JP2022141144A - Ultrasonic diagnostic device, control method of ultrasonic diagnostic device, and control program of ultrasonic diagnostic device - Google Patents

Abstract

To provide an ultrasonic diagnostic device capable of forming an accurate trace line.SOLUTION: In an ultrasonic diagnostic device, a first signal strength maximum point Q1a where signal strength becomes maximum is searched for when determining a trace point indicating a maximum velocity from a Doppler spectrum; a first trace candidate point Q1b is set on a higher speed area side than the first signal strength maximum point Q1a in a first peak mountain M1 including the first signal strength maximum point Q1a of the Doppler spectrum; a second signal strength maximum point Q2a where signal strength becomes maximum next to the first signal strength maximum point Q1a is searched for on a higher speed area side than the first trace candidate point Q1b in the Doppler spectrum; a second trace candidate point Q2b on a higher speed area side than the second signal strength maximum point Q2a is set in a second peak mountain M2 including the second signal strength maximum point Q2a of the Doppler spectrum; and either the first trace candidate point Q1b or the second trace candidate point Q2b is determined as a trace point using a predetermined criterion.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to an ultrasonic diagnostic apparatus, an ultrasonic diagnostic apparatus control method, and an ultrasonic diagnostic apparatus control program.

2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus equipped with an auto-trace function that measures the blood flow velocity and the like of a subject using the Doppler principle and automatically draws a trace line on the obtained Doppler waveform is known. It is In this type of ultrasonic diagnostic apparatus, for example, a PW (pulse wave) mode and a CW (continuous wave) mode are used as the Doppler mode. In the former PW mode, ultrasonic pulses are transmitted into the body, and Doppler information extracted from a sample gate set at a specific depth is frequency-analyzed, resulting in a Doppler spectrum (blood velocity A Doppler waveform is formed from the signal intensity of each In the latter CW mode, continuous wave ultrasonic waves are transmitted and reflected waves from the ultrasonic beam axis are received. Doppler information is extracted from the received signal thus obtained, and a Doppler waveform is formed in the same manner as described above.

FIG. 1A is a diagram showing an example of a Doppler waveform. FIG. 1B is a diagram showing an example of a Doppler spectrum obtained at a certain timing (timing indicated by an arrow in FIG. 1A).

The Doppler spectrum is a frequency characteristic that indicates the velocity component of the movement of the observation object that changes from moment to moment. For example, as shown in FIG. ) is the spectrum information. Further, the Doppler waveform is information on the temporal change in the speed of movement of the observation target (that is, the Doppler shift frequency) generated based on the time-series Doppler spectrum. is the horizontal axis, the velocity (that is, Doppler shift frequency) is the vertical axis, and the signal intensity (also referred to as power) of each velocity (that is, frequency component) is expressed as luminance (gradation).

The auto-trace function determines the maximum velocity of the movement of the observed object as a trace point in each time-series Doppler spectrum, and forms a trace line for the Doppler waveform based on the trace point.

In the actual diagnosis scene, various diagnoses are made using such trace lines. , VTI (Velocity-Time Integral) is used to evaluate left ventricular contractility. As an example of blood flow evaluation by PSV, there is a carotid artery stenosis evaluation by detecting the maximum velocity point in one heartbeat on a trace line as PSV. In addition, as an example of cardiac left ventricular contractility evaluation by VTI, a PW Doppler velocity waveform is acquired in the left ventricular outflow tract of the heart, VTI (that is, area) is calculated from the trace line, and VTI and blood flow blockage are calculated. There is an evaluation that calculates the cardiac output from the area and the like.

From such a background, in this type of ultrasonic diagnostic apparatus, it is required to form a trace line with high accuracy. , and when the data value exceeds a preset threshold a predetermined number of times in a predetermined frequency width, the position at which the data value first exceeds the threshold is set as the highest frequency. .

JP-A-8-229039

By the way, in the ultrasonic diagnostic apparatus according to the prior art, a peak point (representing the position where the signal intensity takes the maximum value; the same applies hereinafter) is extracted from the Doppler spectrum, and at the peak mountain including the peak point, the peak A point having a signal strength lower than that of the point by a predetermined amount is determined as a trace point representing the maximum speed of movement of the observed object.

However, in general, noise components (thermal noise, clutter signals, etc.) are superimposed on the Doppler spectrum in addition to signal components that depend on the movement of the observed object (for example, blood flow). In the extraction algorithm for the maximum velocity of such an ultrasonic diagnostic apparatus, noise components may be extracted from the Doppler spectrum as the maximum velocity of the movement of the observation target. For example, in FIG. 1B, two peaks appear in the Doppler spectrum, but here, the position of v2 included in the second peak is originally determined as the maximum velocity of the movement of the observation target. This represents a situation in which the position of v1 in the first peak derived from the noise component has been determined as the maximum velocity (that is, the trace point) of the movement of the observation target. In this way, if the trace point is determined at an erroneous position, for example, as shown in FIG. It will present an erroneous diagnosis result.

The present disclosure has been made in view of the above problems, and when executing the Doppler mode, accurately extracts the maximum velocity of the movement of the observation target from the Doppler spectrum, and forms a highly accurate trace line for the Doppler waveform. An object of the present invention is to provide an ultrasonic diagnostic apparatus, a control method for the ultrasonic diagnostic apparatus, and a control program for the ultrasonic diagnostic apparatus, which make it possible.

The main disclosure that solves the above-mentioned problems is
a transmitting/receiving unit that transmits/receives ultrasonic waves using an ultrasonic probe and obtains a received signal related to ultrasonic echoes from an object to be observed in the subject;
a Doppler signal processing unit that frequency-analyzes Doppler information included in the received signal and generates a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a Doppler waveform generation unit that generates a Doppler waveform based on the time-series Doppler spectrum that is sequentially output from the Doppler signal processing unit;
In each of the time-series Doppler spectra sequentially output from the Doppler signal processing unit, a trace point representing the maximum velocity of the movement of the observation object is determined, and a trace line is drawn for the Doppler waveform based on the trace point. a trace processing portion forming;
with
The trace processing unit
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side from the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
It is an ultrasound diagnostic device.

