JP6245853B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus.

  The ultrasonic diagnostic apparatus acquires biological information of a subject by transmitting an ultrasonic wave into the subject using an ultrasonic probe and receiving a reflected wave thereof.

  By using the ultrasonic Doppler method and the ultrasonic pulse reflection method together, a single ultrasonic probe obtains the tomographic image and blood flow information of the subject, and superimposes the blood flow information on the tomographic image in sequential color display. An ultrasound diagnostic apparatus is known. For example, the ultrasonic diagnostic apparatus displays a tomographic image as a B (Brightness) mode image.

The principle by which the ultrasonic diagnostic apparatus obtains blood flow information will be described. When the ultrasonic diagnostic apparatus transmits ultrasonic waves to the position where blood flows in the subject (blood flow position), the center frequency of the transmitted ultrasonic waves is shifted by the Doppler shift frequency by the flowing blood cells. To do. When the center frequency (reference frequency) of the transmitted ultrasonic wave is “fc”, the Doppler shift frequency is “fd”, and the reception frequency received by the ultrasonic probe is “f”,
f = fc + fd.

When the blood flow velocity is “V”, the angle between the direction of the ultrasonic beam and the blood flow direction is “θ”, and the sound velocity is “c”, the reference frequency fc and the Doppler shift frequency fd are approximately It is expressed by a formula.
fd = (2 × V × cos θ) × fc / c
The ultrasonic diagnostic apparatus can detect the Doppler shift frequency “fd” and obtain the blood flow velocity “V” based on the above-described relational expression.

  A Doppler scan when the ultrasonic diagnostic apparatus obtains blood flow information according to the above-described principle will be described with reference to FIGS. FIG. 6 is a schematic diagram showing an outline of Doppler scan. FIG. 7 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to the prior art. For example, the ultrasonic diagnostic apparatus first transmits / receives ultrasonic pulses repeatedly in the direction A to a predetermined scanning region in the subject from the ultrasonic probe. Next, the ultrasonic diagnostic apparatus transmits and receives ultrasonic pulses repeatedly in the direction B a plurality of times. In the same manner, the ultrasonic diagnostic apparatus repeats transmission / reception of ultrasonic pulses sequentially, for example, several times in the direction Z. The number of repeated transmissions / receptions per direction (scanning line) is set in advance.

  The aforementioned Doppler scan is performed by the ultrasonic diagnostic apparatus having the configuration shown in FIG. For example, when the ultrasonic diagnostic apparatus transmits an ultrasonic pulse a plurality of times in the direction A, the ultrasonic probe 100 receives a reflected wave that is Doppler-shifted at a blood flow position in the subject. The ultrasonic probe 100 converts the received reflected wave into an electric signal and outputs it to the receiving circuit 200. The reception circuit 200 amplifies the electric signal and outputs it to the phase detection circuit 300. The phase detection circuit 300 detects a Doppler shift signal for the received signal. The phase detection circuit 300 detects a Doppler shift signal for each observation point SP set along the transmission direction of the ultrasonic pulse, and outputs it to the frequency analyzer 400. The frequency analyzer 400 performs frequency analysis on the Doppler shift signal and outputs the Doppler shift data to a DSC (Digital Scan Converter) 500 as Doppler shift data. The DSC 500 performs scan conversion on the Doppler shift data and outputs it to the display unit 600 as image data. The display unit 600 displays this image data as a blood flow distribution image along the direction A. For example, the ultrasonic diagnostic apparatus performs the same operation in each direction from the direction B to the direction Z, and causes the display unit 600 to display a blood flow distribution image along each direction. The ultrasonic diagnostic apparatus displays the blood flow distribution image on the display unit 600 in real time by repeating the above operation for each set time interval (frame rate).

  Note that the Doppler shift data includes noise that changes for each Doppler shift data obtained at regular time intervals. In order to reduce this time-varying noise, the ultrasonic diagnostic apparatus weights and adds the latest Doppler deviation data and past Doppler deviation data for a plurality of frames, and averages these Doppler deviation data. Persistence processing for making image data of one frame is known. By this persistence processing, noise included in the Doppler shift data can be reduced, and image data with an improved S / N ratio can be obtained.

