JP4386757B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus for forming a tomographic image or the like in a subject, and more particularly to a configuration for controlling the waveform of generated ultrasonic waves.

  An ultrasonic diagnostic apparatus transmits and receives an ultrasonic wave from a probe (probe) having a single plate vibrator or a plurality of vibrators to a subject such as a body, and processes a reception signal obtained from the probe. The tomographic image and blood flow information in the subject can be displayed on a monitor (display) and observed.

FIG. 6 shows a transmission signal applied to the single plate vibrator in one ultrasonic scanning line and a reception signal received from one reflector, and the transmission signal Sa of FIG. 6A is applied to the vibrator. Thus, the generated ultrasonic wave is transmitted toward the reflector (subject). Then, the ultrasonic wave returning from the reflector is received by the same vibrator, and the reception signal Ra shown in FIG. 6B is obtained. The waveform g ₁ in FIG. 6 (B) is a leakage of the transmitted signal.

FIG. 7 shows enlarged waveforms of the transmission signal and the reception signal. The transmission signal Sa has an amplitude a ₀ (about several tens to several hundreds V) and a pulse width t ₀ as shown in FIG. 7A. As shown in FIG. 7B, the amplitude (maximum amplitude A ₀ ) of the received signal Ra changes, for example, the waveform of the ultrasonic wave (generation) period H ₀ of 5 to 6 cycles, as shown in FIG. Become. In such a received signal Ra, the shorter the ultrasonic period H ₀ , the higher the distance resolution, and the higher the amplitude (wave height), the higher the sensitivity.

JP 2002-34975 A JP 2002-52025 A JP 2002-65671 A

  By the way, in the ultrasonic diagnostic apparatus, it is desired to further improve the image quality of the ultrasonic image. However, if the above-described distance resolution and detection sensitivity in the ultrasonic transmission / reception wave are increased, the image can be easily observed with high image quality. Can be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of improving the distance resolution and detection sensitivity and obtaining an ultrasonic image that can be easily observed with high image quality. is there.

In order to achieve the above object, the invention according to claim 1 is a probe having at least one transducer that generates an ultrasonic wave of period Ha when a pulse signal having an amplitude a ₁ and a pulse width t ₁ is given. In the ultrasonic diagnostic apparatus for forming an ultrasonic tomographic image, a pulse signal having an amplitude a ₂ smaller than the amplitude a ₁ and a pulse width t ₂ smaller than the pulse width t ₁ is used as a transmission signal. to children, Rutotomoni feeds transmission signals of a plurality of times as ultrasonic waves formed in this transmission signal to the ultrasonic generation period formed by the previous transmission signals of the same scan line period occurs, the last By variably adjusting the delay amount of the current transmission signal subsequent to, when the period of the ultrasonic waveform is T, continuous ultrasonic waves are generated with a deviation of nT / 4 (n: odd number), and Departure shorter than occurrence period Ha Characterized by combining the ultrasonic period Hb.
The invention according to claim 2, deviation is generated drives out of one cycle multiple ultrasound (T), and controlling so that the amplitude of the combined ultrasound increases.

According to the configuration of the present invention, an ultrasonic wave transmitted / received in one ultrasonic scanning line (one direction) is formed by a plurality of transmission (pulse) signals. The synthesized ultrasonic waveform can be arbitrarily changed by adjusting the timing, that is, by controlling the delay amount of the second and subsequent ultrasonic waves with respect to the first ultrasonic wave. Then, traditional to generate two ultrasound having a small adjusting the amplitude (wave height) for example 1/4 (3 / 4,5 / 4, etc.) by shifting cycles than by combining a short ultrasonic generation period Therefore, the distance resolution can be increased. Further, in the case of claim 2 , for example, by combining two ultrasonic waves shifted by one cycle, the amplitude is increased, so that the detection sensitivity can be increased.

  According to the ultrasonic diagnostic apparatus of the present invention, the distance resolution and the detection sensitivity can be increased by changing the delay amount of the second and subsequent ultrasonic waves with respect to the first ultrasonic wave, thereby controlling the ultrasonic waveform. It is possible to obtain an ultrasonic image that is easy to observe with image quality.

  FIG. 1 shows the overall configuration of the ultrasonic diagnostic apparatus according to the embodiment, and FIG. 2 shows the configuration of the transmission unit of FIG. In the ultrasonic diagnostic apparatus shown in FIG. 1, a transmission unit 12 that performs transmission processing and a reception unit 13 that performs reception processing are connected to a transducer (single or plural) 11 provided in a probe. The unit 13 includes a detection circuit 14 that detects a received signal, an A / D converter 15 that performs analog-digital conversion on the output of the detection circuit 14, and the output of the A / D converter 15 from the sound ray space data to the physical state. A digital scan converter (DSC) 16 that converts space data (scan conversion) is connected. Further, a control circuit 17 that controls each of the above circuits and a monitor 18 that displays an ultrasonic image based on the output of the DSC 16 are provided.

