _N. Similarly right distribution is to the original distribution copied between f _N from 3f _N. This can be said to be a preparatory work for “weighting” to be described later.

Next, in the speed range displayed on the display unit 25 and in the previous turn-back area, a weighting process for applying an appropriate weight to the distribution of Vp and Vm according to the BLS at that time is performed (step S6). If the distribution is simply within the display range, it may become discontinuous in the vicinity of the return and may not be discriminated. In order to avoid such a situation, the velocity distribution of Vp and Vm is expanded to ± 3 Nyquist frequency (f _N ) and weighting is performed in order to ensure continuity with some consideration of aliasing.

The example shown in FIG. 6 is a case where a trapezoidal weight function is employed when BLS is not performed. Although weighting coefficients within the display area is unchanged at 1, minus side, between the -2f _N of -f _N, the weighting coefficient is changed linearly from 0 to 1. In contrast, the plus side, between the f _N of 2f _N, weighting coefficients linearly changing from 1 to 0.

  In the case shown in FIG. 6, since BLS is not performed, the weighting function is a symmetrical isosceles trapezoid. When BLS is performed, as shown in FIG. 7, it becomes a trapezoid whose target property has collapsed. The basic shape of the weighting function is a trapezoidal shape, but is not limited thereto, and modified examples such as a rectangle, a normal distribution, a Gaussian distribution, etc. are used according to the distribution of the velocity histogram of the Doppler waveform of the diagnostic region. You can also.

  When the weighted distributions of Vp and Vm are obtained, statistical value calculation processing is subsequently performed in order to estimate the upper limit and lower limit of the speed range (step S8). This statistical value calculation process is roughly divided into two methods.

  One is a normal distribution model in which the mean and variance are calculated from the weighted distribution of Vp, and the mean ± coefficient * σ is the estimated value of the upper and lower limits of the speed range. For example, there is a 3-sigma method in which the upper and lower limits of the speed range are standard deviations of the average value V3 of the Vp distribution. An example is shown in FIG. In this case, only the upper limit or only the lower limit can be set according to the distribution of the velocity histogram of the Doppler waveform of the diagnostic region.

  Similarly, the upper limit and the lower limit can be obtained for Vm, but the coefficient * σ is set larger than that for Vp.

  The other is a post-smoothing threshold processing model in which values corresponding to the coefficient% of the peak value from the weighted Vp distribution are estimated values of the upper and lower speed ranges. Specifically, first, the weighted distribution of Vp is smoothed, and from the peak value, for example, a value of −6 dB is set as a histogram threshold, and the limit at which the smoothed Vp distribution is initially equal to or lower than the histogram threshold is set. The upper and lower limits of the speed range are estimated. An example is shown in FIG. In this case as well, as in the case of the normal distribution model, only the upper limit or only the lower limit can be set according to the distribution of the velocity histogram of the Doppler waveform of the diagnostic region.

  The upper and lower limits can be obtained in the same way for Vm, but the coefficient * σ is set to be smaller than in the case of Vp. Further, the search for the threshold value starts from the peak position in the vertical direction on the frequency axis, and the first point that is equal to or lower than the threshold value is estimated as the upper limit and the lower limit of the speed range (see FIG. 8).

  Among these, the smoothed threshold processing model is more effective for estimating the velocity range of pulsatile blood flow, and the normal distribution model is used for estimating the velocity range of the venous system with fewer pulsations than the arterial system. Tends to fit. Therefore, these models can be selectively used according to the distribution of the velocity histogram of the Doppler waveform of the diagnostic region.

  It is also possible to use a combination of the above methods. For example, the method of selecting the larger one of the upper and lower limits of Vp and Vm obtained with the normal distribution model, or the speed range of the upper and lower limits of Vp and Vm obtained with the smoothed threshold processing model There is a way to select the larger one. A method of selecting a larger velocity range from the upper and lower limits of Vp and Vm obtained by both the normal distribution model and the smoothed threshold processing model, and both the normal distribution model and the smoothed threshold processing model There is also a method of selecting the maximum speed range from the upper and lower limits of Vp and Vm obtained in (1).

  When the upper limit and the lower limit of the speed range for each observation time are thus estimated, the speed range is sequentially updated (step S10). This is because the upper and lower limit estimated values of the speed range obtained by statistical value calculation processing within the observation time are automatically set to values greater than the estimated value from the range table registered in advance in the Doppler range of the parameter setting unit 36. It is done by selecting automatically. Conventionally, the user manually switches the Doppler speed range whenever necessary. Note that how many times the estimated value obtained, for example, 1.1 times or 1.5 times is set as the upper limit and the lower limit, is input from the user interface 37 as a parameter via the parameter setting unit 36 (hereinafter referred to as the parameter). It is called “range coefficient”).

