JP2500937B2 - Ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION [Table of Contents] Outline Industrial field of application Conventional technology and problems to be solved by the invention Means for solving problems Problems Working Example Example of invention [Outline] Phased array type search Equipped with a two-dimensional phased array type probe in which a plurality of tentacles are arranged in the thickness direction, the array elements in the thickness direction are selectively synchronized with each other, and the presence or absence of obstacles in front of each array element is detected. Then, when an obstacle is detected in any one of the array elements, a means for detecting that the synchronized array element also has an obstacle, and an effective array element detected by the detecting means as having no obstacle on the front surface And a two-dimensional detection width of an effective array element that is stored in the storage means and has a width that is continuous in the scanning direction and has an equal width in the thickness direction. A selection means for selecting a two-dimensional detection width capable of obtaining an opening according to the degree, and selecting an opening in the thickness direction having a scanning width according to the diagnostic depth to focus the ultrasonic beam in the thickness direction. It was done.

[Industrial applications]

The present invention includes a two-dimensional phased array type probe,
The present invention relates to an ultrasonic diagnostic apparatus having at least a continuous wave Doppler measurement function and a function to obtain a B-mode tomographic image, and particularly to a continuous wave Doppler measurement and a B-mode tomographic image measurement of a large-diameter two-dimensional phased array type probe. The present invention relates to a method of controlling the opening in the thickness direction when the measurement mode is switched to another measurement mode.

Conventionally, in an ultrasonic diagnostic apparatus equipped with a phased array type probe, for example, morphological measurement / display function of B mode and M mode, pulse Doppler mode, continuous wave (CW)
It has the Doppler measurement function, the two-dimensional color flow mapping mode that has recently become popular rapidly, and the one-dimensional flow profile mode.

However, there is a problem that a good quality continuous wave (CW) Doppler image cannot be obtained due to the inconvenience of having to replace the probe and using it, or due to the limitation of the aperture of the phased array type probe. However, improvement of usability and improvement of image quality have been demanded. Especially, the continuous wave (CW) Doppler mode and other modes such as B mode
There has been a demand for a control method in which two large-diameter phased array type transducers are switched and used.

To further explain the background, a method of measuring blood flow velocity by continuous wave (CW) Doppler has been conventionally known, but it is not used for diagnosing the heart region because it has no distance resolution in principle. It was the current situation.

On the other hand, the pulse Doppler method (a method that also obtains B-mode tomographic images at the same time) provides a maximum blood flow velocity with a reflected signal of an ultrasonic pulse at a specific cycle, although it provides distance resolution. There is a limit to the detectable flow rate,
There is a problem that the degree of jet flow in diseases such as septal defect of the heart and valvular stenosis cannot be displayed.

In addition, recently, a diagnostic method using the two-dimensional color flow mapping mode (including the B-mode tomographic image), which is useful for rough qualitative diagnosis of blood flow (for example, the existence of the jet flow and the direction thereof) is available. However, in order to obtain a two-dimensional distribution map, the number of repetitions of ultrasonic pulses per scanning direction is
There is a problem that the accuracy of blood flow measurement is poor because it is limited to about 4 to 16 (for normal diagnosis depth).

Therefore, combination diagnosis is used in order to compensate for each strength and weakness and to perform efficient ultrasonic diagnosis.
As a typical example, a method of determining the location of the blood flow on the B-mode tomographic image by the pulse Doppler method or the two-dimensional color flow mapping method described above and obtaining the maximum blood flow velocity at that location by continuous wave (CW) Doppler And is known as a particularly useful method because the absolute value of the blood flow velocity can be measured.

However, in general, separate probes must be used for the above two Doppler measurements, and even in the improved method using only one phased array type probe at present, as will be described later. , It is necessary to divide and use the phased array type probe, and the originally narrow aperture becomes more and more narrow, resulting in the spread of the ultrasonic beam and the poor S / N ratio at a long distance. There is a problem that continuous wave (CW) Doppler images cannot be obtained, and there is a need for an ultrasonic diagnostic apparatus that can perform continuous wave (CW) Doppler measurement with a large diameter using a single phased array probe. Has become.

