Ultrasound diagnostic equipment, methods, and programs

Abstract

To reduce the effects of residual multiplexing on color Doppler image data while suppressing the decrease in frame rate of color Doppler image data. [Solution] The ultrasound diagnostic apparatus of this embodiment generates a color Doppler image using multiple transmitted and received data obtained by transmitting and receiving ultrasound multiple times on the same scan line. The ultrasound diagnostic apparatus comprises an acquisition unit and a generation unit. The acquisition unit collects multiple transmitted and received data by transmitting and receiving ultrasound multiple times on a predetermined scan line. The generation unit determines the number of transmitted and received data that will not be used for generating the color Doppler image, according to the influence of echo signals transmitted and received in a time phase prior to the multiple transmitted and received ultrasound transmissions on the predetermined scan line, and generates a color Doppler image using multiple transmitted and received data obtained by subtracting the number of transmitted and received data from the first transmitted and received data from the multiple transmitted and received data collected by the acquisition unit.

Description

Technical Field

[0001] The embodiments disclosed in the present specification and drawings relate to an ultrasonic diagnostic apparatus, a method and a program.

Background Art

[0002] There is an ultrasonic diagnostic apparatus that images an internal state of a subject by transmitting and receiving ultrasonic waves to and from the subject. In such an ultrasonic diagnostic apparatus, each of various modes for generating each of various image data is set.

[0003] In an ultrasonic diagnostic apparatus, when transmitting and receiving ultrasonic waves through electronic scanning, if the signal intensity of a scanning line immediately before a position is switched is relatively strong, an unattenuated signal may be superimposed (received) on the scanning line after the position is switched (current scanning line) as a residual signal. This phenomenon is called residual multiple echo.

[0004] Such residual multiple echo may occur, for example, in a color Doppler mode (blood flow display mode) in which color Doppler image data representing blood flow of a subject is generated and a color Doppler image based on the color Doppler image data is displayed on a display. When an ultrasonic diagnostic apparatus performs phase detection (phase demodulation) performed in the color Doppler mode using a signal affected by residual multiple echo, since the correlation between a plurality of signals is relatively weak, the color Doppler image displayed on the display may include noise such as a striped pattern as an artifact. When residual multiple echo occurs, for example, the scanning position of an ultrasonic probe is changed to reduce residual multiple echo, which is one of the factors causing a decrease in examination efficiency.

[0005] Another technique for reducing residual multiplexing is dummy rate transmission. For example, dummy rate transmission is a technique in which ultrasound is transmitted and received for the scan line immediately before the position changes, then a specific time is waited, and then the transmission and reception of ultrasound for the current scan line begins after the specific time has elapsed. By waiting for a specific time, the intensity of the residual signal is sufficiently reduced. As a result, different residual signals are not received for each of the multiple scan lines. In other words, similar residual signals are received for each of the multiple scan lines. This reduces residual multiplexing.

[0006] However, with dummy rate transmission, the system waits for a specific time after transmitting and receiving ultrasound for the scan line immediately before the position changes, which can reduce the frame rate and impair real-time performance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-127640 [Patent Document 2] Japanese Patent Publication No. 2010-158417 [Overview of the project] [Problems that the invention aims to solve]

[0008] One of the problems that the embodiments disclosed herein and in the drawings aim to solve is to reduce the effect of residual multiplexing on color Doppler image data while suppressing a decrease in the frame rate of the color Doppler image data. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0009] The ultrasound diagnostic apparatus of this embodiment generates a color Doppler image using multiple transmitted and received data obtained by transmitting and receiving ultrasound multiple times on the same scan line. The ultrasound diagnostic apparatus comprises an acquisition unit and a generation unit. The acquisition unit collects multiple transmitted and received data by transmitting and receiving ultrasound multiple times on a predetermined scan line. The generation unit determines the number of transmitted and received data that will not be used for generating the color Doppler image, according to the influence of echo signals transmitted and received in a time phase prior to the multiple transmitted and received ultrasound transmissions on the predetermined scan line, and generates a color Doppler image using multiple transmitted and received data obtained by subtracting the number of transmitted and received data from the first transmitted and received data from the multiple transmitted and received data collected by the acquisition unit. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram showing an example configuration of an ultrasound diagnostic apparatus according to the first embodiment. [Figure 2] Figure 2 is a diagram illustrating an example of the first ultrasonic scanning and the second ultrasonic scanning in the normal mode according to the first embodiment. [Figure 3] Figure 3 shows an example of the positions of multiple scan lines (positions in spatial coordinates of image data) in each scan of the first ultrasonic scan and the second ultrasonic scan according to the first embodiment. [Figure 4] Figure 4 illustrates the dummy rate transmission performed by the ultrasound diagnostic device in the comparative example when the dummy rate mode is set as the scanning mode. [Figure 5] Figure 5 shows an example of a data sequence input to an eigenvector type MTI filter in the normal mode shown in Figure 2. [Figure 6] Figure 6 shows an example of a data sequence input to an eigenvector type MTI filter in the residual multiple reduction mode according to the first embodiment. [Figure 7] Figure 7 is a flowchart showing an example of the process performed by the ultrasound diagnostic device according to the first embodiment. [Figure 8]FIG. 8 is a diagram showing an example of a color Doppler image displayed by the ultrasonic diagnostic apparatus according to the first embodiment. [Figure 9] FIG. 9 is a block diagram showing a configuration example of an ultrasonic diagnostic apparatus according to the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining an example of a first ultrasonic scan and a second ultrasonic scan in a normal mode according to the second embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a data sequence input to an eigenvector-type MTI filter in a residual multiple reduction mode according to the second embodiment. [Figure 12] FIG. 12 is a diagram for explaining an example of a first ultrasonic scan and a second ultrasonic scan in a dummy rate mode according to the second embodiment. [Figure 13] FIG. 13 is a flowchart showing a flow of an example of processing executed by the ultrasonic diagnostic apparatus according to the second embodiment. [Figure 14] FIG. 14 is a diagram showing an example of a color Doppler image displayed by the ultrasonic diagnostic apparatus according to the second embodiment. [Figure 15] FIG. 15 is a diagram for explaining features of a color Doppler image generated by the ultrasonic diagnostic apparatus according to the second embodiment for each combination of a level and a scanning mode. [Figure 16] FIG. 16 is a block diagram showing a configuration example of an ultrasonic diagnostic apparatus according to the third embodiment. [Figure 17] FIG. 17 is a diagram for explaining an example of processing for detecting residual multiples in the third embodiment. [Figure 18] FIG. 18 is a diagram for explaining an example of processing for detecting the presence or absence of pulsatility in the third embodiment. [Figure 19] FIG. 19 is a diagram for explaining an example of processing for detecting the presence or absence of pulsatility in the third embodiment. [Figure 20] FIG. 20 is a flowchart showing a flow of an example of processing executed by the ultrasonic diagnostic apparatus according to the third embodiment. [Figure 21]FIG. 21 is a diagram for explaining an example of first ultrasound scanning in mode-divided scanning. [Figure 22] FIG. 22 is a diagram showing an example of positions of a plurality of scanning lines (positions in spatial coordinates of image data) in first ultrasound scanning in mode-divided scanning. MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, an ultrasound diagnostic apparatus, method and program according to each embodiment will be described with reference to the drawings. In the following description, components denoted by the same reference numerals perform the same operations, and duplicate descriptions may be omitted as appropriate. In addition, the embodiments can be combined with other embodiments or conventional techniques within a range that does not cause contradiction in processing contents.

[0012] (First Embodiment) FIG. 1 is a block diagram showing a configuration example of an ultrasound diagnostic apparatus 1 according to the first embodiment. As illustrated in FIG. 1, the ultrasound diagnostic apparatus 1 according to the first embodiment includes an apparatus main body 100, an ultrasound probe 101, an input device 102, and a display 103.

[0013] The ultrasonic probe 101 has, for example, multiple elements (piezoelectric transducers, piezoelectric elements). These multiple elements generate ultrasound based on a drive signal supplied from the transmitting circuit 111 of the transmitting / receiving circuit 110 of the device body 100. Specifically, when a voltage (transmitting drive voltage) is applied to the multiple elements by the transmitting circuit 111, the multiple elements generate ultrasound with a waveform corresponding to the transmitting drive voltage. The waveform of the transmitting drive voltage indicated by the drive signal is the waveform of the voltage applied to the multiple elements. In other words, the ultrasonic probe 101 transmits ultrasound corresponding to the magnitude of the applied transmitting drive voltage. The ultrasonic probe 101 also receives reflected waves from the subject P, converts the received reflected waves into reflected wave signals which are electrical signals, and outputs the reflected wave signals to the device body 100. The ultrasonic probe 101 also has, for example, a matching layer provided on the elements and a backing material that prevents the propagation of ultrasound backward from the elements. The ultrasonic probe 101 is detachably connected to the device body 100.

[0014] When ultrasound is transmitted from the ultrasound probe 101 to the subject P, the transmitted ultrasound is reflected one after another by discontinuities in acoustic impedance within the subject P's internal tissues, and the reflected waves are received by multiple elements of the ultrasound probe 101. The amplitude of the received reflected waves depends on the difference in acoustic impedance at the discontinuities where the ultrasound is reflected. Furthermore, when the transmitted ultrasound pulse is reflected by the surface of a moving object such as moving blood flow or the heart wall, the reflected waves undergo a frequency shift due to the Doppler effect, depending on the velocity component of the moving object relative to the ultrasound transmission direction. The ultrasound probe 101 then outputs the reflected wave signal to the receiving circuit 112 of the transmitting / receiving circuit 110, which will be described later.

[0015] The ultrasonic probe 101 is detachably attached to the main unit 100 of the device. When scanning a two-dimensional area within the subject P (two-dimensional scanning), the operator connects a 1D array probe, for example, in which multiple elements are arranged in a row, to the main unit 100 as the ultrasonic probe 101. Examples of 1D array probes include linear ultrasonic probes, convex ultrasonic probes, and sector ultrasonic probes. When scanning a three-dimensional area within the subject P (three-dimensional scanning), the operator connects a mechanical 4D probe or a 2D array probe to the main unit 100 as the ultrasonic probe 101. A mechanical 4D probe can perform two-dimensional scanning using multiple elements arranged in a row, similar to a 1D array probe, and can also perform three-dimensional scanning by oscillating the multiple elements at a predetermined angle (oscillation angle). A 2D array probe can perform three-dimensional scanning using multiple elements arranged in a matrix, and can also perform two-dimensional scanning by focusing and transmitting ultrasound.

[0016] The input device 102 is implemented by input means such as a mouse, keyboard, buttons, panel switches, touch command screen, foot switch, trackball, or joystick. The input device 102 receives various setting requests from the operator of the ultrasound diagnostic device 1 and transfers the received setting requests to the device body 100. In this embodiment, the input device 102 includes a residual multiplexing reduction button (not shown). For example, the operator presses the residual multiplexing reduction button when they want to reduce the effect of residual multiplexing on color Doppler image data while suppressing a decrease in the frame rate of the color Doppler image data.

[0017] The display 103 may, for example, display a GUI (Graphical User Interface) for the operator of the ultrasound diagnostic device 1 to input various setting requests using the input device 102, or display ultrasound images based on ultrasound image data generated by the device body 100. The display 103 is implemented using a liquid crystal monitor or an OLED (Organic Light Emitting Diode) monitor, etc. The display 103 is an example of a display unit.

[0018] The device body 100 generates ultrasonic image data based on reflected wave signals transmitted from the ultrasonic probe 101. The ultrasonic image data shown is an example of image data. The device body 100 can generate two-dimensional ultrasonic image data based on reflected wave signals corresponding to the two-dimensional region of the subject P transmitted from the ultrasonic probe 101. Furthermore, the device body 100 can generate three-dimensional ultrasonic image data based on reflected wave signals corresponding to the three-dimensional region of the subject P transmitted from the ultrasonic probe 101. As shown in Figure 1, the device body 100 includes a transmit / receive circuit 110, a buffer memory 120, a B-mode processing circuit 130, a Doppler processing circuit 140, an image generation circuit 150, an image memory 160, a storage circuit 170, and a control circuit 180.

[0019] The transmitting / receiving circuit 110, under the control of the control circuit 180, causes the ultrasonic probe 101 to transmit ultrasound and the ultrasonic probe 101 to receive reflected ultrasound waves (echoes). In other words, the transmitting / receiving circuit 110 performs scanning via the ultrasonic probe 101. In this specification, for example, "transmitting / receiving" means acquiring data on a single scan line by transmitting and receiving ultrasound, and "scanning" means the repetition of "transmitting / receiving". Transmitting and receiving ultrasound is also simply referred to as ultrasonic transmission and reception. Transmitting and receiving ultrasound means, for example, transmitting ultrasound and receiving the reflected waves of the transmitted ultrasound. "Scanning" is also referred to as ultrasonic scanning. For example, "scanning" means both "transmitting / receiving" and "scanning". Note that the transmitting / receiving circuit 110 is an example of a transmitting / receiving unit. The transmitting / receiving circuit 110 has a transmitting circuit 111 and a receiving circuit 112. The transmitting circuit 111 is an example of a transmitting unit, and the receiving circuit 112 is an example of a receiving unit.

[0020] The transmitting circuit 111, under the control of the control circuit 180, supplies a drive signal to the ultrasonic probe 101, thereby causing the ultrasonic probe 101 to transmit ultrasound. The transmitting circuit 111 includes a rate pulser generation circuit, a transmission delay circuit, and a transmitting pulser. When scanning a two-dimensional region within the subject P, the transmitting circuit 111 causes the ultrasonic probe 101 to transmit an ultrasonic beam for scanning the two-dimensional region. When scanning a three-dimensional region within the subject P, the transmitting circuit 111 causes the ultrasonic probe 101 to transmit an ultrasonic beam for scanning the three-dimensional region.