Also, in other aspects,
A control method for an ultrasonic diagnostic apparatus,
A first process of transmitting and receiving ultrasonic waves using an ultrasonic probe to obtain a received signal related to ultrasonic echoes from an observation target within the subject;
a second process of frequency-analyzing the Doppler information contained in the received signal to generate a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a third process for generating a Doppler waveform based on the time-series Doppler spectrum sequentially output in the second process;
In each of the time-series Doppler spectra sequentially output in the second processing, a trace point representing the maximum velocity of the movement of the observation target is determined, and a trace line is formed for the Doppler waveform based on the trace point. a fourth process to
with
In the fourth process,
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side from the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
control method.

Also, in other aspects,
A control program for an ultrasonic diagnostic apparatus,
A first process of transmitting and receiving ultrasonic waves using an ultrasonic probe to obtain a received signal related to ultrasonic echoes from an observation target within the subject;
a second process of frequency-analyzing the Doppler information contained in the received signal to generate a Doppler spectrum representing signal strength for each speed of movement of the observed object;
a third process for generating a Doppler waveform based on the time-series Doppler spectrum sequentially output in the second process;
In each of the time-series Doppler spectra sequentially output in the second processing, a trace point representing the maximum velocity of the movement of the observation target is determined, and a trace line is formed for the Doppler waveform based on the trace point. a fourth process to
with
In the fourth process,
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side of the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
control program.

According to the ultrasonic diagnostic apparatus according to the present disclosure, when executing the Doppler mode, it is possible to accurately extract the maximum velocity of the movement of the observation target from the Doppler spectrum and form a highly accurate trace line for the Doppler waveform. is.

A diagram showing an example of a Doppler waveform A diagram showing an example of a Doppler spectrum obtained at a certain timing (the timing of the arrow in FIG. 1A) 1 is a diagram showing an example of an appearance of an ultrasonic diagnostic apparatus according to an embodiment of the present invention; FIG. 1 is a diagram showing an example of the overall configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention; FIG. FIG. 1 is a diagram showing an example of the configuration of a Doppler signal processing section of an ultrasonic diagnostic apparatus according to an embodiment of the present invention; FIG. 4 is a flowchart showing a specific example of the operation of the trace processing section of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 4 is a diagram showing a method of extracting trace candidate points by the trace processing unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 4 is a diagram illustrating processing for determining final trace points from trace candidate points in the trace processing unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 4 is a diagram illustrating processing for determining final trace points from trace candidate points in the trace processing unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 4 is a diagram illustrating processing for determining final trace points from trace candidate points in the trace processing unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 4 is a diagram illustrating processing for determining final trace points from trace candidate points in the trace processing unit of the ultrasonic diagnostic apparatus according to the embodiment of the present invention; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in the trace processing unit according to Modification 1; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in the trace processing unit according to Modification 1; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in the trace processing unit according to Modification 1; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in the trace processing unit according to Modification 1; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in a trace processing unit according to Modification 2; FIG. 11 is a diagram for explaining processing for determining final trace points from trace candidate points in a trace processing unit according to Modification 2; FIG. 12 is a flowchart showing a specific example of the operation of the trace processing unit according to Modification 3;

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functions are denoted by the same reference numerals, thereby omitting redundant description.

[Configuration of ultrasonic diagnostic apparatus]
The configuration of an ultrasonic diagnostic apparatus (hereinafter referred to as "ultrasonic diagnostic apparatus A") according to an embodiment of the present invention will be described below with reference to FIGS. 2 to 4. FIG.

FIG. 2 is a diagram showing an example of the appearance of the ultrasonic diagnostic apparatus A. As shown in FIG. FIG. 3 is a diagram showing an example of the overall configuration of the ultrasonic diagnostic apparatus A. As shown in FIG.

The ultrasonic diagnostic apparatus A is used for visualizing the shape, properties, or dynamics inside a subject as an ultrasonic image for image diagnosis. In this embodiment, as an example of an object to be observed by the ultrasonic diagnostic apparatus A, blood flow flowing through a blood vessel of a subject is taken up. However, the object to be observed by the ultrasonic diagnostic apparatus A may be tissue other than the blood flow of the subject.

The ultrasonic diagnostic apparatus A includes an ultrasonic diagnostic apparatus main body 100 and an ultrasonic probe 200, as shown in FIG.

The ultrasonic probe 200 transmits an ultrasonic beam (here, about 1 to 30 MHz) into the subject (for example, a human body), and, of the transmitted ultrasonic beam, the ultrasonic wave reflected inside the subject. It works as an acoustic sensor that receives echoes and converts them into electrical signals.

The user operates the ultrasonic diagnostic apparatus A by bringing the ultrasonic beam transmitting/receiving surface of the ultrasonic probe 200 into contact with the subject to perform ultrasonic diagnosis. Any probe such as a convex probe, a linear probe, a sector probe, or a three-dimensional probe can be applied to the ultrasonic probe 200 .

The ultrasonic probe 200 includes, for example, a plurality of transducers (for example, piezoelectric elements) arranged in a matrix, and the driving states of the plurality of transducers can be turned on and off individually or in units of blocks (hereinafter referred to as “channels”). ), and includes a channel switching unit (for example, a multiplexer) for switching control. Each transducer of the ultrasonic probe 200 converts a voltage pulse generated by the ultrasonic diagnostic apparatus main body 100 (transmitting unit 1a) into an ultrasonic beam, transmits the ultrasonic beam into the subject, and transmits the ultrasonic wave reflected in the subject. An echo is received, converted into an electric signal (hereinafter referred to as a "received signal"), and output to the ultrasonic diagnostic apparatus main body 100 (receiving unit 1b).

The ultrasonic diagnostic apparatus main body 100 includes a transmission/reception unit 1 (transmission unit 1a, reception unit 1b), a tomographic image generation unit 2, a Doppler signal processing unit 3, a display processing unit 4, a monitor 5, an operation input unit 6, and a control device. 10.

The transmitter 1 a of the transmitter/receiver 1 is a transmitter that transmits a voltage pulse as a drive signal to the ultrasonic probe 200 . The transmission unit 1a includes, for example, a high-frequency pulse oscillator, a pulse setting unit, etc. (none of which are shown). The transmission unit 1a adjusts the voltage pulse generated by the high-frequency pulse oscillator to the voltage amplitude, pulse width, and transmission timing set by the pulse setting unit, and transmits the voltage pulse for each channel of the ultrasonic probe 200. FIG.

The transmission unit 1a has a pulse setting unit for each of the plurality of channels of the ultrasonic probe 200, and is capable of setting the voltage amplitude, pulse width and transmission timing of the voltage pulse for each of the plurality of channels. For example, the transmitter 1a changes the target depth by setting appropriate delay times for a plurality of channels, or generates different pulse waveforms (for example, one pulse in B mode, PW Doppler In mode, 4 waves of pulses are sent out).