[Problems to be solved by conventional technology and invention]

FIG. 4 is a diagram for explaining a conventional continuous wave (CW) Doppler measurement method, (a) shows a case of a compound probe,
(B) shows the case of the division control method.

As mentioned above, conventional continuous wave (CW) Doppler measurement and B
Since different probes were used for mode measurement and two-dimensional color flow mapping measurement, the accuracy of angle correction for continuous wave (CW) Doppler measurement and the accuracy of determination of measurement position were rough. Was becoming.

Therefore, a composite probe and a division control method have been considered, but each has a problem that is not sufficient.

In the case of a compound probe: See figure (a). The conventional phased array type probe 11a has a continuous wave (C
W) Transmitting probe 11b is combined.

In this method, in the continuous wave (CW) mode, there is a problem that sufficient focusing cannot be obtained because the accuracy of focusing is the focus only by the receiving probe.

In addition, this method has a problem that the contact surface with the living body becomes large, the operability is poor, and the sound field is disturbed by being caught by an obstacle such as a rib and the measurement accuracy deteriorates.

In case of division control method: See Fig. (B). In this method, phased array type probe 11a is used.
Is used for transmission and reception, and is disclosed in Japanese Patent Application No. 60-248270 (Japanese Patent Application Laid-Open No. 62-106747) by the present applicant.

In this method, since the conventional phased array type probe 11a for B mode is used, it is not affected by obstacles such as ribs and the operability is improved, but the phased array probe with an originally narrow diameter is used. Since the array-type probe 11a is divided, there is a problem that the aperture at the time of transmission and reception is further narrowed and the focus is weakened. Therefore, the received signal level is also lowered because energy is dispersed, and S / at distance
There was a problem that the N ratio became worse and a good quality continuous wave (CW) Doppler image could not be obtained.

In view of the above-mentioned conventional drawbacks, the present invention aims to control the aperture in the thickness direction by using a large-diameter two-dimensional phased array type probe.

[Means for solving problems]

FIG. 1 is a diagram showing a configuration example of an ultrasonic diagnostic apparatus of the present invention.

In the present invention, (1) a two-dimensional phased array type probe in which a plurality of phased array type probes for scanning in a one-dimensional direction are arranged in the thickness direction, and by controlling the opening in the thickness direction, An ultrasonic diagnostic apparatus for focusing an ultrasonic beam in the thickness direction, wherein the phased array arranged in the thickness direction is used to detect the presence or absence of an obstacle existing in front of each array element of the phased array type probe. Means for selectively synchronizing the array elements of the array-type probe with each other, and when an obstacle is detected in any one of the array elements, a means for detecting that the synchronized array element also has an obstacle; Means for storing the arrangement form of the effective array elements detected by the front surface as having no obstacle, and the effective array element width stored in the storage means and continuous in the one-dimensional scanning direction. Selecting means for detecting the two-dimensional detection width of the effective array element having the same width in the direction, and selecting the two-dimensional detection width capable of obtaining an opening according to the diagnostic depth.

[Action]

That is, according to the present invention, the array elements of the phased array type probe arranged in the thickness direction are selectively synchronized with each other, and the presence or absence of an obstacle existing on the front surface of each of the array elements is detected, When an obstacle is detected in one array element, it is also detected that there is an obstacle in the synchronized array element, and the arrangement form of the effective array element detected as having no obstacle on the front side is stored. At
The two-dimensional detection width of the effective array element that is continuous in the scanning direction and has the same width in the thickness direction is selected and controlled so as to adapt to the aperture according to the diagnostic depth. Since focusing is performed, there is a special effect that an ultrasonic diagnostic apparatus that can obtain an opening in the thickness direction having a sufficient scanning width necessary for diagnosis can be constructed.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. The above-mentioned FIG. 1 is a diagram showing an example of the configuration of the ultrasonic diagnostic apparatus of the present invention. The transmission selection control circuit 3, the reception selection control circuit 4, the obstacle detection pulse generation circuit 2, the obstacle detection circuit 5, and related Analog switches I-IV 6a, 7a, 7b, 6b are necessary means for carrying out the present invention. The same reference numerals indicate the same objects throughout the drawings.

