JP2758192B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to an ultrasonic wave which collects a reflected component of an ultrasonic wave transmitted toward a subject from the subject and uses the collected component for diagnosis. It relates to a diagnostic device.

(Prior Art) In an ultrasonic diagnostic apparatus, an ultrasonic wave is transmitted toward a subject by applying a drive pulse (also referred to as an excitation pulse), and a reflected component (ultrasonic echo) from the subject is applied. Is provided.

In an actual ultrasonic diagnostic apparatus, a plurality of ultrasonic probes of different types are prepared, and are appropriately used depending on a diagnosis target site and a use.

In an ultrasonic diagnostic apparatus that includes an ultrasonic probe that is configured by arranging a plurality of ultrasonic transducers in an array and that enables electronic scanning (linear scan, sector scan) of ultrasonic waves, the ultrasonic transducer of the probe is A transmission / reception circuit is provided which has a plurality of transmission channels for driving pulse application and a plurality of reception channels for ultrasonic echo signal processing. This transmission / reception circuit is dedicated to the ultrasonic probe for electronic scanning, and the input / output impedance and the like of the ultrasonic transducer in the probe are set to optimal values.

(Problems to be Solved by the Invention) Meanwhile, in such an ultrasonic diagnostic apparatus, ultrasonic information of the subject is collected using a probe other than the ultrasonic probe for electronic scanning, for example, an ultrasonic probe for mechanical scanning. Sometimes you want to. An ultrasonic probe for mechanical scanning is composed of a plurality of ring-shaped ultrasonic transducers arranged concentrically, and an annular array type that enables electronic focusing, and a circular ultrasonic probe Although a single type having a vibrator is mentioned, the area of the vibrator is larger than the vibrator of the electronic scanning ultrasonic probe in any probe,
Conversely, the impedance is small. As described above, since the transmission / reception circuit is optimally designed for the transducer in the electronic scanning ultrasonic probe, even if the transmission / reception circuit is used as it is to drive the mechanical scanning ultrasonic probe, the (Ultrasonic vibrator) Ultrasonic information of the subject can be increased by high S due to a decrease in drive capability and a decrease in S / N ratio in the receiving system.
It is difficult to collect at the / N ratio, and it is absolutely necessary to separately add a transmission / reception circuit dedicated to the ultrasonic probe for mechanical scanning. However, if a transmission / reception circuit dedicated to the mechanical scanning ultrasonic probe is added, the size and cost of the apparatus are increased.

Therefore, the present invention eliminates the above-mentioned disadvantages. In addition to the ultrasonic probe for electronic scanning, the use of an ultrasonic probe having a smaller number of ultrasonic transducers than the number of channels of the transmission / reception circuit, such as an ultrasonic probe for mechanical scanning, is used. It is an object of the present invention to provide an ultrasonic diagnostic apparatus capable of improving the S / N ratio of ultrasonic information at a small size and at a low cost.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, in an ultrasonic diagnostic apparatus according to the present invention, a plurality of transmission system channels for applying drive pulses to an ultrasonic transducer, A transmitting / receiving circuit having a plurality of receiving system channels for processing an acoustic echo signal, an ultrasonic probe having a smaller number of ultrasonic vibrators than the number of channels of the transmitting / receiving circuit, and switching connection of each vibrator And an output terminal of the high-voltage switch group corresponding to a plurality of transmission system channels is connected in parallel to the ultrasonic transducer in the ultrasonic probe. And the input means of the high voltage switch group corresponding to a plurality of receiving system channels are arranged in parallel with the ultrasonic transducer in the ultrasonic probe. A second means for enabling reception processing of the same ultrasonic echo signal in a plurality of channels by connecting the same, and the same means for a transmission system channel or a reception system channel connected in parallel. It is characterized by providing a delay. Here, a protection resistor against an overcurrent may be provided corresponding to the transmission channel.

(Operation) FIG. 7 shows an equivalent circuit when a plurality of transmission system channel output terminals are connected in parallel to the ultrasonic transducer by the first means.

In the figure, VP is a pulser output voltage (considered as an internal electromotive force) for each transmission system channel, ZP is an output impedance of the pulser, and ZL is an input impedance of the ultrasonic transducer.

Here, assuming the case of one pulsar, the voltage V′L between both ends of the ultrasonic transducer in this case is For example, under the condition of ZL = ZP, V'L = VP / 2.

