JP2012254216A - Ultrasonic diagnostic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set the optimum gain adjustment in harmonic imaging.SOLUTION: This ultrasonic diagnostic equipment includes a transmission part 11, a receiving part 12, an image forming part 16, a determination part 19a and a setting part 19b. The transmission part 11 transmits ultrasonic waves of respective scanning lines a plurality of times by a scanning sequence for harmonic imaging. The receiving part 12 has a preamplifier 12a comprising a sensitivity correction part for performing weighting corresponding to a first coefficient with respect to the respective reflected waves of the ultrasonic waves transmitted a plurality of times by the same scanning lines and a scanning sequence weighting part for performing weighting by a second coefficient. The determination part 19a determines a combination of the values of the first and second coefficients used in the formation of the ultrasonic image becoming minimum in brightness value in a plurality of the ultrasonic images altered in the values of the first and second coefficients formed in the image forming part 16 as a setting coefficient and the setting part 19b sets the setting coefficient to the preamplifier 12a.

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus.

  Conventionally, amplitude modulation (AM) and phase modulation (PM) are known as imaging methods (CHI: Contrast Harmonic Imaging) by ultrasonic contrast. In AM and PM, a plurality of ultrasonic transmissions having different amplitudes and phases are performed on the same scanning line a plurality of times, thereby suppressing the fundamental wave component derived from the tissue and the higher harmonics derived from the contrast agent (microbubble, bubble). A contrast image in which the wave component is emphasized is generated.

  For example, in AM, an ultrasonic wave having the same phase and an amplitude ratio of “1: 2” is transmitted twice, such as (0.5, 1.0). In AM, for example, difference data in which harmonic components are emphasized by subtracting data obtained by circuit-doubling data obtained by the first reception from data obtained by the second reception is obtained. And a contrast image is generated from the difference data.

  Further, in PM called “Pulse Subtraction method” or “Pulse Inversion method”, for example, (1.0, −1.0), an ultrasonic wave having the same amplitude and a phase different by 180 degrees is transmitted twice. To do. Then, in PM, for example, by adding the data obtained by the first reception and the data obtained by the second reception, the addition data in which the harmonic component is emphasized is generated, and the contrast image is generated from the addition data. Generated.

  In addition, AMPM is also known in which effects of both AM and PM can be obtained by combining AM and PM. In AMPM, an ultrasonic wave having a waveform having a different amplitude and phase, such as (−0.5, 1.0, −0.5), is transmitted three times, so that a signal from a contrast bubble is mainly imaged. Turn into.

  In ultrasound contrast, the contrast sensitivity is determined by the ratio of “bubble” to “tissue”. Therefore, if the bubble signal is constant, the smaller the tissue signal, the better. In the above-described AM, PM, and AMPM, the contrast sensitivity is usually increased by lowering the sound pressure to lower the tissue signal. By imaging the harmonic components, artifacts due to side lobes and the like are reduced and the image quality of the B-mode image is improved. Therefore, AM, PM, and AMPM can also be used for B-mode image imaging. It is used as.

  Here, in CHI and THI harmonic imaging, when AM, PM, and AMPM are executed, gain adjustment is performed by an analog circuit in ultrasonic transmission processing and processing for received reflected waves. However, there are variations in the characteristics of the analog circuit, which may prevent the fundamental wave component from being sufficiently suppressed.

JP 2009-18161 A

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus capable of easily setting optimum gain adjustment in harmonic imaging.

  The ultrasonic diagnostic apparatus according to the embodiment includes a transmission unit, a reception unit, an image generation unit, a determination unit, and a setting unit. The transmission unit transmits an ultrasonic wave a plurality of times on each scanning line according to a predetermined scanning sequence for performing harmonic imaging. The receiving unit weights each reflected wave of the ultrasonic wave transmitted a plurality of times on the same scanning line according to a first coefficient that is a weighting coefficient, and each reflected wave And an analog circuit including a scan sequence weighting unit that performs weighting according to the second coefficient that differs depending on the scan sequence. The image generation unit changes the value of the first coefficient and the value of the second coefficient as an ultrasonic image using synthesized data obtained by combining the reflected waves for each scanning line weighted by the first coefficient and the second coefficient. A plurality of ultrasonic images are generated. The determination unit is configured to detect a reflected wave used for generating an ultrasonic image having a minimum luminance value among a plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed. A combination of values of the first coefficient and the second coefficient used for weighting by the analog circuit is determined as a setting coefficient. The setting unit sets the setting coefficient in the analog circuit as a weighting coefficient when performing harmonic imaging.

FIG. 1 is a diagram for explaining a configuration example of an ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram (1) for explaining AMPM. FIG. 3 is a diagram (2) for explaining AMPM. FIG. 4 is a diagram for explaining an example of analog gain adjustment for reception sensitivity correction. FIG. 5 is a diagram for explaining an example of input / output characteristics of an analog circuit. FIG. 6 is a diagram for explaining a conventional weighting coefficient optimization process. FIG. 7 is a diagram for explaining an example of AMPM gain and analog gain change settings according to the first embodiment. FIG. 8 is a diagram for explaining an ultrasonic image generated by the change setting of the AMPM gain and the analog gain illustrated in FIG. FIG. 9 is a diagram for explaining optimum gain determination processing by the determination unit. FIG. 10 is a diagram for explaining the optimum gain determination process using the interpolation process. FIG. 11 is a diagram (1) for explaining a determination process using a noise frame. FIG. 12 is a diagram (2) for explaining the determination process using the noise frame. FIG. 13 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 14 is a diagram (1) for explaining a modification of the first embodiment. FIG. 15 is a diagram (2) for explaining a modification of the first embodiment. FIG. 16 is a diagram for explaining the second embodiment.

  Hereinafter, embodiments of an ultrasonic diagnostic apparatus will be described in detail with reference to the accompanying drawings.

(First embodiment)
First, the configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram for explaining a configuration example of an ultrasonic diagnostic apparatus according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus according to the first embodiment includes an ultrasonic probe 1, a monitor 2, an input device 3, and an apparatus main body 10.

  The ultrasonic probe 1 has a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission unit 11 included in the apparatus main body 10 to be described later. The ultrasonic probe 1 receives a reflected wave from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer provided in the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like. The ultrasonic probe 1 is detachably connected to the apparatus main body 10.

  When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another at the discontinuous surface of the acoustic impedance in the body tissue of the subject P, and the ultrasonic probe is used as a reflected wave signal. 1 is received by a plurality of piezoelectric vibrators. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected by the moving blood flow or the surface of the heart wall depends on the velocity component of the moving object in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  For example, the ultrasonic probe 1 according to the first embodiment is an ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a line, and the plurality of piezoelectric vibrators arranged in a line is a transmission unit 11 described later. An ultrasonic wave is generated based on the drive signal supplied from the. Thereby, the ultrasonic probe 1 scans the subject P two-dimensionally with ultrasonic waves.

