JPH01141649A - Ultrasonic doppler blood flow observation apparatus - Google Patents

Abstract

PURPOSE:To enhance the accuracy of diagnosis, by providing a detector capable of detecting the output corresponding to its own variations for a unit time to an ultrasonic probe and providing a means for informing an alarm only when the output of the detector exceeds a predetermined level. CONSTITUTION:An acceleration sensor 13 is mounted on an ultrasonic probe 1 and the output thereof is taken in a processor 14. A threshold value alphath is applied to sensor output S1 and, when the sensor output S1 exceeds the threshold value alphath, an H-level signal 4 (other than this, an L-level signal) is outputted as a signal S2 for a time T through time delay Td. The alarm sound generating part 16 receiving the signal S2 from a processor 14 operates a speaker 17 at the generation time of the signal S2, that is, in the display timing of Doppler data obtained by the sudden movement of the probe 1 to output alarm sound and calls an observer's attention to that erroneous data is displayed. Therefore, without subjecting erroneous blood flow data generated with the movement of the ultrasonic probe 1 to diagnosis, the accuracy of diagnosis can be enhanced.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention utilizes ultrasonic transmission/reception waves and the Doppler effect to obtain blood flow velocity information as functional information accompanying the movement of a moving object within a living body. The present invention relates to an ultrasonic Doppler blood flow observation device that obtains and visualizes images, and particularly relates to an ultrasonic Doppler blood flow observation device with an improved imaging method.

(Prior art) Ultrasonic diagnostic methods use anatomical information, typically represented by B-mode images, movement information of in-vivo organs, typically represented by M-mode images, and the Doppler effect, typically represented by blood flow imaging. Functional information associated with the movement of moving objects within a living body is used for diagnosis.

Further, typical methods for scanning inside a living body using ultrasound waves include electronic scanning and mechanical scanning. Here, the electronic scanning method will be explained.

In other words, in the case of linear electronic scanning using an array-type ultrasonic probe made up of a plurality of ultrasonic transducers arranged in parallel, one unit of the plurality of ultrasonic transducers is 17. This is a method of transmitting an ultrasonic beam by exciting an ultrasonic transducer, for example, by sequentially shifting the pitch by one transducer and excitation so that the position of one unit of element changes one after another. By scanning, the transmission point position of the ultrasonic beam is electronically shifted (7 steps).

And so that the ultrasound beam is focused as a beam,
The excitation timing of the excited ultrasonic transducers is shifted between those located at the center of the beam and those located on the sides2, and the resulting phase difference between the sound waves generated by each ultrasonic transducer is utilized. Then, the reflected ultrasound waves are focused.

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 in [7] 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, in the imaging method, in addition to a B-mode image in which signals accompanying ultrasound transmission and reception are combined to form a tomographic image, an M-mode image based on fixed scanning in the same direction is typical. This represents the temporal change in the ultrasonic wave transmitting/receiving site, and is particularly suitable for diagnosing moving organs such as the heart.

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 Motion information of moving objects can be obtained. According to this, the direction of blood flow and the state of the flow (disturbed or regular) at a certain position in the body,
Blood flow conditions such as flow patterns and velocity values can be known.

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, or clutter components.

Then, the signal that has passed through the filter is subjected to frequency analysis.

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

The above-mentioned ultrasonic transmission system, a B or M mode imaging processing system that obtains B or M mode image information and processes it in black and white, a blood flow imaging processing system that obtains blood flow velocity information and performs color processing, and these Some apparatuses include a display system that displays images alone or in a superimposed manner.

In the following explanation, a device that has at least the function of obtaining blood flow velocity information and displaying an image will be referred to as the ultrasound Doppler blood flow visualization #1 device, and of course, it will also include the above-mentioned B or M mode image information. Get blood flow speed information and both! li5! Devices that can be displayed on the screen are also included in the classification of ultrasonic Doppler blood flow observation devices, and the description will be made assuming that they do not require black-and-white or color processing.