On the other hand, when M (M = 2, 3, 4,...) Pulsars are connected in parallel as shown in FIG.
Is Since ZL >> ZP / M is satisfied under the parallel condition of a plurality of ZP, VL _n1 VP is obtained, and the voltage drop due to the output impedance ZP of the pulser can be ignored. Therefore, when a plurality of transmission channel output terminals are connected in parallel to the ultrasonic transducer, the load driving capability of the transmission circuit is improved. For this reason, the transmission level of the ultrasonic wave increases, and the S / N ratio of the ultrasonic information improves due to the increase in the transmission level.

FIG. 8 shows an equivalent circuit when a plurality of receiving system channel input terminals are connected in parallel to the ultrasonic transducer by the second means. In the figure, Zs is the output impedance of the ultrasonic vibrator, Vs is the output signal voltage of the ultrasonic vibrator (reception echo including no noise), VN is the noise voltage, and AMP is the preamplifier in each reception channel. (Amplification degree Av = 1), and ADD is an adder. Vs and VN are simultaneously inputted to M (M = 2, 3, 4,...) Preamplifiers (AMP) at the same time. In this case, since the signal components are correlated with each other, they are added M times, but the noise components of the preamplifier are not correlated. Will be added. When the input conversion noise Vni of the preamplifier (AMP) 9 is larger than the output noise VN of the ultrasonic transducer, the output voltage Vout becomes It is expressed as Therefore, the S / N ratio in the receiving system is That is, when VN <Vni, the S / N ratio in the receiving system is improved.

Here, the transmission / reception circuit including a plurality of pulsars, a plurality of preamplifiers, and an adder is originally dedicated to the ultrasonic probe for electronic scanning, and is not newly added. Therefore, according to the present invention, an ultrasonic diagnostic apparatus that enables the use of an ultrasonic probe having a smaller number of ultrasonic transducers than the number of channels of the transmitting / receiving circuit, such as an ultrasonic probe for mechanical scanning, is reduced in size and cost. Can be provided.

It should be noted that the load (ultrasonic transducer) drive capability has been improved or the receiving system
By improving the S / N ratio, the S / N of ultrasonic information as a whole
Since it is possible to improve the ratio, it is ideal to have both of the first and second means. However, the object of the present invention can be achieved even with either one.

(Examples) Hereinafter, the present invention will be specifically described based on examples shown in the drawings.

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to one embodiment of the present invention. In the figure, reference numeral 1a denotes a connector, and the ultrasonic probe is detachably connected to the apparatus main body by the connector 1a. 2-1 to 2-m are transmission delay units for delaying the drive timing of the transducer in the ultrasonic probe, and 3-1 to 3-m are pulsers for generating drive pulses used for exciting the transducer. is there. Reference numeral 4 denotes a group of high-voltage switches for switching connection of the vibrator. 6-1 to 6-m
Are preamplifiers for amplifying ultrasonic echo signals (ultrasonic information) input from the vibrator via the high-voltage switch group 4, and 7-1 to 7-m denote the preamplifiers 6-1 to 6-m.
A reception delay unit that delays the output of −m, and 8 is an adder that adds the outputs of the reception delay units 7-1 to 7-m. Reference numeral 9 denotes an echo signal processing unit which takes in the output of the adder 8 and processes the echo signal. Reference numeral 10 denotes a digital scan converter mainly composed of a frame memory. Reference numeral 11 denotes a digital scan converter. This is a display unit for visualizing the output.

The pulsars 3-1 to 3-m and the transmission delay unit 2-1
To 2-m, preamplifiers 6-1 to 6-m, reception delay unit 7-
The transmission / reception circuit 14 includes 1 to 7-m and the adder 8.

Also, a probe for identifying the type of ultrasonic probe
The ID is recognized by the CPU 13. CPU13
Has a transmission / reception control means 12 and a driving condition setting means 15 functionally. The transmission / reception control means 12 includes the high-voltage switch group 4,
Transmission delay units 2-1 to 2-m, reception delay units 7-1 to 7-
It controls the operation of m and the like. Drive condition setting means 13
Is for recognizing the type of the ultrasonic probe based on the probe ID information, and setting driving conditions of the ultrasonic probe based on the recognition result.

FIG. 2 shows a state in which the electronic scanning ultrasonic probe 16 is connected to the apparatus main body via connectors 1a and 1b (1a is an apparatus main body side connector, and 1b is a probe side connector). The ultrasonic probe 16 is configured by arranging a plurality of transducers 19 in an array, and linear scanning can be performed by switching on and off the switches in the high-voltage switch group 4.

