JPS59218144A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic diagnostic apparatus capable of displaying an ultrasonic tomographic image as well as a frequency distribution of ultrasonic echoes.

[Technical background of the invention]

A conventional ultrasonic diagnostic apparatus transmits an ultrasonic beam into a living body, detects its echo, converts it into an electrical signal, and obtains a tomographic image based on the zero echo intensity.

However, a living body is made up of various tissues, and each side of the living body has frequency-dependent attenuation characteristics. Therefore, the attenuation characteristics depending on the biological frequency differ. However, when considering the human body, if we specify a specific part, such as the abdomen, the distribution of organs is almost the same even if we look at each individual, although there are differences in the depth position.

Therefore, being able to see the echo frequency distribution at the position of the ultrasound tomogram along with the ultrasound tomogram is extremely useful in analyzing the image.

For example, if there is tissue that does not exist in a normal living body, such as cancerous tissue, in the ultrasound diagnosis site, the above frequency distribution will change in the vicinity of that location, so if the tissue is large enough to be easily overlooked in a tomographic image. However, it is possible to discover it from the frequency distribution. Furthermore, although the frequency of echoes varies depending on the depth, the frequency of the echoes depends on the composition, so it is possible to estimate the composition.

However, conventional devices do not actively utilize this relationship between living tissues and echo frequencies, and diagnose only based on the echo intensity distribution, so there are limits to their diagnostic ability. .

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and actively utilizes the frequency-dependent attenuation characteristics of living tissue to display images of the echo intensity distribution in the living body and the frequency-dependent attenuation characteristics in the living body. [Summary of the Invention] In other words, in order to achieve the above object, the present invention aims to provide an ultrasonic diagnostic apparatus that can dramatically improve diagnostic ability by scanning an ultrasonic beam. In an ultrasonic diagnostic apparatus that obtains an ultrasonic tomographic image by detecting an echo and displaying it as an image on a monitor device with a brightness corresponding to the level of the echo in correspondence with the ultrasonic beam position, the ultrasonic tomographic image is means for specifying a frequency analysis position in an image; means for displaying a marker at an ultrasound tomographic position on the monitor device corresponding to the specified position; and when an ultrasound beam scans a position corresponding to the specified position; a frequency analysis means for frequency-analyzing the detection output of the echo according to the depth at which the echo was obtained; and the monitor device as an image showing the frequency level distribution state by making the frequency analysis result correspond to the depth at which the echo was obtained. When a desired position in an ultrasonic tomographic image is specified, the detection output of the echo when the ultrasonic beam scans the specified position is frequency-analyzed, and an image of the frequency distribution state is obtained by the frequency analysis. The ultrasonic tomographic image and the frequency distribution state of echoes in the living body at a desired position in the tomographic image can be objectively observed by displaying it on a monitor device (display device).

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of application of the present invention to an ultrasonic diagnostic apparatus using a linear electronic scan method. I am Takukanko.

Further, 2 is a microcomputer that controls the entire device, 3 is its input port, and 4 is its output port. Reference numeral 5 is a transmission/reception control device which is controlled by the microcomputer 2 and controls the transmission and reception of ultrasound, the transmission/reception position, focus, etc.; A transmission delay line group that sets a delay time to the specified depth specified by the microcomputer 2. The delay line corresponds to the number of ultrasonic transducer elements for one set used for transmission and reception in the probe 1. There are as many as required.