First, assuming that the number of piezoelectric elements for obtaining a normal B-mode tomographic image is N, in the case of a heart, it is called a window (acoustic window) through which ultrasonic waves pass between ribs, and it has an opening of about 10 mm. In order to eliminate the grating lobe generated in the strip-shaped piezoelectric element, it is necessary to have a pitch of 1/2 wavelength or less, and it is about 0 for a 3.5 MHz ultrasonic wave that is usually used for diagnosing a living body. Since a pitch of 2 mm or less, that is, N = 48,64 is used, here, an example using a phased array type ultrasonic probe 11 composed of twice (ie, 2N) piezoelectric elements is used. Will be described.

The operation modes of the ultrasonic diagnostic apparatus are roughly classified into a B image mode, a continuous wave (CW) Doppler mode, and a failure detection mode. For pulse Doppler, two-dimensional color flow mapping, etc., the B image mode is used. Works with.

In the fault detection mode, first, the control circuit 1 instructs the fault detection mode to the analog switches II7a and III7b, and switches the switches connected to all the drivers 12 to connect to the obstacle detection pulse generation circuit 2, and similarly. The switch connected to the reception amplifier 13 is switched to connect to the obstacle detection circuit 5.

Next, the transmission selection control circuit 3 is controlled by the control circuit 1.
And the reception selection control circuit 4 with the same number, for example, “# 1”
The combination of the driver 12 and the receiving amplifier 13 is selected, the obstacle detection pulse generation circuit 2 subsequently generates an obstacle detection pulse, and the ultrasonic pulse for detecting obstacles from the '# 1' piezoelectric element 11 'to the living body. To send.

The reflection (echo) signal from the living body is captured by the piezoelectric element 11 'of'# 1 ', passes through the receiving amplifier 13 of'# 1 ', and the obstacle detection circuit 5 detects the presence or absence of an obstacle. The detection result is sent to the control circuit 1.

The control circuit 1 then controls the combination of the driver # 2 and the reception amplifier, and in the same manner, the presence or absence of an obstacle is detected and sent to the control circuit 1.

In this way, by sequentially switching the combination of the driver 12 and the receiving amplifier 13, the presence or absence of an obstacle in front of all the piezoelectric elements 11 'is detected, and the state table thereof is stored in the control circuit 1.

The obstacle detecting operation of the obstacle detecting circuit 5 is, as disclosed by the applicant of the present application in Japanese Patent Laid-Open No. 56-52043, for example, a piezoelectric element 11 'located at an obstacle such as a rib.
The presence or absence of the obstacle can be detected by detecting the difference between the ultrasonic wave reflected signal received by the ultrasonic wave and the ultrasonic wave reflected signal received by the piezoelectric element 11 'located between the ribs.

Next, in the B image mode, the control circuit 1 switches the analog switches II7a and III7b to the direction in which they are connected to the analog switches I6a and IV6b.

Then, under the control of the control circuit 1, in the above state table, K
Transmission selection control circuit 3 is selected by selecting within (but K ≦ N)
Then, the reception selection control circuit 4 selects the combination of the driver 12 and the reception amplifier 13 having the number corresponding to the piezoelectric element.

Furthermore, the analog switch I6a is controlled, the outputs of the K transmission delay circuits 8a are connected to the selected driver 12, and at the same time, the analog switch IV6b is controlled to change the selected reception amplifier 13 to the K reception delay circuits. Connect to.

Here, the transmission timing control in the B-mode pulse generation circuit 10, the sector scan in the transmission delay circuit 8a and the reception delay circuit 8b, the focus delay tap switching control, and the timing control are the normal B-mode tomographic images. Since this is a well-known control for display, pulse Doppler measurement, color flow mapping measurement, etc., it is omitted here.