The receiving unit 1 b of the transmitting/receiving unit 1 is a receiver that receives and processes received signals related to ultrasonic echoes generated by the ultrasonic probe 200 . The receiver 1b includes a preamplifier, an AD converter, a reception beamformer, and a processing system switcher (all not shown).

The receiving unit 1b amplifies a reception signal associated with a weak ultrasonic echo for each channel with a preamplifier, and converts the reception signal into a digital signal with an AD conversion unit. Then, the reception unit 1b performs phasing addition of the reception signals of the respective channels in the reception beamformer, thereby combining the reception signals of the plurality of channels into one and making it acoustic line data. In addition, the receiving unit 1b controls switching of the transmission destination of the received signal generated by the receiving beamformer in the processing system switching unit, and depending on the operation mode to be executed, the tomographic image generating unit 2 or the Doppler signal processing Output to one side to the part 3.

The tomographic image generating unit 2 acquires a received signal from the receiving unit 1b during B-mode operation and generates a tomographic image (also referred to as a B-mode image) inside the subject.

For example, when the ultrasonic probe 200 transmits a pulsed ultrasonic beam in the depth direction, the tomographic image generating unit 2 temporally continuously detects the signal intensity (Intensity) of the ultrasonic echo detected thereafter. and store it in the line memory. Then, as the ultrasonic beam from the ultrasonic probe 200 scans the inside of the subject, the tomographic image generation unit 2 sequentially accumulates the signal strength of the ultrasonic echo at each scanning position in the line memory, Generate two-dimensional data that is Then, the tomographic image generating unit 2 generates a tomographic image by converting the signal intensity of the ultrasonic echo detected at each position inside the subject into a luminance value.

The tomographic image generator 2 includes, for example, an envelope detection circuit, a dynamic filter, and a logarithmic compression circuit. The envelope detection circuit performs envelope detection on the received signal to detect signal strength. The logarithmic compression circuit logarithmically compresses the signal strength of the received signal detected by the envelope detection circuit. A dynamic filter is a band-pass filter whose frequency characteristics are changed according to depth, and removes noise components contained in received signals.

The Doppler signal processing unit 3 acquires received signals from the receiving unit 1b in the PW Doppler mode, CW Doppler mode, and tissue Doppler mode, and detects the Doppler shift frequency with respect to the transmission frequency of the ultrasonic echo from blood flow. . Then, the Doppler signal processing unit 3 sequentially outputs to the display processing unit 4 information related to the Doppler spectrum representing the signal intensity for each Doppler shift frequency (that is, for each velocity of blood flow). It should be noted that the blood flow velocity and the Doppler shift frequency are directly proportional to each other as shown in the following equation (1).
V=c/2 cos θ×Fd/F0 (1)
(However, V: blood flow velocity, F0: transmission frequency (or reception frequency) of ultrasonic beam, Fd: Doppler shift frequency, c: velocity of sound in vivo, θ: beam direction of ultrasonic beam and blood flow direction crossing angle)

For example, in the PW Doppler mode operation, the Doppler signal processing unit 3 synchronizes with the pulse repetition frequency when the ultrasonic probe 200 transmits a pulsed ultrasonic beam at regular intervals according to the pulse repetition frequency. to sample the received signal associated with the ultrasonic echo. Then, the Doppler signal processing unit 3, for example, based on the phase difference between the ultrasonic echo related to the n-th ultrasonic beam and the ultrasonic echo related to the (n+1)-th ultrasonic beam from the same sample gate position, the Doppler shift Detect frequency.

FIG. 4 is a diagram showing an example of the configuration of the Doppler signal processing unit 3 that performs PW Doppler. The Doppler signal processing unit 3 that performs PW Doppler includes, for example, a bandpass filter 3a, a quadrature detection unit 3b, a lowpass filter 3c, a range gate 3d, an integration circuit 3e, a wall motion filter 3f, and an FFT analysis unit 3g. be done. The bandpass filter 3a removes unnecessary frequency components. The quadrature detection unit 3b mixes the received signal with a reference signal in phase with the transmitted ultrasonic pulse and a reference signal with a phase different from the transmitted ultrasonic pulse by π/2 to generate a quadrature detection signal. The low-pass filter 3c removes the high frequency component of the quadrature detection signal to generate a reception signal related to the Doppler shift frequency. Range gate 3d acquires only ultrasonic echoes from the sample gate depth. The integration circuit 3e integrates the received signal acquired by the range gate 3d. The wall motion filter 3f removes low frequencies to remove clutter components (ultrasonic echoes from tissues). The FFT analysis unit 3g frequency-analyzes the Doppler shift frequency component of the received signal thus obtained.

The ultrasonic diagnostic apparatus A can selectively execute PW Doppler mode, CW Doppler mode, and tissue Doppler mode when acquiring Doppler information (that is, Doppler shift frequency) representing the movement of the observation target. may be Further, when executing the Doppler scan mode, the ultrasonic diagnostic apparatus A continuously performs only the Doppler mode and a Simultaneous mode in which the Doppler mode and the B mode and/or the color flow mode are simultaneously executed in a time division manner. It may be possible to select an Update mode to be executed immediately.

The display processing unit 4 acquires the tomographic image output from the tomographic image generating unit 2 and the Doppler spectrum output from the Doppler signal processing unit 3 and generates a display image to be displayed on the monitor 5 .

The display processing unit 4 has a Doppler waveform generation unit 4a and a graphics processing unit 4b.

The Doppler waveform generator 4a generates a Doppler waveform based on the time-series Doppler spectra sequentially output from the Doppler signal processor 3, for example. The Doppler waveform, as shown in FIG. 1A, is information on the temporal change in the velocity of the movement of the observed object (that is, the Doppler shift frequency) generated based on the time-series Doppler spectrum. is expressed in the form of a single line, and the signal intensity for each blood flow velocity (that is, for each Doppler shift frequency) is expressed by the brightness of the pixel.

The graphic processing unit 4b performs various types of image processing on the tomographic image output from the tomographic image generating unit 2 and the Doppler waveform image generated by the Doppler waveform generating unit 4a. Then, the graphic processing unit 4b uses these tomographic images and Doppler waveform images to generate display images.

Further, when the control device 10 (here, the trace processing unit 12) designates the information of the trace line to be formed for the Doppler waveform, the graphics processing unit 4b creates a trace line for the image of the Doppler waveform. A superimposed image (see FIG. 1A) is generated.