Here, we will consider actual diagnosis. That is, the ultrasound probe is generally held and operated by the operator, and the ultrasound probe itself may be moved suddenly due to the need to change the diagnosis site. in this case,
Ultrasonic Doppler blood flow observation equipment obtains information due to the movement of objects existing in the wave transmission and reception directions of the ultrasound probe, but it is also subject to Doppler deviation due to the movement of the ultrasound probe itself. Therefore, information from this probe movement may be superimposed on Doppler information from blood cells, resulting in a Doppler pattern that is a hindrance to diagnosis. For example, a two-dimensional color ultrasound Doppler blood flow observation device displays a color image that can be mistaken for blood flow, which is clinically undesirable.

(Problems to be Solved by the Invention) As described above, in the conventional technology, this type of ultrasonic Doppler blood flow observation device uses the Doppler effect to measure the behavior of blood cells in the direction of ultrasonic wave transmission and reception. Since it is used for observation at the ultrasonic wave transmitting/receiving end, that is, the behavior of the ultrasonic probe, it was natural to consider the behavior of the ultrasonic probe, but compared to the technical focus on improving detection accuracy and image quality. The reality is that no consideration has been given to this, and improvements have been desired.

Therefore, an object of the present invention is to provide an ultrasonic Doppler blood flow system that makes it possible to improve the accuracy of diagnosis as a result, without using erroneous blood flow information that occurs due to the movement of an ultrasound probe for diagnosis. The purpose of this invention is to provide a current observation device.

[Structure of the Invention] (Means for Solving the Problems) The present invention is characterized by taking the following measures in order to solve the above problems and achieve the object. That is, the present invention transmits and receives ultrasonic waves from an ultrasound probe to a subject, and detects the Doppler-shifted signal from the received signal through a filter to obtain blood flow velocity information. In the ultrasonic Doppler blood flow observation device which obtains the obtained results and displays the images as images on a display system, the ultrasonic probe is provided with a detector capable of detecting an output corresponding to the amount of fluctuation in the ultrasonic probe itself in a unit time. The present invention is characterized in that it is further provided with means for issuing a warning sound or warning display when the output of the detector exceeds a predetermined level.

(Function) According to such a configuration, the predetermined level is set so as to be able to detect fluctuations in the ultrasound probe that generate unnecessary Doppler signals to the extent that they interfere with blood flow image observation. Therefore, when the ultrasound probe moves beyond the above level, the observer should be informed that the blood velocity information displayed on the display system is incorrect information due to fluctuations in the ultrasound probe. Therefore, it is possible to improve the accuracy of diagnosis without using erroneous blood flow information generated due to movement of the ultrasound probe for diagnosis.

(Embodiment) An embodiment of the ultrasonic Doppler blood flow observation device according to the present invention will be described below with reference to the drawings. Figure 1 shows this example 2.
A block diagram showing the configuration of a dimensional color ultrasound Doppler blood flow observation device, Fig. 2 is a waveform diagram explaining the operation of the main parts of the same embodiment, and Figs. 3 (a), (b), and (c) are the same embodiment. This is an example of the display on the display section.

In FIG. 1, an ultrasound probe 1 is driven to transmit by a wave transmitting/receiving circuit 2, so that the ultrasound pulses transmitted from the ultrasound probe 1 to a living body undergo Doppler shift due to blood cells flowing inside the living body. The ultrasonic echo becomes an ultrasonic echo accompanied by fd, and is received by the ultrasonic probe 1 and the wave transmitting/receiving circuit 2. A phase detector 3 obtains a signal consisting of a Doppler shift signal due to blood cells and a clutter component from the received ultrasound echo.

Next, the signal is converted into a digital signal by the A/D converter 4, and the clutter component is removed by the filter 5.The Doppler shift signal from the blood cells is converted into a digital signal by the autocorrelation method, etc. in order to obtain a color Doppler image in real time. The frequency is analyzed by the analyzer 6, and the average value fd of the Doppler shift fd,
Dispersion value σ2 of Doppler shift fd. The average intensity of the Doppler shift fd, etc. can be obtained. Here, by performing the above-described series of processes while scanning the ultrasound beam from one side to the other in correspondence with the sector scan screen, information on two-dimensionally distributed blood flow can be detected.

