JP4079392B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus that obtains image diagnostic information such as a tomographic image of a subject using ultrasonic waves. In particular, when a diagnostic target is a tissue such as a moving organ, the aspect can be easily grasped. The present invention relates to an ultrasonic diagnostic apparatus.
[0002]
[Prior art]
In an ultrasonic apparatus, as an image display mode for diagnosing the motion state of an organ in a subject, a Doppler mode for displaying blood flow motion information, a color flow mapping mode, an M mode, and the like are known. Among these, the M mode for displaying the luminance change on the ultrasonic beam in a specific ultrasonic transmission / reception direction in the tomographic image over time, or the luminance change on an arbitrary line independent of the ultrasonic transmission / reception direction over time. The arbitrary direction M mode (Omni Directional M mode, ODM mode) to be displayed is the shape of the image data (luminance data) on the line and the passage of time on the axis of the graph, respectively. In order to confirm an arbitrary area, it is necessary to repeat the M mode and the ODM mode several times, and there is a possibility of overlooking a change over time of a portion not set on an arbitrary line.
[0003]
In addition, the color flow mapping mode is a two-dimensional display method, but basically displays blood flow information and does not display the motion state of the tissue.
[0004]
In Japanese Patent Laid-Open No. 3-121058, difference processing between adjacent images in time series is performed, or two images of arbitrary time phases are extracted from image data arranged in time series, and difference processing is performed between these images. Although an ultrasonic apparatus for displaying the difference image obtained in these colors is proposed, when the noise on the extraction screen is large, the noise is emphasized and displayed. In an example of using average information called SCC (scanning correlation) or the like, a technique for reducing noise by taking an addition average in an abdominal region has been used. However, for images with low correlation between frames (such as in the field of cardiovascular measurement) (with significant changes in images between frames), the averaging method is used because the effect of the previous frame remains and the image becomes tailed. It wasn't.
[0005]
In addition, since a large movement of the tissue over time such as a heartbeat can be easily found by B-mode scanning, it is only necessary to perform M-mode diagnosis on that portion.
[0006]
[Problems to be solved by the invention]
However, in the case of minute movements of tissue caused by an original myocardial infarction or ventricular aneurysm being hindered by the original pulsation, it is difficult to determine with a B-mode image or an M-mode image. was there.
[0007]
More specifically, in the M mode, it is necessary to find out by scanning the M mode in a plurality of directions. Also, finding a B-mode scan requires a lot of clinical experience and skill. For example, when diagnosing arteriosclerosis where the elasticity of the blood vessel is lost and the vasoconstriction / expansion of the blood vessel is slow, or changes in the motion state due to partial necrosis of the myocardium It must be made. In this case, in the method disclosed in Japanese Patent Laid-Open No. 3-121058, even components such as speckle noise are extracted, and an image in which noise components are also displayed in color may be obtained.
[0008]
In the circulatory organ field, when the heart valve is depicted, there is a problem in that it is difficult to grasp the motion state of the tissue to be noticed because the reflection intensity of the non-motion tissue is high and the brightness of the motion tissue is relatively low.
[0009]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ultrasonic diagnostic apparatus that can easily diagnose minute dynamics of a tissue.
[0010]
[Means for Solving the Problems]
The object is to receive and amplify a probe that transmits and receives ultrasonic waves into the subject, an ultrasonic transmitter that transmits ultrasonic waves to the probe, and a reflected echo signal from within the subject. An ultrasonic receiver, a frame memory that records the reflected echo signal in a plurality of frame memories for each frame in a time series, an image display unit that displays the recorded reflected echo signals in a time series as a read image, and Control means for controlling the operation of the ultrasonic transmission unit to the image display unit, and a plurality of read pixel data recorded in the plurality of frame memories and read from a plurality of addresses corresponding to the tissues in the subject. Correlation information calculation means for calculating an average value for each pixel data of the address of the address, wherein the correlation information calculation means uses a plurality of addresses using the calculated average value. Calculating a variance value for each pixel, wherein, among the plurality of pixels pixel value calculated by the variance value and the average value calculated by the correlation information calculation means corresponds to the tissue in the subject A value of a pixel of interest (referred to as a “pixel of interest”), and means for determining whether the value of the pixel of interest is within a predetermined pixel value range , based on the determination result of the determination unit It is accomplished by setting the hue and luminance of the pixel of interest in accordance with the variance value calculated by the correlation information calculation unit Te.