[0021] The rate pulser generation circuit, under the control of the control circuit 180, repeatedly generates rate pulses at a predetermined pulse repetition frequency (PRF) to form a transmitted ultrasonic wave (transmitted beam). The rate pulses pass through the transmit delay circuit, applying voltages to the transmit pulser with different transmit delay times. For example, the transmit delay circuit provides each rate pulse generated by the rate pulser generation circuit with a transmit delay time for each element necessary to focus the ultrasonic waves generated from the ultrasonic probe 101 into a beam and determine the transmit directivity. The transmit pulser supplies a drive signal (drive pulse) to the ultrasonic probe 101 at a timing based on the rate pulse. That is, the transmit pulser applies a voltage (transmit drive voltage) with a waveform indicated by the drive signal to the ultrasonic probe 101 at a timing based on the rate pulse. The transmit delay circuit arbitrarily adjusts the transmission direction of the ultrasonic waves from the element surface by changing the transmit delay time applied to each rate pulse.

[0022] The drive pulse is transmitted from the transmitting pulser through the cable to the element in the ultrasonic probe 101, where it is converted from an electrical signal to a mechanical vibration. That is, when a voltage is applied to the element, the element vibrates mechanically. The ultrasound generated by this mechanical vibration is transmitted into the living body (inside the subject P). Here, the ultrasound, which has a different transmission delay time for each element, is focused and propagates in a predetermined direction.

[0023] The transmitting circuit 111, under the control of the control circuit 180, has the function of instantaneously changing the transmission frequency, transmission drive voltage, etc., in order to execute a predetermined scanning sequence. In particular, the change in the transmission drive voltage is achieved by a linear amplifier type oscillator circuit that can instantly switch the value of the transmission drive voltage, or by a mechanism that electrically switches multiple power supply units. The transmission frequency is, for example, the center frequency of the transmitted ultrasonic wave.

[0024] The ultrasonic waves transmitted by the ultrasonic probe 101 reach an element inside the ultrasonic probe 101, where they are converted from mechanical vibrations into electrical signals (reflected wave signals), and these reflected wave signals are input to the receiving circuit 112. The receiving circuit 112 includes a preamplifier, an A / D (Analog to Digital) converter, a quadrature detection circuit, etc., and performs various processing on the reflected wave signals transmitted from the ultrasonic probe 101 to generate reflected wave data. The receiving circuit 112 then stores the generated reflected wave data in the buffer memory 120.

[0025] The preamplifier amplifies the reflected wave signal for each channel and performs gain adjustment (gain correction). The A / D converter converts the gain-corrected reflected wave signal into a digital signal by A / D conversion. The quadrature detection circuit converts the digitally converted reflected wave signal into a baseband in-phase signal (I signal, I: In-phase) and a quadrature signal (Q signal, Q: Quadrature-phase). The quadrature detection circuit then stores the I signal and Q signal (IQ signal) as reflected wave data in the buffer memory 120.

[0026] The receiving circuit 112 performs various processes on the reflected wave signal transmitted from the ultrasonic probe 101 to generate reflected wave data. The receiving circuit 112 then stores the generated reflected wave data in the buffer memory 120.

[0027] The receiving circuit 112 generates two-dimensional reflected wave data from the two-dimensional reflected wave signal transmitted from the ultrasonic probe 101. The receiving circuit 112 also generates three-dimensional reflected wave data from the three-dimensional reflected wave signal transmitted from the ultrasonic probe 101.

[0028] In this embodiment, the ultrasound diagnostic device 1 can perform various processes in real time. For example, the ultrasound probe 101 successively transmits reflected wave signals for one frame to the receiving circuit 112. Each time the receiving circuit 112 receives a reflected wave signal for one frame transmitted from the ultrasound probe 101, it generates reflected wave data for one frame from the reflected wave signal for one frame. Each time the receiving circuit 112 generates reflected wave data for one frame, it stores the reflected wave data for one frame in the buffer memory 120.

[0029] The buffer memory 120 is a memory that temporarily stores reflected wave data generated by the transmitting and receiving circuit 110. For example, the buffer memory 120 is configured to store a predetermined number of frames of reflected wave data. When the buffer memory 120 has stored a predetermined number of frames of reflected wave data, and a new frame of reflected wave data is generated by the receiving circuit 112, the buffer memory 120, under the control of the receiving circuit 112, discards the oldest frame of reflected wave data generated and stores the newly generated frame of reflected wave data. For example, the buffer memory 120 can be implemented using semiconductor memory elements such as RAM (Random Access Memory) or flash memory.

[0030] The B-mode processing circuit 130 reads reflected wave data from the buffer memory 120, performs various signal processing on the read reflected wave data, and outputs the processed reflected wave data as B-mode data to the image generation circuit 150. The B-mode processing circuit 130 can be implemented, for example, by a processor. The B-mode processing circuit 130 is an example of a B-mode processing unit.

[0031] For example, whenever a new frame of reflected wave data is stored in the buffer memory 120, the B-mode processing circuit 130 reads out the newly stored frame of reflected wave data. The B-mode processing circuit 130 then performs various signal processing operations on the read frame of reflected wave data to generate a new frame of B-mode data. Each time the B-mode processing circuit 130 generates a frame of B-mode data, it outputs the newly generated frame of B-mode data to the image generation circuit 150. The following describes some examples of the various signal processing operations performed by the B-mode processing circuit 130.

[0032] For example, the B-mode processing circuit 130 performs quadrature detection on the reflected wave data read from the buffer memory 120, and then applies logarithmic amplification and envelope detection processing to generate B-mode data in which the signal strength (amplitude strength) of each sample point is represented by brightness. The B-mode processing circuit 130 then outputs the generated B-mode data to the image generation circuit 150.

[0033] The Doppler processing circuit 140 reads reflected wave data from the buffer memory 120, performs various signal processing on the read reflected wave data, and outputs the processed reflected wave data as Doppler data to the image generation circuit 150. The Doppler processing circuit 140 can be implemented, for example, by a processor. The Doppler processing circuit 140 is an example of a Doppler processing unit.

[0034] For example, whenever a new frame of reflected wave data is stored in the buffer memory 120, the Doppler processing circuit 140 reads out the newly stored frame of reflected wave data. The Doppler processing circuit 140 then performs various signal processing operations on the read frame of reflected wave data to generate a new frame of Doppler data. Each time the Doppler processing circuit 140 generates a frame of Doppler data, it outputs the newly generated frame of Doppler data to the image generation circuit 150. The following describes some examples of the various signal processing operations performed by the Doppler processing circuit 140.

[0035] For example, the Doppler processing circuit 140 performs frequency analysis on the reflected wave data read from the buffer memory 120 to extract motion information of moving objects (blood flow, tissue, contrast agent echo components, etc.) based on the Doppler effect from the reflected wave data, and generates Doppler data showing the extracted motion information. For example, the Doppler processing circuit 140 extracts average velocity, average variance, and average power values ​​as motion information of moving objects at multiple points, and generates Doppler data showing the extracted motion information of moving objects. The Doppler processing circuit 140 outputs the generated Doppler data to the image generation circuit 150.

[0036] Using the functions of the Doppler processing circuit 140 described above, the ultrasound diagnostic device 1 can perform the color Doppler method, also known as the color flow mapping (CFM) method. In the color flow mapping method, ultrasound is transmitted and received multiple times for each of the multiple scan lines. In the color flow mapping method, an MTI (Moving Target Indicator) filter is applied to the data sequence at the same location to suppress signals originating from stationary or slow-moving tissue (clutter signals) and extract signals originating from blood flow (blood flow signals). The color flow mapping method then estimates blood flow information such as blood flow velocity (average velocity), blood flow variance (mean variance value), and blood flow power (average power value) from this blood flow signal. The Doppler processing circuit 140 outputs color Doppler data showing the blood flow information estimated by the color flow mapping method to the image generation circuit 150.

[0037] The Doppler processing circuit 140 according to this embodiment uses an adaptive MTI filter that changes its coefficients according to the input signal. For example, the Doppler processing circuit 140 uses a filter called an "Eigenvector Regression Filter" as the adaptive MTI filter. Hereinafter, an adaptive MTI filter using eigenvectors, called an "Eigenvector Regression Filter," will be referred to as an "eigenvector type MTI filter."

[0038] The eigenvector type MTI filter calculates eigenvectors from the correlation matrix and then calculates coefficients used for clutter suppression from these calculated eigenvectors. This method is an application of techniques used in principal component analysis, the Karhunen-Loeve transform, and the eigenspace method.

[0039] The Doppler processing circuit 140 according to the first embodiment, which uses an eigenvector type MTI filter, calculates a correlation matrix for the first divided region, described later, from a data sequence of consecutive reflected wave data at the same position (same sample point). The Doppler processing circuit 140 then calculates the eigenvalues ​​of the correlation matrix and the eigenvectors corresponding to those eigenvalues. The Doppler processing circuit 140 then calculates a matrix obtained by reducing the rank of a matrix in which each eigenvector is arranged based on the magnitude of each eigenvalue, and uses this matrix as a filter matrix to suppress the clutter component.

[0040] The Doppler processing circuit 140 then uses a filter matrix to identify a data sequence from a series of reflected wave data at the same location (same sample point) in which the clutter component has been suppressed and the blood flow signal originating from blood flow has been extracted. The Doppler processing circuit 140 then performs calculations such as autocorrelation calculations using the identified data sequence to estimate blood flow information. The Doppler processing circuit 140 then outputs color Doppler data showing the estimated blood flow information to the image generation circuit 150. In this way, the Doppler processing circuit 140 outputs color Doppler data to the image generation circuit 150 for each of the first divided regions, which will be described later.

[0041] The B-mode processing circuit 130 and the Doppler processing circuit 140 are capable of processing both two-dimensional and three-dimensional reflected wave data.

[0042] The image generation circuit 150 generates various types of ultrasound image data from the B-mode data, second harmonic components, and third harmonic components output from the B-mode processing circuit 130, as well as from the Doppler data and color Doppler data output from the Doppler processing circuit 140. For example, the image generation circuit 150 is implemented by a processor.

[0043] For example, the image generation circuit 150 generates two-dimensional B-mode image data from the two-dimensional B-mode data generated by the B-mode processing circuit 130, in which the intensity of the reflected wave is represented by brightness. The image generation circuit 150 also generates two-dimensional Doppler image data or two-dimensional color Doppler image data in which motion information or blood flow information is visualized from the two-dimensional Doppler data or color Doppler data generated by the Doppler processing circuit 140. The two-dimensional Doppler image data in which motion information is visualized and the two-dimensional color Doppler image data in which blood flow information is visualized are velocity image data, dispersion image data, power image data, or image data that combines these.

[0044] Here, the image generation circuit 150 generally converts the scan line signal sequence of the ultrasonic scan into a scan line signal sequence of a video format, such as that used in televisions (scan conversion), and generates ultrasonic image data for display. For example, the image generation circuit 150 generates ultrasonic image data for display by performing coordinate transformations on the data output from the B-mode processing circuit 130 and the Doppler processing circuit 140 according to the ultrasonic scanning mode of the ultrasonic probe 101. In addition to scan conversion, the image generation circuit 150 may also perform various image processing steps, such as image processing that regenerates an average brightness image using multiple image frames after scan conversion (smoothing process), or image processing that uses a differential filter within the image (edge ​​enhancement process). Furthermore, the image generation circuit 150 may synthesize various parameter text information, scales, body marks, etc., into the ultrasonic image data.

[0045] Furthermore, the image generation circuit 150 generates 3D B-mode image data by performing a coordinate transformation on the 3D B-mode data generated by the B-mode processing circuit 130. The image generation circuit 150 also generates 3D Doppler image data by performing a coordinate transformation on the 3D Doppler data generated by the Doppler processing circuit 140. In other words, the image generation circuit 150 generates "3D ultrasound image data (volume data)" from the "3D B-mode image data and 3D Doppler image data". Then, the image generation circuit 150 performs various rendering processes on the volume data to generate various 2D image data for display on the display 103.

[0046] The rendering process performed by the image generation circuit 150 includes, for example, generating MPR image data from volume data using the Multi-Planer Reconstruction (MPR) method. Another rendering process performed by the image generation circuit 150 is volume rendering (VR), which generates 2D image data that reflects 3D information. The image generation circuit 150 is an example of an image generation unit.

[0047] B-mode data and Doppler data are ultrasound image data before scan conversion processing, while the data generated by the image generation circuit 150 is ultrasound image data for display after scan conversion processing. B-mode data and Doppler data are also referred to as raw data.

[0048] The image memory 160 is a memory that stores various image data generated by the image generation circuit 150. The image memory 160 also stores data generated by the B-mode processing circuit 130 and the Doppler processing circuit 140. The B-mode data and Doppler data stored in the image memory 160 can be retrieved by the operator after a diagnosis, for example, and become ultrasound image data for display via the image generation circuit 150. For example, the image memory 160 can be implemented using semiconductor memory elements such as RAM (Random Access Memory) or flash memory, a hard disk, or an optical disk.

[0049] The memory circuit 170 stores control programs for scanning, image processing, and display processing, as well as various data such as diagnostic information (e.g., patient ID, physician's findings, etc.), diagnostic protocols, and various body marks. The memory circuit 170 is also used, if necessary, to store data stored in the image memory 160. For example, the memory circuit 170 can be implemented using semiconductor memory elements such as flash memory, a hard disk, or an optical disk.

