JPH074803Y2 - Ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that shares a pulse Doppler method and a continuous wave Doppler method.

[Prior Art] An ultrasonic diagnostic apparatus based on the continuous wave Doppler method continuously transmits ultrasonic waves from the transducer for transmission to the inside of the subject, and transmits reflected waves from the inside of the subject to the transducer for transmission. It is received by the receiving transducer installed and is suitable for knowing the maximum blood flow velocity, that is, the maximum pressure difference.

On the other hand, an ultrasonic diagnostic apparatus using the pulse Doppler method transmits ultrasonic waves intermittently from the transducer to the inside of the subject, and the reflected wave from the inside of the subject is reflected by the same transducer until the next transmission. Is to be received.

An ultrasonic diagnostic apparatus using the pulse Doppler method transmits high-frequency ultrasonic waves to the inside of the subject, so that high distance resolution can be obtained, and it is suitable for knowing the direction and velocity of local blood flow, and its temporal change. .

[Problems to be Solved by the Invention] By the way, an ultrasonic diagnostic apparatus based on the continuous wave Doppler method uses a rectangular wave including a harmonic of a fundamental frequency to simultaneously perform transmission and reception. The waves affect the received signal as crosstalk, causing saturation of the receiving circuit and the Doppler processing circuit.

In order to reduce the influence of crosstalk, it is necessary to narrow the band of the signal applied to the transducer.

On the other hand, the ultrasonic diagnostic apparatus using the pulse Doppler method needs to have a wide band in order not to deteriorate the distance resolution.

Therefore, a shared machine having both the ultrasonic diagnostic function by the continuous wave Doppler method and the ultrasonic diagnostic function by the pulse Doppler method has a problem that it is difficult to realize because conflicting conditions are required. It was

The present invention was made to solve the above problems,
An object of the present invention is to provide an ultrasonic diagnostic apparatus that satisfies the conditions required in the continuous wave Doppler method and the pulse Doppler method, respectively.

[Means for Solving the Problems] An ultrasonic diagnostic apparatus according to the present invention includes an oscillating means for outputting a rectangular wave signal having a predetermined frequency, and an ultrasonic wave detecting means based on the rectangular wave signal.
In parallel with the low-pass filter, which is connected to the ultrasonic probe and removes the high frequency range of the signal output from the transmitting means, and the low-pass filter which outputs the signal necessary for driving the ultrasonic probe. Connected, open when transmitting a continuous wave,
A switch for closing the pulse wave is transmitted.

[Operation] In the ultrasonic diagnostic apparatus configured as described above, when the oscillating means outputs the rectangular wave signal, the transmitting means converts the rectangular wave signal into a signal necessary for driving the ultrasonic probe and outputs the signal. in this case,
The switch opens to send a continuous wave to the subject. or,
The switch is closed when the pulse wave is transmitted to the subject.
When the switch is opened, only the signal component of the fundamental frequency of the rectangular wave signal is transmitted to the subject, and when the switch is closed, the rectangular wave signal is directly transmitted to the subject.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a main part of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In FIG. 1, 1 is an oscillator that outputs a rectangular wave signal of a predetermined fundamental frequency, 2 is a wave transmission circuit that outputs the electric power required to drive the ultrasonic probe 5 based on the rectangular wave signal, and 3 is a rectangle. A low pass filter that selects only the signal component of the fundamental frequency f ₀ from the wave signal is closed during ultrasonic diagnosis by the pulse Doppler method, so that the output signal of the transmission circuit 2 is output as it is and the continuous wave Doppler method is used. The switch 5 for outputting the output signal of the wave transmission circuit 2 through the low-pass filter 3 by opening it for ultrasonic diagnosis by means of 5 is an ultrasonic probe for transmitting ultrasonic waves.

The oscillator 1 is composed of a crystal oscillator, ceramics, or the like, and outputs a rectangular wave signal having a magnitude of ₀ to 5 V including the fundamental frequency f ₀ as shown in FIG.

Next, the operation of the ultrasonic diagnostic apparatus shown in FIG. 1 will be described.

First, when the oscillator 1 outputs a rectangular wave signal, the wave transmission circuit 2
Outputs sufficient electric power to drive the ultrasonic probe 5 and output an ultrasonic signal based on the rectangular wave signal.

When performing ultrasonic diagnosis by the continuous wave Doppler method, the switch 4 is open. Therefore, as for the rectangular wave signal, only the signal component of the fundamental frequency f ₀ is selected through the low-pass filter 3 and transmitted from the ultrasonic probe 5 to the subject (not shown).

Also, when performing ultrasonic diagnosis by the pulse Doppler method,
Switch 4 is closed. Therefore, the rectangular wave signal is directly transmitted from the ultrasonic probe 5 to the subject through the switch 4.

When switching from continuous wave Doppler to pulse Doppler or vice versa, it is necessary to change the output of the wave transmission circuit 2 for acoustic power control.

[Effects of the Invention] As described above, according to the present invention, the transmitting means converts the rectangular wave signal output from the oscillating means into a signal necessary for driving the ultrasonic probe and outputs the continuous wave. To open the switch, open the switch to send the signal output from the wave sending means to the inside of the subject through the low-pass filter, and to send the pulse wave, close the switch to output the wave sending means. Since the signal is transmitted as it is into the subject, an ultrasonic diagnostic apparatus that has both an ultrasonic diagnostic function by the continuous wave Doppler method and an ultrasonic diagnostic function by the pulse Doppler method, which originally require mutually contradictory frequency bands. Has an effect that can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the operation of the low pass filter shown in FIG. 1 ... Oscillator, 2 ... Transmission circuit, 3 ... Low pass filter, 4 ... Switch, 5 ... Ultrasonic probe.

Claims (1)

[Scope of utility model registration request] 1. An ultrasonic diagnostic apparatus for outputting a continuous wave ultrasonic wave and a pulse wave ultrasonic wave having a predetermined frequency, an oscillating means for outputting a rectangular wave signal having a predetermined frequency, and an ultrasonic probe based on the rectangular wave signal. , A low-pass filter that is connected to the ultrasonic probe and outputs a signal necessary for driving the low-pass filter that removes a high frequency band of the signal output by the wave transmitting means.
An ultrasonic diagnostic apparatus comprising: a switch that is connected in parallel to the low-pass filter and that is opened when transmitting a continuous wave and closed when transmitting a pulse wave.