JPH08238241A - Ultrasonic echo detection method and apparatus and ultrasonic image camera - Google Patents

Abstract

PURPOSE: To realize a method and apparatus which achieve a detecting of an echo from a non-linear echo source accurately and an ultrasonic image camera. CONSTITUTION: An ultrasonic echo detector which has an ultrasonic vibrator 101, an ultrasonic wave transmitting means 301 which applies a transmitted signal to the ultrasonic vibrator 101 to transmit an ultrasonic wave into a subject and an echo detecting means 303 to detect an echo signal from the inside of the subject includes a harmonic wave component blocking means 302 to block a harmonic component of a transmitted signal of the ultrasonic wave transmitting means 301.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic echo detecting method and apparatus and an ultrasonic image capturing apparatus.
More specifically, the present invention is a method and apparatus for detecting echoes from an echo source having a non-linear ultrasonic reflection characteristic and an ultrasonic imaging apparatus.

[0002]

2. Description of the Related Art In a medical ultrasonic imaging apparatus, ultrasonic waves are transmitted inside a subject and the internal structure of the subject is imaged based on the echo signal. Some echo sources, like some contrast agents (foaming agents), return the echo of, for example, the second harmonic component of the transmitted ultrasonic wave due to the nonlinearity of the reflection characteristics. When imaging is performed using a different contrast agent, the inside of the subject is imaged based on the second harmonic component of the echo signal.

[0003]

An ultrasonic transducer that generates ultrasonic waves to be transmitted into a subject may be driven by a saturated output voltage, that is, a rectangular wave voltage in order to increase the power efficiency of a driving circuit. In many cases, however, due to the harmonic components contained in the rectangular wave voltage, the ultrasonic wave transmitted into the subject also contains the harmonic components. For this reason, there is a disadvantage that the echo from the echo source having no non-linearity also contains higher harmonic components, which makes it indistinguishable from the echo from the original non-linear echo source.

The present invention has been made to solve the above problems, and an object thereof is to realize a method and apparatus for correctly detecting an echo from a non-linear echo source and an ultrasonic imaging apparatus.

[0005]

A first means for solving the above-mentioned problems is a method for driving an ultrasonic transducer to transmit an ultrasonic wave into a subject and detecting an echo signal corresponding to the ultrasonic wave. The ultrasonic echo detection method is characterized in that harmonic components of a transmission signal of the ultrasonic transducer are blocked.

A second means for solving the above-mentioned problems is an ultrasonic wave transmitting means for applying a transmission signal to the ultrasonic transducer to transmit an ultrasonic wave into the subject, and an echo from the inside of the subject. An ultrasonic echo detecting apparatus having echo detecting means for detecting a signal, comprising: an ultrasonic echo preventing means for preventing a harmonic component of a transmission signal of the ultrasonic transmitting means. It is a detection device.

In the second means for solving the above-mentioned problems, it is preferable that the harmonic component blocking means has a variable frequency band because it can be applied to a plurality of ultrasonic transducers having different frequencies.

In the second means for solving the above-mentioned problems, it is preferable that the function of the higher harmonic wave component blocking means can be switched between valid and invalid in order to expand the range of use of the apparatus.

A third means for solving the above-mentioned problems is an ultrasonic transducer, and ultrasonic wave transmitting means for transmitting a ultrasonic wave to the inside of a subject by giving a transmitting signal to the ultrasonic transducer. In an ultrasonic imaging apparatus having an echo detecting means for detecting an echo signal from the inside of a subject and an image forming means for forming an image based on the output signal of the echo detecting means, the ultrasonic wave transmitting means transmits the wave. It is an ultrasonic imaging apparatus characterized by comprising a harmonic component blocking means for blocking a harmonic component of a signal.

[0010]

In the first means for solving the problem, the harmonic component is removed from the transmission signal of the ultrasonic transducer.

In the second means and the third means for solving the problem, the harmonic component blocking means removes the harmonic component from the transmission signal of the ultrasonic oscillator.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an apparatus of an embodiment of the present invention, and FIG. 2 is a block diagram of an ultrasonic imaging apparatus using the apparatus of an embodiment of the present invention. The method of the embodiment of the present invention is shown by the operation of the apparatus of the embodiment of the present invention.

First, an ultrasonic imaging apparatus using the apparatus of the embodiment of the present invention will be described. In FIG. 2, 1 is a probe, 11 is a cable, 2 is a cable connector, Reference numeral 3 is a transmission / reception circuit, 4 is a logarithmic amplification circuit, 5 is an envelope detection circuit, 6 is a digital scan converter, 7 is a display, 8 is a control circuit, and 9 is an operating unit.