As a result, the operation in the B image mode without noise is executed by using only the piezoelectric element group having no obstacle in front.

The above-mentioned means for selecting the piezoelectric element group 11 of K or less is, for example, (K + 1) / 2th transmission delay circuit 8a / reception so that the central portion of the piezoelectric element group 11 having no obstacle in front is adopted. Channel of delay circuit 8b is (L + M) / 2nd driver
12 / Assigned to connect with the receiving amplifier 13. However, L is a driver 12 / reception amplifier 13 without obstacles in front.
Is the first number of M, the driver 12 /
This is the end number of the reception amplifier 13.

Next, in continuous wave (CW) Doppler mode, the piezoelectric elements with no obstacles in front of No.L to No.M are divided into one for continuous wave (CW) transmission and one for continuous wave (CW) reception. To use.

This piezoelectric element 11 'is divided into a transmitter and a receiver,
As described above, the method of performing continuous wave (CW) Doppler measurement is disclosed by the applicant of the present application in Japanese Patent Application No. 60-248270.

By using this method, for example, transmission is defocused with a small aperture, and the direction of the continuous wave (CW) Doppler measurement is determined by the direction of the reception beam focused with a large aperture, or both transmission and reception are focused. Can be set to a certain point, and the desired division according to the application can be performed by emphasizing the continuous wave (CW) Doppler measurement information at that point. A case will be described in which the values are substantially equal.

In this case, the piezoelectric element 11 'used for transmission has the No. from Lth to (L + M) / 2th, and the piezoelectric element 11' used for reception has {(L + M) / 2} + 1st to Mth. Until
No. The allocation of these is the control circuit 1,
This is performed using the above-mentioned state table, and the transmission selection control circuit 3 is instructed by the result thereof from the corresponding L-th to (L +
The receiving selection control circuit 4 corresponds to the drivers 12 of No. M) / 2 up to {(L + M) / 2} + 1th to Mth.
Select the No. receiving amplifier.

At the same time, the selected driver 12 is instructed by the control circuit 1.
And the output channel of the transmission delay circuit 8a is connected by the analog switch I6a. Similarly, the selected reception amplifier 13 and the input channel of the reception delay circuit 8b are connected by the analog switch IV6b.

On the other hand, control circuit 1 instructs tap switching control of a delay circuit that determines the direction and focus of a desired ultrasonic beam.

After the above signal route setting, a continuous wave (CW) signal is transmitted from the continuous wave (CW) generation circuit 9, and an echo continuous wave (CW) signal from the living body is analyzed by a continuous wave (CW) analysis. Sent to the department for normal continuous wave (CW) Doppler analysis.

Although each operation mode has been independently described above,
The control circuit 1 controls the activation of each mode. However, the B image mode and the continuous wave (CW) Doppler mode are activated manually by the operator, but in the fault detection mode, if the detection depth is about 30 mm, it will be repeated 40 μs.
Therefore, for example, by thinning the number of ultrasonic beams to about 50 (2 ms) and automatically using the display frames, it is possible to prevent the operator from being aware of the failure detection mode. Therefore, the ultrasonic diagnosis performed by switching the B image mode and the continuous wave (CW) Doppler mode according to the present invention becomes more effective.

Next, a case where the present invention is applied to a two-dimensional array type probe, specifically, a thickness division type probe will be described.

FIG. 2 is a diagram for explaining the features of the thickness division type probe.

In an ultrasonic diagnostic apparatus using a normal phased array type probe, focusing of the ultrasonic beam in the scanning direction of the phased array type probe is performed as shown in FIG. Good focusing is obtained because it is controlled electronically. Specifically, by observing with a narrow aperture ds at a short distance and observing with a wide aperture de at a long distance, a good ultrasonic beam focusing can be obtained as shown in the drawing (shown by hatching).