[0050] The control circuit 180 controls the entire process of the ultrasound diagnostic device 1. Specifically, the control circuit 180 controls the processing of the transmission circuit 111, the reception circuit 112, the B-mode processing circuit 130, the Doppler processing circuit 140, and the image generation circuit 150 based on various setting requests input from the operator via the input device 102, and various control programs and data read from the memory circuit 170. The control circuit 180 also controls the display 103 to display an ultrasound image based on ultrasound image data for display stored in the image memory 160. For example, the control circuit 180 controls the display 103 to display a B-mode image based on B-mode image data or a color Doppler image based on color Doppler image data. The control circuit 180 also controls the display 103 to display a color Doppler image superimposed on a B-mode image.

[0051] The control circuit 180 is an example of a display control unit or a control unit. The control circuit 180 is implemented, for example, by a processor.

[0052] Furthermore, the control circuit 180 controls the ultrasonic scanning by controlling the ultrasonic probe 101 via the transmitting and receiving circuit 110.

[0053] In this description, the term "processor" refers to circuits such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), Application Specific Integrated Circuit (ASIC), or programmable logic device (e.g., Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), or Field Programmable Gate Array (FPGA)). The processor performs its functions by reading a program stored in the memory circuit 170 and executing the read program. Alternatively, instead of storing the program in the memory circuit 170, the processor may be configured to directly incorporate the program into its circuitry. In this case, the processor performs its functions by reading and executing the program incorporated into the circuitry. In this embodiment, each processor is not limited to being configured as a single circuit; multiple independent circuits may be combined to form a single processor, and its functions may be realized in this way. Furthermore, the multiple circuits in Figure 1 (for example, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generation circuit 150, and the control circuit 180) may be integrated into a single processor to realize their functions. That is, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generation circuit 150, and the control circuit 180 may be integrated into a single processing circuit realized by the processor. In addition, the transmitting / receiving circuit 110, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generation circuit 150, and the control circuit 180 may be integrated into a single processing circuit including the processor.

[0054] The overall configuration of the ultrasound diagnostic apparatus 1 according to the first embodiment has been described above.

[0055] In the first embodiment, the ultrasound diagnostic device 1 is initially set to normal mode as the scanning mode. In normal mode, the transmitting and receiving circuit 110 alternately performs a first ultrasound scan (first ultrasound scan) and a second ultrasound scan (second ultrasound scan) on the subject P via the ultrasound probe 101. The scanning method of the first ultrasound scan is to divide a first region (first range) formed by multiple scan lines into multiple divided regions (first divided regions), and perform ultrasound transmission and reception in each of the multiple first divided regions. The first region is, for example, the interior region of the subject P. In this embodiment, the ultrasound diagnostic device 1 performs the CFM method described above on the data sequence of reflected wave data obtained by the first ultrasound scan to generate color Doppler image data for each first divided region.

[0056] The transmitting / receiving circuit 110 performs a first ultrasonic scan using ultrasonic transmitting / receiving conditions for acquiring color Doppler image data. Then, each time a new color Doppler image data is generated for each of the first divided regions, the control circuit 180 displays a color Doppler image based on the newly generated color Doppler image data in the region of the entire color Doppler image displayed on the display 103 that corresponds to the newly generated color Doppler image data. If a color Doppler image is already displayed in the region of the display 103 that corresponds to the newly generated color Doppler image data, the control circuit 180 updates the display content of the region that corresponds to the newly generated color Doppler image data with a color Doppler image based on the newly generated color Doppler image data.

[0057] In typical color Doppler ultrasound, ultrasound transmission and reception are performed multiple times in the same direction, and blood flow signals are extracted from the received signals. The data sequence of reflected wave signals (reflected wave data) obtained from the same location through such ultrasound transmission and reception is called a packet. The packet size is the number of ultrasound transmissions and receptions performed in the same direction to obtain one frame of blood flow information. The packet size in general color Doppler ultrasound is variable, for example, between 5 and 16. The performance of the eigenvector type MTI filter improves with a larger packet size, but increasing the packet size reduces the frame rate.

[0058] The ultrasound diagnostic device 1 can process data sequences at the same position in each frame in the frame direction (time direction). For example, the ultrasound diagnostic device 1 can change the MTI filtering process from processing finite-length data packets to processing infinite-length data. As a result, the ultrasound diagnostic device 1 can improve the performance of the MTI filter, making it possible to detect blood flow information related to low-velocity blood flow.

[0059] The control circuit 180 according to the first embodiment causes the second ultrasonic scan of the subject P to be performed in the scanning configuration described below, along with the first ultrasonic scan.

[0060] The control circuit 180 divides the second region (second range) formed by multiple scan lines into multiple divided regions (second divided regions), and causes the ultrasonic probe 101 to perform a second ultrasonic scan for each of the multiple second divided regions in a time-division manner during the first ultrasonic scan, via the transmit / receive circuit 110. The second region is, for example, the area inside the subject P. The scanning mode of the second ultrasonic scan is a scanning mode in which ultrasonic transmission and reception are performed for each of the multiple second divided regions. The transmit / receive circuit 110 performs the second ultrasonic scan using ultrasonic transmission and reception conditions for acquiring B-mode image data.

[0061] The control circuit 180 then, each time a new B-mode image data is generated for each of the second divided regions, displays a B-mode image based on the newly generated B-mode image data in the region of the B-mode image displayed on the display 103 that corresponds to the newly generated B-mode image data. If a B-mode image is already displayed in the region of the display 103 that corresponds to the newly generated B-mode image data, the control circuit 180 updates the display content of the region that corresponds to the newly generated B-mode image data with a B-mode image based on the newly generated B-mode image data.

[0062] As described above, the transmitting and receiving circuit 110 alternately performs a first ultrasonic scan for each of the multiple first divided regions and a second ultrasonic scan for each of the multiple second divided regions via the ultrasonic probe 101. With this scanning configuration, the ultrasonic diagnostic apparatus 1 according to the first embodiment can independently set the ultrasonic transmission and reception conditions (image quality conditions) for the first ultrasonic scan and the second ultrasonic scan.

[0063] An example of the transmission and reception sequence of ultrasound for the first and second ultrasound scans in normal mode will be described. Figure 2 is a diagram illustrating an example of the first and second ultrasound scans in normal mode according to the first embodiment. Figure 3 is a diagram showing an example of the positions of multiple scan lines (positions in spatial coordinates of image data) in each scan of the first and second ultrasound scans according to the first embodiment.

[0064] In Figure 2, k, k+1, k+2, ..., k+12, k+13 indicate the order of ultrasound transmission and reception. k is an integer greater than or equal to 1. Also in Figure 2, the twelve circular frames represent the first ultrasound scan for the first divided region. Also in Figure 2, the two rectangular frames represent the second ultrasound scan for the second divided region. Furthermore, n or n+1 within the circular frames is an identifier indicating the scan line within the first divided region to which ultrasound is transmitted and received by the first ultrasound scan, and is a value indicating the order of the scan lines within the first divided region, as well as information indicating the spatial coordinate position of such scan lines. Furthermore, m or m+1 within the rectangular frames is an identifier indicating the scan line within the second divided region to which ultrasound is transmitted and received by the second ultrasound scan, and is a value indicating the order of the scan lines within the second divided region, as well as information indicating the spatial coordinate position of such scan lines. Here, n is an odd number greater than or equal to 1, and is less than or equal to N, which will be described later. Furthermore, m is an integer greater than or equal to 1 and less than M, which will be described later. In the following explanation, the scan line in the first divided region identified by the identifier s (where s is an integer) will be referred to as the "first scan line s". Similarly, the scan line in the second divided region identified by the identifier t (where t is an integer) will be referred to as the "second scan line t".

[0065] The examples in Figures 2 and 3 show the case where the first region is formed by N scan lines (rasters), the second region is formed by M scan lines, the first region is divided into (N / 2) first sub-regions, and the second region is divided into M second sub-regions. That is, the first region is a region containing N scan lines, namely scan line 1, scan line 2, ..., scan line N, and the second region is a region containing M scan lines, namely scan line 1, scan line 2, ..., scan line M. Here, N is an integer greater than or equal to 2 and is a multiple of 2. Also, M is an integer greater than 1. The " / " operator represents division. Therefore, the examples in Figures 2 and 3 show the case where each of the multiple first sub-regions is formed by two first scan lines, and each of the multiple second sub-regions is formed by one scan line.

[0066] As shown in Figure 2, the transmitting / receiving circuit 110 scans the second divided region including the second scan line m by transmitting and receiving ultrasound along the second scan line m as the k-th transmission / reception. Then, B-mode image data corresponding to the second divided region including the second scan line m is generated from the reflected wave data obtained by scanning the second divided region including the second scan line m. In this specification, transmitting and receiving ultrasound along a certain scan line is synonymous with performing the transmission and reception of ultrasound on a certain scan line.

[0067] The transmitting / receiving circuit 110 then transmits and receives ultrasound along the first scan line n as the (k+1)th transmission / receive, and transmits and receives ultrasound along the first scan line n+1 as the (k+2)th transmission / receive. Then, as shown in Figure 2, the transmitting / receiving circuit 110 repeats transmitting and receiving ultrasound along the first scan line n and the first scan line n+1 from the (k+3)th transmission / receive to the (k+12th)th transmission / receive. In this way, since the two first scan lines n and n+1 are transmitted and received alternately, the number of alternating stages, which indicates the number of scan lines that are transmitted and received alternately, is 2. The group of two first scan lines n and n+1 that are transmitted and received alternately is called an alternating stage group. In this way, the transmitting / receiving circuit 110 scans the first divided region including the first scan line n and the first scan line n+1. As a result, six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1 are obtained.

[0068] Then, a data sequence containing six reflected wave data corresponding to the first scan line n is input to an eigenvector type MTI filter to obtain color Doppler data. Similarly, a data sequence containing six reflected wave data corresponding to the first scan line n+1 is input to an eigenvector type MTI filter to obtain color Doppler data. In other words, the packet size of the eigenvector type MTI filter in this case is 6. From these obtained color Doppler data, color Doppler image data corresponding to the first segmented region including the first scan line n and the first scan line n+1 is generated.

[0069] Then, the transmitting / receiving circuit 110, as the k+13th transmit / receive, scans the second divided region including the second scan line m+1 by transmitting and receiving ultrasound along the second scan line m+1. From the reflected wave data obtained by scanning the second divided region including the second scan line m+1, B-mode image data corresponding to the second divided region including the second scan line m+1 is generated.

[0070] The transmitting / receiving circuit 110 then alternately performs the first ultrasonic scan and the second ultrasonic scan to scan all of the first divided regions and all of the second divided regions, that is, to scan the entire area of ​​the first region and the entire area of ​​the second region. This yields one frame of color Doppler image data corresponding to the first region and one frame of B-mode image data corresponding to the second region. The transmitting / receiving circuit 110 then repeats scanning the entire area of ​​the first region and the entire area of ​​the second region multiple times. This yields multiple frames of color Doppler image data and multiple frames of B-mode image data, and the display 103 displays the B-mode image as a moving image in real time, as well as the color Doppler image superimposed on the B-mode image as a moving image in real time.

[0071] In normal mode, the first and second ultrasonic scans are performed alternately. However, the residual signal (residual echo) of the last ultrasonic wave transmitted in the second ultrasonic scan may fall within the reception period of the reflected wave of the first ultrasonic wave transmitted in the first ultrasonic scan. This is thought to be because the transmitting / receiving circuit 110 (ultrasonic probe 101) transmits the ultrasonic wave in the first ultrasonic scan before receiving the reflected wave from the depths of the last ultrasonic wave transmitted in the second ultrasonic scan.

[0072] For example, in the case shown in Figure 2, the residual signal of the ultrasound transmitted along the second scan line m as the k-th transmission / reception falls within the reception period of the reflected ultrasound transmitted along the first scan line n as the k+1th transmission / reception. Therefore, the reflected wave signal of the first scan line n obtained by the k+1th transmission / reception output from the ultrasound probe 101 contains the residual signal and is thus affected by the residual signal.

[0073] Here, each of the residual signals of the ultrasound transmitted along the first scan line n+1 as the k+2th, k+4th, k+6th, ..., k+10th transmission and reception enters the reception period of the reflected ultrasound transmitted along the first scan line n as the k+3rd, k+5th, k+7th, ..., k+11th transmission and reception. However, the residual signals contained in each of the reflected wave signals of the first scan line n obtained by the k+3rd transmission and reception, the k+5th transmission and reception, the k+7th transmission and reception, ..., k+11th transmission and reception output from the ultrasound probe 101 are similar signals because the transmission and reception that give rise to the residual signals are based on the same ultrasound transmission and reception conditions (ultrasound transmission and reception conditions for collecting color Doppler image data). Therefore, residual signals contained in the reflected wave signal of the first scan line n obtained from the k+3rd, k+5th, k+7th, ..., and k+11th transmissions are unlikely to cause artifacts in color Doppler images.

[0074] On the other hand, the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception output from the ultrasound probe 101 is a signal generated by the second ultrasound scan based on the ultrasound transmission and reception conditions for acquiring B-mode image data, not the transmission and reception based on the ultrasound transmission and reception conditions for acquiring color Doppler image data. Therefore, the appearance of the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception is significantly different from the appearance of the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+3), (k+5), (k+7), ..., (k+11) transmission and reception. Consequently, the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception is imaged as an artifact, causing artifacts in the color Doppler image.

