JP5380114B2 - Ultrasonic diagnostic apparatus and ultrasonic diagnostic apparatus control method - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus that transmits / receives ultrasonic waves to / from a subject and generates an ultrasonic image of a diagnostic region using an echo signal based on the received ultrasonic waves, and a control method thereof. More specifically, the present invention relates to an ultrasonic diagnostic apparatus that adjusts the gain of an echo signal and a control method thereof.

  In recent years, an ultrasonic wave is transmitted toward the inside of a subject, and an ultrasonic wave reflected from an organ or the like of the subject (hereinafter, this reflected ultrasonic wave is referred to as “ultrasonic echo”) is received. The echo is converted into an electrical signal (hereinafter, this electrical signal is referred to as an “echo signal”), and the echo signal is subjected to signal processing such as logarithmic compression, envelope detection, delay addition processing, etc. 2. Description of the Related Art Ultrasonic diagnostic apparatuses that generate an ultrasonic image that is an image of a cross section in a subject by performing image processing such as conversion are widely used.

  In the above-described ultrasonic diagnostic apparatus, an amplifying unit that uniformly amplifies an echo signal (specifically, an amplifier (amplifier) is configured, and more specifically, an LNA (Low Noise Amplifier). Etc.), a TGC (Time Gain Compensation) unit that amplifies the echo signal with sensitivity according to the depth from the body surface in order to compensate for the attenuation of the ultrasonic wave in vivo, and an echo that is an analog signal An A / D conversion unit that converts a signal into a digital signal and a control unit that controls these are provided. This amplification factor is also referred to as gain, and the setting of the amplification factor may be referred to as “gain setting” below. Further, gain setting and converting gain may be referred to as gain adjustment.

  The input echo signal is amplified by the amplification unit, and further, the amplified echo signal is amplified by TGC with a gain that increases with the passage of the reception time, and the amplified echo signal is amplified. After the echo signal is converted into a digital signal by the A / D converter, the signal processing and image processing described above are performed on the echo signal changed to the digital signal.

  Here, in the ultrasonic diagnostic apparatus, various imaging and images such as a B mode for generating a tomographic image of a subject using the amplitude value of an echo signal, and a Doppler mode for acquiring blood flow information using phase information, etc. It has a generation mode (hereinafter referred to as “imaging mode”). And the strength of the echo signal acquired according to the kind of imaging mode, in other words, the amplitude of the echo signal acquired differs. For example, an echo signal in Doppler mode (that is, an echo signal from a blood flow) is very weak, that is, a signal having a small amplitude, compared to an echo signal in a B mode (that is, an echo signal from a bone or an organ). It is. Therefore, the gain may be small in the B mode, and the gain needs to be increased in the Doppler mode. That is, if amplification is performed on an echo signal acquired in the Doppler mode using the same gain as that in the B mode, the S / N ratio is deteriorated because the gain is insufficient. On the contrary, if the echo signal acquired in the B mode is amplified using the same gain as that in the Doppler mode, the gain is too large and the dynamic range becomes insufficient and becomes saturated. Therefore, in the B mode, gain setting that emphasizes avoidance of saturation is necessary, and in Doppler mode, gain setting that emphasizes improvement of S / N is necessary. As described above, the gain setting in the ultrasonic diagnostic apparatus differs depending on the imaging mode, that is, for each imaging purpose.

  Furthermore, the amplitude of the echo signal varies depending on the region to be scanned (target region) and also varies depending on the patient's body shape.

  Therefore, ideally, the amplitude of the echo signal is measured for each type of imaging mode, the patient's body shape, and the target region, and the optimal gain that achieves the best S / N with that amplitude and does not cause saturation. It is desirable to make settings.

  In order to perform such gain adjustment, conventionally, a technique has been adopted in which a threshold of the dynamic range of the A / D converter is provided in the A / D converter, and the gain setting of the amplifier is changed based on this threshold (for example, Patent Documents) 1) is proposed.

JP-A-10-85212

  However, there is a limit on the amplitude that can be output by the LNA arranged in the amplification unit, and the limit of the amplitude that can be output exceeds the limit of the signal that is actually output by the LNA (hereinafter referred to as “LNA saturation”). )) Only allowed LNA saturation. Here, “allowing saturation of LNA” means that a signal outside the limit range is not used. In this regard, with the technique described in Patent Document 1, saturation of the A / D converter can be prevented, but it is difficult to avoid saturation of the LNA in the amplification unit.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an ultrasonic diagnostic apparatus that improves S / N and avoids saturation of an amplifier (LNA).

In order to achieve the above object, an ultrasonic diagnostic apparatus according to claim 1 transmits an ultrasonic wave toward an object via an ultrasonic probe having a plurality of transducers, and reflects the ultrasonic wave reflected by the object. Transmission / reception means for receiving echo signals based on acoustic echoes, signal processing means for performing signal processing including logarithmic compression and envelope detection on the echo signals, and image processing including coordinate transformation on the echo signals subjected to the signal processing And an image processing means for generating image data, and a display control means for displaying an ultrasonic image on a display means based on the image data . first amplifier and the amplification means and a plurality of types of different amplitudes of the reference signals for a plurality chromatic and other amplifier arranged in parallel with the first amplifier for amplifying an amplification factor of echo signals is set from transducer Raised The reference signal generating means compares the amplitude of the received echo signal with the reference signal, and determines the magnitude of the amplitude of the received echo signal in a plurality of stages corresponding to the amplitude of the reference signal. The comparison determination means and the correspondence between the plurality of stages and the amplification factor are stored in advance so that the amplification factor becomes smaller as the amplitude of the echo signal increases in accordance with the step. Control means for selecting the amplification factor corresponding to the magnitude step determined by the step, and setting the amplification factor of the first amplifier to the selected amplification factor; and the amplified echo signal as a digital signal and a a / D converting means for converting said control means, the amplification factor of the other amplifier, the first greater than the set amplification factor of the amplifier, and each differently set And is characterized in a control child said amplifying means to amplify the echo signals thus received by switching sequentially the amplification factor is greater the other amplifiers from the first amplifier in response to the passage of time.