However, the focusing of the ultrasonic beam in the thickness direction is performed by a fixed ultrasonic lens, and it cannot be said that the focusing is so good as shown in FIG. Especially, the ultrasonic beam at a short distance is thick.

Therefore, in recent ultrasonic diagnostic equipment, for example,
(C) As shown in the figure, for the thickness division type probe,
Attempts have been made to control the aperture of the ultrasonic lens, and as shown by the diagonal lines, an ultrasonic beam having a relatively good focusing at both a short distance and a long distance can be obtained.

When such a thickness division type probe is used, the aperture of the transmission is usually de '
Use a large opening.

At this time, when a part of the probe hits an obstacle such as a rib as shown in FIG. 3D, ultrasonic noise is generated due to multiple reflection between the rib and the probe, and scanning is performed. Similar to direction, it will significantly degrade the ultrasound image.

In order to avoid this, an obstacle detecting means as shown in FIG. 3 is used.

FIG. 3 is a diagram showing a configuration example of a thickness division type probe.

First, as shown in FIG. 3A, the thickness division type probes are arranged in the outer arrays 1 ′ to 2N ′, 1 ″ to 2N ″, and the middle array 1
~ 2N, and the outer array 1 '~ 2N', 1 "~ 2N"
Are connected by a common electrode, and the switches SW1 'to SW2N' are turned on to determine whether or not there is an obstacle in front of the outer array.
By the same method as the obstacle detection means described in FIG. 1,
Next, the switches SW1 to SW2N are turned on, and the presence of obstacles in front of the middle array is investigated.

As a result, the states of both the outer array and the inner array are stored in the state table described in the embodiment of FIG.

An example of the state table at this time is schematically shown in FIG. In this figure, the array surrounded by a thick frame is referred to as an effective piezoelectric element having no obstacle in front. In this figure,
'B'and'C'indicate the piezoelectric elements effective only in the array on the inner side, and'A' indicates the piezoelectric elements effective on both the outer side and the inner side.

A method of driving the piezoelectric element when a B-mode tomographic image is obtained using such a thickness division type probe will be described.

(1) The above status table is searched to check whether or not a sufficient scan width A that can be used by both the inner and outer arrays has been secured. If so, the inner and outer sides included in the width of A 'ON' the analog switch corresponding to the piezoelectric element
As the above, the same control as previously described with reference to FIG. 1 is performed. The opening control in the thickness direction is performed by the method described with reference to FIG.

(2) If the sufficient scanning width A cannot be secured, the analog switch corresponding to only the inner piezoelectric element is turned on, and the same control as described above with reference to FIG. 1 is performed.

In this way, using the thickness division type ultrasonic probe,
By focusing with the ultrasonic lens also in the thickness direction, a highly accurate ultrasonic tomographic image can be obtained.

Next, in continuous wave (CW) Doppler mode, for example,
The method of dividing the thickness division type probe into two equal parts is as follows (c),
The case of A + B> C will be described with reference to FIG.

(1) If A> B, then regarding the piezoelectric element in the A region, A
It can be identified by + B / 2. (C) The piezoelectric element indicated by the diagonal lines in the drawing is not used and is divided into two parts.

Then, for example, in order to increase the transmission energy of the ultrasonic waves, the analog switch described in FIG. 1 is controlled so that the one longer in the thickness direction {right side in FIG. (C)} is selected for transmission. .

(2) Similarly, in the case of A <B, the piezoelectric element in the shaded area in FIG. In this case, as is apparent from the figure, the usage is the same as that of a normal one-dimensional array.

As described above, the present invention detects the presence or absence of an obstacle in front of the piezoelectric element and obtains a B-mode tomographic image with an effective element group having no obstacle, and a two-dimensional arrayed probe in the scanning direction. And divided into two in the thickness direction, in continuous wave (CW) Doppler mode, for continuous wave (CW) transmission and reception,
Higher quality and easier to use by combining the technique of using each two-dimensional phased array type probe with a technique of dividing the two-dimensional phased array type probe into a plurality in the scanning direction and the thickness direction, for example, aperture control It is characterized by the realization of an ultrasonic diagnostic device with a switching function between B mode and continuous wave (CW) Doppler mode.