That is, an ultrasonic device using a linear electronic scanning method, for example, uses a predetermined number of adjacent ultrasonic transducer elements as one set.
An excitation pulse is applied to each group of ultrasonic vibrating elements, and each of them is excited to generate ultrasonic waves. The ultrasonic wave transmitted from the ultrasonic transducer element has a phase difference, and the interference caused by this phase difference is used to obtain an ultrasonic beam. Therefore, in order to provide this phase difference, there are at least as many delay lines as the number of ultrasonic transducer elements for one set, and each delay line is determined by the focal position and beam diameter of the ultrasonic beam. The bird can give the pulse the necessary delay time of the corresponding ultrasonic transducer. In addition, in order to linearly scan the ultrasonic beam, the above-mentioned "excitation" in the probe 1 is necessary.
It is necessary to sequentially shift the positions of one set of ultrasonic transducer elements, but this is done by, for example, a switching device (not shown) that selectively switches the ultrasonic transducer elements under the control of the transmission/reception control device 5. This is done by selecting the ultrasonic vibrating element to be excited.

Reference numeral 7 denotes a pulsar group that generates ultrasonic excitation and irradiation. Correspondence is established with the delay lines of group 6, and a trigger pulse is applied after a delay of one hour determined by each corresponding delay line, thereby outputting an ultrasonic excitation pulse. This - Lusa group 7
The output ultrasonic excitation/gusus from each of the four generators is applied to each ultrasonic vibrating element at a corresponding position in one set of ultrasonic vibrating element groups selected by the aforementioned switching device (not shown). Excite.

In addition, when the same number of pulsers as the number of ultrasonic transducer elements are provided, the pulser corresponding to the one set of ultrasonic transducer elements at the position corresponding to the ultrasonic beam generation position is selected and the trigger pulse is generated. Give and excite.

In this case, a switching device is not required. 8 is a Noriamp group that amplifies the detection output of the ultrasonic echo detected by each of the excited ultrasonic transducer elements;
Reference numeral 9 denotes a reception delay line group for delaying the output of each ultrasonic transducer element that is amplified and output by the Noriamp group 8. The reception delay line group 9 has the number of ultrasonic transducer elements for one set, and is controlled by the transmission/reception control device 5 to delay one hour of transmission and reception of ultrasonic echoes for each corresponding ultrasonic transducer element. The necessary delay time is set by controlling the focal point position at the time.

Further, here, after the detection outputs of the respective ultrasonic transducer elements are delayed, they are added and synthesized into one echo signal.

10 is a receiving circuit that performs reception processing such as amplification, detection, logarithmic compression, etc. on this combined echo signal, and 11 is a receiving circuit that converts the digitized data of the echo signal that is outputted from this receiving circuit 10 into the echo signal. It is an image memory that records at pixel positions corresponding to the depth position in the living body and the ultrasound beam generation position on the probe 1. The recording position and readout position of this image memory 1 are controlled by the microcomputer 2. This is done by means of a control output provided via output port 4 under.

Reference numeral 12 denotes a frequency analyzer which receives multiple combined echo signals outputted from the reception delay line group 9 and analyzes the frequency thereof. Reference numeral 13 designates the frequency analysis output output from the frequency analyzer 12 as According to the frequency spectrum of the sound wave beam, correction is made to the level that can be obtained when this is 7 rats, and the level of the sound wave, which varies depending on the frequency, is normalized, that is, the frequency distribution level of the transmitted ultrasound is made uniform. There is a frequency normalization unit that normalizes the frequency distribution to the level originally obtained when the frequency distribution is performed. After converting the frequency analysis output synorized by this frequency normalization unit 13 into digital data, the frequency position and depth are converted into digital data. is stored in the corresponding pixel position of the image memory 11 in correspondence with the pixel position. Frequency analysis is performed by giving brightness (gradation) according to the level of each frequency. Furthermore, the storage location in the image memory 11 is determined by the microcomputer 2 via the multiple output ports 4 while corresponding to the frequency and depth.

14 is a switch for setting the echo signal frequency analysis position in the ultrasonic tomographic image.This switch 14 has two switches, SWR for rightward shift and SWL for leftward shift. By selecting and pressing the switch, a switch output is given to the microcomputer 2 via the input port 3, and the echo signal frequency analysis position is shifted in accordance with the time the button is pressed.

