JPH04146736A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To obtain an image having the superior image quality of the deep part of a living body by setting the receiving/transmission aperture for ultrasonic wave large without setting the luster pitch rough, by setting the apparent element pitch of a piezoelectric vibrator element large, and spreading the receiving/ transmission aperture for ultrasonic waves. CONSTITUTION:A number of piezoelectric vibrator elements 10 are arranged in a prescribed element pitch (alpha) in straight line form or curved form. In the ordinary case, ultrasonic waves are sent and received in delaying for each piezoelectric vibrator element 10. When the receiving/transmission aperture is set to two times (or n-times. In this case, (n) is an integer) of that in the ordinary case, ultrasonic waves are received and transmitted by every other (or by every n-th piece) piezoelectric vibrator elements. Since the element pitch (alpha) of the piezoelectric element 10 is set to two times (or n-times) of that of piezoelectric element, also the receiving/transmission aperture for the supersonic wave is increased to two times (or n-times). Further, since the actual element pitch (alpha) of the piezoelectric element 10 is fine, the luster pitch can be made fine, and since the scanning line density does not vary, the deterioration of the image quality can be prevented.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is an ultrasonic diagnostic method that transmits and receives ultrasound waves to and from a living body using a piezoelectric vibrator to obtain tomographic images and blood flow information of the living body. The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus in which the ultrasonic transmitting and receiving aperture of the piezoelectric vibrator is improved.

(Prior Art) Generally, in an ultrasound diagnostic device, a piezoelectric vibrator that performs electrical/acoustic conversion emits ultrasound pulses to a living body, and ultrasonic pulses are emitted from the bloodstream, tissues of internal organs, and tissue boundaries. It receives sound wave reflection signals to non-invasively obtain blood flow velocity information or displays internal tomographic images to perform medical diagnosis regarding the shape and size of various organs and the state of tissues.

Conventionally, in a B-mode image obtained by such an ultrasonic diagnostic apparatus, as shown in FIG. The finer the raster pitch β, the better the image quality.

That is, in the case of high-density scanning, the raster pitch β was set to half the element pitch α (see Figure 3C), and in the case of low-density scanning, it was set equal to the element pitch α (see Figure 3). .

(Problems to be Solved by the Invention) However, in the conventional ultrasonic diagnostic apparatus described above,
Since the raster pitch β is determined by the element pitch α, in order to improve the image quality, the element pitch α can be made finer to increase the scanning line density, which increases the number of channels of the device, especially when taking images of deep parts of the living body. Since the number of channels is limited to 48 channels, 96 channels, 128 channels, etc., all channels are used up, and therefore the diameter of ultrasonic transmission and reception (-element pitch x number of channels)
You won't be able to get enough of it. For this reason, sufficient focus is not applied, resolution decreases, and graininess decreases.
There was a problem that the image had a large horizontal flow.

Therefore, if the element pitch α is widened in order to increase the aperture, there is a problem in that the raster pitch β becomes coarser and the image quality deteriorates.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an ultrasonic diagnostic apparatus that has a large aperture without making the raster pitch coarse, and can obtain high-quality images of deep parts of a living body.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above-mentioned object, the present invention provides an ultrasonic diagnostic apparatus in which a large number of piezoelectric vibrators for transmitting and receiving ultrasonic waves are arranged. By selectively driving the vibrator, the apparent element pitch of the piezoelectric vibrator is increased, and the ultrasonic transmission/reception aperture is widened.

Alternatively, by collectively driving a predetermined number of the piezoelectric vibrators in block units, the apparent element pitch of the piezoelectric vibrators is increased, and the ultrasonic transmission/reception aperture is widened.

(Function) In the present invention, by driving a large number of piezoelectric vibrators selectively or collectively in a predetermined number in block units,
By increasing the apparent element pitch and widening the ultrasonic transmitting and receiving aperture, a sufficient transmitting and receiving aperture can be obtained even when taking images of deep parts of the living body. Furthermore, at this time,
Since the actual element pitch is fine, the raster pitch becomes fine and the scanning line density is maintained.

(Embodiment) An embodiment of the ultrasonic diagnostic apparatus of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a diagram showing an example of an ultrasonic transmission/reception pattern. According to the drawings, a large number of piezoelectric vibrators 10 are arranged in a linear or curved manner with a predetermined element pitch α. Normally, ultrasonic waves are transmitted and received with a delay applied to each piezoelectric vibrator 10 (see FIG. 1C). Make the transmitting and receiving aperture twice the normal size (or n times).

However, if you want to take n as a natural number, use piezoelectric vibrator 10
Ultrasonic waves are transmitted and received every other (or every nth) piece (see Figure 1). In this way, by doubling the apparent element pitch α of the piezoelectric vibrator 10 (or n times), the ultrasonic transmission/reception aperture also becomes twice (or n times) larger. Further, at this time, since the actual element pitch α of the piezoelectric vibrator 10 is small, the raster pitch (not shown) is made fine, so that the scanning line density does not change, so that deterioration of image quality can be prevented. Alternatively, the apparent element pitch α of the piezoelectric vibrators 10 can be increased by driving two (or n) of the above-mentioned large number of piezoelectric vibrators 10 in block units, thereby increasing the ultrasonic transmission and reception aperture. You can also do that. Note that since the actual element pitch α at this time is small, the raster pitch can be made fine and deterioration of image quality can be prevented (see FIG. 1C). Note that 3 is an electrode.

Thus, as shown in FIG. 2, conventionally, the size of the aperture was limited as the depth of the living body increased (see diagram B), or according to this embodiment, the size of the aperture was limited as the depth of the living body increased. As the diameter increases, the apparent element pitch α can be increased to widen the aperture (see diagram A).

[Effects of the Invention] As explained above, according to the present invention, by selectively driving a large number of piezoelectric vibrators arranged in a linear or curved shape, or by driving a predetermined number of piezoelectric vibrators in block units,
By increasing the apparent element pitch and widening the ultrasonic transmitting and receiving aperture, a sufficient aperture can be obtained even when taking images of deep parts of the living body.Furthermore, since the actual element pitch is fine, the raster pitch can be obtained finely, thereby improving the scanning line density. Therefore, focusing can be improved, resolution can be improved, and granularity can be improved, so high-quality images can be obtained and diagnostic accuracy can be improved. In addition, the above-mentioned problems can be solved by the effect that the number of channels can be reduced.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the device of the present invention. Figure 1 shows an example of an ultrasound transmission/reception pattern, and Figure 2 shows the depth of a living body and the spread of the ultrasound transmission/reception aperture. FIG. 3 is a diagram showing the relationship between element pitch and raster pitch in a conventional example. 1.10...Piezoelectric vibrator, 2...Scanning line, α...Erennotovich, β...Raster pitch.

Claims (2)

[Claims] (1) In an ultrasonic diagnostic device in which a large number of piezoelectric vibrators that transmit and receive ultrasound waves are arranged, by selectively driving the large number of piezoelectric vibrators,
An ultrasonic diagnostic device characterized in that the apparent element pitch of the piezoelectric vibrator is increased to widen the ultrasonic transmission/reception aperture. (2) In an ultrasonic diagnostic device in which a large number of piezoelectric vibrators that transmit and receive ultrasonic waves are arranged, by driving a predetermined number of the piezoelectric vibrators in block units, the apparent An ultrasonic diagnostic device characterized by increasing the element pitch and widening the ultrasonic transmitting and receiving aperture.