  The input device 3 includes a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, a joystick, etc., receives various setting requests from an operator of the ultrasonic diagnostic apparatus, The various setting requests received are transferred. For example, the input device 3 according to the first embodiment includes a “gain optimization switch” for receiving a start of a gain optimization process described later from an operator. Further, for example, the input device 3 according to the first embodiment receives various setting information used for a gain optimization process described later from the operator.

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus to input various setting requests using the input device 3, and displays an ultrasonic image generated in the apparatus main body 10. To do.

  The apparatus main body 10 is an apparatus that generates ultrasonic image data based on the reflected wave received by the ultrasonic probe 1, and as shown in FIG. 1, a transmission unit 11, a reception unit 12, a buffer 13, and B A mode processing unit 14, a Doppler processing unit 15, an image generation unit 16, an image memory 17, an image processing unit 18, a control unit 19, and an internal storage unit 20 are included.

  As shown in FIG. 1, the transmission unit 11 includes a rate pulse generator 11 a, a transmission delay circuit 11 b, and a transmission pulser 11 c, and supplies a drive signal to the ultrasonic probe 1. The rate pulser generator 11a repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. The rate pulse applies a voltage to the transmission pulser 11c while having different transmission delay times by passing through the transmission delay circuit 11b. That is, in the transmission delay circuit 11b, the rate pulsar generator 11a determines the transmission delay time for each piezoelectric vibrator necessary to determine the transmission directivity by focusing the ultrasonic wave generated from the ultrasonic probe 1 into a beam shape. For each rate pulse that occurs. The transmission pulser 11c applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse.

  The drive pulse is transmitted from the transmission pulser 11c via the cable to the piezoelectric vibrator in the ultrasonic probe 1, and then converted from an electrical signal to mechanical vibration in the piezoelectric vibrator. This mechanical vibration is transmitted as an ultrasonic wave inside the living body. Here, the ultrasonic waves having different transmission delay times for each piezoelectric vibrator are converged and propagated in a predetermined direction. That is, the transmission delay circuit 11b arbitrarily adjusts the transmission direction from the piezoelectric vibrator surface by changing the transmission delay time given to each rate pulse.

  The transmission unit 11 has a function capable of instantaneously changing a transmission frequency, a transmission drive voltage, and the like in order to execute a predetermined scan sequence based on an instruction from the control unit 19 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching its value or a mechanism for electrically switching a plurality of power supply units.

  The reflected ultrasonic wave transmitted from the ultrasonic probe 1 reaches the piezoelectric vibrator inside the ultrasonic probe 1 and is then converted from a mechanical vibration to an electrical signal (reflected wave signal) by the piezoelectric vibrator. Input to the unit 12. As shown in FIG. 1, the receiving unit 12 includes a preamplifier 12a, an A / D converter 12b, and a reception delay adding circuit 12c, and performs various processes on the reflected wave signal received by the ultrasonic probe 1. To generate reflected wave data.

  The preamplifier 12a performs gain adjustment by amplifying the reflected wave signal for each channel. The A / D converter 12 b converts the gain-corrected reflected wave signal into digital data by A / D converting the gain-corrected reflected wave signal. The reception delay adding circuit 12c gives the reception delay time necessary for determining the reception directivity to the digital data. The reception delay adding circuit 12c performs addition processing of digital data given the reception delay time to generate reflected wave data. By the addition processing of the reception delay adding circuit 12c, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is enhanced.

  As described above, the transmission unit 11 and the reception unit 12 control transmission directivity and reception directivity in transmission / reception of ultrasonic waves.

  The buffer 13 is a buffer that temporarily stores the reflected wave data output from the receiving unit 12. For example, the buffer 13 is a first-in / first-out (FIFO) memory that stores reflected wave data for several frames, stores reflected wave data for a predetermined frame, and newly reflects reflected data for one frame. Is output, the reflected wave data for one frame with the oldest generation time is discarded, and the newly output reflected wave data for one frame is stored.

  The reflected wave data for one frame is reflected wave data for generating one ultrasonic image, and the transmission unit 11 has a scanning range formed by a plurality of scanning lines (scan lines). By allowing the ultrasonic probe 1 to perform ultrasonic transmission / reception, the reception unit 12 outputs reflected wave data for one frame.

  The B-mode processing unit 14 reads the reflected wave data generated by the receiving unit 12 from the buffer 13, performs logarithmic amplification, envelope detection processing, logarithmic compression, and the like on the read reflected wave data to obtain signal strength (amplitude). Data (B mode data) whose intensity is expressed by brightness is generated.

  The Doppler processing unit 15 reads the reflected wave data generated by the receiving unit 12 from the buffer 13, and extracts the motion information based on the Doppler effect of the moving body within the scanning range by performing frequency analysis of the read reflected wave data. Data (Doppler data) is generated. Specifically, the Doppler processing unit 15 generates Doppler data obtained by extracting an average speed, a variance value, a power value, and the like over multiple points as movement information of the moving body. More specifically, the Doppler processing unit 15 generates color Doppler data for generating a color Doppler image indicating the dynamics of blood flow, or tissue Doppler data for generating a tissue Doppler image indicating the dynamics of the tissue. .

  The image generation unit 16 generates ultrasonic image data from the data generated by the B mode processing unit 14 and the Doppler processing unit 15. That is, the image generation unit 16 generates B-mode image data in which the intensity of the reflected wave is expressed by luminance from the B-mode data generated by the B-mode processing unit 14. In addition, the image generation unit 16 generates color Doppler image data as an average speed image, a dispersed image, a power image, or a combination image representing moving body information from the Doppler data generated by the Doppler processing unit 15.

  Here, the image generation unit 16 generally converts (scan converts) a scanning line signal sequence of ultrasonic scanning into a scanning line signal sequence of a video format typified by a television or the like, and displays ultrasonic waves for display. Generate image data. Specifically, the image generation unit 16 generates ultrasonic image data for display by performing coordinate conversion in accordance with the ultrasonic scanning mode of the ultrasonic probe 1. In addition, the image generation unit 16 synthesizes character information, scales, body marks, and the like of various parameters with the ultrasonic image data.

  The image memory 17 is a memory that stores the image data generated by the image generation unit 16. The image memory 17 can also store data generated by the B-mode processing unit 14 and the Doppler processing unit 15.

  The image processing unit 18 is a processing unit that performs image processing using the ultrasonic image data generated by the image generation unit 16. As shown in FIG. 1, the image processing unit 18 according to the first embodiment includes an average luminance value calculation unit 18a, an S / N measurement unit 18b, and an interpolation processing unit 18c. The average luminance value calculation unit 18a is a processing unit that calculates the average luminance value of a predetermined region from the luminance values in the ultrasonic image. The S / N measurement unit 18b is a processing unit that measures a signal-to-noise ratio (S / N) of an ultrasonic image. The interpolation processing unit 18c is a processing unit that calculates an estimated value by interpolation processing such as approximate calculation. The average luminance value calculation unit 18a, the S / N measurement unit 18b, and the interpolation processing unit 18c will be described in detail later.

