JPS63102749A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Prior Art and Problems to be Solved by the Invention Means for Solving the Problems Actions Examples Effects of the Invention [Previously Required] Phased Array In an ultrasonic diagnostic apparatus equipped with a phased array type probe and having at least a continuous wave Doppler measurement function and a function of obtaining a 1B mode tomographic image, the front surface of the array element when the phased array type probe is brought into contact with a living body. and a means for selecting a part of the phased array probe as a continuous wave transmitting element and the other part as a continuous wave receiving element. , the effective array elements selected by the means for detecting obstacles are used for continuous wave Doppler transmission and for continuous wave Doppler reception.

Alternatively, it is configured to switch to a B-mode tomographic image or the like to perform large-diameter continuous wave Doppler measurement, B-mode tomographic image measurement, or the like.

[Industrial application field]

The present invention relates to an ultrasonic diagnostic apparatus equipped with a phased array type probe and having at least a continuous wave Doppler measurement function and a function of obtaining a B-mode tomographic image. The present invention relates to a control method for switching between wave Doppler measurement and other measurement modes such as 1B mode tomographic image measurement.

Conventionally, in an ultrasonic diagnostic apparatus equipped with a phased array type probe, for example, B mode is used.

It has Doppler measurement functions such as M-mode morphometric measurement and display functions, pulsed Doppler mode, continuous wave (CW) Doppler mode, two-dimensional color flow manping mode, and one-dimensional flow profile mode, which have recently become popular. are doing.

However, there are problems such as the inconvenience of using the probe, such as having to replace the probe, and the inability to obtain high-quality continuous wave (CW) Doppler images due to the limited diameter of the phased array probe. As a result, improvements in usability and image quality were required. In particular, continuous waves (
CW) Doppler mode.

There is a growing demand for a control system in which a single large-diameter phased array probe is switched between and other modes such as B mode.

To explain the background further, a continuous wave (CW) Doppler method for measuring blood flow velocity has been known for a long time,9 but it has not been used for diagnosis of the heart W& region because it does not have distance resolution in principle. This was the current situation.

On the other hand, the method of measuring blood flow velocity using the pulsed Doppler method (a method that also obtains B-mode tomographic images) provides distance resolution, but at the same time, it measures blood flow using reflected signals of ultrasound pulses with a specific period, so the maximum There is a problem in that there is a limit to the detectable flow velocity, and it is not possible to display the degree of jet flow in diseases such as cardiac septal defects and valvular stenosis.

In addition, recently, a diagnostic method using the two-dimensional color flow mapping mode (including B-mode tomographic images) has been developed, which is useful for rough qualitative diagnosis of blood flow (for example, diagnosing the presence of the jet flow and its direction). However, in order to obtain a two-dimensional distribution map, the number of repetitions of ultrasonic pulses in the scanning direction is 4.
There was a problem in that the accuracy of blood flow measurement was limited to about 16 to 16 (in the case of normal diagnostic depth) and the accuracy of blood flow measurement was poor.

Therefore, in order to compensate for the advantages and disadvantages of each and perform an efficient ultrasound diagnosis, a combination diagnosis is used. Typical examples include the above-mentioned pulsed Doppler method or two-dimensional color flow mapping method. This is a method that determines the location of blood flow on a mode tomogram and determines the maximum blood flow velocity at that location using continuous wave (CW) Doppler. It is known as a particularly useful method because it can measure the absolute value of blood flow velocity. There is.

However, for -i, separate probes must be used for the above two Doppler measurements, and even with the current improved method that uses only one phased array probe, As will be explained later, it is necessary to use the phased array probe in parts, and the originally narrow aperture becomes narrower and narrower, resulting in the ultrasonic beam being spread out and the S/N ratio being poor at long distances. However, there is a problem in that it is not possible to obtain high-quality continuous wave (CW) Doppler images, and ultrasonic diagnosis that uses a single phased array probe and can perform large-diameter continuous wave (CW) Doppler measurements is recommended. There is a growing demand for equipment.

[Prior art and problems to be solved by the invention] Fig. 4 is a diagram explaining the conventional continuous wave Doppler measurement method, in which (a) shows the case of a composite probe; b) shows the case of the split control method.