[0075] Furthermore, each residual signal of ultrasound transmitted along the first scan line n as the k+1th, k+3rd, k+5th, ..., k+11th transmission and reception enters the reception period of the reflected ultrasound transmitted along the first scan line n+1 as the k+2nd, k+4th, k+6th, ..., k+12th transmission and reception. However, the residual signals included in the reflected wave signal of the first scan line n+1 obtained by the k+2nd transmission and reception, the reflected wave signal of the first scan line n+1 obtained by the k+4th transmission and reception, the reflected wave signal of the first scan line n+1 obtained by the k+6th transmission and reception, ..., k+12th transmission and reception output from the ultrasound probe 101 are similar signals because the transmission and reception that give rise to the residual signals are based on the same ultrasound transmission and reception conditions (ultrasound transmission and reception conditions for collecting color Doppler image data). Therefore, the residual signals contained in the reflected wave signal of the first scan line n+1 obtained by the k+2th, k+4th, k+6th, ..., and k+12th transmissions are unlikely to cause artifacts in color Doppler images.

[0076] As described above, the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission is imaged as an artifact, causing artifacts in color Doppler images. Therefore, dummy rate transmission can be considered to reduce residual multiplexing. An ultrasound diagnostic device that performs such dummy rate transmission will be described as the ultrasound diagnostic device of the comparative example. Figure 4 is a diagram illustrating the dummy rate transmission performed by the ultrasound diagnostic device of the comparative example when the dummy rate mode is set as the scanning mode. In describing the ultrasound transmission and reception sequence in dummy rate transmission in the dummy rate mode shown in Figure 4, we will mainly explain the differences from the ultrasound transmission and reception sequence in the normal mode shown in Figure 2.

[0077] In Figure 4, k, k+1, k+2, ..., k+14, k+15 indicate the order of ultrasound transmission and reception. Also in Figure 4, the two adjacent triangular frames and the twelve adjacent circular frames indicate the first ultrasound scan for the first divided region. Furthermore, n or n+1 within the triangular frames are identifiers indicating the scan lines within the first divided region to which ultrasound is transmitted by the first ultrasound scan. These values ​​indicate the order of the scan lines within the first divided region, as well as information indicating the spatial coordinate position of such scan lines.

[0078] As shown in Figure 4, the comparative example ultrasound diagnostic apparatus scans a second divided region including the second scan line m by transmitting and receiving ultrasound along the second scan line m as the k-th transmission / reception. The ultrasound diagnostic apparatus then generates B-mode image data corresponding to the second divided region including the second scan line m from the reflected wave data obtained by scanning the second divided region including the second scan line m.

[0079] The ultrasound diagnostic device then transmits ultrasound along the first scan line n as the (k+1)th transmission and reception, and transmits ultrasound along the first scan line n+1 as the (k+2)th transmission and reception. However, the receiving circuit of the ultrasound diagnostic device does not generate reflected wave data from the reflected ultrasound waves obtained in the (k+1)th and (k+2)th transmissions and receptions. Alternatively, the circuit downstream of the receiving circuit of the ultrasound diagnostic device does not generate various data using the reflected wave data generated from the reflected ultrasound waves obtained in the (k+1)th and (k+2)th transmissions and receptions.

[0080] Then, as shown in Figure 4, the ultrasound diagnostic device repeatedly transmits and receives ultrasound along the first scan line n from the k+3rd transmission to the k+14th transmission, and then transmits and receives ultrasound along the first scan line n+1. In this way, the ultrasound diagnostic device scans the first divided region including the first scan line n and the first scan line n+1. As a result, six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1 are obtained.

[0081] The ultrasound diagnostic device then inputs a data sequence containing six reflected wave data corresponding to the first scan line n into an eigenvector type MTI filter to obtain color Doppler data. Similarly, the ultrasound diagnostic device inputs a data sequence containing six reflected wave data corresponding to the first scan line n+1 into an eigenvector type MTI filter to obtain color Doppler data. In this case, the packet size of the eigenvector type MTI filter is 6. The ultrasound diagnostic device then generates color Doppler image data corresponding to the first segmented region containing the first scan line n and the first scan line n+1 from this obtained color Doppler data.

[0082] The ultrasound diagnostic device then scans the second divided region including the second scan line m+1 by transmitting and receiving ultrasound along the second scan line m+1 as the k+15th transmission / reception. The ultrasound diagnostic device then generates B-mode image data corresponding to the second divided region including the second scan line m+1 from the reflected wave data obtained by scanning the second divided region including the second scan line m+1.

[0083] The ultrasound diagnostic device then alternately performs a first ultrasound scan and a second ultrasound scan to scan all of the first divided regions and all of the second divided regions, that is, to scan the entire area of ​​the first region and the entire area of ​​the second region. This yields one frame of color Doppler image data corresponding to the first region and one frame of B-mode image data corresponding to the second region. The ultrasound diagnostic device then repeats scanning the entire area of ​​the first region and the entire area of ​​the second region multiple times. This yields multiple frames of color Doppler image data and multiple frames of B-mode image data. The display on the ultrasound diagnostic device shows the B-mode images as real-time moving images, and the color Doppler images superimposed on the B-mode images are also shown as real-time moving images.

[0084] Here, the residual signal of the ultrasound transmitted along the second scan line m as the k-th transmission / reception enters the reception period of the reflected ultrasound wave transmitted along the first scan line n as the (k+1)th transmission / reception. However, in the ultrasound diagnostic apparatus according to the comparative example, the reflected wave signal obtained from the (k+1)th transmission / reception does not contribute to the generation of color Doppler image data.

[0085] To illustrate with a specific example, in the example shown in Figure 4, each residual signal of the ultrasound transmitted along the first scan line n+1 as the k+2th, k+4th, k+6th, ..., k+12th transmission and reception enters the reception period of the reflected ultrasound transmitted along the first scan line n as the k+3rd, k+5th, k+7th, ..., k+13th transmission and reception. However, the residual signals contained in each of the reflected wave signals of the first scan line n obtained by the k+3rd transmission and reception output from the ultrasound probe 101, the reflected wave signal of the first scan line n obtained by the k+5th transmission and reception, the reflected wave signal of the first scan line n obtained by the k+7th transmission and reception, ..., k+13th transmission and reception are similar signals because the transmission and reception that give rise to the residual signals are based on the same ultrasound transmission and reception conditions (ultrasound transmission and reception conditions for collecting color Doppler image data). Therefore, residual signals contained in the reflected wave signal of the first scan line n obtained by the k+3rd, k+5th, k+7th, ..., and k+13th transmissions are unlikely to cause artifacts in color Doppler images.

[0086] In the example shown in Figure 4, the ultrasound diagnostic device in the comparative example does not need to perform the k+1th transmission and reception. However, because sequencing and data handling become difficult, and it is difficult to predict the degree of residual multiple occurrences in advance, it is preferable for the ultrasound diagnostic device in the comparative example to perform the k+1th transmission and reception.

[0087] The ultrasound diagnostic device in the comparative example can reduce the effect of residual multiplexing on color Doppler image data. However, as shown in Figure 4, generating color Doppler image data corresponding to one first segmented region requires 14 transmissions, from the (k+1)th transmission to the (k+14th)th transmission. As a result, the frame rate of the color Doppler image data decreases in the ultrasound diagnostic device in the comparative example.

[0088] Figure 5 shows an example of the data sequence input to the eigenvector type MTI filter in the normal mode shown in Figure 2. As shown in Figure 5, in the normal mode, six reflected wave data obtained from the k+1th transmission and reception, the k+3rd transmission and reception, ..., the k+9th transmission and reception, and the k+11th transmission and reception, and six reflected wave data obtained from the k+2nd transmission and reception, the k+4th transmission and reception, ..., the k+10th transmission and reception, and the k+12th transmission and reception are input to the eigenvector type MTI filter. This yields color Doppler image data corresponding to the first divided region including the first scan line n and the first scan line n+1.

[0089] Here, the packet size of the eigenvector type MTI filter is variable. Therefore, by utilizing the fact that the packet size is variable, the ultrasound diagnostic apparatus 1 according to the first embodiment performs the processing described below so as to reduce the effect of residual multiplexing on the color Doppler image data while suppressing a decrease in the frame rate of the color Doppler image data.

[0090] Figure 6 shows an example of a data sequence input to the eigenvector type MTI filter in the residual multiplex reduction mode according to the first embodiment. The ultrasound diagnostic device 1 is set to residual multiplex reduction mode when the residual multiplex reduction button described above is pressed by the operator. In this way, when the residual multiplex reduction button is pressed, the ultrasound diagnostic device 1 switches to residual multiplex reduction mode. In residual multiplex reduction mode, the transmitting and receiving circuit 110 alternately performs the first ultrasound scan and the second ultrasound scan, similar to when the first ultrasound scan and the second ultrasound scan are performed alternately in the normal mode.

[0091] However, as shown in Figure 6, in residual multiplexing reduction mode, of the six reflected wave data obtained from the k+1th, k+3rd, ..., k+9th, and k+11th transmissions and receptions, five reflected wave data obtained from the k+3rd, ..., k+9th, and k+11th transmissions and receptions are input to the eigenvector type MTI filter. Also, of the six reflected wave data obtained from the k+2nd, k+4th, ..., k+10th, and k+12th transmissions and receptions, five reflected wave data obtained from the k+4th, ..., k+10th, and k+12th transmissions and receptions are input to the eigenvector type MTI filter. In other words, the packet size of the eigenvector type MTI filter in residual multiplexing reduction mode is 5. As a result, color Doppler image data corresponding to the first divided region including the first scan line n and the first scan line n+1 is obtained.

[0092] Thus, in residual multiplexing reduction mode, the ultrasound diagnostic device 1 generates color Doppler image data without using reflected wave data affected by residual multiplexing, which causes artifacts, such as reflected wave data based on the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception. Therefore, in residual multiplexing reduction mode, the ultrasound diagnostic device 1 can reduce the effect of residual multiplexing on color Doppler image data.

[0093] Furthermore, in residual multiplexing reduction mode, the ultrasound diagnostic device 1 can generate color Doppler image data corresponding to one first segmented region in 12 transmissions, from the (k+1)th transmission to the (k+12th)th transmission, by setting the packet size of the eigenvector type MTI filter to 5. Therefore, the ultrasound diagnostic device 1 can suppress a decrease in the frame rate of the color Doppler image data.

[0094] Here, in the ultrasound diagnostic device 1, a predetermined reference value is set to "10 times (10)" as the number of transmissions and receptions required to obtain the reflected wave signal used when generating color Doppler image data corresponding to one first segmented region. The predetermined reference value is less than the number of transmissions and receptions required to obtain the reflected wave signal used when generating color Doppler image data corresponding to one first segmented region in the dummy rate mode described above, which is "12 times". Then, in the first ultrasound scan in the residual multiplex reduction mode, the ultrasound diagnostic device 1 performs the first ultrasound scan such that the reflected wave signal used when generating color Doppler image data corresponding to one first segmented region is obtained with a number of transmissions and receptions of "10 times" or less than the predetermined reference value. For example, the ultrasound diagnostic device 1 generates color Doppler image data representing the region corresponding to the 10 transmissions and receptions (one first segmented region) of the first region, based on 10 reflected wave signals obtained from 10 transmissions and receptions (10 transmissions and receptions from the k+3rd to the k+12th transmissions and receptions), which is "10 times" or less than the predetermined reference value, as at least a part of the color Doppler image data representing the entire first region. Here, the 10 transmissions from the k+3rd transmission to the k+12th transmission are, for example, an example of a second predetermined number of transmissions.

[0095] Therefore, according to the ultrasound diagnostic apparatus 1 of the first embodiment, it is possible to reduce the effect of residual multiplexing on color Doppler image data while suppressing a decrease in the frame rate of color Doppler image data.

[0096] In the residual multiple reduction mode, the ultrasound diagnostic device 1 does not need to perform the k+2th transmission and reception. However, it is preferable for the ultrasound diagnostic device 1 to perform the k+1th transmission and reception due to difficulties in data handling, etc.

[0097] Next, an example of the flow of processing performed by the ultrasound diagnostic device 1 according to the first embodiment will be described. Figure 7 is a flowchart of an example of the flow of processing performed by the ultrasound diagnostic device 1 according to the first embodiment. The processing shown in Figure 7 is performed when the operator operates the input device 102 and inputs an instruction to the control circuit 180 to superimpose a color Doppler image onto the B-mode image in order to perform an examination of the subject P.

[0098] As shown in Figure 7, the ultrasound diagnostic device 1 alternately performs a first ultrasound scan and a second ultrasound scan (see Figure 2) in normal mode on the subject P to generate B-mode image data and color Doppler image data (step S101).

[0099] The ultrasound diagnostic device 1 then superimposes a color Doppler image, based on color Doppler image data, onto a B-mode image, based on B-mode image data generated in the set scanning mode, and displays it on the display 103 (step S102). The scanning mode may be the normal mode, which is initially set, or the residual overlay reduction mode, which is set in step S104.

[0100] Then, the control circuit 180 of the ultrasound diagnostic device 1 determines whether or not the residual multiple reduction button has been pressed by the operator (step S103). If the control circuit 180 determines that the residual multiple reduction button has been pressed by the operator (step S103: Yes), it proceeds to step S104. In this specification, pressing the residual multiple reduction button and turning on the residual multiple reduction button are synonymous. On the other hand, if the control circuit 180 determines that the residual multiple reduction button has not been pressed by the operator (step S103: No), it proceeds to step S105.

[0101] The ultrasound diagnostic device 1 alternately performs a first ultrasound scan and a second ultrasound scan in residual multiple reduction mode on the subject P to generate B-mode image data and color Doppler image data (step S104), and then proceeds to step S105.