  FIG. 9 is a diagram in which the upper and lower limits of the speed range subjected to statistical value calculation processing by the normal distribution model and the smoothed threshold processing model are superimposed on the temporal change of the Vp and Vm distribution weighted in the ± 3 Nyquist interval. (A) is for Vp and (b) is for Vm. From this figure, it can be seen that the speed range changes following the changes of Vp and Vm.

  FIG. 10 is a diagram showing the change over time of the speed range. Here, an example in which the baseline is not shifted is shown. Vp and Vm at a certain time are displayed in a full display area of the display unit 25 between “upper limit” and “lower limit” shown in FIG. That is, the Doppler spectrum image is enlarged and displayed in a time zone where the upper limit / lower limit is narrow. In addition, since the Doppler spectrum image does not exceed the upper limit / lower limit, there is no possibility of aliasing or the like.

  As can be seen from this figure, the fluctuation of the speed range follows the Doppler spectrum image with high accuracy although there is a slight time delay. The speed range is observed at regular intervals, and the value of the speed range is selected from the values in the range table registered in advance. In a stepwise manner.

  Here, if auto BLS is not selected in advance (step S10: No), the auto range / auto BLS processing unit 49 repeats the above processing until an instruction to end is given (step S16: No).

  On the other hand, when the auto BLS is selected in advance (step S10: Yes), the auto range / auto BLS processing unit 49 executes an automatic update process of BLS (step S14). This automatic update process of BLS is performed so that the BLS comes to the center of the upper limit and the lower limit of the speed range when there is no change in the speed range of a specific section. This is a measure for preventing this because the display may become unstable when the automatic update process of BLS is performed sequentially. This specific section can be selected via the parameter setting unit 36 by inputting from the user interface 37. It is also possible to select to press the switch to fix the PRF (ie, fix the speed range) and then perform BLS.

  FIG. 11 shows the upper and lower limits of the speed range and the baseline shift, which are statistically calculated by the normal distribution model and the smoothed threshold processing model, over time with the Vp and Vm distributions weighted in the ± 3 Nyquist interval. (A) is for Vp, and (b) is for Vm. Also from this figure, it can be seen that the speed range and the baseline shift change following changes in Vp and Vm.

  FIG. 12 is a diagram showing the temporal variation of the speed range and the baseline shift. Vp and Vm at a certain time are displayed in a full display area of the display unit 25 between “upper limit” and “lower limit” shown in FIG. That is, the Doppler spectrum image is enlarged and displayed in a time zone where the upper limit / lower limit is narrow. In addition, since the Doppler spectrum image does not exceed the upper limit / lower limit, there is no possibility of aliasing or the like.

  In the figure, the line that crosses the center in the height direction to the left and right indicates the variation in the position of the base line (BL = 0). When the Doppler spectrum image is unevenly distributed above or below the base line, the necessary display area can be greatly enlarged by shifting the base line in this way. As can be seen from this figure, the fluctuation of the baseline follows the Doppler spectrum image with high accuracy.

  The auto range / auto BLS processing unit 49 repeats the above processing until an instruction to end is given (step S16: No). That is, a loop is formed in which the next range is determined while observing each time.

(PID control)
Thus, the auto range / auto BLS processing unit 49 performs automatic adjustment step by step based on the current speed range and the position of the baseline. In addition, it is necessary to quickly follow changes in pulsation and how the probe is applied (angle). Therefore, in order to increase the response speed, it is effective to perform feedback control. The Doppler ultrasonic diagnostic apparatus according to the present embodiment includes a PID control circuit 50 in the parameter setting unit 37. In the present embodiment, PID control is shown as an example of control for increasing the response speed. However, a smoothing filter such as an IIR (Infinite Impulse Response) type having a response optimal for control may be provided.

  As shown in FIG. 13, the PID control circuit 50 includes, for example, a comparator 51, a regulator 52, and a converter 53.

  The comparator 51 compares the range coefficient r selected as the target value by the user interface 37 with the speed range estimated value normalized with the current speed range. The comparison result is sent to the adjuster 52 as a deviation e.