JP 2004-16612 A

  However, when Doppler scanning is newly started after freeze release or after changing the scanning area, past Doppler shift data for the above-described persistence processing is not required. At this time, the ultrasonic diagnostic apparatus displays an image based on the Doppler shift data not subjected to the above-described persistence processing on the display unit. Since this image is an image that expresses a lot of noise, it is poor in visibility for the user, and is an image that causes annoyance and stress.

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus capable of reducing stress applied to a user by an image that represents a large amount of noise when Doppler scanning is started after freeze release or after changing a scanning area. is there.

The ultrasonic diagnostic apparatus according to this embodiment performs Doppler scan using ultrasonic waves on a scanning region in a subject, and obtains an echo signal based on a reflected wave from the subject. The ultrasonic diagnostic apparatus includes a data generation unit, a persistence processing unit, and an output control unit. The data generation unit sequentially generates Doppler shift data based on the echo signal. The persistence processing unit is configured to store one or more pieces of the Doppler shift data and to perform a filtering process for averaging the latest Doppler shift data and the stored Doppler shift data. The output control unit reduces the output of the first frame after receiving an initialization signal for initializing the Doppler shift data stored in the persistence processing unit , and then filters the frames to be filtered. Control to increase the output .

1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to an embodiment. 1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to an embodiment. The schematic diagram showing the outline of the ultrasound diagnosing device of embodiment. The flowchart showing operation | movement of the ultrasonic diagnosing device of embodiment. The block diagram showing the composition of the ultrasonic diagnostic equipment concerning the modification of an embodiment. The schematic diagram showing the outline of the conventional ultrasonic diagnostic apparatus. The block diagram showing the structure of the conventional ultrasonic diagnostic apparatus.

[Constitution]
FIG. 1 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus 1a of this embodiment. The ultrasound diagnostic apparatus 1a performs Doppler scanning using ultrasound on the scanning region of the subject. The ultrasonic diagnostic apparatus 1a includes an ultrasonic probe 2, an electronic scanning unit 3, an orthogonal detection unit 4, an MTI (Moving Target Indicator) calculation unit 5, an output control unit 6, a display control unit 7, and system control. The unit 8 includes a display unit 9 and an operation unit 10.

(Ultrasonic probe 2)
The ultrasonic probe 2 transmits an ultrasonic wave to the subject and receives a reflected wave from the subject as an echo signal. As the ultrasonic probe 2, a one-dimensional array probe in which a plurality of ultrasonic transducers are arranged in a line in the scanning direction or a two-dimensional array probe in which a plurality of ultrasonic transducers are arranged two-dimensionally is used. . The form of the ultrasonic probe 2 may be appropriately selected from linear correspondence, sector correspondence, convex correspondence, and the like.

(Electronic scanning unit 3)
The electronic scanning unit 3 performs a scan for obtaining a tomographic image of the subject and a Doppler scan for obtaining blood flow information of the subject. The electronic scanning unit 3 includes a reference signal generator 31, a delay line 32, a pulser circuit 33, a preamplifier 34, an adder 35, and a detector 36.

  The reference signal generator 31 outputs a reference signal representing the reference frequency fc to the delay line 32, the mixer 42a, and the 90-degree phase shifter 41. For example, the reference frequency fc is preset. Further, the reference signal generator 31 may receive designation of the reference frequency fc by the user.

  The delay line 32 gives a delay time for determining the transmission directivity to the received reference signal and outputs the pulse signal to the pulsar circuit 33 when transmitting the ultrasonic wave. In addition, the delay line 32 gives a delay time for determining the reception directivity to the echo signal received from the preamplifier 34 when receiving the ultrasonic wave, and outputs it to the adder 35.

  The pulsar circuit 33 includes a pulsar corresponding to the number of paths (channels) corresponding to each ultrasonic transducer, generates a drive pulse at a transmission timing based on a delay time given by the delay line 32, and the ultrasonic probe 2 To each ultrasonic transducer. The ultrasonic transducer generates ultrasonic waves based on this drive pulse.