  FIG. 2 shows two configurations [(A), (B)] in the transmission unit 12, and FIG. 2 (A) shows a case where a transmission signal is output a plurality of times from one transmission circuit. Configuration, FIG. 2B shows a configuration in the case where a plurality of transmission signals are output from two transmission circuits. 2A is provided with one transmission circuit 12a and a delay circuit 12b. The delay circuit 12b receives a first transmission (pulse) signal by a delay amount control signal from the control circuit 17. The delay (time) of the transmission (pulse) signal for the second and subsequent times is set. That is, the delay circuit 12b supplies a trigger signal delayed by a predetermined amount (d) from the input transmission trigger to the transmission circuit 12a, and the transmission circuit 12a first inputs the transmission trigger from the control circuit 17 directly. The first transmission signal is output, and then the second transmission signal delayed by a predetermined amount (d) based on the trigger signal input from the delay circuit 12b is output.

  2B includes a first transmission circuit 12c, a second transmission circuit 12d, and a delay circuit 12e. In this case, the first transmission to which a transmission trigger from the control circuit 17 is input. A first transmission signal is output by the circuit 12c. Then, the delay circuit 12e forms a trigger signal delayed by a predetermined amount (d) from the transmission trigger signal, and the second transmission signal delayed by the predetermined amount (d) by the second transmission circuit 12d receiving this trigger signal. Is output. In addition, when outputting a transmission signal three times or more sequentially, the transmission circuit (12d) and the delay circuit (12e) may be further added, or a plurality of transmission signals may be formed by two sets of transmission circuits and delay circuits. May be formed and output.

The outline of the configuration of the embodiment is as described above. Next, the operation when ultrasonic waves are formed by two transmission signals will be described. FIG. 3 shows a transmission signal given to a single plate vibrator and a reception signal received from a single reflector. In the embodiment, as shown in FIG. 1 transmission signals S ₁ and the second transmission signal S ₂ is continuously output, the two transmission signals are applied to the transducer 11. In this transducer 11, the ultrasonic waves obtained from the respective transmission signals are combined, and the combined ultrasonic waves are transmitted to and received from the subject, and reception of ultrasonic waves reflected from a single reflector is received. The signal is like the received signal Rb in FIG. The waveform g ₂ in FIG. 3 (B) is a leakage of the transmitted signal.

Then, in the embodiment, the delay amount of the first transmission signals S ₁ shown in FIG. 3 (A) to a second transmission signal S ₂ (time) d, by variably adjusting the distance as shown in FIGS. 4 and 5 Resolution and sensitivity can be increased. FIG. 4 shows a waveform when the distance resolution is increased. As shown in FIG. 4A, when a transmission signal S ₀ having an amplitude a ₁ and a pulse width t ₁ is used, the waveform is formed by this signal S ₀ . ultrasonic (reception) waveform has a waveform R ₁ of the ultrasonic generation period Ha as shown in FIG. 4 (B). Then, as shown in FIG. 4 (C), the the transmission signal _{S 0} first transmission signal _{S 01,} as the second transmission signal _{S 02,} for example by using the preconditioned interval delay _{d 1} I than, as shown in FIG. 4 (D), 2 nd delay amount of the ultrasonic wave _{R 2} for ultrasonic waveform _{R 1} for the first time that occurs in the transducer 11 (time) _{D 1} T / 4 (T: ultrasonic wave period), and these ultrasound (ultrasonic (wave received waveform R ₁ and R ₂₎ waveform R ₃ which was synthesized) is obtained. The ultrasonic wave R ₃ is longer by T / 4 time than ultrasonic generation period Ha, it is higher than when the amplitude (wave height) generates the ultrasonic waves transmitted signal S ₀ once.

Here, when the amplitude of the ultrasonic wave in FIG. 4 (D) is reduced so as to decrease to the level of FIG. 4 (B), the ultrasonic wave generation period as shown by the ultrasonic waveform _Rb1 in FIG. 4 (F). it can be seen that H _b1 is shorter than the period Ha. Therefore, in the embodiment, as shown in FIG. 4 (E), for example, an amplitude smaller than the transmission signal S _{0 in} FIG. 4 (A) (a ₂ <a ₁ ) so that such an ultrasonic waveform can be obtained. ), By using the first and second transmission signals S ₁ and S ₂ (amplitude a ₁ , pulse width t ₁ ) having a small pulse width (t ₂ <t ₁ ), the ultrasonic generation period H _b1 is short. A sound wave [FIG. 4 (F)] is generated to increase the distance resolution. Further, in FIG. _4F , the period H _b1 can be made shorter than before, and the amplitude of the ultrasonic wave can be kept higher than before, and in this case, the detection sensitivity can be increased. Note that the delay amount between the ultrasonic waves may be set to a value other than nT / 4, and the ultrasonic wave generation period _Hb1 can be shortened also by this.