The ultrasonic diagnostic apparatus control method according to claim 5 , a step of transmitting an ultrasonic wave to a subject, a step of receiving the ultrasonic wave reflected by the subject and converting it into an echo signal, and the received echo signal A comparison determination step for comparing the amplitude of the reference signal with the reference signal and determining the amplitude of the received echo signal in a plurality of steps corresponding to the amplitude of the reference signal; The magnitude of the amplitude determined by the comparison determination means is based on the correspondence between the plurality of stages and the amplification factor so that the amplification factor becomes smaller as the amplitude of the echo signal increases in response to the amplification factor selection step of selecting a gain, set the first amplifier for amplifying the echo signals from one of said oscillator the amplification factor of echo signals to the selected amplification factor corresponding to the stage, the first Increase A plurality of other amplifiers arranged in parallel with the amplifier are set so as to be larger than the set amplification factor and different from each other, and the amplification factor is sequentially increased from the first amplifier as time passes. A control step of controlling to amplify the echo signal by switching to the amplifier of the above, an amplification step of amplifying the received echo signal at the set amplification factor, and an A / D for converting the amplified echo signal into a digital signal A conversion step, a signal processing step for performing signal processing including logarithmic compression and envelope detection on the echo signal converted into the digital signal, and image processing including coordinate conversion for the echo signal subjected to the signal processing And an image processing stage for generating image data, and an image display stage for displaying an ultrasonic image on a display unit based on the image data. Than is.

According to the ultrasonic diagnostic apparatus according to claim 1 and the ultrasonic diagnostic apparatus control method according to claim 5, when the amplitude is large, the gain of the amplifier is decreased according to the amplitude of the input echo signal. When the amplitude is small, the gain can be adjusted to increase. Thereby, it is possible to improve the S / N of the amplified echo signal and reduce the saturation of the attenuator.

Block diagram of an ultrasonic diagnostic apparatus according to the present invention The schematic diagram for demonstrating the structure of the reference signal generation part which concerns on 1st Embodiment, a comparison part, an amplification part, and a control part. The figure of the flowchart of the operation | movement of the gain adjustment by the ultrasonic diagnosing device which concerns on 1st Embodiment. The figure of an example of the amplification part in the ultrasonic diagnostic equipment concerning a 2nd embodiment The figure of an example of the input screen for performing the setting of the gain concerning a 3rd embodiment

[First Embodiment]
Hereinafter, an ultrasonic diagnostic apparatus according to a first embodiment of the present invention will be described. FIG. 1 is a block diagram showing functions of the ultrasonic diagnostic apparatus according to this embodiment.

  The ultrasonic probe 001 is provided with a plurality of transducers 011. In the case of a two-dimensional array probe, for example, thousands of transducers 011 are arranged. Each transducer 011 is individually connected to a transmission circuit 101 described later. Each transducer 011 is individually connected to an LNA (Low Noise Amplifier) 200 described later. Then, the pulse voltage input from the transmission circuit 101 is received. The transducer 011 generates an ultrasonic wave based on the received pulse signal, and transmits the ultrasonic wave toward the subject. Further, the transducer 011 receives an ultrasonic echo reflected from the subject, converts the received echo signal into a voltage, generates an echo signal, and outputs the echo signal to the connected LNA 200.

  As shown in FIG. 1, the transmission / reception unit 100 includes a transmission circuit 101, an amplification unit 102, a TGC (Time Gain Compensation) 103, an A / D conversion unit 104, a reference signal generation unit 105, a comparison unit 106, and a control unit 107. ing. The transmission / reception unit 100 corresponds to “transmission / reception means” in the present invention.

  The transmission circuit 101 generates a pulse voltage and transmits the pulse voltage to each transducer 011 disposed in the ultrasonic probe 001.

  The amplification unit 102 includes a plurality of LNAs 200 connected to each transducer 011 of the ultrasonic probe 001. That is, the same number of LNAs 200 as the vibrators 011 are arranged. The LNA 200 is an amplifier (amplifier) capable of changing the gain. Here, the gain is an amplification factor for amplifying the amplitude of the input echo signal. That is, the larger the gain, the larger the echo signal is amplified, and the smaller the gain, the smaller the echo signal is amplified. Hereinafter, changing the gain by setting the gain may be referred to as gain adjustment. Further, the amplitude of the signal that can be output from the LNA 200 is determined. In other words, when the amplitude of the amplified signal exceeds the amplitude of the signal that can be output by the LNA 200 when the echo signal is amplified, the portion exceeding the amplitude of the signal that can be output by the LNA 200 Output as the maximum value of the amplitude.