  The preamplifier 34 amplifies the echo signal from each ultrasonic transducer of the ultrasonic probe 2 for each reception channel, and outputs the amplified signal to the delay line 32. The adder 35 adds the echo signals received from the delay line 32. By this addition, the reflection component from the direction corresponding to the reception directivity is emphasized. The adder 35 outputs the added echo signal to the detector 36, the mixer 42a, and the mixer 42b. The detector 36 detects the envelope of the echo signal from the adder 35 and generates B-mode data representing a tomographic image of the subject. The detector 36 outputs the B mode data to the first DSC 71.

(Orthogonal detector 4)
The quadrature detection unit 4 includes a 90-degree phase shifter 41, a mixer 42a, a mixer 42b, a low-pass filter 43a, and a low-pass filter 43b. The 90 degree phase shifter 41 adds a 90 degree phase difference to the reference signal from the reference signal generator 31, and outputs the result to the mixer 42b. The mixer 42a combines the reference signal from the reference signal generator 31 and the echo signal from the adder 35 and outputs the synthesized signal to the low-pass filter 43a. The mixer 42b synthesizes the reference signal to which the 90-degree phase difference is added by the 90-degree phase shifter 41 and the echo signal from the adder 35 and outputs the synthesized signal to the low-pass filter 43b. Here, the signal output from each of the mixer 42a and the mixer 42b includes a frequency component “2fc + fd” obtained by combining the reference frequency fc and the Doppler shift frequency fd. Each of the low-pass filter 43a and the low-pass filter 43b removes the high-frequency component “2fc” from the frequency components “2fc + fd” of the signals received from the mixer 42a and the mixer 42b. Output as phase detection output signal.

(MTI calculation unit 5)
The MTI operation unit 5 includes an A / D converter 51a, an A / D converter 51b, an MTI filter 52a, an MTI filter 52b, a data generation unit 53, and a persistence processing unit 54. The A / D converter 51a and the A / D converter 51b respectively convert the phase detection output signals received from the low-pass filter 43a and the low-pass filter 43b into digital signals, and output them to the MTI filter 52a and the MTI filter 52b, respectively. To do.

  The MTI filter 52a and the MTI filter 52b reduce low frequency components among frequency components included in the inputs from the A / D converter 51a and the A / D converter 51b, respectively. Thereby, a high frequency component is extracted among the frequency components contained in the input from each of the A / D converter 51a and the A / D converter 51b. Note that the filter characteristics of the MTI filter 52a and the MTI filter 52b reduce low frequency components based on reflected waves from a tissue moving at a relatively slow speed such as a heart wall, and reduce from a tissue moving at a relatively high speed such as a blood cell. Is set in advance so as to extract a high-frequency component based on the reflected wave. Each of the MTI filter 52 a and the MTI filter 52 b outputs the extracted high frequency component to the autocorrelation calculation unit 531.

  The data generation unit 53 sequentially generates Doppler shift data based on the echo signal. The Doppler shift data is data representing shift frequency data, speed data, distributed data, or power data, which will be described later. Further, every time the data generation unit 53 generates the Doppler shift data, the data generation unit 53 may attach a frame number, which is a serial number from when the initialization signal is received, to the Doppler shift data. The initialization signal is a signal based on a scan area change instruction or a freeze release instruction. For example, the system control unit 8 outputs an initialization signal to the persistence processing unit 54 and also outputs an initialization signal when receiving a scan region change instruction or freeze release instruction from the user via the operation unit 10. A control signal indicating this is output to the data generation unit 53. The data generation unit 53 attaches the serial number from when this control signal is received to the Doppler shift data as a frame number. The data generation unit 53 includes an autocorrelation calculation unit 531, a speed calculation unit 532, a variance calculation unit 533, and a power calculation unit 534.

  The autocorrelation calculation unit 531 performs frequency analysis for each observation point SP on the high frequency components received from the MTI filter 52a and the MTI filter 52b. For example, the autocorrelation calculation unit 531 amplifies the received high frequency component based on a preset gain value. The autocorrelation calculation unit 531 obtains the Doppler shift frequency fd by performing frequency analysis on the amplified high frequency component for each observation point SP. The autocorrelation calculation unit 531 obtains a Doppler shift frequency fd for each preset time interval (frame rate), and uses the calculated Doppler shift frequency fd as the shift frequency data, a speed calculation unit 532, a dispersion calculation unit 533, And sequentially output to the power calculation unit 534.