〔The invention's effect〕

As described above in detail, the ultrasonic diagnostic apparatus of the present invention includes a two-dimensional phased array probe and has at least a continuous wave Doppler measuring function and a function to obtain a B-mode tomographic image. In the case where the two-dimensional phased array type probe is brought into contact with a living body, a means for detecting an obstacle existing in front of the array element and a part of the two-dimensional phased array type probe are continuously waved. Of the effective array element selected by the means for detecting the obstacle and the means for selecting the other part as the receiving element for the continuous wave, and the continuous wave Doppler transmitting, the continuous wave Doppler receiving, or , B-mode tomographic images, etc. are switched to perform large-diameter continuous wave Doppler measurement, B-mode tomographic image measurement, etc., so high-quality, easy-to-use B-mode and continuous wave (C
W) A Doppler mode switching function has been added, and it has become possible to make maximum use of a place (acoustic window) where there are no obstacles, an ultrasonic beam with good focusing is obtained, and the resolution of diagnostic information is improved. There is an effect that a sound wave diagnostic apparatus can be constructed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of an ultrasonic diagnostic apparatus of the present invention, FIG. 2 is a diagram explaining the features of a thickness division type probe, and FIG. 3 is a configuration example of a thickness division type probe. Fig. 4 and Fig. 4 are diagrams explaining the conventional continuous wave (CW) Doppler measurement method. In the drawing, 1 is a control circuit, 2 is an obstacle detection pulse generation circuit, 3 is a transmission selection control circuit, 4 is a reception selection control circuit, 5 is an obstacle detection circuit, and 6a and 6b are analog switches I, IV, 7a, 7b is an analog switch II, III, 8a is a transmission delay circuit, 8b is a reception delay circuit, 9 is a continuous wave (CW) generation circuit, 10 is a B-mode pulse generation circuit, 11 is an ultrasonic probe, 11 'is Piezoelectric element, 12 is a driver, 13 is a receiving amplifier, ds, de are apertures in the scanning direction, ds ', de' are apertures in the thickness direction, and 1 '~ 2N', 1 "~ 2N" are outer ultrasonic probes. 1 to 2N and the ultrasonic probe on the inner side, SW1 to SW2N, SW1 'to SW2N' are switches.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Wataru Yagi Watanabe, Nakahara-ku, Kawasaki City, 1015 Kamiotanaka, Fujitsu Limited (72) Inventor Nobushi Iwashita 1015, Kamikodanaka, Nakahara-ku, Kawasaki City, Fujitsu Limited (72) Invention Naritaka Nakao 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Fujitsu Limited (72) Inventor Shinichi Amamiya 1015, Kamiotanaka, Nakahara-ku, Kawasaki Within Fujitsu Limited (56) Reference JP 61-146242 (JP, A) JP 56-52043 (JP, A) JP 59-108539 (JP, A) JP 57-122852 (JP , A)

Claims (1)

(57) [Claims] 1. A two-dimensional phased array type probe in which a plurality of phased array type probes for scanning in one dimension are arranged in the thickness direction, and the thickness direction is controlled by controlling an opening in the thickness direction. Is an ultrasonic diagnostic apparatus for focusing the ultrasonic beam, which is arranged at symmetrical positions in the thickness direction when detecting the presence or absence of obstacles in front of each array element of the phased array type probe. A means for selecting and synchronizing the array elements of the phased array probe, and when an obstacle is detected in any one array element, a means for detecting that there is an obstacle in both of the synchronized array elements, Means for storing the arrangement form of the effective array elements detected by the means as having no obstacle on the front surface, and an effective array element width stored in the storage means and continuous in the one-dimensional scanning direction. An ultrasonic wave, comprising: a selection unit that detects a two-dimensional detection width of an effective array element having an equal width in a thickness direction and selects a two-dimensional detection width that provides an opening according to a diagnostic depth. Diagnostic device.