FIG. 3 shows a state in which an annular array type mechanical sector scanning ultrasonic probe 17 is connected to the apparatus main body via connectors 1a and 1b '. The ultrasonic probe 17 includes a plurality of ring-shaped ultrasonic transducers 17 arranged concentrically. The number of the ultrasonic transducers 20 in the ultrasonic probe 17 is smaller than the number of channels of the transmission / reception circuit 14. The probe-side connector 1b 'is connected in parallel for every four channels.
It is designed to be driven in channel units. That is, when the high-voltage switch group 4 is turned on, the transmission system channel output terminals for four channels (meaning the pulser output terminals).
Alternatively, the receiving system channel input terminals (meaning the preamplifier output terminals) for four channels are connected in parallel to one ultrasonic transducer 20. Therefore, the first and second means of the present invention are realized by the probe side connector 1b 'in which a plurality of connector pins are short-circuited and the high voltage switch group 4 as shown in FIG.

Next, the operation of the embodiment device configured as described above will be described.

When the electronic scanning ultrasonic probe 16 is mounted on the apparatus main body (see FIG. 2), the driving condition setting means 15 in the CPU 13 recognizes the probe 16 and executes a linear scan under the control of the transmission / reception control means 12. The obtained ultrasonic information is processed by the echo signal processing unit 9, and is displayed on the display unit via the digital scan converter 10.
Displayed on 11. The operation of each unit in this case is the same as that of the conventional device.

Next, when an ultrasonic probe 17 for mechanical sector scanning is mounted on the apparatus main body (see FIG. 3), the probe 17 is recognized by the drive condition setting means 15 in the CPU 13, and is controlled under the control of the transmission / reception control means 12. A sector scan is performed. In this embodiment, four of the pulsars 3-1 to 3-m are connected in parallel to each of the ultrasonic transducers of the ultrasonic probe 17 in transmitting the ultrasonic wave, and the preamplifier 6 is connected in receiving the ultrasonic wave. -1 to 6-m
Are connected in parallel. That is, the output of the transmission system channel and the input of the reception system channel are connected in parallel in units of four channels by the action of the high voltage switch group 4. According to this, at the time of transmission, each ultrasonic transducer is driven in parallel by four transmission system channels, and at the time of reception, the same ultrasonic echo is received and processed by four reception system channels. . Therefore, for the reasons described above, the load (ultrasonic transducer) driving capability of the transmission system is improved, and the S / N ratio of the reception system is improved.

In the mechanical sector scan by the probe 17, the delay time of the transmission delay units 2-1 to 2-m and the reception delay units 7-1 to 7-m is different for each channel connected in parallel to the ultrasonic transducer. Will be the same.

As described above, in the apparatus of the present embodiment, the parallel connection of the plurality of pulser output terminals and the parallel connection of the plurality of preamplifier input terminals are performed by the action of the high-voltage switch group 4, so that the device is originally dedicated to the ultrasonic probe for electronic scanning. Transmitter / receiver circuit 14
However, the optimization for the annular array type is performed, and good ultrasonic information can be collected. Further, since a transmission / reception circuit dedicated to the annular array type mechanical sector scanning ultrasonic probe is not required, an increase in the size of the apparatus and an increase in cost can be avoided.

 Next, another embodiment will be described.

In the above embodiment, since a plurality of transmission system channel output terminals are connected in parallel to the same ultrasonic transducer, if there is a variation in delay time between the transmission system channels or a malfunction, etc. This is equivalent to short-circuiting the ends, and there is a risk of circuit breakdown due to the flow of overcurrent.

Therefore, in order to prevent this, as shown in FIG.
It is preferable to provide a protection resistor 21 for the overcurrent of the transmission system channel for each channel. This resistor 21 may be inserted and connected at any point as long as it is in series with the transmission system channel output terminal, but if another ultrasonic probe, such as the ultrasonic probe 16 for electronic scanning, is used for switching, (See FIG. 2), the ultrasonic probe side as shown in FIG.
Specifically, it is preferable to arrange it in the probe side connector 1b '. In this case, only when the annular array type mechanical sector scanning ultrasonic probe 17 is used, the protection resistor 21 is connected in series with the transmission system channel output terminal, and the other ultrasonic probe switching is performed. In the case of use, the involvement of the protection resistor 21 can be eliminated.

 Here, the value of the protection resistor 20 is determined as follows.

FIG. 5 shows an equivalent circuit when the transmission system channel output terminal is connected in parallel to the ultrasonic transducer in the configuration of FIG. VP1 to VPM are pulse output voltages for each transmission channel, ZP is the output impedance of the pulser,
ZL is the input impedance of the ultrasonic transducer.

The maximum current at the time of transmission and I _MAX, the value of the protection resistor 21 is R, when the voltage of the transmitted pulse (wave height) was VH, to obtain the _{R 0 ≒ VH / I MAX R} 0 = R + R from the relation of ZP Can be.