[0011]
A probe that transmits and receives ultrasonic waves into the subject; an ultrasonic transmitter that generates and transmits ultrasonic waves that drive the probe; and a reflected echo from within the subject. An ultrasonic receiving unit for receiving and amplifying a signal; means for recording the reflected echo signal in a plurality of frame memories in time series; an image display unit for displaying the reflected echo signal in time series as a read image; In an ultrasonic apparatus comprising an ultrasonic transmission unit or a means for controlling the operation of the image display unit, the reflected echo signals of successive frames in time series are read from the plurality of frame memories, and each pixel corresponding to each frame is read out. This is achieved by an ultrasonic diagnostic apparatus comprising means for calculating correlation information over time and means for generating and displaying an image based on the correlation information.
[0012]
Also, a probe that transmits / receives ultrasonic waves to / from the subject, an ultrasonic transmission / reception unit that drives the probe to generate ultrasonic waves and processes the received reflected echo signals, and the ultrasonic transmission / reception unit A memory unit that records a plurality of frames of ultrasonic image data in a subject including a motion by digitizing a reflected echo signal from the object and writing a digital signal from the memory unit for each scanning line of the ultrasonic beam A digital scan converter unit for forming data, an image display unit for converting the image data from the digital scan converter unit into an analog image and displaying it as an image, a control circuit unit for controlling the operation of each component, and the memory unit In an ultrasonic diagnostic apparatus comprising a correlation circuit unit that reads out continuous multiple frames of image data in parallel and grasps the correlation over time. It is achieved by the ultrasonic diagnostic apparatus and displaying the information obtained by the correlation circuit adds the correlation information to the image currently displayed using the original by the image display unit.
[0013]
Also, the present invention is achieved by an ultrasonic diagnostic apparatus characterized in that consecutive images are simultaneously read out in parallel when reading out image data of a plurality of frames from the memory unit of the ultrasonic body.
In addition, the present invention is achieved by an ultrasonic diagnostic apparatus that simultaneously reads out images after a plurality of frames in parallel when reading a plurality of frames of image data.
[0014]
Specifically, the previous problem is solved by displaying a diagnostic image (for example, a color display image) to which tissue motion information is added in B-mode scanning. Since the motion information is a change in the image with the passage of time, the cross-correlation (average or variance) of each pixel of the image over a plurality of frames is calculated, digitized, and displayed in color according to the degree. Hue may be given according to the numerical value of the correlation, or a threshold value set in the numerical value may be set, and the portion may have the same hue. This method differs from Japanese Patent Application Laid-Open No. 3-121058, which is the method described in Japanese Patent Application No. 9-51413, which compares a plurality of frames of data using a statistical method, Speckle noise, etc. can be determined and displayed accordingly.
[0015]
In cardiovascular measurement, the distance from the average value is used as a parameter, and the pixels below the threshold value are set to a hue that is difficult to see (for example, blue), and the other parts are set to normal white to emphasize the exercise situation. It can be displayed, and it becomes easy to grasp the dynamics.
[0016]
By taking the cross-correlation of each pixel of the tissue (pixel) over a plurality of frames and giving a hue according to the correlation of the tissue (pixel), it is easy to grasp the motion state of the tissue. In addition, since the difference between adjacent images is not drawn as in the prior art, it is statistically processed. Therefore, based on the method proposed in Japanese Patent Application No. 9-51413, the component considered as speckle noise is Therefore, the possibility of drawing a color image in which noise components are extracted and displayed can be reduced. In addition, when it is desired to separate the pixels of interest from those that are not using the distance (dispersion) from the average and grasp the change state, the pixels with less dispersion are compared with the pixels with larger dispersion. By making the hue difficult to adhere to, it is possible to easily observe the movement state of the tissue.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an ultrasonic diagnostic apparatus of the present invention will be described with reference to the drawings.
1 is a block diagram of an ultrasonic diagnostic apparatus for explaining an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the ultrasonic diagnostic apparatus of FIG. 1, and FIG. 3 is an image obtained by the operation of FIG. This is a display example comparing normal findings and abnormal findings.
[0018]
First, a configuration example of the ultrasonic diagnostic apparatus of the present invention will be described with reference to FIG.
The ultrasonic diagnostic apparatus includes a probe 1, an ultrasonic transmission / reception circuit 2 electrically connected to the probe 1, image memories 3 and 4 electrically connected to the ultrasonic transmission / reception circuit 2, respectively. Luminance hue conversion unit 6, correlation information detection circuit unit 8 electrically connected to image memories 3 and 4, image processing unit 7 electrically connected to luminance hue conversion unit 6, image processing unit 7, Correlation between an electrically connected digital scan converter (DSC) unit 9, an image display unit 10 electrically connected to the DSC unit 9, an ultrasonic transmission / reception circuit 2, a luminance hue conversion unit 6, and an image processing unit 7 An information detection circuit unit 8 and a control circuit unit 5 electrically connected to the DSC unit 9 are provided.