As mentioned above, conventional continuous wave (C) Doppler measurement and B
In mode measurements, two-dimensional color flow manipulating measurements, etc., measurements were taken using separate probes, so continuous wave (
(J) Accuracy of angle correction for Doppler measurement.

The accuracy of determining the measurement position was poor.

Therefore, a composite probe or a single-split control force type was considered, but
There were problems with each of them that could not be said to be sufficient.

■ In the case of a composite probe: (a) See figure. Continuous wave (C
The transmitting probe 11b of W) is combined.

In this method, in the continuous wave (open) mode, the focusing accuracy is determined only by the receiving probe, so there is a problem that sufficient focusing cannot be obtained.

In addition, with this method, the contact surface with the living body is large,
In addition to poor operability, there were problems in that the device could get caught on obstacles such as ribs, disrupting the sound field and reducing measurement accuracy.

■ In the case of split control method: see figure (b) In this method, the phased array probe 11a is used separately for transmission and reception.
This is disclosed in Japanese Patent No. 0-248270.

In this method, since the conventional B-mode phased array probe 11a is used, it is not affected by obstacles such as ribs, and the operability is improved. Since the phased array type probe 11a is divided, the aperture at the time of transmission 1 and reception is naturally narrower.
There is a problem that the focus becomes weak, and as a result, the received signal level also decreases due to energy dispersion, resulting in poor S/N ratio at long distances, making it impossible to obtain high-quality continuous wave (CW) Doppler images. There was a problem.

In view of the above-mentioned conventional drawbacks, the present invention aims to provide a method for performing continuous wave (CW) Doppler measurement using a large diameter phased array probe.

[Means for solving problems]

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

In the present invention, (1) an ultrasonic diagnostic apparatus including a phased array type probe 11 and having at least a continuous wave Doppler measurement function and a function of obtaining a B-mode tomographic image; means 3 and 4 for selecting a part of the array elements constituting the probe 11 as continuous wave transmitting elements and the other part as continuous wave receiving elements; Means 2.7a, 7b for detecting obstacles present in front of the array elements and selecting valid array elements with no obstacles in front.

5 + 6 a + 6 b.

Switching and controlling the effective array element consisting of a plurality of elements selected by the means 2, 7a, 7b, 5.6a, and 6b for continuous wave Doppler transmission, continuous wave Doppler reception, or B-mode tomographic image. The apparatus includes means 1, 9, and 10, and is configured to perform ultrasonic measurement by switching between continuous wave (emission) Doppler measurement, B-mode measurement, and the like.

(2) The phased array type probe 1 is divided into a plurality of pieces in the thickness direction.

[Effect]

That is, according to the present invention, a phased array probe is provided and at least has a continuous wave Doppler measurement function.

In an ultrasonic diagnostic apparatus having a function of obtaining a B-mode tomographic image, means for detecting an obstacle present in front of the array element when the phased array probe is brought into contact with a living body; By providing means for selecting a part of the probe as a continuous wave transmitting element and the other part as a continuous wave receiving element, the effective array elements selected by the obstacle detecting means can be For continuous wave Doppler transmission.

It is designed to perform large-diameter continuous wave Doppler measurement, B-mode tomographic image measurement, etc. by switching to continuous wave Doppler reception or B-mode tomographic image measurement, so it has high quality and easy-to-use B mode. , it is possible to construct an ultrasonic diagnostic apparatus with a continuous wave (CW) Doppler mode switching function.

〔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, in which the transmission selection control circuit 3. Reception selection control circuit 4
．． Obstacle detection pulse generation circuit 2. Obstacle detection circuit 5. Related analog switches 1 to ■6a, 7a, 7b, 6
b is the means necessary to carry out the present invention. Note that the same reference numerals refer to the same objects throughout the plan.

First, the number of piezoelectric elements to obtain a normal B-mode tomographic image is N.
Then, in the case of a cardiac device, the window between the ribs is the window through which ultrasound waves pass (
acoustic window), 10 m
It has an aperture of about 17 m, and in order to eliminate the grating lobes that occur in the strip-shaped piezoelectric element, it is necessary to
The pitch must be 2 wavelengths or less, and the pitch is approximately 0.2 m for 3.5 Mllz ultrasound, which is normally used for diagnosis of living organisms.
Since a pitch of m or less, that is, the above N = 48.64, is used, here, an example using a phased array type ultrasonic probe 11 consisting of twice that number (i.e., 2N) of piezoelectric elements is used. I will explain about it.