  The LNA 200 receives an input of a control signal from the control unit 107 described later, and the gain is set to a value specified by the control signal.

  The LNA 200 receives an echo signal input from the transducer 011. Then, the LNA 200 amplifies the echo signal with the set gain. Further, the LNA 200 outputs the amplified echo signal to the TGC 103.

  The amplifying unit 102 corresponds to the “amplifying unit” in the present invention, and each LNA 200 provided in the amplifying unit 102 corresponds to the “first amplifier” in the present invention.

  The TGC 103 has a storage unit such as a memory. And TGC103 has memorize | stored the function of a response | compatibility with multiple types of time passages and gains in its memory | storage part. The TGC 103 receives a control command from the control unit 107 to be described later, and selects a function specified by the control command from the stored functions.

  The TGC 103 receives an echo signal input from the LNA 200. Then, the TGC 103 uses the selected function to change the gain corresponding to the elapsed time, and amplifies the input signal.

  By this amplification by the TGC 103, the amplitude of any echo signal from the echo signal due to reflection at the shallow portion to the echo signal due to reflection at the deep portion is adjusted to be large, and further, an A / D conversion unit 104 described later. The amplitude of the echo signal is amplified so as to reach a value close to the upper limit of the dynamic range.

  The TGC 103 outputs the amplified echo signal to the A / D conversion unit 104. This TGC 103 corresponds to “gain correction means” in the present invention.

  The A / D conversion unit 104 is configured by an A / D converter. The A / D converter 104 receives an echo signal input from the TGC 103. The A / D conversion unit 104 converts an input echo signal, which is an analog signal, into a digital signal using an A / D converter. Then, the A / D conversion unit 104 outputs the echo signal converted into the digital signal to the signal processing unit 002. The A / D converter 104 corresponds to the “A / D converter” in the present invention.

  The reference signal generation unit 105 generates a plurality of reference signals having different amplitudes. In the present embodiment, two types of signals are generated: a reference signal R1 and a reference signal R2 (amplitude magnitude is reference signal R1 <reference signal R2). Here, FIG. 2 is a schematic diagram for explaining the configuration of the amplification unit 102, the reference signal generation unit 105, the comparison unit 106, and the control unit 107. A portion indicated by a dotted line in FIG. 2 corresponds to a reference signal generation unit. Specifically, as illustrated in FIG. 2, the reference signal generation unit 105 generates a reference signal having a different amplitude by changing a voltage to be output by arranging a plurality of resistors. Here, in the present embodiment, the two signals have different amplitudes, but this number may be other numbers. And the more the types of amplitude, the finer the amplitude of the echo signal can be determined. Then, the reference signal generation unit 105 outputs the generated two types of signals having different wavelengths to the comparison unit 106. The reference signal generator 105 corresponds to “reference signal generator” in the present invention.

  The comparison unit 106 is a part represented by a one-dot chain line in FIG. As illustrated in FIG. 2, the comparison unit 106 includes the same number of comparators 210 as the reference signals generated by the reference signal generation unit 105. In the present embodiment, the comparison unit 106 includes two comparators, a comparator 211 and a comparator 212. Hereinafter, when the comparator 211 and the comparator 212 are not distinguished, they are simply referred to as “comparator 210”. The comparison unit 106 receives the reference signals of different wavelengths input from the reference signal generation unit 105 by different comparators 210. In the present embodiment, the reference signal R1 is received by the comparator 211, and the reference signal R2 is received by the comparator 212. Further, each comparator 210 receives an input of the same signal as the echo signal received by the amplifying unit 102. Then, each comparator 210 compares the amplitude of the echo signal with the amplitude of the reference signal. Specifically, the comparator 211 compares the amplitude of the echo signal with the amplitude of the reference signal R1, and the comparator 212 compares the amplitude of the echo signal with the amplitude of the reference signal R2. Each comparator 210 then outputs the magnitude relationship between each reference signal and the echo signal to the control unit 107. In the following description, it is assumed that the amplitude of the echo signal is larger than the amplitude of the reference signal R1 and smaller than the reference signal R2. That is, the comparator 211 outputs to the control unit 107 a result that the amplitude of the echo signal is larger than the amplitude of the reference signal R1. Further, the comparator 212 outputs to the control unit 107 a result that the amplitude of the echo signal is smaller than the amplitude of the reference signal R2. Determining the magnitude relationship with each reference signal corresponds to “determining the magnitude of the amplitude of the echo signal stepwise” in the present invention. In other words, the amplitude of the reference signal is in a stage where the magnitude of the amplitude is determined, and it can be determined which of the stages it is in by comparing the magnitude relationship with the reference signal. In the present embodiment, the magnitude of the amplitude of the echo signal is determined in three stages, that is, less than the reference signal R1, less than the reference signal R1, less than the reference signal R2, and greater than the reference signal R2.

  The control unit 107 includes a CPU and storage areas such as a hard disk and a memory. The control unit 107 stores in advance a table in which its comparison result (that is, the magnitude level of the amplitude of the echo signal) and the corresponding gain are stored in its own storage area. In this embodiment, when the echo signal is E, the control unit 107 displays the LNA 200 when E ≦ R1 (this inequality sign represents the magnitude relationship of the amplitude of the signal represented by each symbol. The same applies hereinafter). 2 stores LNA 201 with a gain of 21 dB, stores RNA 200 with a gain of 18 dB when R1 <E ≦ R2, and stores LNA 203 with a gain of 15 dB when R2 <E. Yes. For convenience of explanation, FIG. 2 schematically shows a configuration in which three amplifiers, LNA 201, LNA 202, and LNA 203 are arranged. However, as described above, LNA 200 is actually a single amplifier whose gain is variable. is there.

