JPH02164353A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To make detailed diagnosis on vital parts from viewpoint of cardiac movement by the use of a certain quantity of image memory by not taking in images to be collected at an even pitch but at uneven pitch, and reproducing at this pitch. CONSTITUTION:The vital position on a cardiograph is from R-wave till several hundreds msecs, and the movement in this range shall preferably be withfaster frame pitch. However there is no such a quick movement thereafter, and longer to a certain degree does not constitute obstruction for ovserving it. It shall therefore be T=T1+T2, and from R-wave till T2 division it shall be a high speed frame with DELTAt1, while in the residual period T2=T-T1, image shall be stored at a frame pitch of DELTAt2(DELTAt1>DELTAt2). Accordingly DELTAt2 can be determined by DELTAt2=(T-T1)/(N-T1/DELTAt1), where N is image memory and DELTAt1 is high speed frame pitch. DELTAt2 is determined by DELTAt2=mxtau, where m is number of rasters and tau is rate period), and the method adopted shall be such as to vary m or tau.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic diagnostic apparatus that uses ultrasound to obtain B-mode images and two-dimensional blood flow velocity images, and in particular relates to an ultrasonic diagnostic apparatus that uses ultrasound to obtain B-mode images and two-dimensional blood flow velocity images. The present invention relates to an ultrasonic diagnostic device that can be suitable for diagnosis.

(Prior Art) A B-mode image is formed in the ultrasonic diagnostic method as follows. In other words, in the case of linear electronic scanning using an array-type ultrasonic probe consisting of multiple ultrasonic transducers arranged in parallel, a plurality of ultrasonic transducers is considered to be one unit, and for this one unit of ultrasonic transducers, This is a method of transmitting an ultrasonic beam by excitation. For example, by sequentially shifting the pitch by one oscillator and changing the position of one unit of element one after another, the ultrasonic beam is transmitted. This is scanning in which the position of the beam transmission point is electronically shifted.

And so that the ultrasound beam is focused as a beam,
The excitation timing of the excited ultrasonic transducers is shifted between those located in the center of the beam and those located on the sides, and the resulting phase difference between the sound waves generated by each ultrasonic transducer is utilized. The reflected ultrasound waves are focused (electronic focus).

Then, the reflected ultrasonic waves are received by the same vibrator that was excited and converted into electrical signals, and the echo information from each transmitted and received wave is formed, for example, as a tomographic image, and the image is displayed on a cathode ray tube or the like.

In addition, in the case of sector electronic scanning, each transducer is excited so that the transmission direction of the ultrasonic beam changes sequentially in a fan shape for each pulse of the ultrasonic beam for one unit of excited ultrasonic transducers. The timing is changed according to a desired direction, and the subsequent processing is basically the same as the linear electronic scanning described above.

In addition to the above-mentioned linear and sector electronic scanning, transducer (
There is also mechanical scanning in which ultrasonic scanning is performed by attaching a probe (probe) to a scanning mechanism and moving the scanning mechanism.

On the other hand, a typical imaging method is B-mode imaging, which combines signals accompanying ultrasound transmission and reception to form a tomographic image.

Further, the ultrasonic Doppler method, of which blood flow imaging is a typical example, is a method of obtaining functional information accompanying the movement of a moving object within a living body and visualizing it, and this will be described in detail below. That is, the ultrasonic Doppler method utilizes the ultrasonic Doppler effect in which when an ultrasonic wave is reflected by a moving object, the frequency of the reflected wave shifts in proportion to the moving speed of the moving object.

Specifically, if an ultrasonic rate pulse or continuous wave is transmitted into a living body and the frequency shift due to the Doppler effect is obtained from the phase change of the reflected wave echo, the moving object at the depth position where the echo was obtained. You can obtain exercise information. This allows us to know the state of blood flow, such as the direction of the flow of blood, the state of the flow (disturbed or regular), the pattern of the flow, the absolute value of the velocity, etc., at a certain position in the living body.

Next, the device will be explained. That is, in order to obtain blood flow information from ultrasonic echoes, ultrasonic pulses are repeatedly transmitted a predetermined number of times in a certain predetermined direction, and phase information is extracted by phase-detecting the received echoes. This signal is digitized and passed through a digital filter to remove non-moving or slow-moving components. Then, the signal that has passed through the filter is subjected to frequency analysis.

As a result, the analyzed frequency is a Doppler shift frequency caused by the movement of a moving object, and can be displayed alone or superimposed on a B-mode image or M-mode image as blood flow information such as a two-dimensional blood flow velocity image. .

There is an apparatus that can display the above B or M mode image and the two-dimensional blood velocity image in the same manner, for example, in a superimposed manner. Such devices use probes that are composed of a linear or sector scanning array probe and a Doppler probe, either in combination or individually. At the designated angle site where a B-mode image is being formed, Doppler ultrasound is transmitted and received to form a Doppler image, such as a two-dimensional blood flow velocity image, which is displayed in a superimposed manner on a monitor.