The operation modes of the ultrasound diagnostic equipment can be roughly divided into three types: 0 image mode, continuous wave (CW) Doppler mode, and fault detection mode. Pulse Doppler, two-dimensional color flow mapping, etc. operate in mode.

In the fault detection mode, the control circuit 1 first instructs the analog switches U7a and I[7b to set the fault detection mode, and switches the switches connected to all drivers 12 to connect to the obstacle detection pulse generation circuit 2. Similarly, switches connected to all reception amplifiers 13 are switched to connect them to the obstacle detection circuit 5.

Next, under the control of the control circuit 1, the transmission selection control circuit 3 and the reception selection control circuit 4 are connected to a driver 12 with the same number, for example, #1'. Select a combination of receiving amplifiers 13,
Subsequently, the obstacle detection pulse generation circuit 2 generates an obstacle detection pulse, and transmits an obstacle detection ultrasonic pulse from the #1 piezoelectric element 11 to the living body.

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

The control circuit 1 then controls the combination of driver and receiving amplifier "#2", and in the same way, the presence or absence of an obstacle is detected and sent to the control circuit 1111.

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

The obstacle detection operation in the obstacle detection circuit 5 is performed by using a piezoelectric element 1 located at an obstacle such as a rib, as disclosed in Japanese Patent Laid-Open No. 56-52043 by the applicant of the present application.
1” received the ultrasonic reflection signal.

The presence or absence of the obstacle can be detected by detecting the difference between the ultrasonic reflection signal received by the piezoelectric element 11' located between the ribs.

Next, in the 0 image mode, the control circuit 1 controls the analog switches II 1a, m 7b to
6a, the orientation is switched to connect to IV 6b.

Subsequently, under the control of the control circuit 1, in the state table, from the piezoelectric element 11' with no obstacles in front,
The transmission selection control circuit 3 and the reception selection control circuit 4 select the driver 12 with the number corresponding to the piezoelectric element. Select a combination of receiving amplifiers 13.

Further, the analog switch I6a is controlled to connect the outputs of the K transmission delay circuits 8a to the selected drivers 12, and at the same time, the analog switch I6b is controlled to connect the selected receiving amplifiers 13 to the selected receiving amplifiers 13. Connect to delay circuit.

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 performed in a normal B-mode tomographic image. display,
Since this is a well-known control for pulsed Doppler measurement, color flow mapping measurement, etc., it will be omitted here.

As a result of the above, noise-free 8-image mode operation is performed using only the piezoelectric element group with no obstacles in front.

The means for selecting the piezoelectric element group 11 within K piezoelectric element groups 11, for example, selects the (+1) 72nd transmission delay circuit 8a so as to select the central part of the piezoelectric element group 11 where there is no obstacle in front.
/The channel of the reception delay circuit 8b is (L+M) /2
The driver 12/reception amplifier 13 is assigned to be connected to the second driver 12/reception amplifier 13. However, L is the starting number of the driver 12/receiving amplifier 13 with no obstruction in front, and M is the ending number of the driver 12/receiving amplifier 13 with no obstruction in front.

Next, in continuous wave (<J) Doppler mode, the continuous wave ((
J) Separately used for transmission and continuous wave (CI4>reception).

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

By using this method, for example, you can try to determine the direction of continuous wave (CW) Doppler measurement by defocusing the transmission beam with a small aperture and focusing the receive beam with a large aperture; or It is possible to set the continuous wave at a certain point and perform the desired division according to the purpose, such as emphasizing the continuous wave (C-assisted Doppler measurement information), but in this example, the aperture for transmission and reception can be A case will be explained in which the values are approximately equal.

In this case, the piezoelectric elements 11' used for transmission are from the Lth to (L+M)/2nd floor, and the piezoelectric elements 11' used for reception are from the ((L+M)/2)+1st to Mth.
It becomes the thing of the floor up to the th floor. These allocations are performed by the control circuit 1 using the above state table, and based on the resulting instructions, the transmission selection control circuit 3 selects the corresponding L-th to (
L+M)/2nd driver 12, the reception selection control circuit 4 corresponds to ((L+M)/2)+1st to M
Select the receiving amplifier for the floor up to the th floor.