  The control unit 107 receives the comparison result input from the comparison unit 106. In the present embodiment, the control unit 107 receives an input of a result of R1 <E ≦ R2 (actually, an input of a result of R1 <E from the comparator 211 and E ≦ R2 from the comparator 212). The control unit 107 selects a corresponding gain with reference to a table stored by itself. In the present embodiment, the control unit 107 selects the LNA 202.

  The control unit 107 outputs a control command for setting the gain to the selected gain to the amplification unit 102. In the present embodiment, the control unit 107 outputs a control signal for setting the LNA 200 to the LNA 202.

  Here, the ultrasonic diagnostic apparatus according to the present embodiment uses a plurality of scanning lines generated by a plurality of ultrasonic beams transmitted to a specific cross section of the subject, An ultrasonic image corresponding to a specific cross section is generated. A unit in which scanning lines necessary for one ultrasonic image are collected is called a frame. That is, the ultrasonic diagnostic apparatus according to the present embodiment generates an ultrasonic image for each frame. If the gain changes in the middle of the frame, the intensity changes in one ultrasonic image and a normal image cannot be generated. Therefore, the comparison unit 106 and the control unit 107 select and set the gain described above in units of frames.

  Further, in the case of imaging in the same patient, the same part, and the same mode, once the gain is adjusted, it is not necessary to adjust the gain again. Therefore, when a test is performed on a certain patient, the control unit 107 first adjusts the above-described gain at the start of the test. When the target part is changed or the mode is changed, the control unit 107 receives an input from the operator, and the control unit 107 adjusts the gain again at the timing when the input is received. . Here, the operator uses the display unit 006 and the input unit 007 provided in the user interface 005 to perform the above-described input.

  However, the received echo signal is input to the comparison unit 106 and also to the amplification unit 102. That is, the frame for which the amplitude of the echo signal is to be compared has already been amplified and output to the TGC 103 when being compared by the comparison unit 106. Therefore, the gain adjustment is performed from the next frame. Therefore, more precisely, the control unit 107 adjusts the gain using the echo signal used in the image generation in the first frame where the inspection is started, and adjusts the second and subsequent frames. Image generation is performed using the obtained gain. In this case, in the first frame, the echo signal is amplified using a predetermined gain. In addition, the control unit 107 adjusts the gain using the echo signal used in the image generation in the first frame after the change of the target region or mode is input, and performs the adjustment for the second and subsequent frames. Image generation is performed using the gain obtained.

  Further, the control unit 107 selects a corresponding function between the elapsed time and the gain used by the TGC 103 in accordance with the set gain of the LNA 200, and outputs a control command for using the selected function to the TGC 103.

  The comparison unit 106 and the control unit 107 described above correspond to “comparison judgment unit” and “control unit” in the present invention.

  In FIG. 2, a switch 220 is arranged. In actuality, however, transmission of pulse voltage to the transducer 011 and reception of an echo signal from the transducer 011 are transmitted and received through the same signal line. Therefore, when the pulse voltage is transmitted to the vibrator 011, the pulse voltage is prevented from being input to the comparison unit 106. That is, when the pulse voltage is transmitted to the vibrator 011, the switch 220 is turned off to block the input of the pulse voltage to the comparison unit 106.

  The signal processing unit 002 visualizes the amplitude information of the echo signal, and generates data such as B-mode data and Doppler data from the echo signal. Specifically, the signal processing unit 002 performs band-pass filter processing on the echo signal input from the transmission / reception unit 100, then detects the envelope of the output signal, and performs logarithmic conversion on the detected data. The compression process is applied. Then, the signal processing unit 002 outputs the generated data to the image processing unit 003. This signal processing unit 002 corresponds to “signal processing means” in the present invention.

  The image processing unit 003 includes a DSC (Digital Scan Converter). The image processing unit 003 receives image data input from the signal processing unit 002. The DSC reads the signal-processed data (raster data) represented by the scanning line signal sequence output from the signal processing unit 002, and converts the raster data into orthogonal coordinate system data based on spatial information ( Scan Conversion processing), an ultrasonic image is generated. The image processing unit 003 outputs the generated ultrasonic image to the display control unit 004. This image processing unit 003 corresponds to the “image processing means” in the present invention.

  The display control unit 004 displays the ultrasound image input from the image processing unit 003 on the display unit 006 provided in the user interface 005. The display control unit 004 corresponds to “display control means” in the present invention. The display unit 006 corresponds to the “display unit” in the present invention.

  The overall control unit 008 performs data exchange between the functional units, adjustment of operation timing of the functional units, and the like. However, in actuality, data is exchanged via the overall control unit 008, but here, for convenience of explanation, it is described that each functional unit directly exchanges data.

  Next, the operation of gain adjustment by the ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to FIG. Here, FIG. 3 is a flowchart of the operation of gain adjustment by the ultrasonic diagnostic apparatus according to the present embodiment.