The average value T of the Doppler shift fd, the variance value σ2 of the Doppler shift fd. Blood flow information such as the average intensity p of the Doppler transition fd is input to a DSC (Digital Nascan Tube Converter) 7. That is, the interpolation unit 7a generates blood flow information on a screen compatible with sector scanning, and performs processing to compensate for missing portions (pixels) by horizontal interpolation for displaying as a two-dimensional image. The data having the information of the two-dimensional image of the sector scan by this interpolation processing is transferred to the color conversion circuit 7.
b, where it is converted into information on the three primary colors R, G, and B. In this case, the blood flow information is a method of converting blood flow information such as the average value fd of the Doppler shift fd, the variance value σ2 of the Doppler shift fd, and the average intensity p of the Doppler shift fd into R, G, and B. It can be expressed in the form of rice plants.

On the other hand, the received echo data from the wave transmitting/receiving circuit 2 is input to the B-mode detection section 8, where the echo is envelope-detected.

The B-mode interpolator 7d of the DSC 6 performs interpolation processing while forming the information obtained here on a sector scan screen. Next, this processing output (this is referred to as Bout) is converted into information on the three primary colors of R, G, and H in the B-mode color conversion section 7d.

In this case, for example, an R-G-B-0,7XBout conversion is used. The output of the B-mode color converter 7d is added to the blood flow information from the color converter circuit 7b by an adding circuit 7e, and is output to the display unit 9, which is a color monitor, according to the TV scanning method. In this way, for example, a blood flow image within the heart is displayed together with a B-mode image of the heart (FIG. 3(a)).

The above is the operation for obtaining a B-mode (two-dimensional) color Doppler image. By performing color Doppler calculations while transmitting and receiving waves on the same scanning line M, the time of the color Doppler image on that scanning line is A change (M-mode color Doppler) image is obtained as shown in FIG. 3(b). That is, the output of the phase detection circuit 3 is sent to the range gate section 10.

The range gate section 10 separates a signal containing the Doppler shift signal at the observation point P on the scanning line M, and removes the clutter component using the Doppler filter 11 to obtain the Doppler shift signal at the observation point P. Fast Fourier transform unit 1
By performing frequency analysis in step 2 and inputting it to the Doppler spectrum interpolation unit 7f of the DSC 7, the time change of the Doppler spectrum corresponding to the blood flow velocity at the observation point P is obtained as shown in FIG. 3(b).

Furthermore, by transmitting and receiving continuous waves (CW) and not using the range gate section 10, Doppler shift signals at all positions on the ultrasound beam M can be obtained, as shown in Fig. 3(c).
) can be obtained.

Here, the most distinctive feature of this embodiment is that an acceleration sensor 13 is attached to the ultrasonic probe 1, and the output of this sensor 13 is taken in by the processor 14. FIG. 2(a) is a waveform diagram of the sensor output S1, and FIG. 2(b) shows the content of signal processing by the processor 14. A threshold value αth is attached to the sensor output S1, and the sensor output S1 is When the threshold αth is exceeded,
Time delay Td (for example, 0.1 seconds) occurs in relation to signal transmission from the wave transmitting/receiving circuit 2 to the interpolation circuit 7a.

) for a period of time T (the rest is an L level signal)
is output S2.

The signal S2 from the processor 14 is output to the character generator 15 and the warning sound generator 16.

Here, the occurrence of Doppler patterns unnecessary for diagnosis due to the movement of the ultrasound probe 1 occurs when the ultrasonic probe 1 is suddenly moved from a near-stationary state, so the above threshold value α
th is set empirically to detect the level of acceleration that corresponds to when the vehicle is suddenly moved from a state close to a stationary state as described above.

The character generator 15 that receives the signal S2 from the processor 14 outputs a character indicating a warning to the color converter 7b of the DSC 7 in accordance with the Doppler mode. As a result, as shown in Figure 3(a), B mode (2
In the color Doppler mode, for example, “D
A display such as "ATAERROR" appears, indicating that the color Doppler image for that frame is invalid.