  The speed calculation unit 532, the variance calculation unit 533, and the power calculation unit 534 each perform a preset calculation based on the received shift frequency data, and obtain blood flow information for each observation point SP. The velocity calculation unit 532 obtains the blood flow velocity for each observation point SP from the blood flow information. The velocity calculation unit 532 outputs the obtained blood flow velocity to the persistence processing unit 54 as velocity data. The variance calculation unit 533 obtains the variance value of the blood flow velocity for each observation point SP in the blood flow information. The variance calculation unit 533 outputs the obtained variance value to the persistence processing unit 54 as variance data. The power calculation unit 534 obtains power that is a value based on the blood flow volume for each observation point SP in the blood flow information. The power calculation unit 534 outputs the obtained power to the persistence processing unit 54 as power data.

  The persistence processing unit 54 is configured to store one or more Doppler shift data, and to perform a filtering process that averages the latest Doppler shift data and the stored Doppler shift data. For example, the persistence processing unit 54 is configured to multiply the Doppler shift data subjected to the filter processing by an output coefficient and output the result. FIG. 2 is a block diagram illustrating the configuration of the persistence processing unit 54. The persistence processing unit 54 includes a storage unit 541, a first multiplier 542, a second multiplier 543, a first adder 544, a third multiplier 545, and a second adder 546. And a fourth multiplier 547.

  The storage unit 541 can store one or more Doppler shift data. Here, one Doppler shift data is one frame of Doppler shift data. The storage unit 541 newly stores the Doppler shift data input from the first adder 544 described later, instead of the stored Doppler shift data. In addition, when there is an initialization signal, the storage unit 541 deletes the stored Doppler shift data.

  The first multiplier 542 receives Doppler shift data from the data generator 53. The Doppler shift data is the latest Doppler shift data. The first multiplication unit 542 multiplies the latest Doppler shift data by the set coefficient and outputs the result to the first adder 544. The second multiplication unit 543 receives the Doppler shift data stored in the storage unit 541, multiplies the Doppler shift data by a coefficient set, and outputs the result to the first adder 544. The first adder 544 adds the input from the first multiplication unit 542 and the input from the second multiplication unit 543 and outputs the result to the storage unit 541 and the second adder 546. The third multiplication unit 545 receives the Doppler shift data stored in the storage unit 541, multiplies the Doppler shift data by a coefficient set, and outputs it to the second adder 546.

  The second adder 546 adds the input from the first adder 544 and the input from the third multiplier 545. Thus, the latest Doppler shift data and past Doppler shift data are weighted and added, and Doppler shift data representing a moving average of these Doppler shift data is obtained. The Doppler shift data corresponds to Doppler shift data subjected to a filtering process that averages the latest Doppler shift data and the stored Doppler shift data. The second adder 546 outputs the Doppler shift data to the fourth multiplier 547.

  The fourth multiplier 547 multiplies the input from the second adder 546 by the output coefficient and outputs the result to the second DSC 72. The persistence processing unit 54 applies the above processing to each of the speed data, the distributed data, and the power data.

  The coefficients in the first multiplier 542, the second multiplier 543, and the third multiplier 545 are set for each operating condition of the ultrasound diagnostic apparatus 1a. This operating condition includes the number of repeated transmissions / receptions per scanning line and the frame rate. For example, in the persistence processing unit 54, the coefficient of the first multiplication unit 542 is set as “1-α”, the coefficient of the second multiplication unit 543 is set as “α”, and the coefficient of the third multiplication unit 545 is set. Is set as “β”. These coefficients “1-α”, “α”, and “β” act as weighting coefficients for weighted addition in the second adder 546. The values of the coefficient “α” and the coefficient “β” may be set as appropriate for each operating condition.