At the same time, the selected driver 12 is
and the output channel of the transmission delay circuit 8a are connected by an analog switch I6a.

Similarly, the connection between the selected receiving amplifier 13 and the input channel of the receiving delay circuit 8b is connected to the analog switch r.
Performed by V 6b.

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

After setting the signal route as described above, a continuous wave (CW) signal is transmitted from the continuous wave (CW) generation circuit 9.
) is sent to the analysis section and subjected to normal continuous wave (C-) Doppler analysis.

Although each operation mode has been described independently above, the control circuit 1 performs activation control of each mode. however,
Activation of the 8-image mode and continuous wave (CW) Doppler mode is performed manually by the operator, but in the obstacle detection mode, assuming a detection depth of approximately 30 mm, it is necessary to repeatedly activate the
For example, the number of ultrasonic beams is 50 μs.
By automatically using the display frame spacing (2ms), it is possible to eliminate the need for the operator to be aware of the fault detection mode. (J) Ultrasonic diagnosis performed by switching between Doppler mode becomes more effective.

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

FIG. 2 is a diagram illustrating the characteristics of the thickness-divided probe.

In an ultrasound diagnostic apparatus using a normal phased array probe, the focusing of the ultrasound beam in the scanning direction of the phased array probe is determined by the receiving dynamic aperture, etc., as shown in Figure (a). 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, good focusing of the ultrasonic beam can be obtained as shown in the figure (indicated by diagonal lines).

However, the focusing of the ultrasonic beam in the thickness direction is performed using a fixed ultrasonic lens, and as shown in FIG. 3(b), the focusing is not very good at present. In particular, the ultrasonic beam at short distances is thick.

Therefore, in recent ultrasound diagnostic equipment, for example, (
c) As shown in the figure, an attempt has been made to control the aperture of the ultrasonic lens for a thickness-divided probe, and as shown by diagonal lines, it is relatively effective at both short and long distances. A well-focused ultrasonic beam can be obtained.

When using such a thickness-divided probe, the transmitting aperture is usually de”
Use a large aperture.

At this time, as shown in figure (d), when a part of the probe hits an obstacle such as a rib, ultrasonic noise is generated due to multiple reflections between the rib and the probe, and the scanning This will significantly degrade the ultrasound image as well as the direction.

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

FIG. 3 is a diagram showing an example of the configuration of a thickness-divided type probe.

First, as shown in figure (a), the thickness-divided probe is divided into outer arrays 1' to 2N', 1' to 2N'', and middle arrays 1 to 2N. 1～2
Connect N' and 1'' to 2N'' with a common electrode, turn on switches SWI' to SW 2N', and check whether there is an obstacle in front of the outer array as explained in Figure 1. Obstacles are detected in the same way as the obstacle detection means, and then the switch S
Turn on WI to SW 2N and check for obstacles in front of the middle array.

As a result, the state table described in the embodiment of FIG. 1 stores the states of both the outer array and the middle array.

An example of the state table at this time is schematically shown in FIG. In this figure, the array surrounded by a large frame is an effective piezoelectric element with no obstacles in front of it.

In this figure, In1%c'' indicates an effective piezoelectric element only in the inner array, and °A'' indicates the outer array.

It shows active piezoelectric elements on both sides.

A method of driving a piezoelectric element when obtaining a B-mode tomographic image using such a thickness-divided probe will be described.

(1) Search the above status table to check whether a sufficient scanning width A that can be used for both the inner and outer arrays has been secured, and if it has been secured, it will correspond to the piezoelectric element during tK AO. Turn the analog switch “on”,
The same control as previously described in FIG. 1 is performed. The opening control in the thickness direction is performed by the method explained in FIG. 2(c).

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

In this way, by using the thickness-divided ultrasound probe and focusing with the ultrasound lens in the thickness direction, a highly accurate ultrasound tomographic image can be obtained.

Next, in continuous wave (CW) Doppler mode, for example,
The method of dividing the thickness-divided probe into two equal parts is shown in (c).
(d) The case A+B>C will be explained with reference to the diagram.

(1) If A>B, then A+
The piezoelectric element indicated by diagonal lines in the diagram (c), which can be identified by B/2, is not used and is divided into two equal parts.