Reference numeral 15 is a television monitor that displays the ultrasound tomographic image read out from the image memory 11 and the distribution image based on the frequency analysis output, and also displays a marker indicating the echo F frequency analysis position as necessary. This marker is written in a corresponding position on the image memory 11 under the control of the microcomputer 2, or a marker generator (not shown) generates a marker signal at the time when the television scanning line scans the above position in accordance with the television scanning. etc., and the image is displayed on the television monitor 15 at the corresponding position in the displayed ultrasonic tomographic image.

Next, the operation of this device having the above configuration will be explained.

The transmission/reception control device 5 operates under the control of the microcomputer 2, and the transmission/reception control device 5 adjusts each delay line of the transmission delay line group 6 to obtain a delay time corresponding to the ultrasonic beam focus position during transmission. Set one hour delay.

A trigger pulse is then applied to the pulsar group 7 through each of these delay lines. The pulser group 7 each generates an ultrasonic excitation nosorus by this trigger pulse, and applies it to the corresponding ultrasonic vibrating element of one set of the ultrasonic beam generation position. As a result, ultrasonic waves are generated from each of the ultrasonic vibrating elements in one group, and an ultrasonic beam is formed which converges at a predetermined depth due to mutual interference. . Echoes from this ultrasonic beam from various depths inside the living body enter the probe 1, are detected by each of the excited ultrasonic vibrating elements, and are converted into electrical signals. . The electrical signals from each ultrasonic vibrating element are amplified separately by the preamplifiers in the serial amplifier group 8, subjected to horizontal focus control to the reception delay line group 9, and are summed and synthesized after aligning the time axes. be done. Then, it is sent to the receiving circuit 10 and the frequency analysis section 12 as a 7-channel signal. The receiving circuit 10 logarithmically compresses, amplifies, and detects the echo signals that have been added and combined, and then converts them into digital data and sends them to the image memory 11. The image memory 11 is given an address signal from the microcomputer 2 at a pixel position corresponding to the scanning position of the ultrasonic beam and the depth of the received ultrasonic echo, and is controlled for writing, so that the data is written to the address corresponding to the address. Data is stored at pixel positions.

Since the ultrasonic beam is sequentially linearly scanned under the control of the microconbeater 2, echo data at each ultrasonic beam position is stored in the image memory 11 by repeating the above operations. In this manner, digital data of an ultrasonic tomographic image obtained by linear scanning is stored in the image memory 1. The data of this ultrasonic tomographic image is read out sequentially in the horizontal direction of the image in accordance with the scanning of the television monitor 15 under the control of the microcomputer 2, and when the horizontal scanning is completed, data of one pixel in the vertical direction of the image is read out. The images are outputted from the image memory 11 by being shifted and read out sequentially in the horizontal direction again. After converting this output into an analog signal, a synchronization signal, a blanking signal, etc. are added to the output to create a composite video signal, which is sent to the television monitor 15. Then, it is displayed on the television monitor 15 as an ultrasonic tomographic image (B-mode image); in addition to this ultrasonic tomographic image, this apparatus is also capable of displaying a frequency distribution image of ultrasonic echoes. i.e. -1
In order to display this frequency distribution image, the position in the ultrasound tomographic image where the frequency distribution is desired to be viewed is specified.

This can be done, for example, by instructing the microconbeater 2 to display the frequency distribution and causing the microconbeater 2 to control the frequency distribution display. That is, in this state, a marker, for example, a single vertical line, indicating the frequency distribution analysis position is displayed on the ultrasonic tomographic image on the television monitor 15.

This marker can be shifted left and right on the ultrasonic tomographic image by operating the switches SWR and SWL for rightward and leftward shifting of the switch 14, and can be set at any position. That is, if the switch SWR for right direction 77 is now pressed, the output of this switch SWR is given to the microconbeater 2 via the input port 3.