  The internal storage unit 20 stores a control program for performing ultrasound transmission / reception, image processing, and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. For example, the internal storage unit 20 stores a scan sequence for performing harmonic imaging. The internal storage unit 20 is also used for storing image data stored in the image memory 17 as necessary.

  The control unit 19 controls the entire processing of the ultrasonic diagnostic apparatus. Specifically, the control unit 19 includes a transmission unit 11, a reception unit based on various setting requests input from the operator via the input device 3 and various control programs and various data read from the internal storage unit 20. 12. Control processing of the B-mode processing unit 14, the Doppler processing unit 15, the image generation unit 16, and the image processing unit 18.

  Further, the control unit 19 controls the display 2 to display the ultrasonic image data for display stored in the image memory 17.

  Here, as shown in FIG. 1, the control unit 19 according to the first embodiment includes a determination unit 19a and a setting unit 19b. The determination unit 19a determines a weighting coefficient for weighting the reflected wave signal when the preamplifier 12a, which is an analog circuit, adjusts the gain. The setting unit 19b controls the receiving unit 12 by setting the weighting coefficient designated by the operator or the weighting coefficient determined by the determination unit 19a for the preamplifier 12a. The determination unit 19a and the setting unit 19b will be described in detail later.

  The overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment has been described above. With this configuration, the ultrasonic diagnostic apparatus according to the first embodiment performs harmonic imaging.

  The B-mode processing unit 14 described above can change the frequency band to be imaged by changing the detection frequency. Further, the B-mode processing unit 14 can perform detection processing using two detection frequencies in parallel on one reflected wave data.

  By using the function of the B-mode processing unit 14, the ultrasonic diagnostic apparatus according to the first embodiment performs harmonic imaging that visualizes harmonic components. As harmonic imaging, contrast harmonic imaging (CHI: Contrast Harmonic Imaging) and tissue harmonic imaging (THI: Tissue Harmonic Imaging) are known. Hereinafter, harmonic imaging will be briefly described with CHI as an example.

  With the above function, the B-mode processing unit 14 uses the reflected wave data at the imaging region of the subject P into which the ultrasound contrast agent has been injected as a reflection source for the ultrasound contrast agent (microbubbles, bubbles) flowing through the imaging region. And the reflected wave data using the tissue existing in the imaging region as a reflection source are separated. Thereby, the image generation part 16 can generate | occur | produce the tissue image which visualized the contrast image which visualized the flowing bubble with high sensitivity, and the structure | tissue in order to observe a form.

  The reflected wave signal from the microbubbles includes many harmonic components that are nonlinear signals. A contrast image is often generated mainly based on a second harmonic (second harmonic) component. On the other hand, the tissue image for morphological observation is mainly generated based on the fundamental wave component.

  For example, the B mode processing unit 14 separates the harmonic component and the fundamental component from the reflected wave data by filtering. However, in the filtering process, the fundamental wave component is not sufficiently removed, and a contrast image in which the fundamental wave component is suppressed and the harmonic component is emphasized may not be generated.

  Therefore, in recent years, amplitude modulation (AM) and phase modulation (PM) have been performed in CHI. In AM and PM, a plurality of ultrasonic transmissions having different amplitudes and phases are performed on the same scanning line a plurality of times, thereby suppressing the fundamental wave component derived from the tissue and the higher harmonics derived from the contrast agent (microbubble, bubble). A contrast image in which the wave component is emphasized is generated.

  In AM, according to the harmonic imaging scan sequence set by the control unit 19, the transmission unit 11 uses the same phase, for example (0.5, 1.0), and an ultrasonic wave whose amplitude ratio is “1: 2”. Are transmitted twice on each scan line.

  In AM, under the control of the control unit 19, the receiving unit 12, for example, reflects the reflected wave signal obtained by the first reception by the preamplifier 12 a with the reflected wave data (the reflected power is multiplied by 4). Wave data) and reflected wave data of the reflected wave signal obtained by the second reception are generated and stored in the buffer 13. The B-mode processing unit 14 combines the two reflected wave data of each scanning line stored in the buffer 13. Specifically, the B-mode processing unit 14 generates difference data for one frame by subtracting two reflected wave data of each scanning line and separating harmonic components. The image generation unit 16 generates an ultrasonic image using the difference data for one frame. Such an ultrasound image is a contrast image in which harmonic components are emphasized, that is, a contrast image in which a signal derived from a tissue is suppressed and a signal from an ultrasound contrast agent is mainly imaged. In particular, in AM, the image quality in the depth direction of a contrast image can be improved.

  Further, in PM called “Pulse Subtraction method” or “Pulse Inversion method”, the transmission unit 11 uses the same harmonic scanning scan sequence set by the control unit 19, for example, (1.0, −1.0). An ultrasonic wave having a waveform whose amplitude is 180 degrees different in amplitude is transmitted twice on each scanning line.

  In the PM, the control unit 19 controls the receiving unit 12 to obtain the reflected wave data of the reflected wave signal obtained by the first reception and the reflected wave data of the reflected wave signal obtained by the second reception. It is generated and stored in the buffer 13. The B-mode processing unit 14 combines the two reflected wave data of each scanning line stored in the buffer 13. Specifically, the B-mode processing unit 14 adds two reflected wave data of each scanning line for one frame and separates harmonic components to generate added data for one frame. The image generation unit 16 generates an ultrasonic image using the addition data for one frame. Such an ultrasound image is also a contrast image in which a signal derived from a living body is suppressed and a signal from an ultrasound contrast agent is mainly imaged. In particular, in PM, the resolution of contrast images can be improved.

  Further, AMPM is also known in which both AM effect and PM effect can be obtained by combining AM and PM. 2 and 3 are diagrams for explaining AMPM. For example, in the AMPM, the transmission unit 11 performs (−0.5, 1.0, −0.5) as shown in FIG. 2A by the harmonic imaging scan sequence set by the control unit 19. The ultrasonic waves having waveforms with different amplitudes and phases are transmitted three times on each scanning line.

  In AMPM, the control unit 19 controls the reception unit 12 to generate three reflected wave data from each of the reflected wave signals obtained by the first to third receptions, and store them in the buffer 13. The B mode processing unit 14 combines the three reflected wave data of each scanning line stored in the buffer 13. Specifically, the B-mode processing unit 14 generates added data for one frame by adding three reflected wave data of each scanning line for one frame and separating harmonic components. Thereby, the image generation part 16 produces | generates a contrast image using the addition data for 1 frame, as shown to (B) of FIG.