FIG. 5 shows a waveform when the detection sensitivity is increased. In this case, the ultrasonic waveform R ₁ of FIG. 5B generated by the transmission signal S ₁ of FIG. Synthesize with deviation. That is, as shown in FIG. 5 (C), the by outputting a pre-adjusted amount of delay d ₂ second transmission signal S ₂ drives out to the first transmission signal S _1, FIG. 5 (B) Ultrasonic two waveforms R ₁ are combined with displacement of one cycle, as shown in FIG. 5 (D), the ultrasonic waveform R _b2 high amplitude is obtained. The ultrasonic wave R _b2 may be the ultrasonic generation period H _b2 but is one cycle longer than the period H _a when not combined, since the large amplitude of the ultrasonic wave, to improve the detection sensitivity Can do.

In the above embodiment, the case where the synthesized ultrasonic wave is generated by the _two transmission signals S ₁ and S ₂ has been described. However, in order to improve the distance resolution or the detection sensitivity, three or more consecutive transmissions (pulses) are performed. Ultrasound synthesized using a signal can be transmitted and received in the same ultrasonic scanning line (transmission / reception direction). In the ultrasonic synthesis described above, a small waveform may remain at the end of the ultrasonic waveform, but detection is not affected if the waveform is small.

  In the above-described embodiment, the delay amount and the number of transmissions of multiple ultrasonic transmissions for increasing the distance resolution or detection sensitivity are set as the probe identification code (probe type) or the ultrasonic frequency and vibration selected / set. Decide on a child. In other words, various types of probes with different transducer characteristics are used in the ultrasonic diagnostic apparatus, and there are cases where the frequency of the ultrasonic wave to be generated can be selected, and the best ultrasonic waveform can be obtained according to these situations. Is required. Therefore, in the embodiment, information on the delay amount (d) of the transmission signal for the second and subsequent times corresponding to the probe identification code or different ultrasonic frequencies and the number of times of output of this transmission signal are stored and held, and the connected probe Control the transmission and reception of ultrasonic waves with the delay amount and number of transmission signals corresponding to this identification code and ultrasonic frequency by determining the identification code or determining the selected and set ultrasonic frequency. Will be.

1 is a circuit block diagram showing an outline of an entire ultrasonic diagnostic apparatus according to an embodiment of the present invention. It is a circuit block diagram which shows two structural examples [FIG. (A), (B)] of the transmission part of an Example. It is a wave form diagram which shows the transmission signal [figure (A)] and the reception signal [figure (B)] with respect to 1 ultrasonic scanning line of an Example. It is an enlarged waveform diagram explaining the waveform synthesis | combination of the ultrasonic wave for improving distance resolution in an Example. It is a wave form diagram explaining the waveform synthesis | combination of the ultrasonic wave for raising detection sensitivity in an Example. It is a wave form diagram which shows the transmission signal [figure (A)] and reception signal [figure (B)] with respect to the conventional 1 ultrasonic scanning line. FIG. 7 is an enlarged waveform diagram of the transmission signal [FIG. (A)] and the reception signal [FIG. (B)] of FIG. 6.

Explanation of symbols

11 ... vibrator, 12 ... transmitter,
12a, 12c, 12d ... transmission circuit,
12b, 12e ... delay circuit,
13 ... receiver, 14 ... detector circuit,
16: DSC (digital scan converter).

Claims (2)

In an ultrasonic diagnostic apparatus comprising a probe having at least one transducer that generates ultrasonic waves of period Ha when a pulse signal having an amplitude a ₁ and a pulse width t ₁ is provided, and forming an ultrasonic tomographic image,
A pulse signal having an amplitude a ₂ smaller than the amplitude a ₁ and a pulse width t ₂ smaller than the pulse width t ₁ is used as a transmission signal, and the transducer is formed with the previous transmission signal in the same scanning line period. that ultrasound Rutotomoni given transmission signals of a plurality of times as ultrasonic waves formed in this transmission signal to the occurrence period is generated by the delay amount of the current transmission signal following the last variable adjustment, When the period of the ultrasonic waveform is T, a continuous ultrasonic wave is generated with a deviation of nT / 4 (n: odd number), and an ultrasonic wave having a generation period Hb shorter than the generation period Ha is synthesized . An ultrasonic diagnostic apparatus characterized by the above. The ultrasonic diagnostic apparatus according to claim 1 , wherein a plurality of ultrasonic waves are generated with a shift of one cycle, and control is performed so that an amplitude of the synthesized ultrasonic wave is increased .

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