JPH03178644A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To execute the image display of variable magnification of a wide range by using one piece of linear array probe by providing an echo filter filtering an input signal with a frequency characteristic corresponding to the depth of an area of a body to be examined being different by the kind of display magnification with the control of a controller. CONSTITUTION:The transmission timing pulse of a repeated frequency corresponding to the depth of a sound field with set display magnification generated by a transmission timing pulse generator 13 is converted to a signal for forming a sound field adapted to display magnification in a transmission beam former 14, and the signal is irradiated from an ultrasonic probe. An echo signal is phased and added so as to conform to the display magnification in a receiving beam former 16, and filtered by an echo filter 18 adjusted to a frequency band corresponding to the depth of the sound field.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an ultrasonic diagnostic device, and in particular changes the sound field scanning form according to a change in display magnification, and the same applies to scanning with different display magnifications. This invention relates to an ultrasonic diagnostic device that can display images.

(Prior Art) An ultrasonic diagnostic apparatus is a device that irradiates a subject with ultrasonic waves and forms a tomographic image using reflected waves from a reflector within the subject for diagnosis. The scanning methods of this ultrasonic diagnostic equipment include mechanical scanning, manual scanning, and electronic scanning, but electronic scanning is superior in terms of freedom of scanning, small size and light weight, and many other aspects, and recently electronic scanning has been mainly used. It is now possible to This electronic scanning type ultrasound diagnostic device uses a switched array type ultrasound probe, and the width of the sound ray,
Depth of focus, direction of sound rays, etc. are electronically controlled. FIG. 6 shows the shape of sound rays and the display screen when the display magnification is changed in such a switched array type ultrasonic diagnostic apparatus. The figure shows, as an example, display magnifications of 0.7 times, 1 times, and 1.4 times the FOV (visible area). A display magnification of 0.7 means that the horizontal length of the display screen is 0.7 compared to the depth of the sound ray. This means that it is 7 times more. Figure 6 (a) is a diagram showing the depth of focus at which the display magnification is 0.7x, 1x, and 1.4x for the same display screen, and (b) is a diagram that shows the depth of focus when the display magnification is 0.7x, 1x, and 1.4x, respectively, for the same display screen. This is a diagram showing the display screen for each depth of focus, where the smaller the magnification, the shorter the horizontal length compared to the vertical length. In the figure, reference numeral 1 denotes a switched linear array type ultrasonic probe for irradiating ultrasonic signals. A, B, and C are the shapes of sound rays when the display magnification is 0.7 times, 1 times, and 1.4 times, respectively. 2 is a display screen that displays echoes from ultrasonic signals scanning each sound field shown in the figure (A), and shows the case where an image with a display magnification of 1.4 is displayed on the screen of display screen 2 - cup. . In the figure, the range indicated by the broken line is the magnification 0. The image range A' in the case of 7, - the range indicated by the dashed line is the image range B' in the case of the magnification of 1, and the image range C' with the magnification of 1.4 is the range of the display screen 2 - the range of the solid line of the cup. It is.

In an ultrasonic device that performs switched array linear scanning in this way, when trying to display a deep depth by changing the display (Δ ratio), when the display magnification is small, the display on the display screen 2 may have a narrow width. The reason why it becomes □ is because the shape of the sound ray becomes a vertically long strip, as is clear from the figure.

(Problems to be Solved by the Invention) The rectangular shape is unavoidable because the scanning width on the sound field side is constant, but it may be very difficult to use. Therefore, it is often preferable to use a convex probe to perform switched array sector scanning to scan a large screen at the back. In addition, in a scanning method in which irradiation is performed from an element at one end of the ultrasonic probe (referred to as the left end), and scanning is performed by sequentially moving from the center to the other end (referred to as the right end), the irradiation is performed from the left end element. When scanning, the sound ray is moved to the left, when it is the center element, the sound ray is directed to the front, and when the rightmost element is set, the sound ray is moved to the right, and so on. In some cases, a sliding aperture face array method is used that simultaneously shifts the azimuth angle of the sound ray.

However, when trying to cover multiple uses with only one probe, the sound field scanning range is narrow (in the case of magnification 1.4 in Figure 6).
The roughness of the sound rays becomes noticeable, making it difficult to obtain a good image.

The present invention has been made in view of the above points, and its purpose is to use one linear array probe to achieve a display magnification of 0.
5x, 0.7x, 1x, 1.4x.

The object of the present invention is to realize an ultrasonic diagnostic apparatus that displays images with variable magnification over a wide range, such as 2x.