The adjuster 52 includes a proportional operation unit 52a, an integration operation unit 52b, and a differentiation operation unit 52c. In the adjuster 52, the steady-state deviation of the deviation e is suppressed to be small in the proportional operation unit 52a, the steady-state deviation of the deviation e is set to 0 in the integration operation unit 52b, and the vibration of the deviation e in the differential operation unit 52c (time change rate). ) Can be kept small. The resulting transfer function Gc (s) is

It is represented by Each term on the second side of Equation (1) indicates proportional, integral, and differential operations in order. Here, _{K P} is a proportional gain, _{T I} is the integral time, _{T D} is the derivative time. These K _P , T _I , and T _D are variably configured, and can be passed without executing T _I and / or T _D.

This is output as a control output u to the auto range / auto BLS processing unit 49 that is the control target. The transfer function Gp (s) of the auto range / auto BLS processing unit 49 is

It is a first-order lag element with a time lag expressed by

  The auto range / auto BLS processing unit 49 sends the spectrum trace waveform normalized in the current speed range as the process output y to the display unit 25 via the measurement unit 33 and also to the converter 53. To do. The converter 53 sends the estimated value of the upper / lower speed range obtained from the speed distribution diagram of the trace waveform to the comparator 51 as a feedback signal z.

  In this feedback control loop, if there is no time delay, that is, if the change of the speed range is small with respect to the observation time, the control can be performed only by the proportional operation. However, when the speed range changes drastically with respect to the observation time, for example, when the range gate is removed due to breathing or the like, the first-order lag element (Gp (s)) that actually exists in the process, etc. Causes a unique response.

Therefore, the comparator 51 automatically determines the values of the coefficients K _P , T _I , and T _{D according} to the comparison result, and sends the information to the adjuster 52 together with the comparison result. Then, the adjuster 52 can perform a calculation by adding a differential element and an integral element based on the given coefficients K _P , T _I , and T _D , and can speed up the response.

  In other words, the PID control unit 50 is configured to perform not only P control and PID control but also PI control and PD control in accordance with the rate of change of the speed range.

  FIG. 14 illustrates a response by this PID control. FIG. 14A shows a response characteristic in the case of P control. As shown in the figure, in the P control, since time is required for the fluctuation, each step is large, and there is a slight time delay for the fluctuation of the Doppler spectrum. In contrast, in FIG. 14B, an ideal response by PID control is added. As indicated by the bold line in FIG. 8, it can be seen that the change of the speed range is performed smoothly and without causing a time delay according to the PID control.

  By providing such a feedback control function, the Doppler ultrasonic diagnostic apparatus can quickly respond to a change in the speed range, and can obtain a stable speed range and baseline shift more quickly.

(Initial value setting)
As shown in FIG. 14A, when the change in the speed range is severe with respect to the observation time, a time delay may occur in the automatic adjustment of the speed range. This is also true when starting the spectral Doppler mode, i.e., starting automatic speed range adjustment. If automatic speed range adjustment is started from a state where the speed range is 0 or maximum, it may take a long time to obtain a desired speed range. Therefore, if a certain initial value is given to the speed range and the processing is started from that value, the time required to reach the desired speed range can be shortened.

  In such a case, first, it is conceivable to set the general speed range of each part to be diagnosed as an initial value. In addition to this, the Doppler ultrasonic diagnostic apparatus according to the present invention is configured to be able to select the use of the color Doppler velocity range value as the initial value.

  When blood flow is measured, usually, the color Doppler mode is first entered to search for blood vessels, that is, to grasp blood flow dynamics in a tomographic image. Then, if necessary, the spectrum Doppler mode is activated, the PW Doppler displays the Doppler signal spectrum in the range gate, and the CW Doppler displays the Doppler signal spectrum on the raster, and performs detailed blood flow measurement.

  In this color Doppler mode, as in the spectrum Doppler mode, there is a color Doppler range, and the user performs an operation for changing this via the user interface 37. The two-dimensional color Doppler image is obtained by mapping the flow velocity at a certain location, as in the case of the spectrum Doppler mode image. Then, it is possible to read the value set in the color Doppler mode and adopt it as an initial value for the speed range and BLS automatic adjustment in the spectrum Doppler mode. And by this adoption, the responsiveness of the speed range and the automatic adjustment of BLS can be improved.

  Further, when the spectrum Doppler mode is suddenly entered from the B mode (this is rarely the case), the above-described general speed range for each diagnostic region can be set to the initial value.

(Update timing)
As described above, the automatic adjustment of the velocity range is performed by sequentially extracting Doppler trace waveform data of the diagnostic site, and thus it is necessary to observe the blood flow for a certain period of time prior to the calculation. This observation time can be set via the user interface t-face 37 from 1 second, 2 seconds, 4 seconds, and 8 seconds in accordance with the aspect of the diagnostic region. The update of the speed range is basically set from 4 seconds, 8 seconds, 12 seconds and 16 seconds. Note that the speed range cannot be updated in a shorter time than the observation time.