On the other hand, using the above-mentioned apparatus, as shown in FIG.
Heart rate synchronized diagnosis using CG waveforms (e.g. R wave as reference)
There is an ECG ultrasound cardiac diagnostic method that performs this.

This involves attaching the electrocardiograph's lead electrode to the subject, obtaining an ECG wave from the electrocardiograph, and using, for example, the R wave of this ECG wave, as a trigger for the ultrasound scan of the first frame. and
Ultrasonic scanning is performed by sequentially setting an interval Δt (frame interval) until the R wave of the next heartbeat is triggered, and T/Δt images are collected and stored in the memory. Here, T is the heartbeat interval.

For image diagnosis or display, for example, images from the systole to the diastole may be continuously displayed from T/Δt images stored in the memory, or from the end of systole to diastole to the beginning of systole. The display can be cycled from mid-systole to end-systole (repeated display), or the display speed can be varied to display slow speed, high speed, or frame-by-frame display. Such a display method allows accurate understanding of the dynamic state of the heart, which is useful.

Here, the frame interval Δt will be considered.

In other words, Δt determines the trigger timing of ultrasonic scanning, and is usually a constant value, for example, 2.
5■See. If this is a normal person,
Since the heartbeat interval T is about 1 sec, the number of images suitable for continuous display is about 40.
0/40-25■See.

(Problems to be Solved by the Invention) As described above, in the conventional technology, the frame interval Δt is kept constant, but this poses a problem in the following points. That is, the heartbeat interval T is about 1 sec in a normal person, but 2 sec in a sick person.
There are some people, and some people are in the 4sec allowance.

Therefore, if Δt is always set to the same value, the heartbeat interval T will vary depending on the subject, so the heart rate during one heartbeat cycle from end systole → diastole → early systole → mid-systole The temporal image may not appear properly, or images for more than one cycle may be collected, or images for less than one cycle may be collected (Δt≠Δt' in Figure 2).
).

Therefore, in continuous display or repeated display, there is a problem that the dynamic state of the heart cannot be accurately known due to overlapping display or discontinuous display. In this case, by having a larger amount of memory than necessary,
Although it is possible to prevent the temporal image of a heartbeat from being less than one cycle, this would also result in collecting more images of more than one cycle than necessary, so it is not practical due to the device configuration. Not the point.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a practical ultrasonic diagnostic apparatus that can accurately determine the dynamic state of the heart and the like.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following means are taken to solve the above problems and achieve the objects.

That is, the present invention performs ultrasonic scanning to generate one frame image every Δt at heartbeat interval T, and
Collect and store Δt images and store the T/Δt
In an ultrasonic diagnostic apparatus that continuously displays two images, at least two intervals T1,
T2 (T-Tl+72), and the Δt is set to a different value for at least two sections T1 and T2, and a section of several hundred -5 ec is set from the R wave of the ECG waveform. In the interval, Δt is set to a smaller value than in other intervals.

(Function) According to this configuration, when collecting images, it is possible to capture images at irregular intervals instead of at regular intervals, and to reproduce them according to the intervals at the time of playback, if necessary. It has the effect of allowing detailed diagnosis of dynamically important parts.

(Embodiment) An embodiment of the ultrasonic diagnostic apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the apparatus of this embodiment, and FIG. 2 is a diagram showing the trigger timing of ultrasonic scanning in the same embodiment.

In FIG. 1, an ultrasonic probe 1 including a large number of minute transducers arranged in parallel has a transmitting/receiving unit that is applied to a subject (not shown) and is capable of performing B-mode scanning, M-mode scanning, Doppler scanning, etc. 2.

The two-dimensional images obtained by the various scanning modes obtained by the transmitting/receiving section 2 are transmitted through an image storage section 3 or directly (in real time) through a switching device 4 to a DSC (digital scan converter) 5 from ultrasonic scanning to a TV. The image is converted into a scan and applied to the monitor 6, where the image is displayed. Here, the transmitting/receiving section 2, the image storage section 3, and the D
The SC5 is controlled by the control unit 7,
Further, the switching operation of the switching device 4 is performed manually by an operator or automatically by a control unit 7. This control section 7 includes a Δt setting means 7a that sets the timing Δt of image acquisition and reproduction, and an interval setting means 7 that sets the intervals T1 and T2.
b, and Δt and T1, as desired by the operator.
It is now possible to set T2.

On the other hand, an inductive electrode 8a of an electrocardiograph 8 is attached to a subject (not shown), and a signal from the inductive electrode 8a is amplified by an isolating type amplifier 8b, and then sent to a heartbeat analysis section 8C as shown in FIG. 2, for example. ECG waves such as those shown in can be obtained. The ECG wave obtained by this electrocardiograph 8 is given to the control section 7, and here, the control section 7 creates a trigger timing for ultrasonic scanning based on the ECG wave and supplies it to the transmitter/receiver section 2. The sound wave scanning bird uses a timing signal to give a control signal to the image storage section 3 and the DSC 5.