(Means for Solving the Problems) The present invention that solves the above problems includes built-in software that selects the scanning method of the sound field by the ultrasonic probe according to the type of display magnification and controls the necessary circuits. controller and
Under the control of the controller, a transmission timing pulse generation circuit generates a transmission timing pulse with a pulse repetition frequency corresponding to λ1 to the depth of the sound field which varies depending on the display magnification; A transmission beamformer that changes into a multi-bit signal having information such as the ignition timing of each element of the ultrasonic probe or the delay amount of the signal input to each element according to the type of the ultrasonic probe, and the control of the controller. , a receiving beamformer that performs phasing and summation of received signals in accordance with the forming format of the transmitting beamformer, and a receiving beamformer that performs phasing and summation of received signals in accordance with the forming format of the transmitting beamformer, and input with frequency characteristics corresponding to the depth of the object area that varies depending on the type of display magnification, under the control of the controller. The device is characterized in that it includes an echo filter that filters the signal.

(Function) The transmission timing pulse, which is generated by the transmission timing pulse generator and has a repetition frequency that corresponds to the depth of the sound field based on the set display magnification, is a signal that forms a sound field that adapts to the display magnification in the transmission beamformer. is converted into and irradiated by an ultrasound probe. The echo signals are phased and summed in a receiving beamformer to match the display magnification, and filtered by an echo filter adjusted to a frequency band corresponding to the depth of the sound field.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. In the figure, the internal structure of the ultrasound probe 1 is schematically shown. A high voltage multiplexer 11 is provided inside the ultrasound probe 1 and sequentially distributes 32 channels of high voltage transmission signals to the 256 channels of element array 12. 13 is a transmission timing pulse generation circuit that generates a timing pulse for transmitting ultrasonic pulses, 1
4 converts the input pulse into a 32-bit signal,
This is a transmitting beamformer for forming sound rays by controlling the ignition timing of each element of the ultrasonic probe 1. 15 is a transmission amplifier that amplifies the power of the output signal of the transmission beamformer 13, a TR switch that prevents the transmission signal from being sent to the reception circuit and prevents the reception signal from going to the transmission circuit, and a amplifier that amplifies the reception signal. This is a TR circuit group consisting of a preamplifier and the like.

Reference numeral 16 denotes a receiving beamformer that performs phase-setting addition of the received signals of the 15 outputs on the TR circuit and converts them into a time-series serial signal.The output thereof is amplified by an amplifier 17 and inputted to one logarithmic compression circuit. A detector 20 detects the output of the logarithmic compression circuit 19 and sends a video signal to a subsequent circuit.

21 has control software built therein, and the transmission timing pulse generation circuit 13.21 operates according to instructions from the control software. Transmission beamformer 14. This is a controller that manually inputs control signals for controlling the operations of the reception beam former 6 and the echo filter 18 to each of the circuits. The controller 21 freely controls which of the elements of the element array 12 is adopted for the transmitting beamformer 14 and the receiving beamformer 16, and how much delay is applied to the adopted element to make it contribute. be able to. Here, it is assumed that the quantization error of the set delay amount is sufficiently small.

Next, the operation of the embodiment configured as described above will be explained. When using the ultrasonic diagnostic apparatus, an operator first sets various operating conditions, including display magnification settings, on the controller 21 via a manual device (not shown). After setting, the operator gives a scan start command using the input device. The transmission timing pulse generation circuit 13 generates a transmission pulse and sends the transmission pulse to the transmission beam former 14 . The pulses generated by this transmission timing pulse generation circuit 13 are as follows:
Under the control of the controller 21, the pulse repetition frequency is changed depending on the depth of the sound field. The transmit beam former 14 is controlled by the controller 21 as follows. In other words, when the display magnification is 1 times the FOV, there is no difference from normal scanning, so for example, scanning is performed in the usual switching method to use all 256 elements of the 256-element linear array, and the transmission beamformer 14 performs only electronic focusing within the aperture adopted each time switching is performed. Display magnification is 0.7x, 0.5
When the magnification and magnification are reduced, that is, when scanning a wider space to be inspected, the traveling direction (azimuth angle) of the beam of the sound ray in the sound field is adjusted in step with the above switch operation as shown in Figure 2. In order to achieve an offset sector scan, a delay distribution is applied so that the beam is irradiated obliquely within the aperture adopted each time the switch is switched.

In other words, there is no delay distribution at the center front, and only electronic focusing is performed, but the element array 12
In addition to electronic focusing, a first-order delay distribution is superimposed so that the beam enters and exits outward as it approaches both ends. On the other hand, when the display magnification increases, such as 1°4x or 2x, the elements within the aperture are weighted or due to electronic focusing so that the sound rays move at a finer pitch than the movement of the adopted aperture by switch operation. Performs vernier control of the delay distribution, etc., and performs linear scanning while controlling the actual position of the sound ray.

This can be summarized as shown in Figure 3.