  On the other hand, an image of a Doppler spectrum is a time waveform, and proceeds while drawing in real time from the left end to the right side on the screen of the display 25 with a bar called a moving bar at the top. When the moving bar reaches the right end, the display is updated again by returning to the left end. This screen update is called scrolling. The time from the left end to the right end of the moving bar is called the scroll speed, and can be selected from 1 second, 2 seconds, 4 seconds, and 8 seconds.

  Therefore, when the moving bar is in the middle of the screen, the speed range cannot be updated on the screen even if the calculation for a certain observation time is completed. That is, the speed range can be updated only when the moving bar is at the left end and the screen is updated. FIG. 15 shows the relationship between scroll speed and speed range update. In the row of scroll speed in this figure, the movement of the moving bar is schematically shown as a triangle. Assuming that the moving bar moves from left to right on the hypotenuse as time passes, the moving bar is at the left end on the screen, and the apex is at the right end on the screen.

  For example, when the scroll speed is set to 1 second and the update timing of the speed range is 4 seconds, the speed range is updated every time the screen is scrolled four times. Such automatic updating four times for one scroll of image display is called 4EOS (End Of Scroll). If it is 8 seconds, the speed range is updated every time the screen is scrolled 8 times, so 8 EOS is obtained. If the scroll speed is set to 2 seconds and the update timing of the speed range is 4 seconds, the speed range is updated with 2EOS.

  However, when the scroll speed is set to 6 seconds, even if the update timing of the speed range is set to 4 seconds, the screen is not updated because the scroll is in progress, and therefore the speed range cannot be updated. Therefore, the speed range is updated at the time of the nearest screen update, that is, 1 EOS is updated every 6 seconds. If performed every 12 seconds, 2EOS is obtained.

  If the speed range is updated in units of seconds as described above, it may not be possible to synchronize with the update of the screen. However, if EOS is used as a unit, such inconvenience does not occur. Therefore, the Doppler ultrasonic diagnostic apparatus includes an EOS setting table as shown in FIG. 16 in the parameter setting unit 36, and assigns speed range update timings according to this table.

  Further, if the scroll speed is set to 8 seconds, for example, even if it is desired to update the speed range in the middle of scrolling, it is necessary to wait for the screen to scroll. Therefore, a process called re-scrolling is performed by pressing a switch on the user interface 37. According to this re-scrolling process, the moving bar moves to the scroll start point (left end) and the image display itself is redone, so that the speed range and the baseline shift can be updated without waiting for the end of scrolling. Is possible.

(Auto BLS after freezing)
What has been described above is the switching of the operation mode in the real-time operation, but automatic BLS can be selected even after freezing. This is because the image data stored in the display audio / video buffer 45 is subjected to the above-described arithmetic processing by the autorange / BLS processing unit 49, and the result is re-measurement processing unit 33 b after the cine-freeze of the measurement unit 33. It implement | achieves by transmitting to the indicator 25 via.

  The baseline is shifted so that the maximum value of the Doppler waveform in the range from the time when the BLS update switch is pressed to a specific time in the past selected in advance falls within the speed range. Thereafter, every time the BLS update switch is pressed, the same baseline position is updated only once.

  In this case, the speed range is not optimized. The BLS only shifts the position of the image and does not change the image size, so it does not affect the image quality. However, changing the speed range of existing image data means that, as with digital zooming of a digital camera, a part of the image is cut out by digital processing, and it looks as if it has been enlarged. This is because the problem that the image becomes coarse occurs.

(Operation switch)
Hereinafter, main operation switches for issuing an instruction to start automatic adjustment of the speed range and BLS and setting various parameters will be described. These operation switches are assigned to buttons on the operation panel of the user interface 37, or displayed on a TCS or a pop-up menu as a GUI that is displayed on the display unit 25. Moreover, you may enable it to operate by several of these methods. An instruction issued by the operation switch or a set parameter is transmitted to each predetermined unit via the parameter setting unit 36.

1) Automatic speed range / BLS adjustment selection switch “Off” that does not perform automatic speed range / BLS adjustment, “Auto speed range” that performs only automatic speed range adjustment, and “Auto” that performs both automatic speed range / BLS adjustment This is a switch for selecting three modes of “speed range / BLS”.