Then, for example, in order to increase the energy of ultrasonic transmission, the analog switch explained in Figure 1 is controlled to select the longer side in the thickness direction (the right side in Figure (C)) for transmission. .

(2) Similarly, in the case of A<B, the piezoelectric element in the shaded area in the figure (d) is not used, and the piezoelectric element is divided into two equal parts.

In this case, as is clear from the figure, the usage is similar to that of a normal one-dimensional array.

In this way, the present invention has two techniques: (1) detecting the presence or absence of an obstacle in front of a piezoelectric element and obtaining a B-mode tomographic image using a group of effective elements without any obstacles, and (2) a phased array probe. In continuous wave (CW) Doppler mode, the technology is divided into CW Doppler mode, and technology is used separately for continuous wave (CW) transmission and reception.
The unique feature lies in the realization of an ultrasonic diagnostic device with a continuous wave (C-) Doppler mode switching function.

[Effects of the Invention] As described above in detail, the ultrasonic diagnostic apparatus of the present invention includes a phased array probe and has at least a continuous wave Doppler measurement function and a function of obtaining a B-mode tomographic image. In a sound wave diagnostic device, when the phased array type probe is brought into contact with a living body, there is a means for detecting an obstacle present in front of the play element, and a part of the phased array type probe is connected to a continuous wave. Means for selecting one part as a transmitting element and the other part as a continuous wave receiving element, and the effective array element selected by the means for detecting an obstacle being used for continuous wave Doppler transmission, continuous wave Doppler reception, or It is designed to perform large-diameter continuous wave Doppler measurement, B-mode tomographic image measurement, etc. by switching to B-mode tomographic images, etc., so it has high quality and easy-to-use B-mode and continuous wave (A) Doppler modes. This has the effect of making it possible to construct an ultrasonic diagnostic device with a switching function.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of an ultrasonic diagnostic apparatus according to the present invention. FIG. 2 is a diagram explaining the characteristics of the thickness-divided probe. FIG. 3 is a diagram showing an example of the configuration of a thickness-divided type probe. FIG. 4 is a diagram explaining a conventional continuous wave (CW) Doppler measurement method. It is. In the drawing, 1 is a control circuit. 2 is an obstacle detection pulse generation circuit. 3 is a transmission selection control circuit, and 4 is a reception selection control circuit. 5 is an obstacle detection circuit. 6a and 6b are analog switches [, IV. 7a and 7b are analog switches n and m. 8a is a transmission delay circuit, and 8b is a reception delay circuit. 9 is a continuous wave (CW) generation circuit. 10 is a pulse generation circuit for B mode. 11 is an ultrasonic probe, and 11゛ is a piezoelectric element. 12 is a driver, 13 is a receiving amplifier. ds and de are apertures in the scanning direction. ds' and de' are openings in the thickness direction. 1'~2N', 1''~2N'' are outer ultrasonic probes. 1-2N and middle ultrasound probe. SW 1 to SW 2N, SW 1' - SW 28" indicate the switches. (a-) ('0) (C) (d-') 3. Begging for food 2.
So 2 History, July Δ% I Ashi (C) (d-) 3rd citizen So 02 (α) CVJ 歿SCW Peng Tom X Summer Jf) Jls■h Shishiba (CW) Dob) Miya Y ;Ken 1)

Claims (2)

[Claims] (1) An ultrasonic diagnostic apparatus comprising a phased array probe (11) and having at least a continuous wave Doppler measurement function and a function of obtaining a B-mode tomographic image, wherein the phased array probe (11) means (3, 4) for selecting a part of the array elements constituting the probe as a continuous wave transmitting element and the other part as a continuous wave receiving element; 11) means (2, 7a, 7b, 5, 6) for detecting obstacles existing in front of the array elements and selecting effective array elements with no obstacles in front
a, 6b) and the effective array element consisting of a plurality of elements selected by the means (2, 7a, 7b, 5, 6a, 6b) for continuous wave Doppler transmission, continuous wave Doppler reception, or B means (1, 9, 10) for controlling switching for mode tomographic images;
An ultrasonic diagnostic device characterized by comprising: (2) The ultrasonic diagnostic apparatus according to claim 1, wherein the phased array type probe (11) is divided into a plurality of pieces in the thickness direction.