(Output control unit 6)
The output control unit 6 controls the output from the persistence processing unit 54 when there is an initialization signal for initializing the Doppler shift data stored in the persistence processing unit 54. For example, the output control unit 6 determines an output coefficient to be multiplied by the filtered Doppler shift data based on the frame number attached to the Doppler shift data. The output control unit 6 controls the output from the persistence processing unit 54 by setting the determined output coefficient in the fourth multiplication unit 547. In this case, the output control unit 6 associates and stores the frame number and the output coefficient in advance, and the Doppler shift data in which the output coefficient associated with the frame number attached to the Doppler shift data is subjected to the filtering process. Is determined as an output coefficient to be multiplied by.

  Here, the relationship between the frame number and the output coefficient will be described. FIG. 3 is a schematic diagram showing the relationship between frame numbers and output coefficients. First, the section from frame number F1 to frame number Fn will be described. The frame number F1 is a frame number attached to the first generated Doppler shift data after receiving the initialization signal. The output coefficient γ1 is an output coefficient associated with the frame number F1. The frame number Fn is a frame number attached to predetermined n-th generated Doppler shift data after receiving the initialization signal. The number of frames n from the frame number F1 to the frame number Fn may be set in advance. The output coefficient γn is an output coefficient associated with the frame number Fn. As described above, the frame number Fi (i: natural number from 1 to n) and the output coefficient γi (i: natural number from 1 to n) are associated with each other. Further, in the section from the frame number F1 to the frame number Fn, the output coefficient γi is associated with the frame number Fi so as to increase monotonously. As the value of the output coefficient γ1, for example, the smallest value among the output coefficients γi such as zero is set (in FIG. 3, the frame number F1 and the output coefficient γ1 are represented by being shifted from the zero position for the sake of explanation. ing). Accordingly, after the initialization signal is received, the fourth multiplier 547 multiplies the Doppler shift data attached with the frame number F1 by the output coefficient γ1 which is the smallest value to obtain data having a small intensity, and The Doppler shift data attached with the frame number Fn is multiplied while gradually increasing the value of the output coefficient to gradually increase the data intensity.

  Next, the section after the frame number Fn will be described. An output coefficient γn is associated with every frame number in this section. Thereby, after receiving the initialization signal, the fourth multiplier 547 multiplies the Doppler shift data attached with the frame numbers after the frame number Fn by a certain value. As the value of the output coefficient γn, for example, “1” may be set in advance.

  For example, every time the persistence processing unit 54 receives the Doppler shift data, the output control unit 6 reads the frame number attached to the Doppler shift data, and performs the persistence processing on the output coefficient associated with the frame number. The fourth multiplier 547 of the unit 54 is set.

  Each time the persistence processing unit 54 receives the Doppler shift data, the output control unit 6 counts the number of received Doppler shift data as a frame number, and outputs an output coefficient associated with the counted frame number. It may be set to 4 multipliers 547. At this time, after receiving the initialization signal, the output controller 6 newly counts the frame number from the beginning. Further, the output control unit 6 may control the coefficient “α”, the coefficient “β”, or both in the same manner as the output coefficient.

(Display control unit 7)
The display control unit 7 includes a first DSC 71, a second DSC 72, a display processing unit 73, an MPX (Multiplexer) 74, and a D / A converter 75. The first DSC 71 receives B-mode data from the detector 36 and scan-converts the B-mode data represented by the ultrasonic scanning line signal sequence into a display coordinate system. The first DSC 71 outputs the scan-converted B mode data to the display processing unit 73.

  The second DSC 72 receives the Doppler shift data from the persistence processing unit 54, and scan-converts the Doppler shift data represented by the signal sequence of the ultrasonic scanning line into a display coordinate system. The second DSC 72 outputs the scanned Doppler shift data to the display processing unit 73.

  The display processing unit 73 receives B-mode data from the first DSC 71, adds luminance information representing the amplitude of the B-mode data in luminance, and outputs the B-mode image data representing the tomographic image of the subject to the MPX 74. The display processing unit 73 receives Doppler shift data from the second DSC 72. The display processing unit 73 stores in advance color information for displaying the Doppler shift data in color. For example, the color information is information indicating that the blood flow approaching the ultrasonic probe 2 is red, the blood flow away from the ultrasonic probe 2 is blue, the magnitude of velocity is expressed in luminance, and the dispersion is expressed stepwise in a green hue. Including. The display processing unit 73 adds color information to the Doppler shift data and outputs the Doppler image data representing the blood flow information of the subject to the MPX 74.