2) Automatic speed range / BLS update timing selection switch “Manual” for manually updating the speed range, and for automatic update, 1 EOS for performing one update per image display, 2 EOS for performing one scroll per scroll, You can select from 3EOS and 4EOS.

3) Observation time setting switch This switch is used to select the number of seconds before the speed range update is turned on to observe the waveform for updating the speed range. You can select from 8 seconds.

4) Range coefficient selection switch This switch is used to select how many times the maximum speed is used as the upper limit of the display in the speed range adjustment. 1.1, 1.2, 1.3, 1.4 You can select from double or 1.5 times.

5) Speed range update switch This switch issues an instruction to update the speed range / BLS when “Manual” is selected with the speed range / BLS update timing selection switch.

6) BLS update switch This switch gives an instruction when shifting the baseline manually during real-time observation or when shifting the baseline after freezing.

7) Statistical value calculation processing selection switch A switch for selecting a model to be used in the speed range adjustment calculation, and can select either a normal distribution model or a smoothed threshold processing model. Also, the method of selecting the larger speed range from the upper and lower limits of Vp and Vm obtained by the normal distribution model, and the speed range of the upper and lower limits of Vp and Vm obtained by the smoothed threshold processing model. Method for selecting larger one, method for selecting larger velocity range among upper and lower limits of Vp or Vm obtained by both normal distribution model and smoothed threshold processing model, normal distribution model and threshold after smoothing It is also possible to have a function of selecting any one of methods for selecting the maximum speed range from the upper and lower limits of Vp and Vm obtained in both processing models.

8) Initial value selection switch The value set in the preceding color Doppler mode is adopted as the initial value of the automatic adjustment of the speed range and BLS in the spectrum Doppler mode, or the general part of the part can be specified by designating the diagnosis part. This switch is used to select whether to set the speed range to the initial value.

(Overall operation)
The overall flow of speed range and baseline shift automatic optimum adjustment will be described in several cases. First, a case where both automatic speed range updating and BLS updating are continuously performed during observation in real time will be described with reference to the flowchart shown in FIG. As a premise, it is necessary that the “automatic speed range / BLS adjustment” switch is selected in the automatic speed range / BLS adjustment selection switch. In addition, it is assumed that one of the auto-trace parameters, the trace line drawing polarity (positive (+ or forward), negative (-or reverse), or both (± or Both) is selected.

  First, when a switch other than “manual” in the automatic speed range / BLS update timing selection switch is selected during Doppler (PW or CW mode) inspection (step S102), a parameter setting unit is set in advance. The speed range set by 36 is sent to the auto range / auto BLS processing section 49 as an initial value (step S104). The switches other than “manual” are any of 1EOS, 2EOS, and 4EOS. As described above, the initial value is a value set in the preceding color Doppler mode or a general speed range of the part set by designating the diagnostic part.

  When the initial value is given, the auto range / auto BLS processing unit 49 performs auto speed range adjustment according to the algorithm shown in FIG. 3 (steps S106 to S110). Note that the processing in steps S106 to S110 corresponds to steps S2 to S8 in FIG. 3, and details thereof are omitted here.

  If it is determined that the speed range needs to be changed as a result of this calculation process (step S112: Yes), the speed range is increased or decreased by one step (step S114). Whether or not the value obtained by multiplying the maximum value of the Doppler waveform in the past specific time previously selected by the observation time setting switch by the range coefficient preset by the range coefficient selection switch is fully displayed on the display 25 -upper limit It is determined whether or not the lower limit has been reached (step S116). In this case, if the polarity of the trace line drawing is set to (positive), it is determined whether or not the maximum range coefficient multiple has been reached for only the upper side of the baseline, and it should be set to (negative). For the lower side only, (both), both the upper and lower sides are judged.

  Here, when it is determined that the speed range has not reached the upper limit / lower limit (step S116: No), the processes of steps S106 to S114 described above are repeated until the speed range is reached.

  On the other hand, when it is determined that the speed range has reached the upper limit / lower limit (step S116: Yes), and when it is determined that the speed range does not need to be changed (step S112: No), the BLS is subsequently adjusted. This is performed (steps S118 to S122). Strictly speaking, the transition to the BLS process is performed after it is confirmed that the upper limit / lower limit has been reached in two observation times in order to ensure the stability of the speed range.

  In the automatic adjustment of BLS, first, the maximum range (MaxVel) above the baseline and the minimum range below (maximum negative value: MinVel) are calculated (step S118). Then, the maximum range is compared with the minimum range, and the shift amount of the baseline is calculated (step S102). This calculation is performed, for example, by setting the average value of the maximum range and the minimum range at the center of the screen and determining the distance between the average value and the baseline BL = 0.