Here, the settings of the ultrasonic scanning trigger timings Δt1, Δt2 and the intervals 'r1, T2 in the control unit 7 will be explained. That is, the first ultrasonic scanning signal is emitted at a time Δtl after the peak of the R wave of the ECG waveform as a reference, and the frame interval Δ is within the interval T1.
A trigger is given every tl, and during interval 12, Δt2
It is assumed that a trigger is given each time.

In general, the important positions in an electrocardiogram are from the R wave to several hundred layers, and the dynamics therebetween are fast, so it is better to have a frame interval as fast as possible. However, after that, the dynamics are not so fast, and even if it takes a little longer, it is still not a problem for observation. Therefore, for example, if T-Tl +72, from R wave to T
The second section is a high-speed frame of Δtl, and the remaining section T2
-T-TI stores images at frame intervals of Δt2 (Δtl>Δt2).

Therefore, if the N1 high-speed frame interval of the image memory is Δ11, Δt2 fine (T-TI) / (N-TI /Δtl)
Δt2 can be determined by

Δt2 is determined by Δt2−mXτ (where m−
A method is adopted in which the number of rasters, τ (heat sorting period), m, or τ is varied.

For example, as shown in FIG. 2, the inter-beat interval T is divided into a front interval TI and a rear interval T2, and the interval T is -400 m5ec.

T2-600■see, the trigger timing interval Δt1 in the previous section TI is set to a smaller value than the normal (25 m5ee), for example, 20 m5ec, and the trigger timing interval Δt2 in the subsequent section T2 is set to a larger value than the normal (255 sec). For example, let it be 50 ■see. However, the storage unit iN of the image storage unit 3 is N-32 in terms of the number of images.
shall be.

Therefore, during the previous section TI (400 msec), Δt
Images were collected every 20 m5ec, and 40
0/20-20 images were obtained, and the post-section T2 (6005s
ec), images are collected every Δt 2 (50 m5 ec), and 12 images are obtained at 600,150.

Therefore, a certain amount of image memory is sufficient, continuity during image reproduction is maintained, and important parts in terms of cardiac dynamics can be memorized in detail.

Furthermore, after image collection, the temporal image group held in the image storage unit 31 can be displayed continuously or repeatedly on the monitor 6 via the switch 4. Continuous display does not occur, and the dynamic state of the heart can be accurately determined. Of course, by operating the switch 4, the time phase group images collected by the transmitter/receiver 2 can be directly displayed on the monitor 6.
It is possible to perform continuous display or repeated display.

Furthermore, images in which the cardiac time phase appears accurately during each period of one heartbeat cycle can be collected at equal intervals without requiring a memory with an unnecessarily large capacity or amount, so it is possible to It is practical.

In addition, in the above, frame interval Δt−number of rusks m×
Since the rate period is τ, the number of rasters is m depending on the diagnosis mode.
and the rate period τ can be changed. In this case, by increasing the number m of ultrasonic rasters (reducing the rate period τ), it becomes possible to collect temporal images with a large imaging range and a shallow depth of field.

On the other hand, when the number m of ultrasound rasters is decreased (the rate period τ is increased), a temporal image with a narrow imaging range and a deep field of view can be collected.

By continuously or repeatedly displaying these time phase images, it becomes possible to accurately know the dynamic state of the heart depending on the diagnosis mode.

The present invention is not limited to the above embodiments, but can be implemented with various modifications without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a practical ultrasonic diagnostic apparatus that can accurately determine the dynamic state of the heart and the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the ultrasonic diagnostic apparatus according to the present invention, FIG. 2 is a trigger timing diagram of ultrasonic scanning in the same embodiment, and FIG. 3 is a diagram of the ultrasonic scanning in the conventional example. FIG. 3 is a trigger timing diagram. 1... Ultrasonic probe, 2... Transmission/reception section, 3...
Image storage unit, 4...Switcher, 5...DSC, 6...
・Monitor, 7...control unit, 7a...Δt setting means,
7b... section setting means, 8... electrocardiograph. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) Ultrasonic scanning to generate one frame image,
It is performed every Δt during the heartbeat interval T based on the ECG waveform, and T/Δt images are collected and stored.
In an ultrasonic diagnostic apparatus configured to continuously display /Δt images, at least two intervals T1 and T2 (T=T
1+T2) and setting the Δt to different values for the at least two sections T1 and T2. (2) The ultrasonic diagnostic apparatus according to claim 1, wherein the Δt is set to a smaller value in an interval of several hundred msec from the R wave of the ECG waveform than in other intervals.