[0019]
The probe 1 transmits an ultrasonic wave to a subject (not shown) and receives a reflected echo signal from the subject. The ultrasonic transmission / reception circuit 2 includes a transmission part that supplies a signal for emitting ultrasonic waves to the probe 1 and a reception part that performs signal processing such as amplifying a reflected echo signal received by the probe 1. The image memory 3 once records the reflected echo signal obtained in the B mode. The image memory 4 also performs the same operation as the image memory 3, but includes frame memories 41 to 4n that record image data of a plurality of frames. For example, a past image (previous image) previously obtained when obtaining continuous images is used. At least one image is recorded. The luminance hue conversion unit 6 reads the reflected echo signal from the image memory 3 and converts it into luminance information for a B-mode image, and converts it to hue information for a Doppler mode image. The image processing unit 7 converts the luminance information and the hue information into image data that is easy to diagnose by performing so-called image processing. The correlation information detection circuit unit 8 simultaneously reads a plurality of pieces of pixel (tissue) information from the image memory 4 in parallel and correlates with the corresponding pixels in the (latest) image data to be displayed (the distance from the average and the variance). The difference or ratio between the value and the distance is calculated, and the hue of the pixel to be displayed is determined. This can be easily created by using a microcomputer or the like. The DSC unit 9 converts an ultrasonic scanning signal into a TV monitor scanning line. The image display unit 10 displays the luminance information and the hue information converted into the image display format on a monitor.
[0020]
Further, in addition to the simple addition / subtraction method, the correlation can be drawn by adopting the method described in Japanese Patent Application No. 9-51413. Then, calculation is performed from the obtained correlation information, or an image to which hue information is added from the correlation information of the pixel is processed and displayed according to the correlation information using a data table prepared in advance. For example, a read-only memory (ROM) is used as the data table.
[0021]
By the way, the movement of the tissue can be recognized by displaying the movement of the luminance pattern of the pixel, but the portion displayed as the difference between frames becomes a difference caused by the movement and is recognized by the presence or absence of the luminance change of each pixel. Therefore, it can be considered that the portion where there is no change in luminance is a tissue with little motion. If this concept is used, the correlation information described above can be used to make it easier to see a valve having a lower brightness than a heart wall having a higher brightness, for example, when examining a circulatory organ.
[0022]
Next, the operation of the ultrasonic diagnostic apparatus configured as described above will be described with reference to FIG.
[0023]
The latest B-mode image is input to the image memory 3 and the image memory 4 and recorded in the frame memory 4n (step 201).
An average value A is calculated for each image address (pixel) from the data in each frame memory (step 202).
A dispersion value D is calculated for each address (pixel) of the image from the data of each frame memory (step 203).
[0024]
Based on the average value A and the variance value D calculated in the above step, the data in the frame memory is graphed as a normal curve as in the method described in Japanese Patent Application No. 9-51413. It is determined whether it is within a predetermined range. Here, it is determined whether or not A-2D <i <A + 2D. If not within the range, the process proceeds to the next step, and if within the range, the process jumps to step 206 (step 204).
[0025]
By this determination, data considered to be unsuitable for calculating the average value such as speckle noise is excluded in advance and the average value A ′ is calculated. Since it is possible to eliminate factors that have a large influence even in noise, it is possible to supply data with a small error range. As a method of deleting information that is not suitable for calculation as an average value, a filter that prepares a data table in advance and processes data to be deleted, which is input inappropriate information, in a form that does not adversely affect the results ( For example, it may be removed using ROM) (step 205).
[0026]
The control circuit unit 5 causes the luminance hue conversion unit 6 to give luminance in accordance with the dispersion value D. For example, the image conversion that makes the heart valve easier to see is set such that the smaller the variance value D is, the closer it is to blue, and the larger the variance value D is, the closer it is to white. Further, a threshold value is provided, and blue may be set when the value is equal to or lower than the threshold value, and white may be set when the value is equal to or higher than the threshold value (step 206).
[0027]
The control circuit unit 5 causes the luminance hue conversion unit 6 to give a hue according to the dispersion value D. For example, according to a data table selected by the control circuit unit 5 based on the variance value D and the graphed data, for example, it may be realized by a ROM or the like to which data of three primary colors are input. The selection of the data table is also determined using the previously used graph (step 207).
[0028]
The control circuit unit 5 controls the DSC unit 9 to convert the luminance information and the hue information into an image display format (step 208).
[0029]
The control circuit unit 5 controls the image display unit 10 to display the luminance information and the hue information converted into the image display format on a monitor (step 209).
[0030]
As described in Japanese Patent Application No. 9-51413, the determination of the graph data can be based on an empirically grasped information pattern as a determination criterion when constructed with firmware recorded in a ROM or the like. The method for deleting information not suitable for calculation as the average value described in step 204 is realized by this method. In this case, the ROM input need only have the amount of information necessary to determine the form of the given graph, so it is not necessary to include luminance information for all frames, and the number of input bits required by compressing the luminance information, etc. Can be reduced. For example, if the luminance information is 3 bits, it is necessary to input 24 bits in 8 frames.