The tomographic image generation unit 2, Doppler signal processing unit 3, and display processing unit 4 are implemented by a digital arithmetic circuit configured by, for example, a DSP (Digital Signal Processor). However, these configurations can be modified in various ways. For example, part or all of them may be realized by hardware circuits, or may be realized by arithmetic processing according to a program.

The monitor 5 is a display for displaying the display image generated by the display processing unit 4, and is configured by, for example, a liquid crystal display.

The operation input unit 6 is a user interface for a user to perform an input operation, and includes, for example, push button switches, a keyboard, a mouse, and the like. The operation input unit 6 converts an input operation performed by a user into an operation signal and inputs the operation signal to the control device 10 .

The control device 10 exchanges signals with the ultrasonic probe 200, the transmitting/receiving unit 1, the tomographic image generating unit 2, the Doppler signal processing unit 3, the display processing unit 4, the monitor 5, and the operation input unit 6, and controls them. General control. The control device 10 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Each function of the control device 10 is implemented by the CPU referring to control programs and various data stored in the ROM and RAM. However, some or all of the functions of the control device 10 are not limited to processing by software, and can of course be realized by a dedicated hardware circuit or a combination thereof.

The control device 10 includes a transmission/reception control section 11 and a trace processing section 12 .

The transmission/reception control unit 11 controls the type of the ultrasonic probe 200 set by the user via the operation input unit 6 (for example, the compex type, the sector type, or the linear type), the depth of the object to be imaged within the subject, Then, the ultrasonic beam transmission/reception conditions are determined based on the imaging mode (for example, B mode, PW Doppler mode, color Doppler mode, or power Doppler mode). Then, the transmission/reception control unit 11 controls each of the transmission unit 1a and the reception unit 1b so as to satisfy the transmission/reception conditions thus determined, and causes the ultrasonic probe 200 to transmit and receive ultrasonic waves.

The trace processing unit 12 determines a trace point representing the maximum speed of the movement of the observation target in each time-series Doppler spectrum sequentially output from the Doppler signal processing unit 3, and based on the trace point, the Doppler waveform is: A trace line is formed (details will be described later). Incidentally, the trace line is formed, for example, by connecting the trace points of the Doppler spectrum output from the Doppler signal processing unit 3 at each time, as shown in FIG. 1A.

Note that the control device 10 may have a measurement section that performs measurement using the trace lines formed by the trace processing section 12 . Such a measurement unit detects, for example, the maximum velocity point in one heartbeat on the trace line as PSV and presents it to the user, or detects the heartbeat from the VTI (that is, the area) in one heartbeat on the trace line, as described above. The output amount may be calculated and presented to the user.

[Detailed configuration of trace processing part]
An example of the detailed configuration of the trace processing unit 12 will be described below with reference to FIGS. 5 to 8B.

FIG. 5 is a flowchart showing a specific example of the operation of the trace processing section 12. As shown in FIG.

FIG. 6 is a diagram showing a method of extracting trace candidate points (representing candidate points for finally determining trace points; the same shall apply hereinafter) by the trace processing unit 12 . FIG. 6 shows a Doppler spectrum acquired at a certain timing, and in FIG. showing.

7A, 7B, 8A, and 8B are diagrams for explaining the process by which the trace processing unit 12 selects final trace points from the trace candidate points Q1b and Q2b extracted by the extraction method of FIG. . FIG. 7A shows a case where the trace candidate point Q1b is selected as the trace point, and FIG. 7B shows a case where the trace candidate point Q2b is selected as the trace point.

The Doppler waveform in FIG. 8A is a Doppler waveform formed from the Doppler spectrum in FIG. 7A and the Doppler spectra obtained before and after the Doppler spectrum. Also, the Doppler waveform of FIG. 8B is a Doppler waveform formed from the Doppler spectrum of FIG. 7B and Doppler spectra obtained before and after the Doppler spectrum.

In general, the Doppler spectrum includes a Doppler signal component based on the motion of an object to be observed (blood flow in this case) and a noise component superimposed thereon. Most of this kind of noise component is thermal noise caused by the electric circuit in the ultrasonic diagnostic apparatus A, and ultrasonic waves from tissues other than the blood flow in the subject (for example, blood vessel walls and organs around the blood vessel). A clutter signal caused by an echo. Thermal noise is generally weak white noise, and by appropriately setting a threshold for signal intensity, it is possible to distinguish between noise components caused by thermal noise and Doppler signal components based on blood flow movement. It is possible. On the other hand, the clutter signal may appear as peaks larger than the Doppler signal, which depends on the motion of blood flow, but its velocity is usually slower than that of blood flow. Therefore, by focusing on the velocity of the Doppler signal, it is possible to distinguish between the clutter signal and the Doppler signal that depends on the movement of blood flow.

Focusing on this point, the inventors of the present application have come up with an algorithm for extracting a Doppler signal that depends on the motion of blood flow from the Doppler spectrum and specifying its maximum velocity. In the prior art according to Patent Document 1, the Doppler spectrum is searched in order from the flow direction side end toward the frequency of 0 Hz to determine the highest frequency (that is, the maximum speed of the movement of the observation target). Therefore, even in a situation where two peaks exist in the Doppler spectrum, as in FIGS. 1A and 1B, the trace point (the position of v2 in FIG. 1B) is determined in the peak existing on the higher speed side. It is possible to However, in the conventional technique according to Patent Document 1, there is a possibility that trace points may be determined in peaks existing on the high-speed side even when the peaks existing on the high-speed side are caused by noise components. In other words, in order to accurately extract the Doppler signal that depends on the motion of blood flow, it is necessary to accurately perform separation processing for dealing with thermal noise and separation processing for dealing with clutter signals. There is

Therefore, the trace processing unit 12 according to the present embodiment first extracts two trace candidate points (hereinafter referred to as "first trace candidate point" and "second trace candidate point") from the Doppler spectrum. (see FIG. 6), and by excluding one of these two trace candidate points presumed to have been generated due to noise, the other trace candidate point becomes the final Determine as a trace point (see FIGS. 7A-8B).

Returning to FIG. 5, the operation of the trace processing unit 12 will be described.

In step S1, the trace processing unit 12 searches for the first signal intensity maximum point at which the signal intensity is maximum in the Doppler spectrum. In the Doppler spectrum of FIG. 6, the point Q1a is determined as the first point of maximum signal intensity.