[0102] Then, the control circuit 180 of the ultrasound diagnostic device 1 determines whether or not to continue the examination (step S105). For example, in step S105, the control circuit 180 determines whether or not the operator has operated the input device 102 and input an instruction to end the examination of subject P (end instruction) to the control circuit 180. If the control circuit 180 determines that no end instruction has been input, it determines to continue the examination (step S105: Yes) and returns to step S102.

[0103] On the other hand, if the control circuit 180 determines that a termination instruction has been input, it decides not to continue the inspection (step S105: No) and terminates the process shown in Figure 7.

[0104] In the process shown in Figure 7, if the residual multiple reduction button, which was turned on, is turned off by the operator, that is, if the state in which the residual multiple reduction button was pressed is released, the ultrasound diagnostic device 1 will alternately perform the first ultrasound scan and the second ultrasound scan in normal mode on the subject P to generate B-mode image data and color Doppler image data.

[0105] Figure 8 shows an example of a color Doppler image displayed by the ultrasound diagnostic device 1 according to the first embodiment. Figure 8 shows a color Doppler image 20 displayed on the display 103 in normal mode, and a color Doppler image 21 displayed on the display 103 in residual multiplex reduction mode.

[0106] Comparing color Doppler image 20 and color Doppler image 21, it can be seen that artifacts due to residual multiplexing occur in color Doppler image 20, but the occurrence of artifacts is suppressed in color Doppler image 21.

[0107] The ultrasound diagnostic apparatus 1 according to the first embodiment has been described above.

[0108] As described above, the ultrasound diagnostic apparatus 1 according to the first embodiment includes a scanning unit that alternately and repeatedly performs two ultrasound scans: a first ultrasound scan which repeatedly transmits and receives at least one first scan line included in a first region under first ultrasound transmission conditions, and a second ultrasound scan which transmits and receives at least one second scan line included in a second region under second ultrasound transmission conditions. As a result, the scanning unit transmits and receives all first scan lines included in the first region and all second scan lines included in the second region. The scanning unit includes, for example, an ultrasound probe 101, a transmit / receive circuit 110, and a control circuit 180, and is implemented by the ultrasound probe 101, the transmit / receive circuit 110, and the control circuit 180. However, the scanning unit may further include other circuits and equipment.

[0109] Furthermore, the ultrasound diagnostic apparatus 1 includes a generation unit that generates Doppler image data representing a first region based on reflected wave signals obtained by transmitting and receiving all first scan lines included in a first region, and generates B-mode image data representing a second region based on reflected wave signals obtained by transmitting and receiving all second scan lines included in a second region. The generation unit includes, for example, a transmitting and receiving circuit 110, a B-mode processing circuit 130, a Doppler processing circuit 140, an image generation circuit 150, and a control circuit 180, and is implemented by the transmitting and receiving circuit 110, the B-mode processing circuit 130, the Doppler processing circuit 140, the image generation circuit 150, and the control circuit 180. However, the generation unit may further include other circuits and devices. Here, the reflected wave signal is, for example, an example of a signal. The Doppler image data is, for example, an example of first image data. The B-mode image data is, for example, an example of second image data.

[0110] Then, in the residual multiplex reduction mode, when the first ultrasonic scan is performed by the scanning unit after the second ultrasonic scan, the generation unit generates color Doppler image data representing the region corresponding to the 10 transmissions (one first divided region) of the first region, based on 10 reflected wave signals obtained from 10 transmissions (10 transmissions from the k+3rd to the k+12th transmission) that are less than or equal to a predetermined reference value of "10 times", excluding the first transmission and reception for a predetermined number of transmissions and receptions (in the example in Figure 6, the first two transmissions and receptions (the k+1th and k+2nd transmissions and receptions)) from all transmissions and receptions in the first ultrasonic scan, as at least a part of the color Doppler image data representing the entire first region. The residual multiplex reduction mode is, for example, an example of the first scanning mode.

[0111] Furthermore, in the residual multiplex reduction mode, when the first ultrasonic scan is performed by the scanning unit after the second ultrasonic scan, the generation unit uses 10 reflected wave signals obtained from 10 transmissions and receptions (10 transmissions and receptions from the k+3rd to the k+12th transmission and reception) that are less than or equal to a predetermined reference value of "10 times", and an eigenvector type MTI filter to generate color Doppler image data indicating the first divided region corresponding to those 10 transmissions and receptions, as at least a part of the color Doppler image data indicating the first region.

[0112] Furthermore, the ultrasound diagnostic apparatus 1 according to the first embodiment includes, as described above, an acquisition unit that collects multiple reflected wave data by transmitting and receiving ultrasound multiple times on the same scan line. The acquisition unit includes, for example, an ultrasound probe 101, a transmitting and receiving circuit 110, and a control circuit 180, and is implemented by the ultrasound probe 101, the transmitting and receiving circuit 110, and the control circuit 180. However, the acquisition unit may further include other circuits and devices. The generation unit generates a color Doppler image using the multiple reflected wave data collected by transmitting and receiving ultrasound multiple times on the same scan line. The acquisition unit collects multiple reflected wave data by transmitting and receiving ultrasound multiple times on a predetermined scan line. In the process of S104, the generation unit determines the number of reflected wave data that will not be used to generate the color Doppler image according to the influence of reflected wave signals (echo signals) transmitted and received in a time phase prior to the multiple ultrasound transmissions and receptions on the predetermined scan line. The generation unit then generates a color Doppler image using multiple reflected wave data (multiple reflected wave data collected by the acquisition unit) obtained by multiple ultrasonic transmissions and receptions on a predetermined scan line, with a predetermined number of reflected wave data points removed, counting from the first reflected wave data point. Reflected wave data is, for example, an example of transmitted and received data.

[0113] Furthermore, in the first embodiment, the generation unit generates a color Doppler image using a number of second-order reflected wave data that is less than or equal to a predetermined reference value, obtained by subtracting the number of first-order reflected wave data from the multiple reflected wave data collected by multiple ultrasonic transmissions and receptions on a predetermined scan line, counting from the first reflected wave data, as the number of reflected wave data not used for generating a color Doppler image.

[0114] Furthermore, in the first embodiment, the generation unit generates a color Doppler image using reflected wave data equal to the number of second reflected wave data and an eigenvector type MTI filter in residual multiplex reduction mode.

[0115] Therefore, as described above, the ultrasound diagnostic device 1 can reduce the effect of residual multiplexing on color Doppler image data while suppressing the decrease in the frame rate of color Doppler image data.

[0116] (Second embodiment) Next, an ultrasound diagnostic apparatus according to the second embodiment will be described. In the description of the second embodiment, components similar to those in the first embodiment will be denoted by the same reference numerals, and their descriptions may be omitted. In addition, the description of the second embodiment will mainly focus on the differences from the first embodiment.

[0117] Figure 9 is a block diagram showing an example configuration of an ultrasound diagnostic apparatus 1a according to the second embodiment. The ultrasound diagnostic apparatus 1a according to the second embodiment differs from the ultrasound diagnostic apparatus 1 according to the first embodiment in that it includes an apparatus body 100a instead of the apparatus body 100. The apparatus body 100a according to the second embodiment differs from the apparatus body 100 in that it includes a control circuit 180a instead of the control circuit 180.

[0118] Figure 10 is a diagram illustrating an example of the first and second ultrasonic scanning in the normal mode according to the second embodiment. Figure 11 is a diagram illustrating an example of the data sequence input to the eigenvector type MTI filter in the residual multiple reduction mode according to the second embodiment. Figure 12 is a diagram illustrating an example of the first and second ultrasonic scanning in the dummy rate mode according to the second embodiment. Figure 13 is a flowchart illustrating an example of the processing flow performed by the ultrasonic diagnostic apparatus 1a according to the second embodiment.

[0119] The process shown in Figure 13 is executed when the operator operates the input device 102 and inputs an instruction to the control circuit 180a to superimpose a color Doppler image onto the B-mode image in order to perform an examination of subject P.

[0120] The processes in steps S101, S102, S103, and S105 shown in Figure 13 are the same as the processes in steps S101, S102, S103, and S105 shown in Figure 7. However, the processes executed by the control circuit 180 in Figure 7 are executed by the control circuit 180a in Figure 13. For example, in step S101 shown in Figure 13, as shown in Figure 10, the ultrasound diagnostic device 1a, similar to the ultrasound diagnostic device 1 in the first embodiment, alternately performs a first ultrasound scan and a second ultrasound scan in normal mode on the subject P to generate B-mode image data and color Doppler image data.

[0121] If the control circuit 180a determines that the residual multiple reduction button has been pressed by the operator (step S103: Yes), it proceeds to step S201. On the other hand, if the control circuit 180a determines that the residual multiple reduction button has not been pressed by the operator (step S103: No), it proceeds to step S105.

[0122] The control circuit 180a obtains from the operator the degree (level) to which residual multiplexing should be reduced, and whether the frame rate or image quality of the color Doppler image data should be prioritized (step S201). For example, in step S201, the control circuit 180a displays multiple levels 1 to 3 on the display 103, allowing the operator to select one of the levels 1 to 3 for reducing residual multiplexing. The higher the level value, the greater the degree to which residual multiplexing is reduced. Also in step S201, the control circuit 180a displays a screen on the display 103 for the operator to select whether the frame rate or image quality of the color Doppler image data should be prioritized. The operator operates the input device 102 to select one of the multiple levels 1 to 3. The operator also operates the input device 102 to select whether the frame rate or image quality of the color Doppler image data should be prioritized. The control circuit 180a obtains the selection made by the operator.

[0123] Then, the control circuit 180a determines whether the operator has chosen to prioritize the frame rate of the color Doppler image data in step S201 (step S202). Here, the frame rate of the color Doppler image data obtained in the residual multiplex reduction mode is higher than the frame rate of the color Doppler image data obtained in the dummy rate mode. Therefore, if the operator has chosen to prioritize the frame rate of the color Doppler image data (step S202: Yes), the ultrasound diagnostic device 1a sets the scanning mode to the residual multiplex reduction mode and alternately performs the first ultrasound scan and the second ultrasound scan in the residual multiplex reduction mode on the subject P to generate B-mode image data and color Doppler image data (step S203), and proceeds to step S105.

[0124] Here, in step S203, processing is performed to reduce residual multiplexing at a level selected by the operator. For example, as shown in Figure 11, at level 1, of the six reflected wave data obtained from the k+1th transmission, k+3rd transmission, ..., k+9th transmission, and k+11th transmission, five reflected wave data obtained from the k+3rd transmission, ..., k+9th transmission, and k+11th transmission are input to the eigenvector type MTI filter. Also, although not shown in Figure 11, similarly, of the six reflected wave data obtained from the k+2nd transmission, k+4th transmission, ..., k+10th transmission, and k+12th transmission, five reflected wave data obtained from the k+4th transmission, ..., k+10th transmission, and k+12th transmission are input to the eigenvector type MTI filter. That is, at level 1, the packet size of the eigenvector type MTI filter is 5. As a result, color Doppler image data corresponding to the first divided region including the first scan line n and the first scan line n+1 is obtained.

[0125] Furthermore, as shown in Figure 11, at level 2, of the six reflected wave data obtained from the k+1th, k+3rd, ..., k+9th, and k+11th transmissions and receptions, four reflected wave data obtained from the k+5th, ..., k+9th, and k+11th transmissions and receptions are input to the eigenvector type MTI filter. Also, although not shown in Figure 11, similarly, of the six reflected wave data obtained from the k+2nd, k+4th, ..., k+10th, and k+12th transmissions and receptions, four reflected wave data obtained from the k+6th, ..., k+10th, and k+12th transmissions and receptions are input to the eigenvector type MTI filter. In other words, at level 2, the packet size of the eigenvector type MTI filter is 4. This yields color Doppler image data corresponding to the first divided region including the first scan line n and the first scan line n+1.

[0126] Furthermore, as shown in Figure 11, at level 3, of the six reflected wave data obtained from the k+1th, k+3rd, ..., k+9th, and k+11th transmissions and receptions, three reflected wave data obtained from the k+7th, k+9th, and k+11th transmissions and receptions are input to the eigenvector type MTI filter. Also, although not shown in Figure 11, similarly, of the six reflected wave data obtained from the k+2nd, k+4th, ..., k+10th, and k+12th transmissions and receptions, three reflected wave data obtained from the k+8th, k+10th, and k+12th transmissions and receptions are input to the eigenvector type MTI filter. In other words, at level 3, the packet size of the eigenvector type MTI filter is 3. This yields color Doppler image data corresponding to the first segmented region including the first scan line n and the first scan line n+1.

[0127] In residual multiplex reduction mode, a higher level value indicates a greater degree of residual multiplex reduction. Conversely, a lower level value results in higher image quality of the color Doppler image data.

[0128] Furthermore, the image quality of the color Doppler image data obtained in dummy rate mode is higher than that of the color Doppler image data obtained in residual multiplex reduction mode. Therefore, if it is selected to prioritize the image quality of the color Doppler image data (step S202: No), the ultrasound diagnostic device 1a sets the scanning mode to dummy rate mode and alternately performs the first ultrasound scan and the second ultrasound scan (see Figure 4) in dummy rate mode on the subject P to generate B-mode image data and color Doppler image data (step S204), and proceeds to step S105.

[0129] In step S204, a process is performed to reduce residual multiplexing at a level selected by the operator. For example, as shown in Figure 12, at level 1, the ultrasound diagnostic device 1a transmits ultrasound along the first scan line n as the (k+1)th transmission and reception, and transmits ultrasound along the first scan line n+1 as the (k+2)th transmission and reception. However, the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate reflected wave data from the reflected ultrasound waves obtained in the (k+1)th and (k+2)th transmissions. Alternatively, the circuit downstream of the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate various data using the reflected wave data generated from the reflected ultrasound waves obtained in the (k+1)th and (k+2)th transmissions.