  Specific processing executed in the AMPM will be described with reference to FIG. First, as illustrated in FIG. 3, the transmission unit 11 uses the AMPM scan sequence so that the ratio between the amplitudes of the first and third transmission ultrasonic waves and the amplitude of the third transmission ultrasonic wave is “1: 2”. In addition, the ultrasonic waves are transmitted three times so that the phases of the first and third transmission ultrasonic waves are different from the positive and negative phases. The waveform of the transmission pulse shown in FIG. 3 is adjusted by the transmission pulser 11c which is an analog circuit.

  In AMPM, in order to avoid signal saturation, the receiving unit 12 performs processing as shown in FIG. In FIG. 3, the reflected wave of the first transmission ultrasonic wave is shown as “rate 1”, the reflected wave of the second transmission ultrasonic wave is shown as “rate 2”, and the reflected wave of the third transmission ultrasonic wave is shown as “rate 3”.

  First, in the AMPM, the analog amplifier is adjusted by an “AMPM gain” that is a weighting coefficient corresponding to the pulse sequence of the AMPM in the preamplifier 12a that is an analog circuit. Specifically, the preamplifier 12a performs gain adjustment of “0 dB” for “rate1” and “rate3”, and performs gain adjustment of “α times” for “rate2”. “Α” is “−6.0 dB” which theoretically doubles the amplitude (4 times the power). That is, “rate2” is set to “α * rate2” by the preamplifier 12a as shown in FIG.

  Then, “rate1” and “rate3” are “0.5 * rate1” by being “0.5 times” by the digital gain in the digitization processing of the A / D converter 12b, as shown in FIG. And “0.5 * rate3”.

  The reflected wave data generated by such processing is combined (added) to become “0.5 * rate1 + α * rate2 + 0.5 * rate3” as shown in FIG. 3, and the added data in which the fundamental wave component is suppressed and Become. That is, the receiving unit 12 performs analog gain adjustment and digital gain adjustment so that the amplitude is ½ (power is ¼) in order to avoid signal saturation.

  Here, the preamplifier 12a normally performs analog gain adjustment for correction of reception sensitivity in addition to the above-described analog gain adjustment by the “AMPM gain”. Hereinafter, a weighting coefficient used for weighting for correction of reception sensitivity is referred to as “analog gain”. FIG. 4 is a diagram for explaining an example of analog gain adjustment for reception sensitivity correction.

  For example, it is assumed that the amplification processing of the preamplifier 12a is in the range of ““ minimum value: 0 dB ”to“ maximum value: 50 dB ””. In this case, the analog gain is set in the range of “0 dB to 50 dB” according to the depth as shown in FIG. Specifically, the analog gain is set according to the time from ultrasonic transmission to reception of the reflected wave signal. That is, the above-mentioned “rate1 to rate3” are reflected wave signals on one scanning line on which analog gain adjustment for reception sensitivity correction is performed according to the depth direction.

  The first and third reflected wave signals are converted into digital signals by adjusting the analog gain with the analog gain that is the “first coefficient” and then adjusting the digital gain. The second reflected wave signal is digitized after being adjusted by an analog gain that is a “first coefficient” and an analog gain adjustment by an AMPM gain that is a “second coefficient”. Become.

  However, the gain adjustment described above is not necessarily the optimum gain adjustment in harmonic imaging.

  That is, as described above, the transmission unit 11 controls the signal amplitude with voltage, but the transmission pulser 11c that applies the drive pulse to the ultrasonic probe 1 is an analog circuit. For this reason, the ratio of the first and third amplitudes to the third amplitude may not be accurately “1: 2” due to variations in the characteristics of the transmission pulser 11c that is an analog circuit. .

  The gain adjustment of “0.5 times” for the first and third reflected wave signals is performed almost accurately because it is digital processing, but the gain adjustment of “α times” for the second reflected wave signal is performed. Analog processing by the preamplifier 12a. Furthermore, gain adjustment for receiving sensitivity correction for each reflected wave signal is also analog processing by the preamplifier 12a. FIG. 5 is a diagram for explaining an example of input / output characteristics of an analog circuit.

  The input / output characteristics of the preamplifier 12a, which is an analog circuit, may be non-linear as illustrated in FIG. Therefore, as described above, theoretically, by setting “α” to “−6.0 dB”, it should be possible to generate a contrast image in which the signal derived from the tissue is the smallest. The optimum AMPM gain (α) is deviated from “−6.0 dB”. In addition, the optimum AMPM gain for each analog gain may differ depending on the input / output characteristics illustrated in FIG.

  Furthermore, the input / output characteristics of the preamplifier 12a, which is an analog circuit, also change depending on the lot of the ultrasonic diagnostic apparatus, the temperature at the time of imaging, and changes with time. Further, the input / output characteristics of the preamplifier 12a, which is an analog circuit, also change when the transmission condition and the transmission voltage are changed for each subject P. For this reason, it is necessary to obtain an optimum AMPM gain for each analog gain every time inspection is performed.

  Therefore, conventionally, in order to obtain the optimum AMPM gain for each analog gain, processing as shown in FIG. 6 is performed by the operator. FIG. 6 is a diagram for explaining a conventional weighting coefficient optimization process. For example, in order to obtain the optimum AMPM gain at “analog gain: 40 dB”, the operator uniformly sets the analog gain to “40 dB”, and further sets the AMPM gain to “−5.4 dB, −5.6 dB, An instruction to generate six ultrasonic images changed to “−5.8 dB, −6.0 dB, −6.2 dB, −6.4 dB” without contrast is given via the input device 3.

  As a result, the image generation unit 16 generates six ultrasonic images as shown in FIG. 6, and these ultrasonic images are displayed on the monitor 2 by the display control process of the control unit 19. The operator refers to the ultrasonic image illustrated in FIG. 6 and specifies α of the ultrasonic image having the lowest luminance. For example, in the example of FIG. 6, the operator specifies that the optimum AMPM gain (α) at “analog gain: 40 dB” is “−6.0 dB”. Conventionally, an optimal AMPM gain for each analog gain has been obtained by performing such processing for each analog gain. That is, conventionally, setting a value (weighting coefficient) that is an optimal combination of the first coefficient and the second coefficient has been a complicated process for the operator.

  Note that the complexity required for setting the weighting coefficient due to the input / output characteristics of the analog gain occurs not only in AMPM but also in the case of performing AM or PM. Further, not only in CHI but also in THI, the complexity required for setting the weighting coefficient due to the input / output characteristics of the analog gain occurs.

  Therefore, in the first embodiment, as shown in FIG. 1, a determination unit 19a and a setting unit 19b are installed. The determination unit 19a and the setting unit 19b automatically set the optimum gain adjustment in harmonic imaging in cooperation with the image generation unit 16 and the image processing unit 18.