For example, the microcomputer 5 and the microcomputer 2 count the internal clock signals for the time when this switch is pressed, use the counted value as position data, and store the position data on the corresponding image memory 1. The marker is moved to the corresponding pixel position and written. Furthermore, when the leftward shift switch is pressed, the internal clock signal is subtracted and counted while the switch SWL is pressed. Therefore, this switch SW
By operating R and SWL, the shimmerer position can be moved and set to the left or right. Then, by reading the image data from the image memory 11, this marker is superimposed and displayed on the ultrasound tomographic image displayed on the television monitor 15.
You can check the set position.

The position data given in this way is associated in advance with the scan position of the ultrasound beam, and the output after adding and combining the detection outputs of echoes from the ultrasound beam transmission at the scan position indicated by this position data is the reception delay. When the signal is sent as an echo signal from the line group 9 side, the frequency analyzer 12 under the control of the microcomputer 2 operates to analyze the frequency distribution of the signal contained in the output, and the level of the signal contained in each frequency. Generates output depending on. Since the time axis of the added and synthesized echo signal corresponds to the depth at which the echo was obtained in the living body, the output of the frequency analysis section 12 is a frequency distribution at each depth position where the depth position is sequentially changed. A signal indicating that. This signal is frequency normalized section 1
3 and frequency normalized.

Frequency normalization here means that the transmission spectrum of the ultrasonic wave (frequency component distribution of the transmitted ultrasound) is not 7rat, so it is necessary to correct the amount of correction required when flattening the transmission spectrum according to the intensity of the transmission spectrum. is applied to the echo spectrum to obtain the absolute distribution.

That is, as shown in FIG. 2(,), the frequency characteristic of the transmission spectrum of the ultrasonic beam itself has a chevron-shaped distribution. Furthermore, if the spectrum of the received echo at a certain depth is as shown in Figure 2(b), the spectrum of this received echo is due to the transmitted spectrum other than 7. Since it cannot be said that all characteristics are accurately reflected, K assumes that the transmit spectrum is flat in order to obtain a received echo spectrum that accurately reflects the attenuation characteristics of the biological tissue so that it can be objectively understood. Then, the amount of correction to make this flat can be obtained based on the transmission spectrum, and the correction can be made by this amount, as shown in Figure 2 (b).
), the attenuation characteristics of the living tissue are accurately expressed for each frequency component, that is, a normalized spectrum as shown in FIG. 2(c) is obtained. Therefore, although FIG. 2(c) shows the attenuation characteristic itself for each frequency component in the living tissue at a certain depth, the attenuation characteristic can be objectively grasped.

In FIGS. 2(a) to 2(c), the vertical axis represents the echo intensity, and the horizontal axis represents the frequency.

Also, to give an example of normalization, now,
At the frequency positions of 2 MHz and 6 MHz, the correction amount at the frequency position AWtA6 of the transmission spectrum shown in FIG. 2 (,) is -20 dB, -10 dB,
Furthermore, the level of the frequency position B2+B6 in the spectrum of the received echo shown in FIG. 2(b) is -35 dB,
If it is -30dB, the level at the frequency position C2*C5 after normalization shown in Figure 2(c) is C2=B2-A2=-35dB (-20dB)=-
15dB.

Cs”B6A6=-30dB-(-10dB)=2
It becomes 0dB.

Note that the transmission spectrum 11 is determined by the characteristics of the probe 1, etc., so this transmission spectrum can be input into the microcomputer 2 in advance and used during normalization, or the transmission spectrum can be actually may be measured by the frequency analysis section 12 and the measured data may be used for normalization.

After frequency analysis of ultrasound echoes for a specific position on the biological tomographic plane, the data obtained by normalization is displayed on a plane with the frequency on the horizontal axis and the depth inside the body on the vertical axis, and the brightness according to the level. It is stored as data in the frequency analysis image storage area on the image memo IJZl. Then, this stored data is sequentially read out from the image memory 11 in accordance with the television scanning, converted into a composite video signal, and then applied to the television monitor 15 to be displayed as an image. This display may be displayed in parallel with the ultrasonic tomographic image on the same screen as shown in FIG. 3, or may be displayed on separate monitors.