In addition, in the case of M mode color Doppler shown in Fig. 3(b) and 1-point Doppler or CW Doppler shown in Fig. 3(C),
The position of the Doppler image and Doppler pattern obtained by the rapid movement of the probe 1 is indicated by a marker such as "Ma2", indicating that the Doppler information at that position is invalid.

Furthermore, the warning sound generating unit 16 that receives the signal S2 from the processor 14 outputs the loudspeaker 1. is activated, outputting a warning sound and alerting observers to the fact that false information is being displayed.

As described above, according to this embodiment, the ultrasonic probe detects rapid fluctuations of the ultrasonic probe 1 by replacing it with acceleration, and generates unnecessary Doppler signals to the extent that it interferes with the observation of blood flow images. By setting the level so that changes in the ultrasound probe 1 can be detected, it becomes possible to notify the observer that the information is incorrect by displaying a warning or sounding an alarm. As a result, it is possible to improve the accuracy of diagnosis without using erroneous blood flow information that occurs due to this for diagnosis.

In addition, the acceleration sensor 1
Since this is done in synchronization with the display timing of blood flow velocity information that is displayed when the output of step 3 exceeds a predetermined level, it is easy to identify when the incorrect information is being displayed. , This also makes it possible to improve the accuracy of diagnosis.

In the above embodiment, an example of a device that can display a blood flow image superimposed on a B-mode image, an M-mode image, etc. was explained, but of course, as an ultrasonic Doppler blood flow observation device, at least blood flow velocity information is The target is those that have the function of being able to obtain images and display images, and the presence or absence of black-and-white or color processing is not specified. Furthermore, instead of the acceleration sensor 13, another detector may be used. In this case, the detector is capable of detecting an output corresponding to its own variation in unit time, and detects when the ultrasonic probe 1 is suddenly moved from a near-stationary state. Use what you can. The invention can be modified in various ways without departing from the gist of the invention.

[Effects of the Invention] As described above, according to the present invention, an ultrasonic probe is provided with a detector capable of detecting an output corresponding to the amount of variation in itself in a unit time, and the output of the detector is set to a predetermined value. When the blood flow information displayed on the display system exceeds the predetermined level, the observer can be informed by a warning sound or warning display that the blood flow information displayed on the display system is post-information. The level is set so that it can detect fluctuations in the ultrasound probe that generate unnecessary Doppler signals to the extent that it interferes with the observation of blood flow images. When this is done, it becomes possible to notify the observer that the blood flow velocity information displayed on the display system is incorrect information due to fluctuations in the ultrasound probe.

Therefore, it is possible to provide an ultrasonic Doppler blood flow observation device that can improve the accuracy of diagnosis without using erroneous blood flow information generated due to the movement of the ultrasound probe for diagnosis. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the ultrasonic Doppler blood flow observation device according to the present invention, Fig. 2 is a waveform diagram explaining the operation of the main parts of the embodiment, and Fig. 3 is the same implementation It is a figure which shows the example of a display of the display part in an example. 1... Ultrasonic probe, 2... Wave transmitting/receiving circuit, 3...
Phase detection circuit, 4... A/D conversion unit, 5... Filter, 6... Frequency analyzer, 7... DSC, 8...
B-mode detector, 9... Display section, 10... Range gate section, 11... Doppler filter, 12... Fast Fourier transform section, 13... Acceleration sensor, 14... Processor, 15 ...Character generator, 16.
... Warning sound generating section, 17... Speaker. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) Ultrasonic waves are transmitted and received from the ultrasound probe to the subject, and the received signal obtained by this is subjected to a Doppler shift and detected through a filter to obtain blood flow velocity information. In an ultrasonic Doppler blood flow observation apparatus configured to display an image on a display system, the ultrasonic probe is provided with a detector capable of detecting an output corresponding to the amount of variation in the ultrasonic probe itself in a unit time, 1. An ultrasonic Doppler blood flow observation device, characterized in that it is provided with means for issuing a warning sound or warning display when the output of the detector exceeds a predetermined level. (2) A patent claim characterized in that a warning sound or a warning display, etc. is provided in synchronization with the display timing of blood flow velocity information displayed when the output of the detector exceeds a predetermined level. The ultrasonic Doppler blood flow observation device according to scope 1.