  First, when the processing of the transmission unit 11, the reception unit 12, and the image generation unit 16 in harmonic imaging is summarized based on the above description, the transmission unit 11 performs each scanning line according to a predetermined scan sequence for performing harmonic imaging. Send ultrasonic waves multiple times. For example, in the AMPM scan sequence, the transmission unit 11 has a ratio of the amplitude of the first and third transmission ultrasonic waves to the amplitude of the third transmission ultrasonic wave of “1: 2”, and The ultrasonic waves are transmitted three times on each scanning line so that the phase of the third transmitted ultrasonic wave and the phase of the third transmitted ultrasonic wave are different.

  In addition, the reception unit 12 weights each reflected wave of the ultrasonic wave transmitted a plurality of times on the same scanning line according to the first coefficient that is a weighting coefficient, and each reflected wave. On the other hand, a preamplifier 12a that is an analog circuit including a scan sequence weighting unit that performs weighting according to a second coefficient that differs according to a scan sequence is provided. That is, the first coefficient is a weighting coefficient set for weighting for reception sensitivity correction, and the second coefficient is a weighting coefficient set for weighting according to the scan sequence. For example, the preamplifier 12a uses a sensitivity correction unit that weights each reflected wave of ultrasonic waves transmitted three times on the same scanning line with an analog gain as a first coefficient, and an AMPM gain (α) as a second coefficient. It has a function with a scan sequence weighting unit that performs weighting.

  In addition, the image generation unit 16 generates an ultrasound image using synthesized data obtained by combining the reflected waves for each scanning line weighted by the first coefficient and the second coefficient. For example, the B-mode processing unit 14 separates the harmonic component from “0.5 * rate1 + α * rate2 + 0.5 * rate3” obtained by adding the three reflected wave data of each scanning line for one frame, thereby obtaining one frame. Is generated. Then, the image generation unit 16 generates an ultrasonic image using the addition data.

  In order to automatically set the optimum gain adjustment in harmonic imaging, the image generation unit 16 according to the first embodiment performs, for example, a superimposition described below by setting a weighting coefficient of the setting unit 19b for the preamplifier 12a. A sound image is generated prior to contrast agent injection.

  That is, the image generation unit 16 according to the first embodiment uses the first coefficient as an ultrasonic image using synthesized data obtained by combining the reflected waves for each scanning line weighted by the first coefficient and the second coefficient. A plurality of ultrasonic images in which the value and the value of the second coefficient are changed are generated. Specifically, the image generation unit 16 uses the same combination of the first coefficient and the second coefficient as the plurality of ultrasonic images in which the first coefficient value and the second coefficient value are changed. Different ultrasonic images are generated in each of a plurality of regions of the image.

  More specifically, the image generation unit 16 uses the first coefficient for the second coefficient having the same value as a plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed. Different ultrasonic images are generated in a plurality of regions of the ultrasonic image having the same value of.

  For example, when the image generation unit 16 has a plurality of ultrasonic images in which the analog gain value and the AMPM gain value are changed, an ultrasonic image having the same analog gain value with respect to the same AMPM gain is used. Different ultrasonic images are generated in each of the plurality of regions. FIG. 7 is a diagram for explaining an example of AMPM gain and analog gain change settings according to the first embodiment.

  For example, the change setting illustrated in FIG. 7 is set by the operator. Alternatively, the change setting illustrated in FIG. 7 is set in advance by the manufacturer when the ultrasonic diagnostic apparatus is shipped. In the change setting illustrated in FIG. 7A, four values of “−5.8 dB, −6.0 dB, −6.2 dB, and −6.4 dB” are sequentially supplied to the preamplifier 12a as the AMPM gain (α). It is changed and set.

  In the change setting illustrated in FIG. 7B, the analog gain value is set by being divided into 11 regions (sections 1 to 11) corresponding to the depth (unit: cm). Sections 1 to 11 are eleven areas set every 1 cm along the depth direction, as shown in FIG. Further, as shown in FIG. 7B, the analog gain of each section is set to “minimum value: 0 dB” in the section 1 and increases by “5 dB” along the depth direction. “Maximum value: 50 dB” is set. That is, in the change setting illustrated in FIG. 7B, the analog gain of “section 1” that is “depth: 0 cm to 1 cm” is set to “0 dB”, and “section that is“ depth: 1 cm to 2 cm ”. It is set when the analog gain of “2” is changed to “5 dB”. Further, in the change setting illustrated in FIG. 7B, the analog gain of “section 10” having “depth: 9 cm to 10 cm” is set to “45 dB”, and the “section” having “depth: 10 cm to 11 cm” is set. 11 ”is set when the analog gain is changed to“ 50 dB ”.

  When the change setting of FIG. 7 is performed by the setting unit 19b, the preamplifier 12a of the receiving unit 12 fixes the analog gain according to the time when the reflected wave signal is received after fixing “α = −5.8 dB”. change. Further, the preamplifier 12a of the receiving unit 12 fixes “α = −6.0 dB” and changes the analog gain according to the time when the reflected wave signal is received. Further, the preamplifier 12a of the receiving unit 12 fixes “α = −6.2 dB” and changes the analog gain according to the time when the reflected wave signal is received. Further, the preamplifier 12a of the receiving unit 12 fixes “α = −6.4 dB” and changes the analog gain according to the time when the reflected wave signal is received. FIG. 8 is a diagram for explaining an ultrasonic image generated by the change setting of the AMPM gain and the analog gain illustrated in FIG.

  Thereby, as shown in FIG. 8, the image generation unit 16 has “α = −5.8 dB” and one ultrasonic image in which the value of the analog gain is 11 types in the sections 1 to 11. Is generated. Further, as illustrated in FIG. 8, the image generation unit 16 generates one ultrasonic image in which “α = −6.0 dB” and the analog gain value is 11 kinds of values in the sections 1 to 11. Generate. As illustrated in FIG. 8, the image generation unit 16 generates one ultrasonic image in which “α = −6.2 dB” and the analog gain value is 11 types in the sections 1 to 11. . Further, as illustrated in FIG. 8, the image generation unit 16 generates one ultrasonic image in which “α = −6.4 dB” and the analog gain value is 11 types of values in the sections 1 to 11. Generate.

  The processing of the image generation unit 16 starts when the operator turns on the “gain optimization switch”.

  The determination unit 19a illustrated in FIG. 1 is used to generate an ultrasonic image having a minimum luminance value among a plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed. The combination of the first coefficient and the second coefficient used by the preamplifier 12a for weighting the reflected wave is determined as a setting coefficient. Specifically, the determination unit 19a extracts the value of the second coefficient that minimizes the luminance value between the regions that are the first coefficient having the same value in each of the plurality of regions of the plurality of ultrasonic images. Determine the setting factor. Then, the setting unit 19b sets the setting coefficient determined by the determination unit 19a in the preamplifier 12a as a weighting coefficient when executing harmonic imaging. Hereinafter, the “setting coefficient” may be described as “optimum gain”.