For example, as shown in FIG. 6, if the offset delay time only CH1 of CH1 to CHM, for other transmission channels and the load ZL, a current flows I ₁ by VP _1. The maximum value of this I ₁ Is And the value of R may be determined so as to satisfy this equation.
However, care must be taken because if R is too large, the load driving capability is greatly reduced.

By providing the protection resistor 21 in this manner, even if there is a malfunction of the delay circuit due to a variation or disturbance noise, an overcurrent does not flow, thereby preventing the circuit from being destroyed. Although the load driving capability is slightly lower than that of the above embodiment due to the presence of the protection resistor 21, the protection resistor 21 can be almost neglected in the case of reception. The improvement of the S / N ratio when the channel input terminal is connected in parallel to the ultrasonic transducer is equivalent to that of the above embodiment, and the S / N ratio of the ultrasonic information of the entire device is And will improve.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made.

For example, in the above-described embodiment, the case where the annular array type mechanical sector scanning ultrasonic probe is used has been described. However, in addition to the ordinary electronic scanning ultrasonic probe, the number of ultrasonic vibrations smaller than the number of channels in the transmission / reception circuit 14 is reduced. The present invention can be applied to all cases where an ultrasonic probe having a probe is used. still,
When a transmission / reception delay time is not required as in the case of a single-type mechanical scanning ultrasonic probe, the delay time may be set to zero.

In the above embodiment, the ultrasonic probe is recognized based on the probe ID information, and the operation of the high voltage switch group 4 is controlled according to the recognition result. However, the ultrasonic probe is displayed on the operation panel of the apparatus. A switch corresponding to the type may be provided, and driving conditions may be set by operating this switch.

Further, in the above-described embodiment, a description has been given of a device having both the first and second means realized by the high voltage switch group 4. However, either one of the means may be omitted.

Further, the present invention can be applied to a device that does not include the high-voltage switch group 4. That is, even in an ultrasonic diagnostic apparatus having a transmission / reception circuit corresponding to the probe having the largest number of ultrasonic transducers among the usable probes and performing ON / OFF control of ultrasonic transmission / reception in this circuit. It is possible to perform the parallel driving of the wave oscillator and the reception processing of the same ultrasonic echo signal in a plurality of channels, and therefore, the same effects as in the above-described embodiment can be obtained. In this case, the first and second means in the present invention are formed by the probe-side connector connected as shown in FIG. 3 and the ultrasonic transmission / reception ON / OFF control unit of the transmission / reception circuit.

[Effects of the Invention] As described above in detail, according to the present invention, in addition to the ultrasonic probe for electronic scanning, an ultrasonic probe having a number of ultrasonic transducers smaller than the number of channels of the transmission / reception circuit can be used. An ultrasonic diagnostic apparatus that improves the S / N ratio of ultrasonic information can be provided at a small size and at low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an ultrasonic diagnostic apparatus according to the present invention, FIGS. 2 and 3 are detailed explanatory views of main parts of the present embodiment, and FIG. 4 is another embodiment. 5, FIG. 5 is an equivalent circuit diagram in the case of the configuration of FIG. 4, FIG. 6 is a timing diagram of a transmission pulse, and FIGS. 7 and 8 are explanatory diagrams of the principle of the present invention. (1b ', 4) ... first means, second means, 14 ... transmission / reception circuit, 19, 20 ... ultrasonic vibrator, 21 ... protection resistor.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A61B 8/00 G01N 29/22

Claims (3)

(57) [Claims] 1. A transmission / reception circuit having a plurality of transmission channels for applying drive pulses to an ultrasonic transducer and a plurality of reception channels for processing an ultrasonic echo signal, and the number of channels of the transmission / reception circuit. A high-voltage switch group corresponding to a plurality of transmission channels in an ultrasonic diagnostic apparatus including an ultrasonic probe having a small number of ultrasonic vibrators and a high-voltage switch group for switching connection of each vibrator First means for enabling parallel driving of the vibrator by connecting the output end of the high-frequency switch group in parallel with the ultrasonic vibrator in the ultrasonic probe, and the high-voltage switch group corresponding to a plurality of receiving system channels. A second method of receiving the same ultrasonic echo signal in a plurality of channels by connecting an input terminal in parallel with an ultrasonic transducer in the ultrasonic probe. At least one of the stages,
An ultrasonic diagnostic apparatus, wherein the same delay is given to a transmission system channel or a reception system channel connected in parallel. 2. The transmission system according to claim 1, wherein a protection resistor for an overcurrent of the transmission system channel is provided for each transmission system channel.
An ultrasonic diagnostic apparatus as described in the above. 3. The ultrasonic diagnostic apparatus according to claim 2, wherein said protective resistor is provided on an ultrasonic probe side.