  Step S001: The transmission circuit 101 of the transmission / reception unit 100 outputs a pulse voltage to the ultrasonic probe 001. The ultrasonic probe 001 converts the inputted pulse voltage into an ultrasonic wave by the vibrator 011 and transmits the ultrasonic wave toward the subject.

  Step S002: The transducer 011 arranged in the ultrasonic probe 001 receives an ultrasonic echo reflected by the subject, converts it into an echo signal, and outputs it to the transmitting / receiving unit 100. The amplification unit 102 of the transmission / reception unit 100 receives the echo signal input from the transducer 011.

  Step S003: The control unit 107 determines whether gain adjustment is necessary. Specifically, in the case where the frame of the currently received echo signal is the first frame after the start of the examination or the first frame after the input of the change of the target part or mode is performed, the control unit 107 Determines that the gain adjustment is necessary, and otherwise determines that the gain adjustment is unnecessary. If it is determined that gain adjustment is necessary, the process proceeds to step S004. If it is determined that gain adjustment is unnecessary, the process proceeds to step S011.

  Step S004: The reference signal generator 105 generates a reference signal R1 and a reference signal R2 having different amplitudes. Then, the reference signal generation unit 105 outputs the generated reference signal R1 and reference signal R2 to the comparison unit 106.

  Step S005: The comparison unit 106 compares the amplitude of the echo signal E input from the transducer 011 disposed in the ultrasonic probe 001 and the amplitudes of the reference signal R1 and the reference signal R2 input from the reference signal generation unit 105, respectively. The comparison is made to determine the magnitude relationship between the amplitude of the echo signal and each of the amplitudes of the reference signal R1 and the reference signal R2. Then, the comparison unit 106 outputs the comparison result to the control unit 107.

  Step S006: Based on the comparison result input from the comparison unit 106, the control unit 107 determines whether or not the amplitude of the echo signal E is equal to or smaller than the amplitude of the reference signal R1. When the amplitude of the echo signal E is equal to or smaller than the amplitude of the reference signal R1, the process proceeds to step S007. When the amplitude of the echo signal E is larger than the amplitude of the reference signal R1, the process proceeds to step S008.

  Step S007: The control unit 107 sets the LNA 200 to the LNA 201 having a gain of 21 dB.

  Step S008: Based on the comparison result input from the comparison unit 106, the control unit 107 determines whether or not the amplitude of the echo signal E is equal to or smaller than the amplitude of the reference signal R2. When the amplitude of the echo signal E is equal to or smaller than the amplitude of the reference signal R2, the process proceeds to step S009. When the amplitude of the echo signal E is larger than the amplitude of the reference signal R1, the process proceeds to step S010.

  Step S009: The control unit 107 sets the LNA 200 to the LNA 202 having a gain of 18 dB.

  Step S010: The control unit 107 sets the LNA 200 to the LNA 203 having a gain of 15 dB.

  Step S011: The amplifying unit 102 amplifies the echo signal input from each corresponding transducer 011 using the LNA 200 connected corresponding to each transducer 011. Then, the amplifying unit 102 outputs the amplified echo signal to the TGC 103.

  Step S012: The TGC 103 further amplifies the echo signal input from the amplifying unit 102 by using a correspondence function between the passage of time and the gain designated from the control unit 107. Then, the TGC 103 outputs the amplified echo signal to the A / D conversion unit 104.

  Step S013: The A / D conversion unit 104 converts the echo signal input from the TGC 103 from an analog signal to a digital signal using an A / D converter. Then, the A / D conversion unit 104 outputs the echo signal converted into the digital signal to the signal processing unit 002.

Step S014: The signal processing unit 002 performs signal processing such as envelope detection and logarithmic compression on the echo signal input from the A / D conversion unit 104. Then, the signal processing unit 002 outputs the echo signal subjected to the signal processing to the image processing unit 003.

  Step S015: The image processing unit 003 performs coordinate transformation or the like on the echo signal input from the signal processing unit 002 to generate an ultrasonic image. Then, the image processing unit 003 outputs the generated ultrasonic image to the display control unit 004.

  Step S016: The display control unit 004 displays the ultrasound image input from the image processing unit 003 on the display unit 006.

  Step S017: The overall control unit 008 determines whether the inspection is finished. If the inspection has not ended, the process returns to step S001. When the examination is finished, the image generation operation in the ultrasonic diagnostic apparatus is finished.

  Here, in the description of the flow described above, the steps are described in the order of step numbers. Actually, however, amplification of the signal of the first frame after the input of change of the first frame or target part or mode from the start of examination is performed. The generation of the image including the image and the adjustment of the gain are performed in parallel processing. That is, in the first frame after the start of examination or the first frame after the input of change of the target part or mode is performed, steps S004 to S010 and steps S011 to S016 are executed simultaneously. Therefore, in the first frame after the start of the examination or the first frame after the input of change of the target region and mode is performed, the image is generated without adjusting the gain.

  Further, in the above description of the flow, the description has been given of the configuration in which the amplitude of the echo signal is determined in three stages using two types of reference signals. However, the types of reference signals are further increased and the amplitude of the echo signal is increased. It is also possible to make the stage of judging the more detailed. In that case, the steps from step S013 to step S017 are divided more finely.

  Furthermore, in this embodiment, the TGC 103 is provided in order to effectively use the dynamic range of the A / D conversion unit 104 and to further amplify a deep depth signal. However, if the amplification of the echo signal by the LNA 200 is sufficient, the TGC 103 is It does not have to be provided.