The probe 1 is connected to the transmitting / receiving circuit 3 by a cable connector 2. The probe 1 is brought into contact with a subject (not shown), transmits an ultrasonic wave into the subject according to a transmission signal given from the transmitting / receiving circuit 3, and detects an echo signal returned from the subject.

The transmission / reception circuit 3 applies a transmission signal to the probe 1 under the control of the control circuit 8 and receives and amplifies the detected echo signal. In addition, in outputting the transmission signal and receiving the ultrasonic detection signal, phase difference of each transmission signal and phasing addition of each reception signal are performed to perform beamforming for determining directivity of ultrasonic transmission and reception. Beam steering for beam forming and ultrasonic beam scanning
g) is performed.

The logarithmic amplification circuit 4 is for amplifying the output signal of the transmission / reception circuit 3 logarithmically. The envelope detection circuit 5 envelope-detects the output signal of the logarithmic amplification circuit 4 to obtain a B-mode image signal.

Under the control of the control circuit 8, the digital scan converter 6 converts the image signal output from the envelope detection circuit 5 into a digital signal and stores the digital signal in an image memory (not shown). The data is output in accordance with the display operation of the display device 7. The display 7 displays the image data given from the digital scan converter 6 as an image under the control of the control circuit 8.

The logarithmic amplification circuit 4, the envelope detection circuit 5, the digital scan converter 6 and the display 7 are an embodiment of the image forming means in the present invention. Control circuit 8
Is a transmitting / receiving circuit 3 and a digital scan converter 6
Also, a control signal is given to the display 7 to control their operations. The operation device 9 is operated by an operator and gives commands and data to the control circuit 8.

FIG. 1 shows the details of a portion including a probe 1, a cable 11, a cable connector 2 and a transmission / reception circuit 3. In FIG. 1, 101 is a transducer array including a plurality of ultrasonic transducers (hereinafter simply referred to as transducers). The ultrasonic transducer of the transducer array 101 is an example of the ultrasonic transducer of the present invention.

Reference numeral 301 is a driver, 302 is a filter, 3
Reference numeral 03 is a receiver, and 304 is a transmission / reception switch. The driver 301 generates a transmission signal, that is, a saturated-wave rectangular-wave oscillator drive voltage, for example, according to an input signal. The driver 301 is an embodiment of the ultrasonic wave transmitting means in the present invention.

The filter 302 blocks the harmonic components contained in the transmission signal of the driver 301 and allows the fundamental frequency component to pass. The filter 302 is an embodiment of the harmonic component blocking means in the present invention.

The receiver 303 receives the ultrasonic wave detection signal of the vibrator and is an embodiment of the echo detecting means in the present invention. The transmission / reception switch 304 transmits a transmission signal to the transducer array 101 during transmission and transmits an ultrasonic wave detection signal to the receiver 303 during reception.

The driver 301, the filter 302,
The receiver 303 and the transmission / reception switch 304 form a set to form a unit transmission / reception circuit 31 for one channel of the transducer array 101. Similar unit circuit 32 to
3n is provided for each channel of the transducer array 101. Note that one channel of the oscillator array 101 is formed by one oscillator or a plurality of vibration microelements.

Next, the operation of the apparatus of the present invention will be described. Under the control of the control circuit 8, the probe 1 and the transmission / reception circuit 3 scan the inside of the subject with ultrasonic waves. The echo reception signal obtained thereby is logarithmically amplified by the logarithmic amplification circuit 4, envelope-detected by the envelope detection circuit 5, input to the digital scan converter 6 as a B-mode image signal, and stored as digital image data. To be done. The image data stored in the digital scan converter 6 is read at the display timing of the display 7 under the control of the control circuit 8 and displayed as an image on the display 7.

At this time, in the transmitting / receiving circuit 3, the driver 301 outputs a rectangular wave transmission signal, but the filter 3
By blocking the harmonic component at 02, only the fundamental frequency component of the transmitted signal is given to the oscillators of the oscillator array 101. Then, the vibrator driven by such a transmission signal generates an ultrasonic wave containing no harmonic component. Therefore, it is assured that when a harmonic component of the transmitted signal is included in the echo signal, it is returned from the non-linear echo source and cannot be originally included in the transmitted signal. That is, the echo signal from the nonlinear echo source can be correctly detected.