The signal processed by the transmission beamformer 14 as described above undergoes processing such as power amplification in the TR circuit 15, and then is sent to the high voltage multiplexer 1 as a 32-bit signal.
1 is man-powered. The high-voltage multiplexer 11 sequentially distributes the 32-bit signal to the elements of 256 channels according to the difference in display magnification, and then excites the element array 12 to emit ultrasonic waves.

The transmitted ultrasonic wave returns as an echo from the reflector,
The signal is converted into an electric signal by the element array 12, converted into a 32-bit signal by the high-voltage multiplexer 11, and sent to the receiving beamformer 16 via the TR circuit 15. The receiving beamformer 16 is controlled by the controller 21 in the same way as the transmitting beamformer 14, and outputs the resultant input signals as pulses representing the echo state. The output signal is amplified by an amplifier 17 and filtered by an echo filter 18. The echo filter 18 is similarly controlled by the controller 21, and its filtering frequency band is changed according to the echo return time to output an optimal signal. The output signal is logarithmically compressed in one logarithmic compression circuit, detected by a wave detector 20, sent to a subsequent circuit, and displayed on a display circuit (not shown).

On this display screen, echoes of the entire sound field are displayed on the screen, regardless of the display magnification. This display screen 2 is shown in FIG. In the figure, when the display magnification is 2x, 1.4x, or 1x, it is displayed on the screen as shown by the solid line, and when the display magnification is 0.7x and 0.5x, it is displayed on the screen as shown by the broken line. Short screen - displayed on the cup.

As explained above, according to this embodiment, the controller 21
By programming, it becomes possible to display transmission waves of different display magnifications under the same conditions on the screen using one linear array probe.

Note that the present invention is not limited to the above embodiments. In the example, a method of scanning with a beamformer using an electronic control method was described, but it is also possible to mechanically move one transducer horizontally.
Of course, < can also be used in systems that employ a moving pantograph mechanism such as convex scan or sector scan. This method can be realized if there is a function to move the vibrator while rotating it within the liquid chamber. Scanning using this method is shown in FIG. In the figure, (
b) The figure is a scan with a display magnification of 1.4 times, and the transducer 22
Figure (B) shows the transducer 22 being moved across the entire width of the ultrasound probe 1 when the display magnification is 1x; ) Figure is a diagram when the display magnification is 0.7 times, where the transducer 22 is swung like a convex scan, and (D) is a diagram at the same magnification.
It is a diagram in which the vibrator 22 is swung like a sector scan.

By controlling the vibrator driving means (not shown) for moving the vibrator 22 in this manner by the controller 21, the same effects as in the embodiment described above can be brought about.

In addition, a method of swinging the vibrator 22 in such a manner as to move a quadrilateral drawn between two points within the super wave probe may also be considered.

(Effects of the Invention) As described above in detail, according to the present invention, the display magnification is 0.5 times using one ultrasonic probe.

It becomes possible to display images with a wide range of variable magnification such as 0.7x, 1x, 1.4x, and 2x on the screen, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram of a sound field formed by this embodiment, FIG. 3 is a diagram showing the scanning format at each display magnification, and FIG. FIG. 5 is a diagram of an image display according to this embodiment, FIG. 5 is a diagram of scanning according to another embodiment of the present invention, and FIG. 6 is a diagram of the shape of a sound field and an image on a display screen by a conventional ultrasonic device. 1... Ultrasonic probe 11... High voltage multiplexer 12... Element array 13... Transmission timing pulse generation circuit 14... Transmission beam former 15... TR circuit group 16... Receiving beamformer 18...Echo filter 19...Logarithmic compression circuit 20...Detector 21...
controller

Claims (2)

[Claims] (1) A controller (21) with built-in software that selects the scanning method of the sound field by the ultrasonic probe (1) according to the type of display magnification and controls the necessary circuits, and control of the controller (21). A transmission timing pulse generation circuit (13) generates a transmission timing pulse with a pulse repetition frequency that corresponds to the depth of the sound field that varies depending on the display magnification, and the controller (21) controls the input pulse signal to be displayed. a transmission beamformer (14) that converts into a multi-bit signal having information such as the ignition timing of each element of the ultrasonic probe (1) or the delay amount of the signal input to each element according to the type of magnification; , Under the control of the controller (21), a receiving beamformer (16) performs phasing and addition of received signals in accordance with the forming format of the transmitting beamformer (14).
), and an echo filter ( ) that filters the input signal with a frequency characteristic corresponding to the depth of the object region that varies depending on the type of display magnification under the control of the controller (21).
18) An ultrasonic diagnostic apparatus comprising: (2) a controller (21) with built-in software that controls the ultrasound probe (1) by selecting the scanning method of the sound field by the ultrasound probe (1) according to the type of display magnification; An ultrasonic diagnostic apparatus comprising: a transducer driving means for controlling the operation of the transducer (22) according to a display magnification under the control of the controller (21).