  More specifically, the determination unit 19a causes the average luminance value calculation unit 18a illustrated in FIG. 1 to calculate the average luminance value in the image. And the determination part 19a performs said extraction process using the average luminance value which the average luminance value calculation part 18a calculated. FIG. 9 is a diagram for explaining optimum gain determination processing by the determination unit.

  First, the determination unit 19a causes the average luminance value calculation unit 18a to calculate the average luminance value of the sections 1 to 11 in each of the four ultrasonic images illustrated in FIG. The calculation result is notified to the determination unit 19a as a list as shown in FIG. 9, for example. The determining unit 19a refers to the list illustrated in FIG. 9, and in the section 7 in which the analog gain is “30 dB”, the average luminance value of “α: −5.8 dB” is “16.32”, and “α : -6.0 dB "average luminance value is" 13.86 "," α: -6.2 dB "average luminance value is" 16.33 ", and" α: -6.4 dB "average Since the luminance value is “19.59”, “α: −6.0 dB” having the minimum average luminance value is extracted. Then, it is determined that the combination of “analog gain: 30 dB, AMPM gain: −6.0 dB” is the optimum gain.

  Similarly, the determination unit 19a refers to the list illustrated in FIG. 9 and the average luminance value of “α: −5.8 dB” is “22.22” in the section 8 where the analog gain is “35 dB”. Yes, the average luminance value of “α: −6.0 dB” is “19.74”, the average luminance value of “α: −6.2 dB” is “17.94”, and “α: −6. Since the average luminance value of “4 dB” is “21.11”, “α: −6.2 dB” that minimizes the average luminance value is extracted. Then, it is determined that the combination of “analog gain: 35 dB, AMPM gain: −6.2 dB” is the optimum gain.

  Here, since the reflected wave signal is received as a signal reflected from various parts in the living body, the second coefficient (AMPM) having the minimum average luminance value depending on the region (sections 1 to 11). (Gain) may not be extracted. Therefore, when the second coefficient that minimizes the luminance value is not extracted between the regions that are the first coefficient having the same value, the determination unit 19a determines other first coefficients that are close to the value of the first coefficient. Using the value of the second coefficient extracted in the region, the value of the second coefficient combined with the value of the first coefficient is estimated.

  Specifically, the determination unit 19a performs the above processing in cooperation with the interpolation processing unit 18c shown in FIG. FIG. 10 is a diagram for explaining the optimum gain determination process using the interpolation process.

  For example, according to an instruction from the determination unit 19a, the interpolation processing unit 18c has an analog gain on the horizontal axis and a luminance value (average luminance value) on the vertical axis that is minimum with respect to the analog gain, as shown in FIG. A graph in which the AMPM gain (α) is plotted is drawn (see the solid line in the figure). Then, when the AMPM gain that minimizes the luminance value (average luminance value) at “analog gain: 20 dB” is not obtained, the interpolation processing unit 18 c selects “optimal AMPM gain: −5. The optimum AMPM gain of “analog gain: 20 dB” is estimated to be “−5.9 dB” from “8 dB” and “optimum AMPM gain: −6.0 dB” of “analog gain: 25 dB” (the dotted line in the figure is reference).

  Similarly, when the AMPM gain that minimizes the luminance value (average luminance value) at “analog gain: 35 dB” has not been obtained, the interpolation processing unit 18 c selects “optimal AMPM gain: −6” of “analog gain: 30 dB”. 0.0 dB ”and“ optimal AMPM gain: −6.2 dB ”of“ analog gain: 40 dB ”, the optimal AMPM gain of“ analog gain: 35 dB ”is estimated as“ −6.1 dB ”(dotted line in the figure) See).

  By the above interpolation processing, the determination unit 19a can determine the optimum AMPM gain for all the analog gains that have been changed and set, and the optimum gain is set in the preamplifier 12a by the setting unit 19b. The

  Furthermore, in the first embodiment, the determination unit 19a performs a determination process as to whether or not to perform a setting coefficient (optimum gain) determination process. Since an ultrasonic signal attenuates as it goes deeper, a signal derived from a living tissue may not be received in the deeper part. When a signal from a living body cannot be received, an optimum AMPM gain (setting coefficient, optimum gain) for each analog gain cannot be obtained. Further, the optimum AMPM gain for each analog gain can be obtained only when the ultrasonic probe 1 is applied to an object that can evaluate a tissue signal such as a phantom or a living body, and the ultrasonic probe 1 is left in the air. Not required in some cases.

  Therefore, in the first embodiment, the following determination process is performed before the optimum gain determination process described with reference to FIGS. 9 and 10. 11 and 12 are diagrams for explaining determination processing using a noise frame.

  First, as illustrated in FIG. 11, the image generation unit 16 according to the first embodiment further generates a noise image (noise frame) that is an ultrasonic image based on a reflected wave received in a state where ultrasonic transmission is stopped. Generate. Specifically, the receiving unit 12 generates reflected wave data of the reflected wave signal received by the ultrasonic probe 1 without applying a driving pulse from the transmitting unit 11 by the control processing of the determining unit 19a, and performs B-mode processing. The unit 14 generates B mode data from the reflected wave data. Thereby, the image generation unit 16 generates a noise frame.

  Then, the determination unit 19a according to the first embodiment has a signal-to-noise ratio (S) between a plurality of ultrasonic images in which the first coefficient value and the second coefficient value are changed, and a noise image (noise frame). / N), it is determined whether or not to determine the setting coefficient.

  For example, the determination unit 19a causes the S / N measurement unit 18b to measure the S / N with the noise frame for each of the sections 1 to 11. Then, the determination unit 19a performs a comparison process between the S / N of each of the sections 1 to 11 and a preset threshold “TH”.

  Here, for example, as shown in FIG. 12A, “S / N that is the S / N for the noise frame of the section 11 (analog gain: 50 dB) in the ultrasonic image of“ AMPM gain: −5.8 dB ”. When “/ N (section 11)” is smaller than TH, the determination unit 19a excludes the section 11 in the ultrasonic image of “AMPM gain: −6.0 dB” from the processing target. That is, the determination unit 19a determines not to perform the setting coefficient (optimum gain) determination process using the section 11 in the ultrasonic image of “AMPM gain: −6.0 dB”.

  Alternatively, for example, as illustrated in FIG. 12B, when the S / N of all sections is smaller than TH in the ultrasonic image of “AMPM gain: −5.8 dB”, the determination unit 19 a It is determined that the determination process of (optimum gain) is to be stopped. That is, when the S / N of all sections is smaller than TH, the determination unit 19a determines that the ultrasonic probe 1 is left in the air and ends the optimum gain determination process. In such a case, the determination unit 19a may display a message such as “Please apply the probe to the living body” on the monitor 2.