[0130] Then, the ultrasound diagnostic device 1a repeatedly transmits and receives ultrasound along the first scan line n from the k+3rd transmission to the k+14th transmission, and then transmits and receives ultrasound along the first scan line n+1. In this way, the ultrasound diagnostic device 1a scans the first divided region including the first scan line n and the first scan line n+1. As a result, six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1 are obtained.

[0131] The ultrasound diagnostic device 1a then inputs a data sequence containing six reflected wave data corresponding to the first scan line n into an eigenvector type MTI filter to obtain color Doppler data. Similarly, the ultrasound diagnostic device 1a inputs a data sequence containing six reflected wave data corresponding to the first scan line n+1 into an eigenvector type MTI filter to obtain color Doppler data. That is, the packet size of the eigenvector type MTI filter when the dummy rate mode is level 1 is 6. The ultrasound diagnostic device 1a then generates color Doppler image data corresponding to the first segmented region containing the first scan line n and the first scan line n+1 from these obtained color Doppler data.

[0132] Furthermore, as shown in Figure 12, at level 2, the ultrasound diagnostic device 1a transmits ultrasound along the first scan line n as the (k+1)th transmission / reception, transmits ultrasound along the first scan line n+1 as the (k+2)th transmission / reception, transmits ultrasound along the first scan line n as the (k+3)th transmission / reception, and transmits ultrasound along the first scan line n+1 as the (k+4)th transmission / reception. However, the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate reflected wave data from the reflected ultrasound waves obtained in each of the (k+1), (k+2), (k+3), and (k+4) transmissions / receptions. Alternatively, the circuit downstream of the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate various data using the reflected wave data generated from the reflected ultrasound waves obtained in each of the (k+1), (k+2), (k+3), and (k+4) transmissions / receptions.

[0133] The ultrasound diagnostic device 1a then repeatedly transmits and receives ultrasound along the first scan line n from the k+5th transmission to the k+16th transmission, and then transmits and receives ultrasound along the first scan line n+1. In this way, the ultrasound diagnostic device 1a scans the first divided region including the first scan line n and the first scan line n+1. As a result, six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1 are obtained.

[0134] The ultrasound diagnostic device 1a then inputs a data sequence containing six reflected wave data corresponding to the first scan line n into an eigenvector type MTI filter to obtain color Doppler data. Similarly, the ultrasound diagnostic device 1a inputs a data sequence containing six reflected wave data corresponding to the first scan line n+1 into an eigenvector type MTI filter to obtain color Doppler data. That is, the packet size of the eigenvector type MTI filter in dummy rate mode at level 2 is 6. The ultrasound diagnostic device 1a then generates color Doppler image data corresponding to the first segmented region containing the first scan line n and the first scan line n+1 from this obtained color Doppler data.

[0135] Furthermore, as shown in Figure 12, at level 3, the ultrasound diagnostic device 1a transmits ultrasound along the first scan line n as the (k+1)th transmission / reception, transmits ultrasound along the first scan line n+1 as the (k+2)th transmission / reception, transmits ultrasound along the first scan line n as the (k+3)th transmission / reception, transmits ultrasound along the first scan line n+1 as the (k+4)th transmission / reception, transmits ultrasound along the first scan line n as the (k+5)th transmission / reception, and transmits ultrasound along the first scan line n+1 as the (k+6)th transmission / reception. However, the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate reflected wave data from the reflected ultrasound waves obtained in each of the (k+1), (k+2), (k+3), (k+4), (k+5), and (k+6) transmission / reception. Alternatively, the circuit downstream of the receiving circuit 112 of the ultrasound diagnostic device 1a does not generate various data using the reflected wave data generated from the reflected ultrasound waves obtained in each of the (k+1), (k+2), (k+3), (k+4), (k+5), and (k+6) transmissions.

[0136] Then, the ultrasound diagnostic device 1a repeatedly transmits and receives ultrasound along the first scan line n from the k+7th transmission to the k+18th transmission, and then transmits and receives ultrasound along the first scan line n+1. In this way, the ultrasound diagnostic device 1a scans the first divided region including the first scan line n and the first scan line n+1. As a result, six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1 are obtained.

[0137] The ultrasound diagnostic device 1a then inputs a data sequence containing six reflected wave data corresponding to the first scan line n into an eigenvector type MTI filter to obtain color Doppler data. Similarly, the ultrasound diagnostic device 1a inputs a data sequence containing six reflected wave data corresponding to the first scan line n+1 into an eigenvector type MTI filter to obtain color Doppler data. That is, the packet size of the eigenvector type MTI filter in dummy rate mode at level 3 is 6. The ultrasound diagnostic device 1a then generates color Doppler image data corresponding to the first segmented region containing the first scan line n and the first scan line n+1 from these obtained color Doppler data.

[0138] In dummy rate mode, a higher level value results in a greater reduction in residual multiplexing. Furthermore, the image quality of the color Doppler image data remains constant regardless of the level value.

[0139] The ultrasound diagnostic apparatus 1a according to the second embodiment has been described above.

[0140] In the second embodiment, the scanning unit includes, for example, an ultrasonic probe 101, a transmitting / receiving circuit 110, and a control circuit 180a, and is realized by the ultrasonic probe 101, the transmitting / receiving circuit 110, and the control circuit 180a. However, the scanning unit may further include other circuits and devices. Also in the second embodiment, the generation unit includes, for example, a transmitting / receiving circuit 110, a B-mode processing circuit 130, a Doppler processing circuit 140, an image generation circuit 150, and a control circuit 180a, and is realized by the transmitting / receiving circuit 110, the B-mode processing circuit 130, the Doppler processing circuit 140, an image generation circuit 150, and the control circuit 180a. However, the generation unit may further include other circuits and devices.

[0141] In the second embodiment, when the first ultrasonic scan is performed by the scanning unit after the second ultrasonic scan in dummy rate mode, the generation unit generates color Doppler image data representing a region corresponding to 12 transmissions and receptions (one first divided region) of the first region, based on 12 reflected wave signals obtained from a fourth predetermined number of transmissions and receptions (12 transmissions and receptions in each of the levels 1 to 3 in Figure 12), which is greater than the second predetermined number, excluding the third predetermined number of transmissions and receptions from the first transmission and reception to the third predetermined number of transmissions and receptions (two transmissions and receptions from the first transmission and reception in level 1 of Figure 12 (two transmissions and receptions indicated by triangular frames) from the first transmission and reception to the third predetermined number of transmissions and receptions (four transmissions and receptions indicated by triangular frames in level 2 of Figure 12, and six transmissions and receptions from the first transmission and reception to the sixth transmission and reception in level 3 of Figure 12), as at least a part of the color Doppler image data representing the entire first region. The dummy rate mode is, for example, an example of the second scan mode.

[0142] Furthermore, in dummy rate mode, when the first ultrasonic scan is performed by the scanning unit after the second ultrasonic scan, the generation unit uses 12 reflected wave signals obtained from a fourth predetermined number of transmissions and receptions and an eigenvector type MTI filter to generate color Doppler image data indicating the first segmented region corresponding to the fourth predetermined number of transmissions and receptions, as at least a part of the color Doppler image data indicating the entire first region.

[0143] In the second embodiment, the input device 102 receives an instruction to prioritize the frame rate of the color Doppler image data (frame rate priority instruction). The input device 102 also receives a specification of a level to reduce residual multiplexing in the color Doppler image data (level specification). When the generation unit receives the frame rate priority instruction and level specification from the input device 102, in the residual multiplexing reduction mode, it changes the number of transmissions and receptions for the first predetermined number of transmissions and receptions (1 for level 1 in Figure 11, 2 for level 2, and 3 for level 3) and the number of transmissions and receptions for the second predetermined number of transmissions and receptions (5 for level 1 in Figure 11, 4 for level 2, and 3 for level 3) so that the total number of transmissions and receptions, "6", remains constant. The generation unit changes the number of transmissions and receptions for the first predetermined number of transmissions and receptions and the number of transmissions and receptions for the second predetermined number of transmissions and receptions. The input device 102 is, for example, an example of a reception unit.

[0144] In the second embodiment, the input device 102 receives an instruction to prioritize the image quality of the color Doppler image data (image quality priority instruction). The input device 102 also receives a level specification to reduce residual multiplexing in the color Doppler image data. When the generation unit receives the image quality priority instruction and the level specification from the input device 102, in dummy rate mode, it changes the number of transmissions and receptions for the third predetermined number of transmissions and receptions without changing the number of transmissions and receptions for the fourth predetermined number of transmissions and receptions.

[0145] In the second embodiment, the generation unit generates a color Doppler image in dummy rate mode using a fourth number of reflected wave data, which is greater than the second number of reflected wave data, obtained by collecting multiple reflected wave data by multiple ultrasonic transmissions and receptions on a predetermined scan line, and excluding a third number of reflected wave data that are not used for generating a color Doppler image, counting from the first transmission and reception.

[0146] In the second embodiment, the generation unit generates a color Doppler image using reflected wave data equal to the number of fourth reflected wave data points and an eigenvector type MTI filter in dummy rate mode.

[0147] In the second embodiment, the input device 102 receives a frame rate priority instruction that prioritizes the frame rate of the color Doppler image and a level specification that reduces residual multiplexing in the color Doppler image. When the generation unit receives the frame rate priority instruction and level specification from the input device 102, in the residual multiplexing reduction mode, it changes the number of first reflected wave data and the number of second reflected wave data so that the sum of the number of first reflected wave data and the number of second reflected wave data remains constant.

[0148] In the second embodiment, the input device 102 receives an image quality priority instruction that prioritizes the image quality of the color Doppler image and a level specification that reduces residual multiplexing in the color Doppler image. When the generation unit receives the image quality priority instruction and level specification from the input device 102, it changes the number of third reflected wave data without changing the number of fourth reflected wave data in dummy rate mode.

[0149] In the second embodiment, the generation unit determines the number of reflected wave data points that are not used for color Doppler image generation in the processing of S203 and S204, according to the influence of reflected wave signals (echo signals) transmitted and received in a time phase prior to multiple ultrasonic transmissions and receptions on a predetermined scan line.

[0150] Figure 14 shows an example of a color Doppler image displayed by the ultrasound diagnostic apparatus 1a according to the second embodiment. Figure 14 shows a color Doppler image 25 displayed on the display 103 in normal mode, a color Doppler image 26 displayed on the display 103 in residual multiplex reduction mode, and a color Doppler image 27 displayed on the display 103 in dummy rate mode.

[0151] Comparing color Doppler image 25 with color Doppler images 26 and 27, it can be seen that artifacts due to residual multiplexing occur in color Doppler image 20, but the occurrence of artifacts is suppressed in color Doppler images 26 and 27. Comparing color Doppler image 26 with color Doppler image 27, the image quality of color Doppler image 27 is better than that of color Doppler image 26. However, as mentioned above, the frame rate of color Doppler image 26 is higher than the frame rate of color Doppler image 27.

[0152] Figure 15 is a diagram illustrating the characteristics of the color Doppler images displayed on the display 103 in the ultrasound diagnostic apparatus 1a according to the second embodiment, for each combination of level and scanning mode. Figure 15 shows a color Doppler image 30 based on color Doppler image data obtained at level 1 in the residual multiplex reduction mode, a color Doppler image 31 based on color Doppler image data obtained at level 3 in the residual multiplex reduction mode, a color Doppler image 32 based on color Doppler image data obtained at level 1 in the dummy rate mode, and a color Doppler image 33 based on color Doppler image data obtained at level 3 in the dummy rate mode.

[0153] Comparing color Doppler image 30 and color Doppler image 31, in terms of the change in image quality from a color Doppler image based on color Doppler image data obtained in normal mode, the change in color Doppler image 31 is greater than the change in color Doppler image 30. Furthermore, the degree of reduction of residual multiplexing in color Doppler image 31 is greater than that in color Doppler image 30.

[0154] Furthermore, comparing color Doppler image 32 and color Doppler image 33, the frame rate of color Doppler image 32 is higher than that of color Doppler image 33. Also, the degree of reduction of residual multiplexing in color Doppler image 33 is higher than that of color Doppler image 32.

[0155] Based on the above, the ultrasound diagnostic apparatus 1a according to the second embodiment can suppress the reduction in frame rate or image quality of color Doppler images, which are important to the operator. Furthermore, the ultrasound diagnostic apparatus 1a according to the second embodiment can reduce residual multiplexing to the level desired by the operator.

[0156] (Third embodiment) Next, an ultrasound diagnostic apparatus according to the third embodiment will be described. In the description of the third embodiment, components similar to those in the first and second embodiments will be denoted by the same reference numerals, and their descriptions may be omitted. In addition, the description of the third embodiment will mainly focus on the differences from the first and second embodiments.

[0157] Figure 16 is a block diagram showing an example configuration of the ultrasound diagnostic apparatus 1b according to the third embodiment. The ultrasound diagnostic apparatus 1b according to the third embodiment differs from the ultrasound diagnostic apparatus 1, 1a in that it includes an apparatus body 100b instead of apparatus bodies 100, 100a. The apparatus body 100b according to the third embodiment differs from apparatus bodies 100, 100a in that it includes a control circuit 180b instead of control circuits 180, 180a.

[0158] Figure 17 is a diagram illustrating an example of the process for detecting residual multiplexing in the third embodiment. Figure 18 is a diagram illustrating an example of the process for detecting the presence or absence of pulsatile in the third embodiment. Figure 19 is a diagram illustrating an example of the process for detecting the presence or absence of pulsatile in the third embodiment. Figure 20 is a flowchart showing an example of the process performed by the ultrasound diagnostic device 1b according to the third embodiment.