  As described above, the ultrasonic diagnostic apparatus according to the present embodiment is configured to be able to adjust the gain of the LNA according to the amplitude of the input echo signal. As a result, LNA saturation is avoided by reducing the gain of the LNA when using an echo signal with a large amplitude, such as in the B mode, or when the amplitude of the echo signal is relatively large due to the patient's body shape or target site. Further, when using an echo signal with a small amplitude such as a Doppler mode, or when the amplitude of the echo signal is relatively small due to the patient's body shape, target site, etc., the SNA is increased by increasing the LNA gain. N can be improved.

[Second Embodiment]
An ultrasonic diagnostic apparatus according to the second embodiment of the present invention will be described below. The ultrasonic apparatus according to the present embodiment is different from the first embodiment in that the gain is changed over time using LNAs having different gains for one echo signal. . Therefore, in the following, gain adjustment by switching the LNA over time will be mainly described. A block diagram of the ultrasonic diagnostic apparatus according to this embodiment is also shown in FIG. In the following description, functional units having the same reference numerals as those in the first embodiment are assumed to have the same functions unless otherwise specified. FIG. 4 is a diagram illustrating an example of an amplifying unit in the ultrasonic diagnostic apparatus according to the present embodiment.

  In the following, first, the configuration of the amplification unit 102 according to the present embodiment will be described, and then the operation of gain adjustment by the control unit 107 and the amplification unit 102 will be described. Here, in the following description, as in the first embodiment, it is assumed that two types of signals, the reference signal R1 and the reference signal R2, are used as the reference signal, and the LNA 200 can set the gain in three stages. And Further, the echo signal input to the amplifying unit 102 is represented as E.

  In the amplification unit 102 according to the present embodiment, as illustrated in FIG. 4, two LNAs 200 (LNA 200 a and LNA 200 b in FIG. 4) are connected to one transducer 011. Each of the LNA 200a and the LNA 200b is an amplifier capable of setting the gain in three stages, and each is an amplifier similar to the LNA 200 schematically shown in FIG. In addition, a multiplier 401 and a multiplier 402 are connected to the LNA 200a and the LNA 200b, and then an output from the LNA 200a and an output from the LNA 200b are added by an adder 403. Here, as the multiplier 401 and the multiplier 402, for example, resistance division may be used.

  Here, in this embodiment, two LNAs 200 are provided for one transducer 011. However, the number of connected LNAs 200 is not particularly limited. As more LNAs 200 are used, it is possible to change the amplification factor with time.

  In the storage area of the control unit 107, when the LNA 200a is set to a gain corresponding to a specific stage of the amplitude of the echo signal, a value indicating how many stages the gain is set to the LNA 200b with respect to that gain Is stored in advance. In the present embodiment, the control unit 107 stores a gain that is one step higher than that of the LNA 200a in the LNA 200b. Here, in the present embodiment, since only two LNAs 200 are connected to one transducer 011, the above description is given. However, when two or more LNAs 200 are connected, The gain may be set so as to sequentially increase the predetermined stages for the LNA 200. Further, in this embodiment, since the magnitude of the amplitude of the echo signal is identified in three stages, the gain in one stage is used. However, the magnitude of the amplitude of the echo signal is identified using more stages. In this case, a gain obtained by increasing a larger level (for example, a gain that is two or three stages higher) may be set in the next LNA 200.

  Further, the control unit 107 stores in advance the switching timing of the LNA 200 to be used among the LNAs 200 connected to one transducer 011. Here, it is assumed that the control unit 107 stores the switching time as t seconds. Furthermore, the control unit 107 stores in advance a switching time from when the switching starts until the switching is completed, so that the output from the LNA 200a and the output from the LNA 200b gradually change within the switching time. The usage rate of each output corresponding to the switching time is stored. Here, it is set to be 1 when the respective usage rates are added. For example, the control unit 107 only needs to store the LNA 200b so that the usage of the LNA 200b is directly proportional to time, and the usage rate of the LNA 200a and the usage rate of the LNA 200b are inversely proportional.

  The control unit 107 is a table in which the gain corresponding to the magnitude level of the amplitude of the echo signal stored based on the magnitude relationship between the amplitude of the reference signal and the amplitude of the echo signal input from the comparison unit 106 is described. , The gain of the LNA 200a arranged in the amplification unit 102 is selected, and the gain of the LNA 200a is set to the gain. Further, the control unit 107 sets a gain corresponding to the upper stage by a predetermined value (a gain of one stage in the present embodiment) in the LNA 200b. Specifically, when R2 <E, the control unit 107 sets the LNA 200a to a gain of 21 dB and sets the LNA 200b to a gain of 18 dB. When R1 <E ≦ R2, the control unit 107 sets the LNA 200a to a gain of 18 dB and the LNA 200b to a gain of 21 dB. Further, when a gain for which there is no more gain is set in the LNA 200a, no gain is assigned to the LNA 200b, or a gain of the same value is assigned to the LNA 200b. For example, when E ≦ R1, the LNA 200a is set to 21 dB, and the gain is not set to the LNA 200b. Here, the LNA 200a in the present embodiment corresponds to the “first amplifier” in the present invention, and the LNA 200b corresponds to the “other amplifier” in the present invention.