  The MPX 74 receives B-mode image data and Doppler image data from the display processing unit 73. The MPX 74 generates display image data for displaying an image obtained by superimposing a Doppler image on a B-mode image. The MPX 74 assigns luminance information of B-mode image data or color information of Doppler image data to each pixel of the display image data, generates display image data representing an image in which the Doppler image is superimposed on the B-mode image, and D / Output to the A converter 75. The D / A converter 75 converts the display image data received from the MPX 74 into an analog signal and outputs the analog signal to the display unit 9.

(System control unit 8)
The system control unit 8 controls the operation of each unit of the ultrasonic diagnostic apparatus 1a. The system control unit 8 controls the output control unit 6 to set the output coefficient. Further, the system control unit 8 controls the electronic scanning unit 3 to set ultrasonic transmission / reception conditions and a scanning region. The system control unit 8 outputs an initialization signal to the persistence processing unit 54 when receiving a freeze release instruction or a scan area change instruction from the user via the operation unit 10. The system control unit 8 stores in advance a computer program for executing the function of each unit of the ultrasonic diagnostic apparatus 1a. The system control unit 8 implements the above functions by executing these computer programs.

(Display unit 9)
The display unit 9 displays an image based on the input from the D / A converter 75. The display unit 9 includes a display device such as a CRT (Cathode Ray Tube) and an LCD (Liquid Crystal Display).

(Operation unit 10)
In response to an operation by the user, the operation unit 10 inputs signals and information corresponding to the contents of the operation to each unit of the apparatus. The operation unit 10 is configured by, for example, a keyboard, a mouse, a touch panel, and the like.

  Note that the MTI calculation unit 5 may include a blank processing unit 55 in the subsequent stage of the persistence processing unit 54. The blank processing unit 55 performs blank processing for preventing received Doppler shift data from displaying a signal having an intensity equal to or lower than a preset threshold.

  Further, in the ultrasonic diagnostic apparatus 1a of this embodiment, the persistence processing unit 54 performs filtering on the inputs from the velocity calculation unit 532, the dispersion calculation unit 533, and the power calculation unit 534. The input from the unit 531 may be subjected to filter processing, and the Doppler shift data subjected to the filter processing may be output to the speed calculation unit 532, the dispersion calculation unit 533, and the power calculation unit 534.

[Operation]
The operation of the ultrasonic diagnostic apparatus 1a of this embodiment will be described. FIG. 4 is a flowchart showing the operation after the ultrasonic diagnostic apparatus 1a receives the initialization signal.

(S001)
The data generation unit 53 attaches the serial number from when the control signal indicating the output of the initialization signal is received to the Doppler shift data as a frame number. The data generation unit 53 outputs the Doppler shift data to the persistence processing unit 54.

(S002)
When the persistence processing unit 54 receives the Doppler shift data, the output control unit 6 reads the frame number attached to the Doppler shift data and outputs the output coefficient associated with the frame number to the persistence processing unit 54. Is set in the fourth multiplication unit 547.

(S003)
The persistence processing unit 54 filters the received Doppler shift data, multiplies the set output coefficient, and outputs the result to the display control unit 7. The display control unit 7 causes the display unit 9 to display an image in which the Doppler image based on the Doppler shift data multiplied by the output coefficient by the persistence processing unit 54 is superimposed on the tomographic image based on the input from the electronic scanning unit 3. .

(S004)
When the frame number of the Doppler shift data is not the predetermined frame number Fn, the process returns to step S001. When the frame number of the Doppler shift data is the predetermined frame number Fn, the process proceeds to step S005.