In step S2, the trace processing unit 12 performs the first peak M1 on the high-speed side of the first signal intensity maximum point Q1a in the first peak M1 including the first signal intensity maximum point Q1a of the Doppler spectrum. Set trace candidate points. For example, the trace processing unit 12 sets the point Q1b as the first trace candidate point in the Doppler spectrum of FIG.

A procedure for setting the trace candidate point (common to the first trace candidate point Q1b and the second trace candidate point Q2b) by the trace processing unit 12 is as follows. That is, the trace points should be set as close as possible to the maximum velocity of the actual observed object motion. This is also important for ensuring that the trace line formed from the trace points covers substantially the entire Doppler waveform when performing area calculations and the like later.

From this point of view, the trace processing unit 12 sets the first trace candidate point on the high-speed region side of the first maximum signal strength point Q1a in the first peak M1. Specifically, in FIG. 6, the trace processing unit 12 is on the high-speed side of the first maximum signal strength point Q1a in the first peak M1, and the signal strength at that point is the first set point. The first trace candidate point Q1b is set at the point having the value TP1.

The first set value TP1 may be a predetermined value, or a value determined based on the signal intensity at the first maximum signal intensity point Q1a (for example, A value obtained by subtracting a predetermined offset from the signal strength). Also, the first set value TP1 may be a value determined from the analysis result of the noise level.

In step S3, the trace processing unit 12 obtains a second signal strength that is the highest next to the first maximum signal strength point Q1a on the high-speed side of the first trace candidate point Q1b in the Doppler spectrum. Search for the maximum point. In the Doppler spectrum of FIG. 6, the point Q2a is determined as the second maximum signal intensity point.

In this step S3, when searching for the second maximum signal intensity point, the search range is not the high-speed side of the first maximum signal intensity point Q1a in the Doppler spectrum, but the first point in the Doppler spectrum. 1 is set on the high speed side of the trace candidate point Q1b. This is because when the search range is set on the high-speed side of the first signal intensity maximum point Q1a in the Doppler spectrum, the second signal intensity is This is because there is a possibility that the maximum point may be determined.

In step S4, the trace processing unit 12 performs the second peak on the high-speed side of the second maximum signal intensity point Q2a in the second peak M2 including the second maximum signal intensity point Q2a of the Doppler spectrum. Set trace candidate points. For example, the trace processing unit 12 sets the point Q2b as the second trace candidate point in the Doppler spectrum of FIG.

The reference when the trace processing unit 12 sets the second trace candidate point Q2b in the second peak M2 is the reference when setting the first trace candidate point Q1b in the first peak M1. is the same as the criteria for For example, in the second peak M2, the trace processing unit 12 selects a point on the high-speed region side of the second maximum signal strength point Q2b, where the signal strength at that point is the second set value TP2, as follows: It is set as the second trace candidate point Q2b.

The second set value TP2 may be a predetermined value, or a value determined based on the signal strength at the second maximum signal strength point Q2b (for example, a value at the second maximum signal strength point Q2b). A value obtained by subtracting a predetermined offset from the signal strength). Also, the second set value TP2 may be the same value as the first set value TP2.

In step S5, the trace processing unit 12 uses a predetermined criterion to exclude one of the first trace candidate point Q1b and the second trace candidate point Q2b that is presumed to have occurred due to noise. By doing so, the other is determined as a trace point.

Here, referring to FIGS. 7A, 7B, 8A, and 8B, the trace processing unit 12 determines a trace point from among the first trace candidate point Q1b and the second trace candidate point Q2b. The criteria for tracing (hereinafter also referred to as “trace point determination criteria”) will be described.

The trace point determination criterion is a criterion set by focusing on the general behavior of noise. In the Doppler spectrum, as described above, white noise such as thermal noise and clutter signals from tissues other than blood flow to be observed tend to appear as large noise components. Here, white noise such as thermal noise appears as a weak signal in each speed range from low speed to high speed in the Doppler spectrum. In addition, clutter signals from tissues other than the blood flow to be observed appear as signals with strong signal intensity in the Doppler spectrum in a lower velocity region than the blood flow. Whether or not a clutter signal is generated depends on the position of the object to be observed, but since white noise such as thermal noise always exists, peaks due to white noise always appear in the Doppler spectrum. .

That is, the two peaks M1 and M2 extracted from the Doppler spectrum in the processing of steps S2 to S4 in the flowchart of FIG. It is considered to correspond to either a peak mountain or a peak mountain based on white noise. Therefore, in a situation where a clutter signal appears, in the process of step S2, the peak based on the clutter signal is extracted as the first peak M1, and in the process of step S4, the peak is extracted based on the blood flow of the observation target. The peak is extracted as the second peak M2 (hereinafter referred to as "first case"). On the other hand, under the condition that no clutter signal appears, the peak depending on the blood flow of the observation target is extracted as the first peak M1 in the process of step S2, and the white noise is used in the process of step S4. The peak is extracted as the second peak M2 (hereinafter referred to as "second case").

From this point of view, the trace point determination criterion determines whether the currently captured Doppler spectrum is in the first case or the second case depending on whether the signal intensity of the second signal intensity maximum point Q2a is less than the threshold. It is determined whether or not it is applicable, and based on this, the final trace point is determined from among the first trace candidate point Q2b and the second trace candidate point Q2b.

Specifically, in the case where the signal intensity of the second maximum signal intensity point Q2a is less than the threshold TH2 (FIGS. 7A and 8A), the trace processing unit 12 converts the first trace candidate point Q1b into the final trace point. When the signal intensity of the second maximum signal intensity point Q2a is equal to or greater than the threshold TH2 (FIGS. 7B and 8B), the second trace candidate point Q2b is determined as the final trace point. This is because when the signal intensity at the second signal intensity maximum point Q2a is less than the threshold TH2, the second peak M2 can be regarded as a peak based on white noise, and the Doppler spectrum captured at this time is "the second This is because it can be presumed that it corresponds to "case". Similarly, when the signal intensity of the second signal intensity maximum point Q2a is equal to or greater than the threshold TH2, the first peak M1 can be regarded as a peak based on the clutter signal, and the Doppler spectrum captured at the present time is "the first This is because it can be presumed that it corresponds to "Case 1".

Note that the threshold TH2 is typically set to a value greater than the second set value TP2. The threshold TH2 is preferably set to an appropriate value in advance by experiments or simulations in order to discriminate peaks appearing due to the blood flow of the observation target and peaks appearing due to white noise from the signal intensity.

