JPH04105645A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To suppress a false Doppler reception signal by a side robe by making an irradiation beam from a second probe cross at one point of a scan surface of a scan image scanned with a first probe. CONSTITUTION:First and second probes 3 and 4 are housed into a roughly rectangular casing 13 and made up of a plurality of vibrators 14, 14.... The vibrators 14, 14... are connected to a cable 15 through an electrode and then, to a transmitting/receiving circuit to form an electronic linear scanning or the like. Array-wise axes 16 of the vibrators 14, 14... of the first probe 3 correspond to a direction of undergoing an electronic linear scanning and coincide with a sectional scan surface 11. Moreover, the array-wise axes 17 of the vibrators 14, 14... of the second probe 4 correspond to a direction of undergoing the linear scanning likewise and coincides with a Doppler scan surface 12. The array-wise axis 16 of the first probe 3 and the array-wise axis 17 of the second probe 4 are so arrange to cross at a specified angle theta.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic probe suitable for use in ultrasonic Doppler blood flow meters and the like.

[Summary of the invention]

The present invention relates to an ultrasonic probe suitable for use in an ultrasonic Doppler blood flow meter, etc., and includes a first probe for detecting a cross section of a subject, and a second probe for transmitting and receiving Doppler beams. In an ultrasonic probe/probe having a probe, the irradiation beam from the second probe crosses only at one point on the scanning surface of the scanned image scanned by the first probe. This is designed to suppress false signals due to side lobes generated by the second probe.

[Conventional technology]

Conventionally, Doppler methods have been used to measure blood flow velocity in living bodies. For example, as shown in Figure 4, the pulsed Doppler method uses a probe (1) to measure blood vessels, etc. of a subject. When an ultrasonic pulse is emitted toward a measurement site and the reflected wave is received, the frequency shifts by a predetermined amount due to the Doppler effect and returns. This shift frequency fd can be determined by setting the transmission frequency to fo, the blood flow velocity to V, the incident angle of the beam to θ, and C to the sound speed.

As can be seen from equation (1), the higher fo (and θ is closer to zero), the larger the value of fd will be.

A blood flow meter called a duplex method is also well known as a method of measuring blood flow velocity using the above-mentioned Doppler method. This duplex method has a probe for forming tomographic images and a probe for transmitting and receiving Doppler beams, and these two probes are switched to measure blood flow, and can be used as an ultrasound probe. Basically, two types of methods are known. As shown in FIG. 5, the first ultrasound probe (5a) includes a first probe (3) for obtaining a tomographic image and a second probe (4) for transmitting and receiving Doppler beams. It is configured so that the tomographic beam (6) and the Doppler beam can be irradiated into the subject by separately providing the second ultrasonic probe (5b).
), as shown in FIG. 6, a single probe (8) is used in common as a tomographic probe and a probe for transmitting and receiving Doppler beams.

To measure blood flow by the duplex method using an ultrasound probe such as the one described above, the first probe (3) or the first or second probe (8) is used to Beam (6
) is transmitted and received into the subject to obtain a B-mode tomographic image, for example, a blood vessel (2) as shown in FIG.

Next, based on this obtained tomographic image, a blood flow measurement site (9) is specified using a marker or the like on the CRT.

Next, a Doppler beam (7) is transmitted and received from the second probe (4) or the first and second probes (8) toward the identified blood flow measurement site (9).

Next, the received Doppler signal is extracted and the blood flow V in the blood vessel (2) is calculated from the shift frequency fd etc. using the method explained in FIG.
etc. are made in a manner that is required.

[Problem to be solved by the invention]

A duplex ultrasonic probe with the above-mentioned conventional configuration,
For example, as shown in Figure 6, the tomographic beam (6) is transmitted and received in the direction of the subject's blood vessel (2) using the first and second probes (8), and the tomographic beam (6) is displayed on the CRT in B mode. After obtaining the image, specify the blood flow measurement site (9) and use the same first and second probes (8) to transmit and receive the Doppler beam (7) in the direction of the subject's blood vessel (2). Suppose we did. These tomographic beam (6) and Doppler beam (7) are X.

Data is sent and received within two planes. At this time, it is well known that, for example, the Doppler beam (7) is not only transmitted and received in the direction of the blood flow measurement site (9), but also that a side lobe (10) is generated. This side lobe (10) depends on the method of forming the ultrasonic beam, but for example, in the electronic sector type scanning method shown in Fig. 7, the side lobe (10) is -
It reaches about 2dB. Such a side lobe (10) is, for example, a blood vessel (2) on a cross-sectional image on a CRT as shown in FIG.
) intersects with the blood vessel (2) at a location other than the blood flow measurement site (9) in the cross section (cross section), and the Doppler signal is reflected from this intersection and is transmitted to the first or second probe. (8), it becomes impossible to distinguish it from the Doppler signal transmitted and received at the blood flow measurement site (9), which reduces the reliability of the blood flow measurement data of the blood vessel (2) obtained. There was a problem.

The present invention was developed in view of the above-mentioned problems, and its purpose is to scan the Doppler beam in such a way that side lobes or grating lobes, etc., that are generated are removed from the blood vessels of the subject to eliminate false artifacts caused by side lobes. This is designed to suppress Doppler received signals.

[Means to solve the problem]

As shown in FIGS. 1A and 1B, the ultrasonic probe of the present invention includes a first probe (3) for detecting a tomographic area of a subject, and a probe (3) for transmitting and receiving Doppler beams, etc. Second probe (4
) in the ultrasonic probe (5), the second probe (4 ) are arranged so that the irradiation beams (7) from the two beams intersect with each other.