  Note that the functions of the average luminance value calculation unit 18a, the S / N measurement unit 18b, and the interpolation processing unit 18c described in the above embodiment may be included in the determination unit 19a.

  Next, processing of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 13 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. In the following, a case where the AMPM gain and analog gain change settings illustrated in FIG. 7 are initially set will be described.

  As shown in FIG. 13, the ultrasonic diagnostic apparatus according to the first embodiment determines whether or not the gain optimization switch has been turned ON by the operator (step S101). Here, when the gain optimization switch is OFF (No in step S101), the ultrasonic diagnostic apparatus according to the first embodiment waits until the optimization switch is turned ON.

  On the other hand, when the gain optimization switch is turned on (Yes at Step S101), the setting unit 19b sequentially changes the settings of the analog gain and the AMPM gain (Step S102). As a result, the image generation unit 16 makes the analog gain value equal to the AMPM gain having the same value as the plurality of ultrasonic images in which the analog gain value and the AMPM gain value are changed in each of the plurality of sections. Different ultrasonic images are generated (step S103).

  Then, the image generation unit 16 generates a noise frame (step S104), and the S / N measurement unit 18b uses the noise frame in response to an instruction from the determination unit 19a to perform S of the ultrasonic image generated in step S103. / N is measured for each section (step S105).

  Then, the determination unit 19a refers to the measured value of S / N and determines whether there is a section that is not a biological scan (step S106). Here, when there is no section that is not a biological scan (No at Step S106), the average brightness value calculation unit 18a calculates an average brightness value for each section according to an instruction from the determination unit 19a (Step S109).

  On the other hand, when there is a section that is not the biological scan (Yes at Step S106), the determination unit 19a further determines whether or not the section that is not the biological scan is the entire section (Step S107). Here, when the section that is not the biological scan is the entire section (Yes at Step S107), the determination unit 19a ends the process. For example, the determination unit 19a displays a message such as “Please apply the probe to the living body” on the monitor 2, and then ends the processing.

  On the other hand, when the section that is not the biological scan is not the entire section (No at Step S107), the determination unit 19a excludes the section that is not the biological scan from the processing target (Step S108), and the average luminance value calculation unit 18a is instructed by the determination unit 19a. Calculates an average luminance value for each section to be processed (step S109).

  Then, the determination unit 19a extracts an AMPM gain (ultrasound image) that minimizes the average luminance value for each section (step S110). Then, the determination unit 19a determines whether or not the AMPM gain that minimizes the average luminance value in all the sections has been extracted (step S111).

  Here, when the AMPM gain that minimizes the average luminance value in all the sections has not been extracted (No in step S111), the interpolation processing unit 18c estimates the AMPM gain of the corresponding section by the interpolation process according to the instruction of the determination unit 19a. Then, the determination unit 19a determines the optimum gain (optimum AMPM gain for each analog gain), the setting unit 19b installs the optimum gain of the preamplifier 12a, and ends the process.

  On the other hand, when the AMPM gain that minimizes the average luminance value in all the sections is extracted (Yes in step S111), the determination unit 19a determines the optimum gain, and the setting unit 19b installs the optimum gain of the preamplifier 12a ( Step S113) and the process is terminated.

  Conventionally, the operator selects the ultrasonic image of the second coefficient (AMPM gain) that minimizes the luminance while changing the first coefficient (analog gain), and sets a combination of these values in the preamplifier 12a. It was. However, as described above, in the first embodiment, the first coefficient value and the first coefficient can be changed by simply setting a pattern for changing the first coefficient (analog gain) and the second coefficient (AMPM gain). A plurality of ultrasonic images in which the value of the two coefficients is changed are generated. In the first embodiment, by extracting an area (section) in which the luminance value is minimum from a plurality of ultrasonic images, the second coefficient value that is optimal for each value of the first coefficient is automatically set. The combination of these values can be automatically set in the preamplifier 12a.

  Therefore, in the first embodiment, optimal gain adjustment in harmonic imaging can be easily set. Further, in the first embodiment, the optimum gain adjustment in harmonic imaging can be easily performed, so that the operator's trouble of performing gain adjustment is reduced. As a result, the examination time is shortened. The burden on the person can be reduced.

  Furthermore, in the first embodiment, by setting the change pattern illustrated in FIGS. 7 and 8, 44 types of combinations of the first coefficient and the second coefficient are performed only by collecting four ultrasonic images. be able to. Therefore, in the first embodiment, optimal gain adjustment in harmonic imaging can be set simply and quickly.

  In the first embodiment, since the extraction process is performed using the average luminance value in the image (within the section) as the luminance value, the calculation process of the index used for the extraction process can be easily performed. In the first embodiment, when the second coefficient that minimizes the luminance value is not extracted, the second coefficient that minimizes the luminance value is estimated by interpolation processing such as approximate calculation. The optimal value of the second coefficient can be determined for each value.

  Further, in the first embodiment, it is determined whether or not the section is to be excluded from the processing target by measuring the S / N using the noise frame, so that the optimum gain can be determined with high accuracy. Further, in the first embodiment, it is determined whether or not the ultrasonic probe 1 is left in the air by measuring the S / N using a noise frame, so that an inappropriate optimum gain is prevented from being set. it can.

  Note that the plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed are not limited to the case illustrated in FIGS. 7 and 8. Hereinafter, a modified example of a plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed will be described with reference to FIGS. 14 and 15. 14 and 15 are diagrams for explaining a modification of the first embodiment.

  The value of the first coefficient (analog gain) set in each section is not limited to the case where the value is set to increase along the depth direction as illustrated in FIGS. 7 and 8. For example, as shown in FIG. 14A, the analog gain value set in each section is set so as to decrease sequentially from “50 dB” to “0 dB” along the depth direction. There may be.

  Further, the analog gain value set in each section is not limited to the case where the analog gain value is set to change along the depth direction as illustrated in FIGS. 7 and 8. For example, the value of the analog gain set in each section may be set so as to change along the azimuth direction as well as the depth direction, as shown in FIG. In the example shown in FIG. 14B, the sections 1 to 10 are further divided into two in the azimuth direction, the analog gain is increased by “2.5 dB” from “0 dB” to “47.5 dB”, and the section 11 is changed to “ The change pattern is “50 dB”. By using the change pattern illustrated in FIG. 14B, the determination unit 19a can determine more combinations of optimum gains.