Note that the trace processing unit 12 according to the present embodiment is configured to perform processing on the assumption that two peaks appear in the Doppler spectrum. This is because, in general, the Doppler spectrum always includes peaks due to white noise such as thermal noise, in addition to peaks due to blood flow velocity. However, before the process of step S1 in the flowchart of FIG. 5, the trace processing unit 12 performs a known pattern recognition process or the like to determine whether or not two peaks of a signal intensity above a certain level appear in the Doppler spectrum. Only when two peaks with a signal intensity above a certain level appear in the Doppler spectrum, the processing of steps S1 to S5 may be performed.

[effect]
As described above, the ultrasonic diagnostic apparatus A according to this embodiment is
a transmitting/receiving unit 1 for transmitting/receiving ultrasonic waves using an ultrasonic probe to obtain a received signal related to ultrasonic echoes from an object to be observed in the subject;
a Doppler signal processing unit 3 that frequency-analyzes Doppler information contained in the received signal and generates a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a Doppler waveform generation unit 4a for generating a Doppler waveform based on the time-series Doppler spectrum sequentially output from the Doppler signal processing unit 3;
In each of the time-series Doppler spectra sequentially output from the Doppler signal processing unit 3, a trace point representing the maximum speed of the movement of the observation target is determined, and a trace line for the Doppler waveform is determined based on the trace point. a trace processing unit 12 forming
with
The trace processing unit 12
searching for a first signal intensity maximum point Q1a where the signal intensity is maximum from the Doppler spectrum;
A first trace candidate point Q1b is set on the high-speed side of the first maximum signal intensity point Q1a in the first peak M1 including the first maximum signal intensity point Q1a of the Doppler spectrum. ,
searching for a second maximum signal strength point Q2a at which the signal strength is maximized next to the first maximum signal strength point Q1a on the high-speed side of the first trace candidate point Q1b in the Doppler spectrum; ,
A second trace candidate point Q2b is set on the high-speed side of the second maximum signal intensity point Q2a in the second peak M2 including the second maximum signal intensity point Q2a of the Doppler spectrum. ,
Using a predetermined criterion, either one of the first trace candidate point Q1b and the second trace candidate point Q2b is determined as the trace point.

Therefore, according to the ultrasonic diagnostic apparatus A according to the present embodiment, in the Doppler spectrum, in addition to peaks depending on the movement of the observation target (for example, blood flow), peaks caused by clutter signals and thermal noise Even when peaks due to .theta. This makes it possible to form a highly accurate trace line with respect to the Doppler waveform.

(Modification 1)
As the trace point determination criterion adopted by the trace processing unit 12, a criterion set by focusing on the general behavior of the movement (for example, blood flow) of the observation target may be used.

9A, 9B, 10A, and 10B are diagrams for explaining the process of determining the final trace point from the trace candidate points Q1b and Q2b in the trace processing unit according to Modification 1. FIG. FIG. 9A represents a case where the first trace candidate point Q1b is determined as the trace point, and FIG. 9B represents a case where the second trace candidate point Q2b is determined as the trace point.

The Doppler waveform of FIG. 10A is a Doppler waveform formed from the Doppler spectrum of FIG. 9A and Doppler spectra obtained at timings before and after that. Also, the Doppler waveform in FIG. 10B is a Doppler waveform formed from the Doppler spectrum in FIG. 9B and Doppler spectra obtained before and after the Doppler spectrum.

The maximum velocity of an object to be observed, such as blood flow, typically varies over time as the heart expands and contracts. However, the Doppler spectrum sampling interval is, for example, several milliseconds to several tens of milliseconds, which is much shorter than the period of motion such as blood flow. Therefore, in general, the maximum velocity of blood flow appearing in the Doppler spectrum at the current time should be regarded as a value close to the maximum velocity of blood flow appearing in the Doppler spectrum one time ago.

From this point of view, the trace point determination criteria according to Modification 1 determine the respective positions (ie , velocity) is compared with the position of the trace point one time ago (that is, velocity), and the one closer to the trace point one time ago is taken as the final trace point. In the Doppler spectra of FIGS. 9A and 9B, point D _t-1 represents the position of the trace point one hour before.

As a result, the trace processing unit 12 according to Modification 1 determines the trace candidate existing at a position closer to the trace point Dt _-1 one time earlier than the first trace candidate point Q1b and the second trace candidate point Q2b. A point is determined as the final trace point. Specifically, when the first trace candidate point Q1b exists at a position close to the trace point Dt _-1 one time earlier (see FIGS. 9A and 10A), the trace processing unit 12 performs the first is determined as the final trace point, and if the second trace candidate point Q2b exists at a position close to the trace point Dt _-1 one time earlier (see FIGS. 9B and 10B ), the trace processing unit 12 determines the second trace candidate point Q2b as the final trace point.

As described above, according to the trace processing unit 12 according to the present modification, even if white noise having a signal intensity similar to that of the movement of the observation target (for example, blood flow) is mixed into the Doppler spectrum, From the Doppler spectrum, it becomes possible to accurately determine the maximum velocity of the movement (for example, blood flow) of the observation target. Also, when a clutter signal is mixed in the Doppler spectrum, the clutter signal is generally slow and the velocity is different from the maximum velocity of the blood flow one time ago. can be determined with certainty.

(Modification 2)
As the trace point determination criterion adopted by the trace processing unit 12, a criterion set by focusing on the general behavior of both noise and movement of the observation target (for example, blood flow) may be used.

11 and 12 are diagrams for explaining the process of determining the final trace point from the trace candidate points Q1b and Q2b in the trace processing section according to Modification 2. FIG. The Doppler waveform of FIG. 12 is a Doppler waveform formed from the Doppler spectrum of FIG. 11 and Doppler spectra obtained at timings before and after that.

The trace point determination criterion (hereinafter referred to as the “third trace point determination criterion”) according to Modification 2 is the trace point determination criterion described in the above embodiment (see FIGS. 7A and 7B) (hereinafter referred to as the “third trace point determination criterion”). 1 trace point determination criterion”) and the trace point determination criterion described in Modification 1 (see FIGS. 9A and 9B) (hereinafter referred to as “second trace point determination criterion”). It is the deciding criterion.

Even noise components resulting from white noise may appear suddenly with high signal strength. If such a noise component has a signal strength greater than the threshold TH2, the first trace point determination criterion may cause erroneous selection of trace points due to such noise component. That is, in this case, the trace processing unit 12 determines that the second peak M2, which appears due to the sudden noise component, is the peak depending on the blood flow to be observed.