  The gain setting by the control unit 107 described above is performed by adjusting the gain using the echo signal used in the image generation in the first frame where the inspection is started, as in the first embodiment. Image generation is performed on the frames using the adjusted gain. In this case, in the first frame, the echo signal is amplified using a predetermined gain. In addition, the control unit 107 adjusts the gain using the echo signal used in the image generation in the first frame after the change of the target region or mode is input, and the second and subsequent frames Image generation is performed using the adjusted gain. When the gain is adjusted, the gains of the LNA 200a and the LNA 200b are fixed and are not changed until the next gain adjustment timing, that is, until the change of the target part or mode is input. .

  Then, the control unit 107 controls to use the LNA 200 a for t time after the echo signal is input from the transducer 011 to the amplification unit 102. Then, the control unit 107 controls the multiplier 401 and the multiplier 402 so that the usage rate of each output corresponding to the stored switching time is reached after the elapse of time t.

  Further, the control unit 107 determines a correspondence function between the passage of time and the gain used by the TGC 103 based on the set gain, and outputs a control command using the determined correspondence function to the TGC 103.

  The amplifying unit 102 receives the control signal from the control unit 107, and the gains of the LNA 200a and the LNA 200b are set.

  The amplification unit 102 receives an input of an echo signal from the corresponding transducer 011 by the LNA 200 (LNA 200a and LNA 200b in the present embodiment) connected to each transducer 011 disposed in the ultrasonic probe 001.

  Further, based on the control signal of the control unit 107, from the start of the echo signal input until t seconds, the multiplier 401 multiplies the output from the LNA 200a by 1, and the multiplier 402 outputs 0 to the output from the LNA 200b. Are added in the adder 403 and output to the TGC 103. That is, only the signal of the LNA 200a is used until t seconds. Next, from t seconds to the completion of switching, the multiplier 401 multiplies the output from the LNA 200a by a value that is gradually decreased from 1 to 0 based on the control signal of the control unit 107, and multiplies. Multiplier 402 multiplies the output from LNA 200b by a value that is gradually increased from 0 to 1. Then, the adder 403 adds them and outputs them to the TGC 103. Further, after completion of the switching, based on the control signal of the control unit 107, the multiplier 401 multiplies the output from the LNA 200a by 0, and the multiplier 402 multiplies the output from the LNA 200b by 1. Then, the adder 403 adds them and outputs them to the TGC 103. That is, after the switching is completed, only the signal of the LNA 200b is used.

  The TGC 103 selects a correspondence function between elapsed time and gain based on the control command input from the control unit 107, and amplifies the echo signal input from the amplification unit 102 based on the correspondence function. Then, the TGC 103 outputs the amplified echo signal to the A / D conversion unit 104.

  Here, in the present embodiment, the control unit 107 adopts a configuration in which the usage rate of each LNA 200 is changed within the switching time and is gradually displaced. However, the addition of signals by the smooth change of the usage rate is adopted. It is possible to use only the output of one of the LNAs 200 without performing the above. In this case, the multiplier 401 and the multiplier 402 are controlled so as to multiply the respective input signals by 0 or 1.

  As described above, the ultrasound diagnostic apparatus according to the present embodiment has a configuration in which the gain can be changed by switching the LNA in accordance with the passage of time when the echo signal is input. In other words, since the echo signal reflected at a deep location is received later than the echo signal reflected at a shallow location, the gain can be adjusted according to the depth at which the ultrasonic waves are reflected. Thereby, since the amplification factor of the signal of the portion with a small amplitude (that is, the echo signal from a deep place) can be increased in the amplification unit, the S / N can be further improved.

  Furthermore, if more LNAs are arranged in the transducer, the gain can be adjusted more finely in response to the passage of time, so that the amplification unit can adjust the depth over the entire range of the received echo signal without providing a TGC. Signal amplification can be performed.

[Third Embodiment]
Hereinafter, an ultrasonic diagnostic apparatus according to a third embodiment of the present invention will be described. The ultrasonic diagnostic apparatus according to the present embodiment is different from the first and second embodiments in that the operator can specify the gain of the LNA. This is because some operators want to use their favorite gains even at the expense of LNA saturation and the like, and this is to cope with such a situation. In the following, the LNA gain designation by the operator will be mainly described. A block diagram of the ultrasonic diagnostic apparatus according to this embodiment is also shown in FIG. In the following description, functional units having the same reference numerals as those in the first embodiment are assumed to have the same functions unless otherwise specified. FIG. 5 is a diagram illustrating an example of an input screen for performing gain setting according to the present embodiment.

  The operator designates and inputs a gain to be set in the LNA 200 provided in the amplification unit 102 in advance. Specifically, the input screen shown in FIG. 5 is displayed on the display unit 006 arranged in the user interface 005. Then, the operator uses the input unit 007 such as a mouse to input by specifying the diagnostic part, the examination mode, and the frequency to be used, which are displayed on the input screen in FIG. To do. At the same time, the operator designates and inputs a gain value to be set in the LNA 200 out of the gains 500 shown in FIG. As the input timing, immediately after the start of the examination, when the imaging mode is changed, or when the examination target part is changed, the input screen shown in FIG. 5 is displayed, and the above-described input is performed.