(S005)
The output control unit 6 sets the output coefficient to the output coefficient γn, which is a constant value, for the Doppler shift data after the predetermined frame number Fn. The persistence processing unit 54 performs filtering on the Doppler shift data after a predetermined frame number Fn, and outputs Doppler shift data multiplied by the output coefficient γn. The display control unit 7 superimposes an image obtained by superimposing the tomographic image based on the input from the electronic scanning unit 3 and the Doppler image based on the Doppler shift data multiplied by the output coefficient γn by the persistence processing unit 54 on the display unit 9. Display.

[effect]
The effect of the ultrasonic diagnostic apparatus 1a of this embodiment will be described. The ultrasonic diagnostic apparatus 1 a includes a data generation unit 53, a persistence processing unit 54, and an output control unit 6. The data generation unit 53 sequentially generates Doppler shift data based on the echo signal. The persistence processing unit 54 is configured to store one or more pieces of Doppler shift data and to perform a filtering process that averages the latest Doppler shift data and the stored Doppler shift data. The output control unit 6 controls the output from the persistence processing unit 54 when there is an initialization signal for initializing the Doppler shift data stored in the persistence processing unit 54. This ultrasonic diagnostic apparatus 1a reduces the output of the Doppler shift data of the frame that is first subjected to the persistence processing after the initialization signal, and then gradually increases the output of the frame that is subjected to the persistence processing. Let This corresponds to the fact that an image including a predetermined number of noises displayed after the initialization signal is displayed with its output weakened. As a result, it is possible to provide the ultrasonic diagnostic apparatus 1a that can reduce the stress applied to the user by the image containing a lot of noise when the Doppler scan is started after the freeze is released or the scan area is changed.

<Modification>
A modification of the ultrasonic diagnostic apparatus 1b according to the above-described embodiment will be described. FIG. 5 is a block diagram showing the configuration of the ultrasonic diagnostic apparatus 1b according to this modification. The ultrasonic diagnostic apparatus 1b of this modification is different from the ultrasonic diagnostic apparatus 1a of the embodiment described above in the processing contents in the system control unit 8 and the output control unit 6. Hereinafter, items different from the above-described embodiment will be mainly described.

  The system control unit 8 includes a transmission / reception control unit. The transmission / reception control unit adds an output coefficient to the echo signal output from the electronic scanning unit 3 to the quadrature detection unit 4. For example, the transmission / reception control unit controls the electronic scanning unit 3 to attach information indicating an output coefficient every time an echo signal for one frame is output. The echo signal accompanied by information indicating the output coefficient is input to the data generation unit 53 through subsequent processing. The information is set to a signal in a frequency band that passes through the subsequent low-pass filter 43a, low-pass filter 43b, MTI filter 52a, and MTI filter 52b. The information representing the output coefficient is set to be a bit string representing the value of the output coefficient in the subsequent processing.

  The transmission / reception control unit stores the frame number and the output coefficient in association with each other. The relationship between the frame number and the output coefficient is the same as that shown in FIG. The transmission / reception control unit controls the electronic scanning unit 3 to attach information indicating the output coefficient γ1 associated with the frame number F1 to the echo signal of the first one frame after the initialization signal is received. Then, the echo signals for one frame are sequentially added to the echo signals of a predetermined number of frames (frame number Fn) while monotonously increasing the value of the output coefficient. The transmission / reception control unit controls the electronic scanning unit 3 to add information indicating the set output coefficient γn to echo signals after a predetermined number of frames.

  The echo signal accompanied by the information indicating the output coefficient is processed by the subsequent quadrature detection unit 4, the A / D converter 51a, the A / D converter 51b, the MTI filter 52a, the MTI filter 52b, and the data generation unit 53. Thereafter, the data is input to the persistence processing unit 54 as Doppler shift data accompanied by a bit string representing an output coefficient.

  The output control unit 6 controls the output from the persistence processing unit 54 by determining the output coefficient attached to the Doppler shift data as an output coefficient to be multiplied by the filtered Doppler shift data. At this time, every time the persistence processing unit 54 receives the Doppler shift data, the output control unit 6 reads the output coefficient attached to the Doppler shift data and sets the output coefficient in the fourth multiplication unit 547. . Thereby, the output from the persistence processing unit 54 is controlled.