On the other hand, according to the second trace point determination criterion, the one closer to the trace point one time ago is determined as the trace point at the current time. It is possible to suppress erroneous selection of trace points due to noise components. However, in the second trace point determination criterion, when the trace processing unit 12 first erroneously selects trace points due to noise components, this causes continuous selection of trace points. It causes wrong selection.

In order to prevent erroneous selection of these trace points, the third trace point determination criterion relies on the reference based on the signal strength of the second maximum signal strength point Q2a and the positional relationship of the trace point one time earlier. The trace point is determined by two criteria, i.

Specifically, the trace processing unit 12 according to this modification first determines whether or not the signal intensity at the second maximum signal intensity point Q2a is less than the threshold TH2. Then, when the signal intensity of the second maximum signal intensity point Q2a is less than the threshold TH2, the trace processing unit 12 according to this modification determines the first trace candidate point Q1b as the trace point. This decision criterion is similar in concept to the first trace point decision criterion.

On the other hand, when the signal intensity of the second maximum signal intensity point Q2a is equal to or greater than the threshold TH2, the trace processing unit 12 according to the present modified example It is determined which one is closer to the trace point one time ago, and the one closer to the trace point one time ago from among the first trace candidate point Q1b and the second trace candidate point Q2b is set as the current time trace point. decide. This decision criterion is similar in concept to the second trace point decision criterion.

As described above, according to the trace processing unit 12 according to the present modification, even when a sudden large noise component occurs, the maximum velocity of the movement of the observation target (for example, blood flow) is appropriately selected from the Doppler spectrum. can be determined with certainty.

(Modification 3)
In the above description, the trace processing unit 12 uses the first trace point determination criterion (see FIGS. 7A and 7B) and the second trace point determination criterion (see FIGS. 9A and 9B) as the criteria for determining the trace points. ), and a third trace point determination criterion (see FIG. 11).

However, the suitability of the first to third trace point determination criteria differs depending on the diagnostic conditions of the ultrasonic diagnostic apparatus A in practice. This is based on the criteria (the second trace point determination criterion, the third trace point determination criterion ) is likely to cause an erroneous selection in cases where the movement of the observation target changes abruptly. In addition, based on the magnitude of the signal intensity of the second maximum signal intensity point Q2a, a criterion for selecting a trace point from the two trace candidate points Q1b and Q2b (first trace point determination criterion, third trace point This is because the point determination criterion) is likely to cause erroneous selection in cases where it is difficult to set the threshold TH2.

From this point of view, the trace processing unit 12 according to this modification sets the reference content of the trace point determination reference based on the diagnostic conditions of the ultrasonic diagnostic apparatus A. FIG. Specifically, the trace processing unit 12 selects from among the first trace point determination criterion, the second trace point determination criterion, and the third trace point determination criterion based on the diagnostic conditions of the ultrasonic diagnostic apparatus A. , selects the decision criteria to use and determines trace points using the selected decision criteria.

FIG. 13 is a flowchart showing a specific example of the operation of the trace processing unit 12 according to Modification 3. As shown in FIG.

The flow chart of FIG. 13 is different from the flow chart of FIG. 5 in that a process of step S0 for setting the criteria used in the process of step S5 is added before step S1. In the processing of step S0, based on the diagnostic conditions of the ultrasonic diagnostic apparatus A, for example, one of the first trace point determination criterion, the second trace point determination criterion, and the third trace point determination criterion is used. This is a process of selecting a decision criterion to be used.

Specific selection criteria employed by the trace processing unit 12 include, for example, the following items.

For example, the trace processing unit 12 determines whether the current Doppler scan mode in the transmitting/receiving unit 1 is an Update mode that executes only the Doppler mode, or a Simultaneous (Simultaneous) mode that simultaneously executes the Doppler mode and the B mode and/or the color mode in a time division manner. The trace point determination criteria to be used may be selected based on the mode. In this case, the trace processing unit 12 uses, for example, the first trace point determination criterion in Simul, and the second trace point determination criterion or the third trace point determination criterion in Update mode. This is because, in the Simul mode, the sampling interval is large, and the waveforms of Doppler spectra adjacent to each other may become discontinuous.

Further, the trace processing unit 12 may select the trace point determination criteria to be used based on whether the Doppler scan mode in the transmitting/receiving unit 1 is PW Doppler, CW Doppler, or TDI (tissue Doppler). In this case, for example, in CW Doppler where noise with low signal intensity is likely to be superimposed on the Doppler spectrum, the trace processing unit 12 selects the first trace point determination criterion or the third trace point determination criterion that can remove noise with the threshold TH2. use. Further, in PW Doppler, in which the continuity of the Doppler spectrum is likely to be maintained, the trace processing unit 12 uses the first trace point determination criterion or the third trace point determination criterion.

When the Doppler scan mode in the transmitting/receiving unit 1 is TDI (tissue Doppler), only tissue signals appear in the Doppler spectrum. The first trace candidate point Q1b may always be adopted as the trace point, neither the first trace point determination criterion nor the third trace point determination criterion.

Further, the trace processing unit 12 may select the trace point determination criteria to be used based on the type of observation target. In this case, for example, in the heart, the flow of blood is complicated, the spectrum waveform of the Doppler spectrum changes greatly, and disturbance due to valves etc. is likely to occur. use. Also, other parts use the first trace point determination criterion, which is compatible with both the Update mode and the Simul mode.

Further, the trace processing unit 12 may select the trace point determination criteria to be used based on the type of the ultrasonic probe 200 used for diagnosis. For example, when a sector probe is selected as the ultrasonic probe 200 to be used for diagnosis, the trace processing unit 12 uses the third trace point determination criterion, and selects another type of ultrasonic probe 200 to be used for diagnosis. probes are selected, the first trace point determination criterion may be used. This is because the sector probe is mainly used when observing the heart.

As described above, according to the trace processing unit 12 according to the present modification, it is possible to set more appropriate trace point selection criteria according to the diagnostic conditions of the ultrasonic diagnostic apparatus A. blood flow) can be determined more accurately.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

According to the ultrasonic diagnostic apparatus according to the present disclosure, when executing the Doppler mode, it is possible to accurately extract the maximum velocity of the movement of the observation target from the Doppler spectrum and form a highly accurate trace line for the Doppler waveform. is.