  Since the BLS is also performed in units of steps, the auto range / auto BLS processing unit 49 uses the BLS parameter setting table in the parameter setting unit 36, for example, the nearest parameter from the 17 stages of BLS parameters from minus Nyquist to plus Nyquist And the baseline is shifted by that value (step S122).

  The auto range / auto BLS processing unit 49 repeatedly performs the above-described processing until there is an instruction to end, specifically, until the “manual” switch is selected in the automatic speed range / BLS update timing selection switch. (Step S124: No).

FIG. 18 is a time chart illustrating an example of the above processing result in time series. The observation times t ₁ , t ₂ , t ₃ , t ₄ ... T _N , t _{N + 1} , t _{N + 2} , t _{N + 3} , t _{N + 4} are obtained after the instruction to start the automatic speed range adjustment is given, that is, the automatic speed range / BLS The transition of a preset time interval after a switch other than “manual” is selected by the update timing selection switch is shown.

The speed range is first set to an initial value, and then updated step by step as the observation time elapses. If the speed range reaches a certain value (at t _{N + 1} ) and is maintained at the next observation time (at t _{N + 2} ), that is, if there is no need to update the speed range, there For the first time, the baseline is shifted by one step. After that, even if the speed range is updated, if it is not continuous twice, the baseline is not shifted.

  If you do not update BLS during real-time observation but only update automatic speed range continuously, the automatic speed range / BLS adjustment selection switch is not “automatic speed range / BLS adjustment” but “automatic speed range”. Assuming that the “adjust” switch is selected, steps S118 to S122 of FIG. 17 are processed according to the skipped flow.

  Next, a case where both automatic speed range update and BLS update are performed only once at any time during observation in real time will be described with reference to the flowchart shown in FIG. As a premise, the automatic speed range / BLS adjustment selection switch must have the “automatic speed range / BLS adjustment” switch selected, and the automatic speed range / BLS update timing selection switch must have the “manual” switch selected. is there. In addition, about the process similar to the case where both automatic speed range update and BLS update are performed continuously, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  First, when the Doppler (PW or CW mode) inspection is being performed, if the speed range update switch is turned on (step S202), both automatic speed range update and BLS update are continuously performed. The calculation of the speed range automatic adjustment is performed (steps S104 to S110).

  If it is determined as a result of this calculation processing that the speed range needs to be changed (step S112: Yes), the speed range is increased or decreased by one step only once (step S114). Then, it is not determined whether or not the speed range has reached the upper limit / lower limit, and the speed range update process is terminated. In this case, as in the case where both automatic speed range update and BLS update are continuously performed, when the polarity of the trace line drawing is set to (positive), the range of the maximum value is set only on the upper side of the baseline. It is determined whether or not the coefficient has been reached. If it is set to (negative), only the lower side is determined.

  Further, when it is determined that the speed range does not need to be updated (step S112: No), the process proceeds to the next step without updating the speed range. However, since the user will select the speed range update switch only when he / she feels the necessity, it is normally updated.

  Thus, when the speed range is manually updated, the speed range is fixed until the next speed range update switch is selected, so that BLS can be performed. Therefore, when the BLS update switch is selected (step S204), the automatic update of BLS is processed in the same manner as when both automatic speed range update and BLS update are continuously performed (steps S118 to S122). The automatic update process ends. If the BLS update switch is not selected, the process ends in the same manner (step S204: No).

  When the user is not satisfied with the updated speed range or BLS, the user can approach the desired setting by repeatedly selecting the speed range update switch or BLS update switch. As a result, the burden on the user is reduced as compared to manually updating the speed range by operating the switch assigned to the operation panel in the conventional apparatus.

FIG. 20 is a time chart illustrating an example of the above processing result in time series. Observation times t ₁ , t ₂ , t ₃ ... T _K , t _{K + 1} , t _{K + 2} ... T _N , t _{N + 1} , t _{N + 2} indicate transitions of time intervals set in advance for updating the speed range.

  When the speed range update switch is turned on, the speed range is set to an initial value. Subsequently, when the speed range update switch is turned ON, the initial value is changed by one step. Therefore, the speed range can be brought close to a desired value by repeatedly turning on the speed range update switch.

  When “Manual” is selected by the automatic speed range / BLS update timing selection switch, the speed range is changed by one step when the speed range update switch is turned on, and is fixed to that value. Therefore, there is no need to wait for the speed range to stabilize for two or more observation times as in the case of continuous automatic speed range updates, and the BLS update switch can be turned on at any time, It is calculated and can be close to the optimum value.