  According to the ultrasonic diagnostic apparatus 1 b of this modification, the output control unit 6 reads the output coefficient attached to the Doppler shift data and sets the output coefficient as the output coefficient from the persistence processing unit 54. As a result, an image including a predetermined number of noises displayed after the initialization signal is displayed with its output weakened. Therefore, it is possible to provide the ultrasonic diagnostic apparatus 1b that can reduce the stress applied to the user by an image representing a large amount of noise when Doppler scanning is started after the freeze is released or after the scanning area is changed.

<Effects common to the embodiment and the modification>
According to the ultrasonic diagnostic apparatus of the embodiment or the modification described above, the output of the Doppler shift data of the frame that is first subjected to the persistence processing after the initialization signal is reduced, and then the persistence processing is performed. Gradually increase the output of the frames being played. Accordingly, it is possible to provide an ultrasonic diagnostic apparatus that can reduce the stress applied to the user by an image that represents a large amount of noise when Doppler scanning is started after freeze release or after changing the scanning region.

  Although the embodiment of the present invention has been described, the above-described embodiment has been presented as an example, and is not intended to limit the scope of the invention. For example, the output signals of the speed calculation unit, dispersion calculation unit, and power calculation unit are input to the persistence processing unit. Speed, dispersion, and power may be obtained.

  These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1a, 1b Ultrasonic diagnostic apparatus 2 Ultrasonic probe 3 Electronic scanning part 4 Orthogonal detection part 5 MTI calculating part 6 Output control part 7 Display control part 8 System control part 9 Display part 10 Operation part 31 Reference signal generator 32 Delay line 33 Pulser circuit 34 Preamplifier 35 Adder 36 Detector 41 90 degree phase shifter 42a, 42b Mixer 43a, 43b Low pass filter 51a, 51b A / D converter 52a, 52b MTI filter 53 Data generation unit 54 Persistence processing unit 55 Blank processing Part 71 First DSC
72 Second DSC
73 Display processing unit 74 MPX
75 D / A converter 531 Autocorrelation calculation unit 532 Speed calculation unit 533 Dispersion calculation unit 534 Power calculation unit 541 Storage unit 542 First multiplication unit 543 Second multiplication unit 544 First adder 545 Third multiplication unit 546 Second adder 547 Fourth multiplier

Claims (5)

An ultrasonic diagnostic apparatus that performs Doppler scanning with ultrasound for a scanning region in a subject and obtains an echo signal based on a reflected wave from the subject,
A data generation unit that sequentially generates Doppler shift data based on the echo signal;
A persistence processing unit configured to store one or more of the Doppler shift data, and to perform a filtering process for averaging the latest Doppler shift data and the stored Doppler shift data;
After there is an initialization signal for initializing the Doppler shift data stored in the persistence processing unit, the output of the first frame is reduced , and then the output of the filtered frame is increased. An output control unit for controlling to
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the initialization signal is a signal based on an instruction to change the scan area or an instruction to release freeze. Each time the data generation unit generates the Doppler shift data, it appends a frame number that is a serial number from when the initialization signal is present to the Doppler shift data,
The persistence processing unit is configured to multiply the Doppler shift data subjected to the filter processing by an output coefficient and output the data.
The output control unit determines the output coefficient by which the Doppler shift data subjected to the filtering process is multiplied based on the frame number attached to the Doppler shift data, thereby the persistence processing unit. The ultrasonic diagnostic apparatus according to claim 1, wherein an output from the control unit is controlled.   The output control unit stores the frame number and the output coefficient in association with each other in advance, and the output coefficient associated with the frame number attached to the Doppler shift data is subjected to the filtering process. The ultrasonic diagnostic apparatus according to claim 3, wherein the ultrasonic diagnostic apparatus is determined as the output coefficient to be multiplied by shift data. A transmission / reception controller for attaching an output coefficient to the echo signal;
The persistence processing unit is configured to multiply the Doppler shift data subjected to the filter processing by an output coefficient and output the data.
The output control unit determines the output coefficient attached to the Doppler shift data as the output coefficient by which the Doppler shift data subjected to the filtering process is multiplied, thereby outputting the output from the persistence processing unit. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is controlled.

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