Another embodiment of the present invention is shown in FIGS. FIG. 3 shows an example in which the filter 302 has a variable frequency band, and is composed of an LC circuit, and a capacitor C having a variable capacitance is used. Since the probe 1 has different ultrasonic frequencies depending on the depth of the search and the required resolution of the image, such a variable filter can be used for a plurality of probes.

The frequency band of the filter 302 is adjusted automatically by determining the type of the probe 1 by the control circuit 8. Alternatively, the operation may be performed by the operator through the scanner 9.

FIG. 4 shows an example in which a plurality of filters each having a different frequency band are prepared and used by switching according to the type of the probe 1. F1 to F4 are a plurality of filters each having a different frequency band, and for example,
Filter F1 is for 10MHz, filter F2 is 7MHz
Filter F3 for 5MHz, filter F4 3.5
It is for MHz. Note that P is a through without a filter.
(through) signal path.

These filters F1 to F4 and the signal path P are two interlocking changeover switches 305 and 30.
6 is used by switching. Changeover switch 3
Switching between 05 and 306 is automatically performed by determining the type of the probe 1 by the control circuit 8. Alternatively, the operation may be performed by the operator through the scanner 9.

It should be noted that the thru without a filter
The signal path P of h) is a path of a transmission signal used when performing normal imaging without paying attention to the nonlinear echo source. By having this signal path P, the function of the filter can be invalidated when the blocking of the harmonic component is unnecessary, and the imaging of the non-linear echo source and the normal imaging of which the non-linear echo source is not particularly focused. The ultrasonic imaging apparatus can be used for both.

FIG. 5 shows an embodiment in which the filter 302 is incorporated in the housing 21 of the cable connector 2.
The buffer amplifier 30 is provided in the path of each reception signal in the housing 21.
7 is also incorporated. With this configuration, it is possible to obtain a probe unit that generates an ultrasonic wave that does not include harmonic components. The filter 302 may be incorporated in the housing of the probe 1 instead of being incorporated in the housing of the cable connector 2.

The ultrasonic wave transmitting means is not limited to the rectangular wave,
A drive signal that is a non-sinusoidal wave due to a harmonic component may be output. Further, the ultrasonic imaging apparatus is not limited to medical ones.

[0033]

As described in detail above, the present invention provides
Since the harmonic components of the transmission signal of the ultrasonic transducer are blocked, it is possible to obtain an ultrasonic echo detection method and device for correctly detecting an echo from a nonlinear echo source, and an ultrasonic image capturing device. To be

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an ultrasonic imaging apparatus using the apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram of an apparatus according to another embodiment of the present invention.

FIG. 4 is a block diagram of an apparatus according to another embodiment of the present invention.

FIG. 5 is a block diagram of an apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 1 probe 11 cable 2 cable connector 3 transmission / reception circuit 4 logarithmic amplification circuit 5 envelope detection circuit 6 digital scan converter 7 indicator 8 control circuit 9 operator 101 oscillator array 301 driver 302 filter 303 receiver 304 transmission / reception switch 31 to 3n unit Transmitter / receiver circuit 305, 306 Changeover switch 307 Buffer amplifier

Claims (5)

[Claims] 1. A method of driving an ultrasonic transducer to transmit an ultrasonic wave into a subject to detect an echo signal, wherein harmonic components of a transmitted signal of the ultrasonic transducer are blocked. And ultrasonic echo detection method. 2. An ultrasonic transducer, ultrasonic wave transmitting means for applying a transmission signal to the ultrasonic transducer to transmit an ultrasonic wave into the subject, and detecting an echo signal from the inside of the subject. An ultrasonic echo detecting apparatus having an echo detecting means, comprising: a harmonic component blocking means for blocking a harmonic component of a transmission signal of the ultrasonic transmitting means. 3. The ultrasonic device according to claim 2, wherein the harmonic component blocking means has a variable frequency band. 4. The ultrasonic device according to claim 2, wherein the function of the harmonic component blocking means can be switched between valid and invalid. 5. An ultrasonic transducer, ultrasonic wave transmitting means for applying a transmission signal to the ultrasonic transducer to transmit an ultrasonic wave into a subject, and an echo signal from the inside of the subject is detected. In an ultrasonic imaging apparatus having an echo detecting means and an image forming means for forming an image based on an output signal of the echo detecting means, a harmonic wave for blocking a harmonic component of a transmission signal of the ultrasonic wave transmitting means. An ultrasonic imaging apparatus comprising a component blocking means.