A Ultrasound diagnostic apparatus 100 Ultrasound diagnostic apparatus main body 1 Transmission/reception unit 2 Tomographic image generation unit 3 Doppler signal processing unit 4 Display processing unit 4a Doppler waveform generation unit 4b Graphic processing unit 5 Monitor 6 Operation input unit 10 Control device 11 Transmission/reception control unit 12 trace processing unit 200 ultrasonic probe

Claims (13)

a transmitting/receiving unit that transmits/receives ultrasonic waves using an ultrasonic probe and obtains a received signal related to ultrasonic echoes from an object to be observed in the subject;
a Doppler signal processing unit that frequency-analyzes Doppler information included in the received signal and generates a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a Doppler waveform generation unit that generates a Doppler waveform based on the time-series Doppler spectrum that is sequentially output from the Doppler signal processing unit;
In each of the time-series Doppler spectra sequentially output from the Doppler signal processing unit, a trace point representing the maximum velocity of the movement of the observation object is determined, and a trace line is drawn for the Doppler waveform based on the trace point. a trace processing portion forming;
with
The trace processing unit
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side from the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
Ultrasound diagnostic equipment. The trace processing unit determines the first trace candidate point as the trace point when the signal intensity at the second maximum signal intensity point is less than a threshold, and determines the signal at the second maximum signal intensity point as the trace point. determining the second trace candidate point as the trace point if the intensity is greater than or equal to the threshold;
The ultrasonic diagnostic apparatus according to claim 1. The trace processing unit selects, of the first trace candidate point and the second trace candidate point, the one whose speed is closer to the trace point determined in the Doppler spectrum one time earlier than the current time. determined as the trace points in the Doppler spectrum;
The ultrasonic diagnostic apparatus according to claim 1. The trace processing unit determines the first trace candidate point as the trace point when the signal intensity at the second maximum signal intensity point is less than a threshold, and determines the signal at the second maximum signal intensity point as the trace point. If the intensity is equal to or greater than the threshold, the one of the first trace candidate point and the second trace candidate point whose speed is closer to the trace point determined in the Doppler spectrum one time earlier is set at the current time. as the trace points in the Doppler spectrum of
The ultrasonic diagnostic apparatus according to claim 1. The trace processing unit sets the reference content of the predetermined reference based on the diagnostic conditions of the ultrasonic diagnostic apparatus.
The ultrasonic diagnostic apparatus according to claim 1. The trace processing unit selects a criterion to be used as the predetermined criterion from among the following criteria A), B), and C) based on the diagnostic conditions of the ultrasonic diagnostic apparatus.
Criterion A) If the signal strength at the second maximum signal strength point is less than a threshold, determine the first trace candidate point as the trace point, and determine the signal strength at the second maximum signal strength point as the If it is equal to or greater than a threshold, determining the second trace candidate point as the trace point;
Criterion B) Of the first trace candidate point and the second trace candidate point, the one whose speed is closer to the trace point determined in the Doppler spectrum one time ago is selected in the Doppler spectrum at the current time determining as said trace point;
Criterion C) If the signal strength at the second maximum signal strength point is less than the threshold, the first trace candidate point is determined as the trace point, and the signal strength at the second maximum signal strength point is If it is equal to or greater than the threshold, the one of the first trace candidate point and the second trace candidate point whose speed is closer to the trace point determined in the Doppler spectrum one time earlier is selected at the current time. determined as the trace points in the Doppler spectrum;
The ultrasonic diagnostic apparatus according to claim 5. The trace processing unit determines whether the Doppler scan mode in the transmitting/receiving unit is a Simultaneous (Simultaneous) mode in which the Doppler mode and the B mode and/or the color flow mode are simultaneously executed in a time division manner, or an Update mode in which only the Doppler mode is continuously executed. setting the criterion content of the predetermined criterion based on the mode;
The ultrasonic diagnostic apparatus according to claim 5 or 6. The trace processing unit sets the reference content of the predetermined reference based on which of PW Doppler, CW Doppler, or tissue Doppler the Doppler scan mode in the transmitting and receiving unit is,
The ultrasonic diagnostic apparatus according to any one of claims 5 to 7. The trace processing unit sets the reference content of the predetermined reference based on the type of the observation target.
The ultrasonic diagnostic apparatus according to any one of claims 5 to 8. The trace processing unit sets the reference contents of the predetermined reference based on the type of the ultrasonic probe,
The ultrasonic diagnostic apparatus according to any one of claims 5 to 9. The observation target is the blood flow flowing through the blood vessel of the subject,
The ultrasonic diagnostic apparatus according to any one of claims 1 to 10. A control method for an ultrasonic diagnostic apparatus,
A first process of transmitting and receiving ultrasonic waves using an ultrasonic probe to obtain a received signal related to ultrasonic echoes from an observation target within the subject;
a second process of frequency-analyzing the Doppler information contained in the received signal to generate a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a third process for generating a Doppler waveform based on the time-series Doppler spectrum sequentially output in the second process;
In each of the time-series Doppler spectra sequentially output in the second processing, a trace point representing the maximum velocity of the movement of the observation target is determined, and a trace line is formed for the Doppler waveform based on the trace point. a fourth process to
with
In the fourth process,
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side from the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
control method. A control program for an ultrasonic diagnostic apparatus,
A first process of transmitting and receiving ultrasonic waves using an ultrasonic probe to obtain a received signal related to ultrasonic echoes from an observation target within the subject;
a second process of frequency-analyzing the Doppler information contained in the received signal to generate a Doppler spectrum representing signal strength for each speed of movement of the observation target;
a third process for generating a Doppler waveform based on the time-series Doppler spectrum sequentially output in the second process;
In each of the time-series Doppler spectra sequentially output in the second processing, a trace point representing the maximum velocity of the movement of the observation target is determined, and a trace line is formed for the Doppler waveform based on the trace point. a fourth process to
with
In the fourth process,
Searching for a first signal intensity maximum point where the signal intensity is maximum from the Doppler spectrum,
In the first peak mountain including the first signal intensity maximum point of the Doppler spectrum, setting a first trace candidate point on the high-speed side from the first signal intensity maximum point,
searching for a second maximum signal strength point at which the signal strength is maximized next to the first maximum signal strength point on the high-speed side of the first trace candidate point in the Doppler spectrum;
Setting a second trace candidate point on the high-speed side of the second signal intensity maximum point in the second peak mountain including the second signal intensity maximum point of the Doppler spectrum,
using a predetermined criterion to determine one of the first trace candidate point and the second trace candidate point as the trace point;
control program.

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