  When updating the automatic speed range only once at any time without updating the BLS during real-time observation, the "Automatic speed range adjustment" switch is selected in the automatic speed range / BLS adjustment selection switch. As a premise, the series of processing in steps S204 to S122 in FIG.

  Next, the case of performing BLS update after freezing will be described with reference to the flowchart shown in FIG. In addition, about the process similar to the case where both automatic speed range update and BLS update are performed continuously, the same code | symbol is attached | subjected and description is abbreviate | omitted. In this case, the operation is performed manually regardless of what is selected by the automatic speed range / BLS update timing selection switch.

  First, when the Doppler (PW or CW mode) inspection is performed, the image is frozen (step S302), and when the BLS update switch is turned on (step S204), first, the parameter setting unit 36 sets in advance. The initial value regarding the BLS is sent to the auto range / auto BLS processing section 49 (step S104).

  Then, the automatic update of BLS is processed only once as in the case described above (steps S118 to S122). Since the speed range is not updated after freezing, the BLS update switch can be turned on at any time without waiting for the speed range to stabilize.

  The processing result in this case is similar to the BLS shown in FIG. 20 in time series. Thereby, even after freezing, the baseline can be shifted, and a Doppler spectrum image that is easier to observe can be obtained.

(Application example)
Two examples observed using the Doppler ultrasonic diagnostic apparatus according to the present invention configured and operated as described above will be described below.

  The first example shown in FIG. 22 is an observation of the carotid artery system. Specifically, 1) observing an ICA (Internal Carotid Artery) with a blood flow peak of 120 cm / s for 10 seconds, and 2) placing a blank for 0.5 seconds and a blood flow peak of 60 cm / s. CCA (Common Carotid Artery) was observed for 10 seconds, 3) a 1 second blank was placed, and an ICA with a blood flow peak of 120 cm / s was again observed for 10 seconds. 4) a 1.2 second blank was observed. Finally, CCA having a blood flow peak of 60 cm / s was observed for 30 seconds.

  As observation conditions, the baseline is fixed at -4, the trace line drawing polarity is set to (positive), the scroll speed is 2 columns per vertical sync signal, 4 seconds, the observation time is 1 EOS, range The coefficient is 1.3 times.

  FIG. 22A shows an example of a statistical value calculation process using a post-smoothing threshold processing model, and FIG. 22B displays changes over time in weighted Vp and Vm distributions. (C) is a figure which shows the time-dependent fluctuation | variation of the speed range obtained by these calculations, and a baseline.

  According to this example, although it generally has high followability, when the blood flow velocity changes intermittently, especially when a blank occurs, the histogram is disturbed immediately after the blank and the response is about 4 seconds. There is a lag.

  In the second example shown in FIG. 23, LV (Left Ventricle) is measured using a sector probe between the ribs. In this example, 1) the blood flow peak gradually increases from 40 cm / s to 60 cm / s in the first 10 seconds, 2) drops from 60 cm / s to 40 cm / s in the next 10 seconds, and 3) the next 10 In second, the speed increases again from 40 cm / s to 60 cm / s. 4) The subsequent 30 seconds are constant at 60 cm / s.

  As observation conditions, the scroll speed is 4 columns per vertical synchronization signal, 4 seconds, the observation time is 2EOS, and the range coefficient is 1.4 times.

  FIG. 23A shows an example of a statistical value calculation process using a post-smoothing threshold processing model, and FIG. 23B shows a time-dependent change in weighted Vp and Vm distributions. (C) is a figure which shows the time-dependent fluctuation | variation of the speed range obtained by these calculations, and a baseline.

  In FIG. 23 (c), PRF1 indicates the upper and lower speed ranges when auto BLS is not performed, and BL1 indicates the baseline in this case. PRF2 indicates the upper and lower speed ranges when auto BLS is performed, and BL2 indicates the baseline in this case.

  According to this example, although a response lag of about 4 seconds is generated in a part, it can be seen that the case where the waveform range continuously changes in this way has relatively good followability.