[Effect]

The ultrasonic probe of the present invention is configured such that the beam (7) transmitted and received from the second probe (4) intersects only at one point on the scanning surface scanned by the first probe (3). Since the first and second probes (3) or (4) are arranged, it is possible to obtain a device that does not receive false signals due to rhinoceros and tropes.

〔Example〕

Hereinafter, one embodiment of the ultrasonic probe of the present invention will be described in detail with reference to FIGS. 1 to 3.

FIG. 1A is a side view of the ultrasonic probe of this example, and FIG. 1B is a front view. In Figure 1A and Figure 1, the first probe (
3) and the second probe (4) are housed in a substantially rectangular casing (13), and the first and second probes (3) and (4) are housed in a plurality of transducers ( 14) It is composed of (14)... These oscillators (14) (14)
... are connected to four cables (15) via electrodes,
It is connected to a transmitting/receiving circuit, and performs, for example, electronic linear scanning.

Inside the above-mentioned casing (13) is a backing material and a first
and a rectangular or rod-shaped ultrasonic vibrator (14) made of barium titanate, PZT, etc. sandwiched between the second matching layer.

For example, about 128 of these vibrators (14) each having a width of about 1 mm are arranged in a 13 cm area. Furthermore, electronic switch circuits and the like are also provided. Transducer (14) of the first probe (3) (14)...
The arrangement direction axis (16) is the direction of electronic linear scanning and coincides with the tomographic scanning plane (11). Furthermore, the arrangement direction axis (17) of the transducers (14) (14), etc. of the second probe (4) is also in the direction of linear scanning,
It coincides with the Doppler scan plane (12). The first probe (
The arrangement direction axis (16) of the third probe (4) and the arrangement direction axis (17) of the second probe (4) are arranged so as to intersect at a predetermined angle θ. This angle is preferably about 5°.

With the first and second probes (3) arranged in this way, for example, the first probe (3) is electronically linearly scanned, and C
The tomographic scanning plane (11) by the tomographic beam (6) when the tomographic image (16) is displayed in B mode on a display device such as RT showing the sagittal section of the blood vessel (2) as shown in Figure 2. Figure 1 A, B
For example, by performing sector scanning with the second probe (4) and scanning the Doppler scanning plane (12) with the Doppler beam (7),
) (see Figures 1A and B) so that the faces intersect. Of course, the scanning methods of the first and second probes are not limited to the electronic linear method and the electronic sector method, but can be appropriately selected in combination with the mechanical sector method, etc. The scanning method of the tentacle may be a fixed beam method. By moving the ultrasound probe (5) over the surface of the subject in this way, the tomographic image (XZ plane image) obtained by the first probe (3) is the sagittal section (
A Doppler sampling point (18) is designated on this tomographic image (16) using the Doppler beam (7) transmitted and received from the second probe (4). This Doppler sampling point l-(18) is the first
The tomographic scanning plane (11) of the probe (3) and the second probe (
4) is the intersection line of the Doppler scan plane (12), and the tomographic image (16
) moves on line (19). Here, the Doppler sampling point (
18), each transducer (
14) By setting the delay amount (delay time) of the delay element connected to (14) to a predetermined value, the Doppler beam (7) is transmitted to the blood flow measurement site (9), and The reception directivity will also be set. Blood flow measurement is carried out in this way, using an ultrasonic probe (5) as in this example.
The fact that the side lobe (10) is not irradiated to the blood vessel (2) due to this is explained in detail in the explanatory diagram of FIG. Figures 3A and B are similar to Figure 2 in that the second probe is placed at the blood flow measurement site (9) of the tomographic image (16) of the blood vessel (2) obtained with the first probe (3). Child(
4) shows the side lobe (10) when the Doppler beam (7) is transmitted and received by the second probe (4).
The side lobe (10) transmitted and received from the blood vessel (2) whose blood flow is to be measured is transmitted and received in a direction different from the tomographic cross section (20) in the X7 plane as shown in Fig. 3B. There is no crossover, there is no Doppler reflected wave from the blood vessel (2), and there is no adverse effect on blood flow measurement.

It is clear that various changes can be made without departing from the spirit of the invention.

〔Effect of the invention〕

According to the ultrasound probe of the present invention, the side lobes, grating lobes, etc. generated from the Doppler beam are removed from the blood vessel in which the blood flow is to be measured, so that the ultrasound probe does not receive false Doppler reflection signals and is accurate. This allows for accurate blood flow measurement.

[Brief explanation of drawings]

Figure 1 is a side and front view of the ultrasonic probe of the present invention, Figure 2 is a side view and front view of the ultrasonic probe of the present invention.
The figure is an explanatory diagram of Doppler sampling point setting, Figure 3 is an explanatory diagram of the relationship between the side lobe of the ultrasound beam and the blood vessel,
Figure 4 is an explanatory diagram of the conventional Doppler method for measuring blood flow, Figure 5
``Figure is a configuration diagram of a conventional separate type probe, Figure 6 is a configuration diagram of a conventional single probe, and Figure 7 is an explanatory diagram of side lobes. (2) is a blood vessel, (3) is the first probe, (4) is the second probe, (5) (5a) (5b) is the ultrasonic probe,
(8) are the first and second probes, and (10) are the side lobes. Agent Matsukuma Hidemori Water Gold 4 UI Hachi Tenshi Momemun and front view 1st drawing blood / l / 12'' wishing position H braten de song r in F setting θ theory BfjEZJ 2nd
figure

Claims (1)

[Scope of Claims] In an ultrasonic probe having a first probe for detecting a cross section of a subject, and a second probe for transmitting and receiving a Doppler beam, etc., the above-mentioned An ultrasonic probe characterized in that the irradiation beam from the second probe intersects only at one point on the scanning surface of the scanned image scanned by the first probe.