Further, in FIG. 3, A is an ultrasonic tomographic image, M is the aforementioned marker, and B is a frequency distribution image at the position of marker M.

The frequency distribution image may be expressed by a change in brightness according to frequency and depth as shown in Fig. 3 (Small), or alternatively, the frequency distribution level may be expressed by a line according to depth as shown in Fig. 4. .

Furthermore, if only the change in frequency due to relative depth is to be known, the frequency normalizing section in FIG. 1 may be omitted.

Further, the present invention can be applied not only to linear electronic scanning but also to diagnostic equipment that obtains ultrasonic tomographic images using other methods such as sector scanning.

〔Effect of the invention〕

As detailed above, the present invention scans an ultrasonic beam, detects its echo, and displays it as an image on a monitor device with a brightness corresponding to the level of the echo in correspondence with the ultrasonic beam position. In an ultrasonic diagnostic apparatus that obtains ultrasonic tomographic images, means for specifying a frequency analysis position in the ultrasonic tomographic image, and means for displaying a marker at an ultrasonic tomographic position on the monitor device corresponding to the specified position. and frequency analysis means for frequency-analyzing the detection output of the echo according to the depth at which the echo was obtained when the ultrasonic beam scans a position corresponding to the specified position, and The means is configured to provide the monitor device (display device) with an image showing the frequency level distribution state corresponding to the depth, and when a desired position in the ultrasonic tomographic image is specified, the specified position is transmitted to the ultrasonic beam. The echo detection output during scanning is frequency-analyzed, and an image of the frequency distribution state resulting from the frequency analysis is displayed on a monitor device, and the ultrasound tomogram and the frequency of the in-vivo echo at a desired position in the tomogram are displayed. By making it possible to objectively observe the distribution state, it is possible to objectively observe the attenuation characteristics of different ultrasound frequencies in living tissue, and in cases where there is a lesion such as cancerous tissue, it is possible to objectively observe the attenuation characteristics of each ultrasound frequency in living tissue. Since a frequency distribution can be seen (that is, a rapid frequency attenuation can be seen, for example), different diagnostic information can be obtained by diagnosing using both an ultrasound tomogram and an image of the frequency distribution state. , it is possible to provide an ultrasonic diagnostic device that is extremely effective in terms of diagnosis.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram for explaining normalization, FIG. 3 is a diagram showing an example of image display of this device, and FIG. 4 is a diagram showing frequency analysis results and other information. It is a figure which shows the example of a display. 1... Nogle? LL,? ...Microcomputer, 3...Input port, 4...Output port, 5...
- Transmission/reception control device, 6... Transmission delay line group, 7
. . . Pulsar group, 8 . . . Prior/f group, 9 . . . Reception delay line group, 10 . Frequency normal "ta, i 4...switch, 15...
TV monitor.

Claims (1)

[Claims] Ultrasonic diagnosis in which an ultrasonic tomographic image is obtained by scanning an ultrasonic beam, detecting its echo, and displaying the image on a display device with a brightness corresponding to the level of the echo in correspondence with the ultrasonic beam position. In the apparatus, means for specifying a frequency analysis position in the ultrasonic tomographic image, means for displaying a marker at an ultrasonic tomographic position on the display device corresponding to the specified position, and a means for displaying a marker at a position corresponding to the specified position on the ultrasonic tomographic image; When the sound wave beam scans, a frequency analysis means □ analyzes the detected output of the echo according to the depth at which the echo was obtained, and a frequency level distribution that corresponds the frequency analysis result to the depth at which the echo was obtained. An ultrasonic diagnostic apparatus characterized by comprising a plurality of means for providing an image to the display device as an image indicating a state.