  The embodiments described above are for illustrative purposes and do not limit the scope of the invention. Accordingly, those skilled in the art can employ embodiments in which each or all of these elements are replaced by equivalents thereof, and these embodiments are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Apparatus main body 3 ECG module 11 Whole controller 21 Transmission / reception part 22 Envelope detector 23 Digital scan converter (DSC)
24 D / A converter 25 Display 26 Quadrature detector 27 RG processing unit 28 Spectrum Doppler processing block 29 PS / ED buffer 30 CFM mode processing block 31 DSP
32 PS / ED detection unit, 32a CPU, 32b peak detection processing unit 33 measurement unit, 33a real-time auto measurement processing unit, 33b re-measurement processing unit after cine freeze 34 video interface (I / F), 34a ping-pong buffer 35 Image storage unit 36 Parameter setting unit 37 User interface 38 Operation panel circuit 39 TCS circuit 40 GUI circuit 41 Wall filter 42 Cine memory buffer 43 FFT spectrum processing unit 44 Vp, Vm trace waveform detection processing unit 45 Audio / video buffer for display 46 Audio processing unit 47 Audio interface (I / F)
48 audio output device 49 auto range / auto BLS processing unit 50 PID control circuit 51 comparator 52 adjuster 53 converter 54 ECG waveform processing unit 55 M / M color processing unit P subject BF blood flow

Claims (7)

In a Doppler ultrasonic diagnostic apparatus that displays a spectrum image based on a spectrum signal of a Doppler frequency that bears information on the flow velocity of the diagnostic region obtained by transmitting and receiving ultrasonic waves toward a diagnostic region including a kinetic fluid in a subject.
Trace means for executing in real time a process of tracing at least one of the maximum flow velocity and the average flow velocity in the frequency direction of the spectrum signal in the time direction and outputting the trace waveform;
Speed range adjusting means for adjusting a Doppler speed range based on a statistical value for at least one distribution of the maximum flow velocity and the average flow velocity at a predetermined observation time;
Setting means for variably setting, as the parameter, a multiple of how many times the estimated value of the upper limit and lower limit of the speed range are set in the display range in order to change the parameter used in the processing of the speed range adjusting means; And a Doppler ultrasonic diagnostic apparatus. In a Doppler ultrasonic diagnostic apparatus that displays a spectrum image based on a spectrum signal of a Doppler frequency that bears information on the flow velocity of the diagnostic region obtained by transmitting and receiving ultrasonic waves toward a diagnostic region including a kinetic fluid in a subject.
Trace means for executing in real time a process of tracing at least one of the maximum flow velocity and the average flow velocity in the frequency direction of the spectrum signal in the time direction and outputting the trace waveform;
Speed range adjusting means for adjusting a Doppler speed range based on a statistical value for at least one distribution of the maximum flow velocity and the average flow velocity at a predetermined observation time;
Baseline adjustment means for calculating the positive side maximum value and the negative side maximum value of the maximum flow velocity, obtaining the shift amount of the baseline in the display of the spectrum image, and adjusting the baseline;
In order to change the parameters used in the processing of the speed range adjusting means and the baseline adjusting means, a multiple of how many times the estimated values of the upper and lower limits of the speed range are set in the display range can be variably set as the parameters. And a setting means for setting. A Doppler ultrasonic diagnostic apparatus comprising: The setting means includes a speed range employed in a color Doppler mode preceding the calculation as a default value for a calculation for adjusting a Doppler speed range executed by the speed range adjustment means, and a predetermined value set in advance for each diagnostic part. 3. The Doppler ultrasonic diagnostic apparatus according to claim 1, wherein any one of the values can be selected. 4. The setting means variably sets, as the parameter, the number of image scrolls to be updated once in synchronization with the scroll of the spectrum image, with the calculation result for each predetermined time by the speed range adjusting means. The Doppler ultrasonic diagnostic apparatus according to any one of claims 1 and 2. 5. The Doppler ultrasound according to claim 4, wherein the setting unit updates the update of the calculation result by the speed range adjusting unit together with the scroll of the spectrum image at an arbitrary time during the scroll of the spectrum image. Diagnostic device. Trace waveform storage means for storing at least one trace waveform of the maximum flow velocity and the average flow velocity is further provided, and after freezing, based on the trace waveform stored in the trace waveform storage means, the baseline adjustment means 3. The Doppler ultrasonic wave according to claim 2, wherein a positive maximum value and a negative maximum value of a maximum flow velocity are calculated, a baseline shift amount in the display of the spectrum image is obtained, and the baseline is adjusted. Diagnostic device. The speed range adjusting unit compares a control target value of a predetermined speed range with a transfer function value fed back from the speed range adjusting unit, and sets parameters of the control system elements P, I, and D according to the difference. 3. The Doppler ultrasonic diagnostic apparatus according to claim 1, wherein the Doppler ultrasonic diagnosis apparatus is variably determined.