[0159] The process shown in Figure 20 is executed when the operator operates the input device 102 and inputs an instruction to the control circuit 180b to superimpose a color Doppler image onto the B-mode image in order to perform an examination of subject P.

[0160] The processes in steps S101, S102, S203, S204, and S105 shown in Figure 20 are the same as the processes in steps S101, S102, S203, S204, and S105 shown in Figure 13. However, the processes executed by control circuit 180a in Figure 13 are executed by control circuit 180b in Figure 20.

[0161] As shown in Figure 20, the control circuit 180b determines whether or not residual multiplexing has occurred in the color Doppler image (step S301). For example, the control circuit 180b attempts to detect residual multiplexing from the color Doppler image data. If residual multiplexing is detected, it determines that residual multiplexing has occurred in the color Doppler image (step S301: Yes) and proceeds to step S302. On the other hand, if residual multiplexing is not detected, the control circuit 180b determines that residual multiplexing has not occurred in the color Doppler image (step S301: No) and proceeds to step S105.

[0162] An example of the processing for the determination in step S301 is described below. When residual multiplexing occurs in color Doppler image data, the color Doppler image data has the following four characteristics: The first characteristic is that the blood flow velocity shown in the color Doppler image data is not constant and is unstable. The second characteristic is that the blood flow power shown in the color Doppler image data is relatively high. The third characteristic is that residual multiplexing occurs in the leading scan line of the alternating stage group (the scan line that is first transmitted and received). The fourth characteristic is that the continuity of residual multiplexing is high in the depth direction.

[0163] Therefore, the control circuit 180b attempts to detect residual multiplexing from color Doppler image data, for example, from the second and third features among the first to fourth features, in the following manner. For example, the control circuit 180b generates a graph 40 from the color Doppler image data, as shown in Figure 17, which shows the power value of residual multiplexing and the power value of noise for each first scan line. The horizontal axis of the graph 40 represents each first scan line, and the vertical axis represents the power value. The control circuit 180b then determines from the graph 40 whether or not first scan lines with residual multiplexing power values ​​above a threshold (see Figure 17) are repeatedly present periodically in the scan line direction (for each alternating stage group). In the example in Figure 17, the control circuit 180b determines that first scan lines with residual multiplexing power values ​​above a threshold are repeatedly present periodically in the scan line direction. If the control circuit 180b determines that a first scan line with a residual multiplexing power value above a threshold is periodically repeated in the scan line direction, it determines that residual multiplexing has been detected from the color Doppler image data (Step S301: Yes). On the other hand, if the control circuit 180b determines that a first scan line with a residual multiplexing power value above a threshold is not periodically repeated in the scan line direction, it determines that residual multiplexing has not been detected from the color Doppler image data (Step S301: No).

[0164] Then, the control circuit 180b automatically determines the degree (level) to reduce residual multiplexing (step S302).

[0165] An example of the processing in step S302 will be described below. The control circuit 180b determines the level to reduce residual multiplexing as follows. For example, each time the control circuit 180b determines in step S105 to continue the examination (step S105: Yes), it determines in step S301 whether or not residual multiplexing has occurred in the color Doppler image. Therefore, if it is repeatedly determined in step S105 to continue the examination (step S105: Yes), it is repeatedly determined in step S301 whether or not residual multiplexing has occurred in the color Doppler image. So, if it is determined in step S301 that residual multiplexing has occurred in the color Doppler image a predetermined number of times in a row (step S301: Yes), the control circuit 180b automatically determines this level by increasing the level to reduce residual multiplexing by one level.

[0166] The control circuit 180b then determines whether or not the blood flow is pulsatile (step S303). For example, the image memory 160 stores multiple color Doppler image data (color Doppler image data for multiple frames) obtained in normal mode. The control circuit 180b then uses these multiple color Doppler image data to determine whether or not the blood flow is pulsatile. For example, the control circuit 180b calculates the average blood flow velocity within each frame. The control circuit 180b then generates a graph 50 showing the average blood flow velocity for each frame, as shown in Figure 18. The horizontal axis of graph 50 represents each frame, and the vertical axis represents the average blood flow velocity. Graph 50 shows the change in the average blood flow velocity between frames. Graph 50 also shows the heart rate of subject P.

[0167] The control circuit 180b then performs a frequency analysis on graph 50 to obtain normalized power values ​​for each frequency. As a result, the control circuit 180b obtains graph 60, which shows the normalized power values ​​for each frequency, as shown in Figure 19. The horizontal axis of graph 60 represents each frequency, and the vertical axis represents the power values ​​normalized within the range of 0 to 1.

[0168] Then, the control circuit 180b determines from graph 60 that if there is a power value among the power values ​​of frequencies other than DC (frequencies other than 0 Hz) that exceeds the threshold th (see Figure 19), then there is pulsatile blood flow (Step S303: Yes). On the other hand, the control circuit 180b determines from graph 60 that if there is no power value among the power values ​​of frequencies other than DC that exceeds the threshold th, then there is no pulsatile blood flow (Step S303: No).

[0169] Here, if there is pulsatile blood flow, temporal resolution is important and real-time performance is required. For this reason, if there is pulsatile blood flow (step S303: Yes), the ultrasound diagnostic device 1b sets the scanning mode to residual multiple reduction mode and alternately performs the first ultrasound scan and the second ultrasound scan in residual multiple reduction mode on the subject P to generate B-mode image data and color Doppler image data (step S203), and proceeds to step S105.

[0170] Furthermore, when there is no pulsatile blood flow, the blood flows at a nearly constant speed, so temporal resolution is not particularly important, and real-time performance is not particularly required. For this reason, when there is no pulsatile blood flow (step S303: No), the ultrasound diagnostic device 1b sets the scanning mode to dummy rate mode and alternately performs the first ultrasound scan and the second ultrasound scan in dummy rate mode on the subject P to generate B-mode image data and color Doppler image data (step S204), and proceeds to step S105.

[0171] Here, in steps S203 and S204, the ultrasound diagnostic device 1b performs a process to reduce residual multiplexing at the level specified in step S302, similar to the second embodiment.

[0172] The ultrasound diagnostic device 1b may also be equipped with an electrocardiograph that acquires an electrocardiogram (ECG) as a biological signal of the subject P. The control circuit 180b may then perform the processing in step S303 using the electrocardiogram acquired by the electrocardiograph. For example, the control circuit 180b compares the heart rate shown in graph 50 with the heart rate shown in the electrocardiogram and calculates a degree of agreement, which indicates the degree to which the heart rate shown in graph 50 and the heart rate shown in the electrocardiogram match. The higher the value of this degree of agreement, the greater the degree to which the heart rate shown in graph 50 and the heart rate shown in the electrocardiogram match. If the degree of agreement exceeds a predetermined threshold, graph 50 is considered to represent the actual heart rate of the subject P, and therefore the control circuit 180b performs the processing in step S303 described above using graph 50. If the degree of agreement is below a predetermined threshold, the graph 50 is considered not to represent the actual heart rate of subject P. Therefore, the control circuit 180b generates a new graph 50 showing the average blood flow velocity for each frame using multiple other color Doppler image data stored in the image memory 160. Then, the control circuit 180b performs the above-described processing using the newly generated graph 50. The control circuit 180b repeatedly performs this processing until the degree of agreement exceeds a predetermined threshold. An electrocardiograph is, for example, an example of an acquisition unit.

[0173] Furthermore, if the degree of agreement is below a predetermined threshold, the control circuit 180b may determine that there is no pulsatile blood flow (step S303: No) instead of generating a new graph 50, and proceed to step S204.

[0174] Furthermore, although we have described the case in step S303 where the control circuit 180b performs a process to determine whether or not blood flow is pulsatile, other processes may be performed in step S303. For example, in step S303, the control circuit 180b identifies at least one pair of adjacent frames (a pair of color Doppler image data) in the frame direction of the color Doppler image data. Then, for each pair, the control circuit 180b calculates the correlation between the two frames in the pair. That is, for each pair, the control circuit 180b calculates the correlation value of the two color Doppler image data.

[0175] If there is only one identified pair, the control circuit 180b determines whether the calculated correlation value is below a predetermined threshold. If the correlation value is below the predetermined threshold (step S303: Yes), the control circuit 180b proceeds to step S203. On the other hand, if the correlation value exceeds the predetermined threshold (step S303: No), the control circuit 180b proceeds to step S204.

[0176] Furthermore, if there are multiple identified pairs, the control circuit 180b calculates the average of the multiple correlation values. The control circuit 180b then determines whether the average of the multiple correlation values ​​is below a predetermined threshold. If the average of the multiple correlation values ​​is below the predetermined threshold (step S303: Yes), the control circuit 180b proceeds to step S203. On the other hand, if the average of the multiple correlation values ​​exceeds the predetermined threshold (step S303: No), the control circuit 180b proceeds to step S204.

[0177] The ultrasound diagnostic apparatus 1b according to the third embodiment has been described above.

[0178] In the third embodiment, the scanning unit includes, for example, an ultrasonic probe 101, a transmitting / receiving circuit 110, and a control circuit 180b, and is implemented by the ultrasonic probe 101, the transmitting / receiving circuit 110, and the control circuit 180b. However, the scanning unit may further include other circuits and devices. Also in the third embodiment, the generation unit includes, for example, a transmitting / receiving circuit 110, a B-mode processing circuit 130, a Doppler processing circuit 140, an image generation circuit 150, and a control circuit 180b, and is implemented by the transmitting / receiving circuit 110, the B-mode processing circuit 130, the Doppler processing circuit 140, an image generation circuit 150, and the control circuit 180b. However, the generation unit may further include other circuits and devices.

[0179] In the third embodiment, the generation unit generates a plurality of color Doppler image data, determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the plurality of color Doppler image data, and if it determines that the blood flow is pulsatile, it generates color Doppler image data indicating a first segmented region corresponding to a second predetermined number of transmissions and receptions in residual multiplex reduction mode as at least a part of the color Doppler image data indicating the first region.

[0180] Furthermore, in the third embodiment, if the generation unit determines that there is no pulsatile blood flow, it generates color Doppler image data indicating a first segmented region corresponding to a fourth predetermined number of transmissions and receptions in dummy rate mode, as at least a part of the color Doppler image data indicating the first region.

[0181] In the third embodiment, the electrocardiograph acquires the electrocardiogram waveform as a biological signal from the subject P. The generation unit then determines whether or not the blood flow is pulsatile based on the blood flow velocity and electrocardiogram waveform shown by the multiple color Doppler image data.

[0182] In the third embodiment, the generation unit determines whether or not residual multiplexing has occurred in the newly generated color Doppler image data each time it generates new color Doppler image data. If the generation unit determines that residual multiplexing has occurred a predetermined number of times consecutively, it identifies a level to reduce the residual multiplexing in the color Doppler image data. If the generation unit determines that there is pulsatile blood flow, it changes the number of transmissions and receptions for the first predetermined number of transmissions and receptions (1 for level 1 in Figure 11, 2 for level 2, and 3 for level 3) and the number of transmissions and receptions for the second predetermined number of transmissions and receptions (5 for level 1 in Figure 11, 4 for level 2, and 3 for level 3) in the residual multiplexing reduction mode, based on the identified level, so that the sum of the number of transmissions and receptions for the first predetermined number of transmissions and receptions (1 for level 1 in Figure 11, 2 for level 2, and 3 for level 3) remains constant at 6.

[0183] Furthermore, in the third embodiment, if the generating unit determines that there is no pulsatile blood flow, it changes the number of transmissions and receptions for the third predetermined number of transmissions and receptions in the dummy rate mode without changing the number of transmissions and receptions for the fourth predetermined number of transmissions and receptions, based on the identified level.

[0184] In the third embodiment, the generation unit generates a plurality of color Doppler image data, and based on the correlation value of at least one pair of two color Doppler image data adjacent in the frame direction among the plurality of color Doppler image data, it generates color Doppler image data indicating a first segmented region corresponding to a second predetermined number of transmissions and receptions in residual multiplexing reduction mode as at least a part of the color Doppler image data indicating the first region, or generates color Doppler image data indicating a first segmented region corresponding to a fourth predetermined number of transmissions and receptions in dummy rate mode as at least a part of the color Doppler image data indicating the first region.

[0185] In the third embodiment, the generation unit generates multiple color Doppler images, determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the multiple color Doppler images, and if it determines that the blood flow is pulsatile, sets the scanning mode of the ultrasound diagnostic device 1b to residual multiplex reduction mode.

[0186] In the third embodiment, the generation unit generates multiple color Doppler images, determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the multiple color Doppler images, and if it determines that the blood flow is not pulsatile, sets the scanning mode of the ultrasound diagnostic device 1b to dummy rate mode.

[0187] In the third embodiment, the generation unit determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the multiple color Doppler images and the electrocardiogram waveform of subject P acquired by the electrocardiograph.

[0188] In the third embodiment, each time a new color Doppler image is generated, the generation unit determines whether or not residual multiplexing has occurred in the newly generated color Doppler image. If it determines that residual multiplexing has occurred for a predetermined number of consecutive times, it identifies a level to reduce the residual multiplexing in the color Doppler image. If it determines that there is pulsatile blood flow, it changes the number of first reflected wave data and the number of second reflected wave data based on the identified level, so that the sum of the number of first reflected wave data and the number of second reflected wave data remains constant in the residual multiplexing reduction.

[0189] Furthermore, in the third embodiment, each time a new color Doppler image is generated, the generation unit determines whether or not residual multiplexing has occurred in the newly generated color Doppler image. If it determines that residual multiplexing has occurred for a predetermined number of consecutive times, it identifies a level to reduce the residual multiplexing in the color Doppler image. If it determines that there is no pulsatile blood flow, it changes the number of third reflected wave data points in dummy rate mode without changing the number of fourth reflected wave data points, based on the identified level.