  In the example shown in FIGS. 7 and 8, the case where the value of the AMPM gain used for the same ultrasonic image is the same has been described. However, the first embodiment may be a case where there are a plurality of AMPM gain values used for the same ultrasonic image. For example, the sections 1 to 11 are divided into two in the azimuth direction. Then, as shown in FIG. 14C, the left region is set to “α: −5.8 dB”, and the analog gain of the sections 1 to 11 in the region “α: −5.8 dB” is set to “0 dB”. ”To“ 50 dB ”is set to increase the analog gain by“ 5 dB ”. Further, as shown in FIG. 14C, the right region is set to “α: −6 · 0 dB”, and the analog gain of the sections 1 to 11 in the region “α: −6 · 0 dB” is set to “0 dB”. ”To“ 50 dB ”is set to increase the analog gain by“ 5 dB ”. By using the change pattern illustrated in FIG. 14C, the number of ultrasonic images used for determining the setting coefficient (optimum gain) can be further reduced.

  Alternatively, in the first embodiment, as a plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed, an ultrasonic wave having the same combination of the first coefficient and the second coefficient value is used. It may be a case where the same ultrasonic image is generated in the image. For example, according to the setting for determining the optimum gain performed by the setting unit 19b, the image generation unit 16 sets the analog gain to “0 dB” as an ultrasonic image of “AMPM gain: −5.8 dB” as illustrated in FIG. 11 images that are changed by “5 dB” from “50 dB” to “50 dB” are generated. Similarly, as illustrated in FIG. 15, the image generation unit 16 includes an ultrasonic image of “AMPM gain: −6.0 dB”, an ultrasonic image of “AMPM gain: −6.2 dB”, and “AMPM gain: −6”. For each of the “.4 dB” ultrasonic images, 11 images with different analog gains are generated.

  Then, the determination unit 19a extracts an ultrasound image having a minimum luminance value between the ultrasound images having the same first coefficient, and extracts the value of the second coefficient used in the extracted ultrasound image. Thus, the setting coefficient (combination of analog gain and AMPM gain) is determined. Note that the luminance value used in such a case may be the average luminance value of the entire image or the average luminance value of the region of interest set in advance in the image.

  However, in the modification shown in FIG. 15, it is necessary to generate 44 ultrasonic images in the optimum gain determination process. Therefore, when determining the optimum gain described above, it is desirable to use a change pattern that can reduce the number of images used in the determination process, as illustrated in FIGS.

(Second Embodiment)
In the second embodiment, a case where the optimum gain setting process is automatically started will be described with reference to FIG. FIG. 16 is a diagram for explaining the second embodiment.

  In the second embodiment, the image generation unit 16, the determination unit 19a, and the setting unit 19b start processing related to the setting of the optimum gain according to a signal from a predetermined external device. In the first embodiment, when the operator turns on the gain optimization switch, the processing related to the setting of the optimum gain is started.

  Normally, at the start of ultrasound contrast, the operator turns on an injection timer to measure the elapsed time. Therefore, in the second embodiment, as illustrated in FIG. 16, the control unit 19 performs gain optimization processing by the image generation unit 16, the determination unit 19 a, and the setting unit 19 b using an injection timer ON as an external device as a trigger. Let it start automatically.

  Thus, in the second embodiment, the gain optimization process can be automatically started.

  In addition, each component of each apparatus illustrated in the drawings described in the first embodiment and the second embodiment described above is functionally conceptual, and is not necessarily physically configured as illustrated. Is not required. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  As described above, according to the first embodiment and the second embodiment, the optimum gain adjustment in harmonic imaging can be easily set.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These 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 their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Monitor 3 Input apparatus 10 Apparatus main body 11 Transmission part 11a Rate pulse generator 11b Transmission delay circuit 11c Transmission pulser 12 Reception part 12a Preamplifier 12b A / D converter 12c Reception delay addition circuit 13 Buffer 14 B mode processing part 15 Doppler processing unit 16 image generation unit 17 image memory 18 image processing unit 18a average luminance value calculation unit 18b S / N measurement unit 18c interpolation processing unit 19 control unit 19a determination unit 19b setting unit 20 internal storage unit

Claims (7)

A transmitter that transmits ultrasonic waves multiple times on each scanning line according to a predetermined scanning sequence for performing harmonic imaging;
A sensitivity correction unit that weights each reflected wave of ultrasonic waves transmitted multiple times on the same scanning line according to a first coefficient that is a weighting coefficient, and a scan sequence for each reflected wave A receiving unit having an analog circuit including a scan sequence weighting unit that performs weighting according to different second coefficients,
As an ultrasonic image using synthesized data obtained by synthesizing the reflected waves for each scanning line weighted by the first coefficient and the second coefficient, a plurality of super images in which the value of the first coefficient and the value of the second coefficient are changed are used. An image generator for generating a sound wave image;
Among the plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed, the analog circuit performs the reflected wave used for generating the ultrasonic image having the minimum luminance value. A determination unit that determines a combination of values of the first coefficient and the second coefficient used for weighting as a setting coefficient;
A setting unit that sets the setting coefficient in the analog circuit as a weighting coefficient when performing harmonic imaging;
An ultrasonic diagnostic apparatus comprising: In the ultrasonic image in which the combination of the first coefficient and the second coefficient is the same as the plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed, Generate the same ultrasound image,
The determination unit extracts an ultrasound image having a minimum luminance value between ultrasound images having the same first coefficient, and extracts a value of a second coefficient used in the extracted ultrasound image. The ultrasonic diagnostic apparatus according to claim 1, wherein the setting coefficient is determined. The image generation unit includes a plurality of ultrasonic images in which the combination of the first coefficient and the second coefficient is the same as the plurality of ultrasonic images in which the value of the first coefficient and the value of the second coefficient are changed. Generate different ultrasound images in each region,
The determining unit extracts the value of the setting coefficient by extracting a value of a second coefficient that minimizes a luminance value between areas that have the same first coefficient in a plurality of areas of each of the plurality of ultrasonic images. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is determined.   The ultrasonic diagnostic apparatus according to claim 1, wherein the determination unit performs an extraction process using an average luminance value in the image.   When the second coefficient having the minimum luminance value is not extracted between the areas having the same value as the first coefficient, the determining unit determines that the first coefficient area has a value close to the value of the first coefficient. The ultrasonic diagnostic apparatus according to claim 3 or 4, wherein the value of the second coefficient combined with the value of the first coefficient is estimated using the value of the second coefficient extracted in this way. The image generation unit further generates a noise image that is an ultrasonic image based on a reflected wave received in a state where ultrasonic transmission is stopped,
Whether the determination unit determines the setting coefficient based on a signal-to-noise ratio between the plurality of ultrasonic images in which the first coefficient value and the second coefficient value are changed, and the noise image. The ultrasonic diagnostic apparatus according to any one of claims 1 to 5, wherein:   The said image generation part, the said determination part, and the said setting part start the process regarding the setting of the said setting coefficient according to the signal from a predetermined | prescribed external device, The any one of Claims 1-6 characterized by the above-mentioned. An ultrasonic diagnostic apparatus according to 1.