  The control unit 107 receives the input gain value of the LNA 200 and sets the gain in the LNA 200. However, in the case of a gain setting similar to the gain setting of the second embodiment, the control unit 107 sets a gain input to a specific LNA 200 among a plurality of LNAs 200 connected to the transducer 011. Then, the gain is set in accordance with a predetermined value for the other LNA 200. When the operator inputs the gain of the LNA 200, the control unit 107 similar to that in the first embodiment or the second embodiment does not control the gain setting.

  On the other hand, when the operator does not input the LNA 200, the same gain setting as that in the first embodiment or the second embodiment is performed.

  As described above, the ultrasonic diagnostic apparatus according to the present embodiment has a configuration in which the operator can prioritize LNA gain designation. As a result, when there is an LNA gain setting preferred by the operator in a specific target region or imaging mode, it is possible to set the value with priority, and to provide more appropriate ultrasonic images for each operator. Can be done.

001 Ultrasonic probe 002 Signal processing unit 003 Image processing unit 004 Display control unit 005 User interface 006 Display unit 007 Input unit 008 Overall control unit 011 Transducer 100 Transmission / reception unit 101 Transmission circuit 102 Amplification unit 103 TGC
104 A / D converter 105 Reference signal generator 106 Comparator 107 Controller 200 LNA

Claims (5)

Transmitting / receiving means for transmitting an ultrasonic wave toward an object via an ultrasonic probe having a plurality of transducers and receiving an echo signal based on an ultrasonic echo reflected by the object;
Signal processing means for performing signal processing including logarithmic compression and envelope detection on the echo signal;
Image processing means for generating image data by performing image processing including coordinate transformation on the echo signal subjected to the signal processing;
Display control means for displaying an ultrasonic image on a display means based on the image data;
An ultrasonic diagnostic apparatus comprising:
The transmitting / receiving means includes
And amplifying means for multiple chromatic a first amplifier for amplifying an amplification factor that is set to echo signals, and another amplifier arranged in parallel with the first amplifier from one transducer,
Reference signal generating means for generating a plurality of types of reference signals having different amplitudes;
Comparison determination means for comparing the amplitude of the received echo signal with the reference signal, and determining the magnitude of the amplitude of the received echo signal in a plurality of stages corresponding to the amplitude of the reference signal;
The correspondence between the plurality of steps and the amplification factor is stored in advance so that the amplification factor becomes smaller as the amplitude of the echo signal increases according to the step, and the determination made by the comparison determination unit Control means for selecting the amplification factor corresponding to a magnitude step and setting the amplification factor of the first amplifier to the selected amplification factor;
A / D conversion means for converting the amplified echo signal into a digital signal;
Equipped with a,
The control means sets the amplification factor of the other amplifier to be larger than the set amplification factor of the first amplifier and different from each other, and sequentially amplifies the amplification from the first amplifier as time elapses. The amplification means is controlled to amplify the received echo signal by switching to the other amplifier having a high rate.
Ultrasonic diagnostic apparatus according to claim and this. The transmission / reception means performs transmission / reception of ultrasonic waves for each frame, which is a unit for acquiring data necessary for generating one image for transmission / reception of ultrasonic waves,
The control means performs amplification of the echo signal in the next frame using the setting of the amplification factor performed based on the magnitude of the amplitude of the echo signal received in the specific frame.
The ultrasonic diagnostic apparatus according to claim 1. The control means, when switching between the first amplifier and the other amplifier, sets a use ratio between the output from the first amplifier or the other amplifier before switching and the output of the other amplifier after switching. The output from the first amplifier or the other amplifier before the switching and the output of the other amplifier after the switching so that the output of the other amplifier after the switching gradually increases. by adding, according to claim 1 as an output obtained by amplifying the echo signals thus received, using said output, wherein the switching is completed, it when it becomes only the output of the other amplifier after the switching An ultrasonic diagnostic apparatus according to 1. The transceiver means of claims 1 to 3, further comprising a gain correction means for increasing the amplification factor with the passage of reception time between the A / D converting means and said amplifying means The ultrasonic diagnostic apparatus as described in any one. Transmitting ultrasound to the subject;
Receiving the ultrasound reflected from the subject and converting it to an echo signal;
A comparison determination step of comparing the amplitude of the received echo signal with the reference signal, and determining the magnitude of the amplitude of the received echo signal in a plurality of stages corresponding to the amplitude of the reference signal;
Based on the correspondence between the plurality of steps and the amplification factor, which is stored in advance, and the amplification factor becomes smaller as the amplitude of the echo signal increases according to the step, the determination by the comparison determination unit An amplification factor selection step for selecting the amplification factor corresponding to the amplitude magnitude step performed;
The amplification factor of the echo signal is set to the selected amplification factor for the first amplifier that amplifies the echo signal from one of the transducers , and the setting is made for the other amplifiers arranged in parallel with the first amplifier. A control stage that is set to be different from each other and set to be different from each other, and is controlled so as to amplify an echo signal by switching from the first amplifier to the other amplifier having the higher amplification ratio sequentially as time elapses ; ,
An amplification step of amplifying the received echo signal at the set amplification factor;
An A / D conversion stage for converting the amplified echo signal into a digital signal;
A signal processing stage for performing signal processing including logarithmic compression and envelope detection on the echo signal converted into the digital signal;
An image processing step of generating image data by performing image processing including coordinate transformation on the echo signal subjected to the signal processing;
An image display step of displaying an ultrasonic image on a display unit based on the image data;
An ultrasonic diagnostic apparatus control method comprising:

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