[0190] In the third embodiment, the generation unit generates a plurality of color Doppler images and sets the scanning mode of the ultrasound diagnostic device 1b to residual multiple reduction mode or dummy rate mode based on the correlation value of at least one pair of two color Doppler images that are adjacent in the frame direction from among the plurality of color Doppler images.

[0191] In the first to third embodiments, we described a case where, between transmission and reception for the second scan line m and the second scan line m+1 (second ultrasonic scan for obtaining B-mode image data), transmission and reception for the first scan line n and the first scan line n+1 (first ultrasonic scan for obtaining color Doppler image data) is performed, and the color Doppler image data is affected by the second ultrasonic scan, and residual signals may cause artifacts in the color Doppler image. However, the situations in which residual signals may cause artifacts in the color Doppler image are not limited to these.

[0192] For example, let's consider a case where the transmitting / receiving circuit 110 performs a mode-division scan (mode-division scanning) by alternately executing a first ultrasonic scan over the entire first region and a second ultrasonic scan over the entire second region of the subject P via the ultrasonic probe 101. In mode-division scanning, the second ultrasonic scan is a scan in which one ultrasonic transmission and reception is performed for each of the second scan lines (M second scan lines) of the second region.

[0193] Figure 21 is a diagram illustrating an example of the first ultrasonic scan in mode-division scanning. Figure 22 is a diagram illustrating an example of the positions of multiple scan lines (positions in spatial coordinates of image data) in the first ultrasonic scan in mode-division scanning. The first ultrasonic scan in mode-division scanning is a scan in which ultrasonic transmission and reception are performed multiple times for each of the N scan lines by changing the alternating stage group, which has 2 alternating stages, for example, as shown in Figures 21 and 22. Specifically, in the example in Figure 21, the scanning unit or acquisition unit described above performs ultrasonic transmission and reception 6 times for two alternating stage groups (first alternating stage group) of first scan lines n-2 (not shown) and n-1 that transmit and receive alternately. As a result, 6 reflected wave data corresponding to the first scan line n-2 and 6 reflected wave data corresponding to the first scan line n-1 are obtained. Subsequently, the scanning or acquisition unit performs ultrasonic transmission and reception six times for two alternating stage groups (second alternating stage group) of the first scan lines n and n+1 that are transmitted and received alternately. This yields six reflected wave data corresponding to the first scan line n and six reflected wave data corresponding to the first scan line n+1.

[0194] In the first ultrasonic scan of the mode-splitting scan, residual signals can cause artifacts in the color Doppler image at the boundaries between alternating stage groups. For example, the residual signal of the last ultrasonic wave transmitted to the first alternating stage group (the ultrasonic wave transmitted along the first scan line n-1 as the k-th transmission / reception) may fall within the reception period of the reflected wave of the first ultrasonic wave transmitted to the second alternating stage group (the ultrasonic wave transmitted along the first scan line n as the k+1th transmission / reception). Therefore, the reflected wave signal of the first scan line n obtained by the k+1th transmission / reception output from the ultrasonic probe 101 contains residual signals and is thus affected by them.

[0195] Furthermore, each residual signal of the ultrasound transmitted along the first scan line n+1 as the k+2th, k+4th, k+6th, ..., k+10th transmission and reception enters the reception period of the reflected ultrasound transmitted along the first scan line n as the k+3rd, k+5th, k+7th, ..., k+11th transmission and reception. However, the residual signals contained in each of the reflected wave signals of the first scan line n obtained by the k+3rd transmission and reception, the k+5th transmission and reception, the k+7th transmission and reception, ..., k+11th transmission and reception output from the ultrasound probe 101 are similar signals because the transmission and reception that give rise to the residual signals are based on the same ultrasound transmission and reception conditions (ultrasound transmission and reception conditions for the second alternating stage group for collecting color Doppler image data). Therefore, residual signals contained in the reflected wave signal of the first scan line n obtained from the k+3rd, k+5th, k+7th, ..., and k+11th transmissions are unlikely to cause artifacts in color Doppler images.

[0196] On the other hand, the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception output from the ultrasound probe 101 is a signal generated by the transmission and reception based on the ultrasound transmission and reception conditions for the first alternating stage group for acquiring color Doppler image data, not the transmission and reception based on the ultrasound transmission and reception conditions for the second alternating stage group for acquiring color Doppler image data. Therefore, the appearance of the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception is significantly different from the appearance of the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+3), (k+5), (k+7), ..., and (k+11) transmissions and receptions. Consequently, the residual signal contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception is imaged as an artifact, causing artifacts in the color Doppler image.

[0197] Furthermore, each residual signal of ultrasound transmitted along the first scan line n as the k+1th, k+3rd, k+5th, ..., k+11th transmission and reception enters the reception period of the reflected ultrasound transmitted along the first scan line n+1 as the k+2nd, k+4th, k+6th, ..., k+12th transmission and reception. However, the residual signals included in the reflected wave signal of the first scan line n+1 obtained by the k+2nd transmission and reception, the reflected wave signal of the first scan line n+1 obtained by the k+4th transmission and reception, the reflected wave signal of the first scan line n+1 obtained by the k+6th transmission and reception, ..., k+12th transmission and reception output from the ultrasound probe 101 are similar signals because the transmission and reception that give rise to the residual signals are based on the same ultrasound transmission and reception conditions (ultrasound transmission and reception conditions for the second alternating stage group for collecting color Doppler image data). Therefore, the residual signals contained in the reflected wave signal of the first scan line n+1 obtained by the k+2th, k+4th, k+6th, ..., and k+12th transmissions are unlikely to cause artifacts in color Doppler images.

[0198] As described above, residual signals contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception are imaged as artifacts and cause artifacts in color Doppler images. Therefore, the ultrasound diagnostic devices 1, 1a, and 1b described above may reduce the residual signals contained in the reflected wave signal of the first scan line n obtained by the (k+1)th transmission and reception using a method similar to the method described above for reducing residual signals contained in the reflected wave signal.

[0199] The program executed by the processor is provided pre-installed in ROM (Read Only Memory) or memory circuits. This program may also be provided as a file in an installable or executable format on computer-readable, non-transient recording media such as CD (Compact Disk)-ROM, FD (Flexible Disk), CD-R (Recordable), or DVD (Digital Versatile Disk). Furthermore, this program may be stored on a computer connected to a network such as the Internet and provided or distributed by downloading it via the network. For example, this program consists of modules containing the processing functions described above. In actual hardware, the CPU reads the program from a recording medium such as ROM and executes it, loading each module into main memory and generating it in main memory.

[0200] According to at least one embodiment described above, it is possible to reduce the effect of residual multiplexing on color Doppler image data while suppressing a decrease in the frame rate of the color Doppler image data.

[0201] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0202] 1,1a,1b Ultrasound diagnostic equipment 101 Ultrasound probe 110 Transmit / Receive Circuit 130 B-mode processing circuit 140 Doppler processing circuit 150 Image generation circuit 180 Control circuits

Claims

1. An ultrasound diagnostic device that generates a color Doppler image using multiple transmitted and received data obtained by transmitting and receiving ultrasound multiple times on the same scan line, A collection unit that collects multiple transmitted and received data by transmitting and receiving ultrasonic waves multiple times on a predetermined scanning line, A generation unit determines the number of transmission and reception data that will not be used for generating a color Doppler image, in accordance with the influence of echo signals transmitted and received in a time phase prior to multiple ultrasonic transmissions and receptions on the predetermined scan line, and generates a color Doppler image using multiple transmission and reception data obtained by subtracting the number of transmission and reception data from the multiple transmission and reception data collected by the acquisition unit, counting from the first transmission and reception data. An ultrasound diagnostic device equipped with the following features.

2. The generating unit is In the first scanning mode, a color Doppler image is generated using a second number of transmitted and received data, which is less than or equal to a predetermined reference value, obtained by subtracting the number of transmitted and received data equal to the first number of transmitted and received data, from the multiple transmitted and received data collected by multiple ultrasonic transmissions and receptions on the predetermined scanning line, as the number of transmitted and received data not used for generating a color Doppler image, counting from the first transmitted and received data. In the second scanning mode, a color Doppler image is generated using a fourth number of transmitted and received data, which is greater than the second number of transmitted and received data, obtained by multiple ultrasonic transmissions and receptions on a predetermined scan line, excluding a third number of transmitted and received data that are not used for generating a color Doppler image, counting from the first transmission and reception. The ultrasound diagnostic apparatus according to claim 1.

3. The generation unit generates a color Doppler image in the first scanning mode using the number of transmitted and received data equal to the number of second transmitted and received data and an eigenvector type MTI filter. The ultrasound diagnostic apparatus according to claim 2.

4. The generation unit generates a color Doppler image in the second scanning mode using the number of transmission and reception data equal to the number of transmission and reception data and an eigenvector type MTI filter. The ultrasound diagnostic apparatus according to claim 2.

5. The system further includes a receiving unit that receives instructions to prioritize the frame rate of the color Doppler image and a specification of a level to reduce residual multiplexing in the color Doppler image. When the generation unit receives the instruction and the designation from the reception unit, in the first scanning mode, it changes the number of first transmitted / received data and the number of second transmitted / received data so that the sum of the number of first transmitted / received data and the number of second transmitted / received data remains constant, and also changes the number of second transmitted / received data. The ultrasound diagnostic apparatus according to claim 2.

6. The system further includes a receiving unit that receives instructions prioritizing the image quality of the color Doppler image and a specification of a level to reduce residual multiplexing in the color Doppler image. When the generation unit receives the instruction and the designation from the reception unit, in the second scanning mode, it changes the number of the third transmitted and received data without changing the number of the fourth transmitted and received data. The ultrasound diagnostic apparatus according to claim 2.

7. The generation unit generates a plurality of color Doppler images, determines whether or not the blood flow is pulsatile based on the blood flow velocity shown in the plurality of color Doppler images, and if it determines that the blood flow is pulsatile, sets the scanning mode of the ultrasound diagnostic device to the first scanning mode. The ultrasound diagnostic apparatus according to claim 2.

8. The generation unit generates a plurality of color Doppler images, determines whether or not the blood flow is pulsatile based on the blood flow velocity shown in the plurality of color Doppler images, and if it determines that the blood flow is not pulsatile, sets the scanning mode of the ultrasound diagnostic device to the second scanning mode. The ultrasound diagnostic apparatus according to claim 2.

9. It further includes an acquisition unit that acquires biological signals from the subject, The generation unit determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the plurality of color Doppler images and the biological signals. The ultrasound diagnostic apparatus according to claim 7.

10. It further includes an acquisition unit that acquires biological signals from the subject, The generation unit determines whether or not the blood flow is pulsatile based on the blood flow velocity shown by the plurality of color Doppler images and the biological signals. The ultrasound diagnostic apparatus according to claim 8.

11. The generating unit is Each time a new color Doppler image is generated, it is determined whether or not residual multiplexing has occurred in the newly generated color Doppler image. When it is determined that residual multiplexing has occurred a predetermined number of times consecutively, the level at which residual multiplexing in the color Doppler image is reduced is identified. If it is determined that the blood flow is pulsatile, then in the first scanning mode, the number of first transmitted / received data and the number of second transmitted / received data are changed, and the number of second transmitted / received data are changed, based on the identified level. The ultrasound diagnostic apparatus according to claim 7.

12. The generating unit is Each time a new color Doppler image is generated, it is determined whether or not residual multiplexing has occurred in the newly generated color Doppler image. When it is determined that residual multiplexing has occurred a predetermined number of times consecutively, the level at which residual multiplexing in the color Doppler image is reduced is identified. If it is determined that there is no pulsatile blood flow, then in the second scanning mode, the number of the third transmitted and received data is changed without changing the number of the fourth transmitted and received data, based on the identified level. The ultrasound diagnostic apparatus according to claim 8.

13. The generation unit generates a plurality of color Doppler images and sets the scanning mode of the ultrasound diagnostic device to the first scanning mode or the second scanning mode based on the correlation value of at least one pair of two color Doppler images that are adjacent in the frame direction among the plurality of color Doppler images. The ultrasound diagnostic apparatus according to claim 2.

14. A method for generating a color Doppler image using multiple transmitted and received data obtained by transmitting and receiving ultrasound multiple times on the same scan line, Multiple transmission and reception data are collected by transmitting and receiving ultrasonic signals multiple times along a predetermined scanning line. The number of transmitted and received data points that are not used for generating a color Doppler image is determined according to the influence of echo signals transmitted and received in a time phase prior to multiple ultrasonic transmissions and receptions on the predetermined scan line. A color Doppler image is generated using multiple transmitted and received data sets, which are obtained by subtracting the number of transmitted and received data sets equal to the number of transmitted and received data sets, starting from the first transmitted and received data set, from the multiple transmitted and received data sets collected. method.

15. A program for causing a computer to perform a process of generating a color Doppler image using multiple transmitted and received data obtained by transmitting and receiving ultrasound multiple times along the same scan line, To the aforementioned computer, A process to determine the number of transmitted and received data points that will not be used for generating a color Doppler image, based on the influence of echo signals transmitted and received in a time phase prior to multiple ultrasonic transmissions and receptions on a predetermined scan line, and A program for generating a color Doppler image using multiple transmitted and received data sets obtained by multiple ultrasonic transmission and reception operations on a predetermined scan line, with the number of transmitted and received data sets removed starting from the first transmitted and received data set and counting from the number of transmitted and received data sets mentioned above.

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