[0031]
The following method can be used to give the hue of the display image. When the pixel data width is 8 bits, in 24-bit color, hue information is displayed at the ratio of the three primary colors with three 8-bit output ROMs. Even if n patterns (for example, 256 patterns) are prepared in consideration of the scanning mode, a 256 kbit ROM may be used. Further, this ROM may have the previous graph data determination part. When a flash ROM or the like is used, the contents of the ROM table are recalculated each time the scanning mode changes, or the contents of the ROM are changed by reading the data recorded in another storage device. An inexpensive storage device such as a ROM and a hard disk can be used.
[0032]
The data table selection signal that gives the hue is such that when the hue is set so as to make the heart valve easier to see, the part of the heart wall with less movement is blue and the valve with large movement is drawn white. Should be prepared.
[0033]
When observing blood vessels with contraction, the hardening of the blood vessels is expressed in color as the difference in distance from the average value, and because it becomes a different color from the surroundings, it can be easily detected, such as the discovery of arteriosclerosis, etc. It is considered useful.
[0034]
For example, FIG. 3 (a) shows the pattern of the dynamics of the heart with normal findings, and FIG. 3 (b) shows the pattern of the dynamics of the heart with findings of myocardial infarction or ventricular aneurysm. As shown, only the dynamic part expands, and the hatched part is colored differently from the normal findings.
[0035]
In the above description, the range of the normal distribution has been described as A ± 2D. However, since the purpose is to exclude numerical values that deviate greatly from the average value, it is possible to include all methods of excluding this type of numerical value. Needless to say.
[0036]
The above embodiment has been described based on the fact that a plurality of frames are time-sequential continuous frames. However, for example, when a defective frame that cannot be used as a continuous frame for some reason is generated by a frame used in a continuous frame. May perform correlation processing such as the average value and variance in a plurality of frames in which the defective frame is skipped.
[0037]
According to the embodiment described above, it is clearly easier to find a disease than in the case of only the B-mode image. Even in this case, in the present invention, since hue information is given based on graphed data, a noise-suppressed image and a color tone considering a time correlation pattern can be given, and a higher quality image than a conventional method can be obtained. Can be provided.
[0038]
Also, if you have a trigger circuit such as ECG synchronization, if you find the average between frames of the same timing, such as the frame at the time of synchronization trigger, and display the variance with respect to the average value, if periodic motion collapses Can capture the symptom of the collapsed movement by making a color image.
[0039]
In addition to the periodic movements as described above, the average period is differentiated into several equal parts, the dispersion with respect to the average is displayed in luminance, and the temporal change is displayed in hue, so that the periodic variation is confirmed by color. Will be able to.
[0040]
In addition, since the difference between the frames of the B-mode image can be provided in an easy-to-see form, a new diagnostic image for observing the tissue motion that seems to have been overlooked so far, and displaying the average value and variance of the pixel brightness is displayed. Will be able to provide.
[0041]
【The invention's effect】
The present invention has an effect of providing an ultrasonic diagnostic apparatus that can easily diagnose minute dynamics of a tissue.
[Brief description of the drawings]
FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus for explaining an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the ultrasonic diagnostic apparatus in FIG. 1;
3 is a display example in which normal findings and abnormal findings are compared in the image obtained by the operation of FIG. 2;
[Explanation of symbols]
3,4 image memory 8 correlation information detection circuit 10 image display unit

Claims (1)

A probe that transmits and receives ultrasonic waves to and from the subject, an ultrasonic transmitter that transmits ultrasonic waves to the probe, and an ultrasonic receiver that receives and amplifies reflected echo signals from within the subject A frame memory that records the reflected echo signal in a time series in a plurality of frame memories for each frame; an image display unit that reads the recorded reflected echo signal in a time series and displays it as an image; and the ultrasonic transmission unit Thru | or the control means which controls operation | movement of the said image display part, and the pixel data of the some address which were recorded on the said some frame memory, and read the pixel data of the some address corresponding to the structure | tissue in the said test object In an ultrasonic apparatus comprising correlation information calculation means for calculating an average value for each data,
The correlation information calculation means calculates a variance value for each pixel of a plurality of addresses using the calculated average value,
The control means is a pixel of interest (“attention pixel”) among a plurality of pixels whose pixel values calculated by the average value and the variance value calculated by the correlation information calculation means correspond to the tissue in the subject. And a means for determining whether or not the value of the target pixel is within a predetermined pixel value range ,
An ultrasonic diagnostic apparatus, wherein the hue and brightness of the target pixel are set according to a variance value calculated by the correlation information calculation unit based on a determination result of the determination unit.

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