JP2000210283A - Motion cycle calculation system for medical moving image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically calculate a motion cycle in a medical moving image based on an image. SOLUTION: This motion cycle calculation system for a medical moving image is equipped with a cyclic motion area extraction part 9 to extract a cyclic motion area to execute cyclic motion in an image based on changes of density of each pixel of the image signal of an ultrasonic tomographic image of medical moving image, an average density calculation part 10 to calculate the average density of a plurality of pixels existing in a micro-area in the cyclic motion area, a change cycle calculation part 11 to calculate the change cycle of average density. The change cycle calculated by the change cycle calculation part 11 is the motion cycle of the cyclic motion area. Consequently the motion cycle in an ultrasonic tomographic image can be automatically calculated only by processing image signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion cycle calculating apparatus for calculating a motion cycle in a medical moving image obtained by various medical diagnostic apparatuses such as an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic tomographic image. The present invention relates to a technique for obtaining a motion cycle in a medical moving image based on the moving image.

[0002]

2. Description of the Related Art At medical sites such as hospitals, ultrasonic diagnostic apparatuses are already used at a general-purpose level. As shown in FIG. 8, a conventional ultrasonic diagnostic apparatus includes a probe (probe) 51 applied to a site of interest of a patient M, a transmitting / receiving unit 52 for transmitting and receiving ultrasonic waves by the probe 51, and a receiving unit. A DSC (Digital Scan Converter) 53 for performing a process of creating an ultrasonic diagnostic image according to a signal, a display monitor 54 for displaying the ultrasonic diagnostic image on a screen,
The control unit 55 controls the SC 53 to execute a predetermined operation. A part of the ultrasonic wave transmitted from the probe 51 is reflected in the body of the patient M and the probe 5
1 and then sent through the transceiver 52
After being converted into an ultrasonic diagnostic image in SC53, the ultrasonic diagnostic image is sent to the display monitor 54 and the ultrasonic diagnostic image is displayed.

In the case of an ultrasonic diagnostic apparatus, a so-called B-mode display ultrasonic tomographic image that non-invasively and in real time displays a slice cross section of a site of interest is particularly useful because the body of the patient M can be directly observed. This so-called B-mode display ultrasonic tomographic image can be applied to a case where a region of interest has a periodic motion such as a circulatory system. For example, in the case of an ultrasonic tomographic image of the heart, it is accompanied by palpitations. The moving image is displayed on the screen of the display monitor 54 as a moving image showing the periodic movement of the heart, and is extremely useful for a doctor to make an appropriate diagnosis.

[0004]

However, in the case of the conventional ultrasonic diagnostic apparatus, it is difficult to observe the heart motion and to know the heart rate (the motion cycle of the heart portion in the moving image) at the same time in real time. It is not enough equipment. Knowing the heart rate as well as the actual movement of the heart in real time allows accurate observation of the heart and a more appropriate diagnosis, but only the movement of the heart can be grasped from the ultrasonic tomographic image displayed in the B mode. I do not know the heart rate.

[0005] The heart rate can be known in real time by using an electrocardiogram signal of an ECG (electrocardiogram) device.
Since an electrocardiogram (G) device and an operation of setting this device to the patient M are required, the use of the ECG device does not mean that the heart rate can be easily determined. Further, in the case of an ultrasonic diagnostic apparatus, a waveform of a so-called M-mode display, which indicates the lapse of time of the movement of the region of interest in the patient M, is usually displayed on the screen of the display monitor 54. Since the waveform in the case is noisy, it is not easy to obtain an accurate heart rate from the waveform displayed in the M mode.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a medical-moving-image motion-period calculating apparatus capable of calculating a motion cycle in a medical moving image such as an ultrasonic tomographic image based on the moving image. And

[0007]

According to a first aspect of the present invention, there is provided an apparatus for calculating a motion cycle of a medical moving image, wherein a periodic motion area for performing a periodic motion is present in the image. An apparatus for calculating a motion cycle of a periodic motion area of a medical moving image, comprising means for calculating a motion cycle of the periodic motion area based on a temporal change of a density value of a pixel of the medical moving image.

According to a second aspect of the present invention, in the medical motion image motion cycle calculating apparatus according to the first aspect, the means for calculating the motion cycle includes a time-varying density value of each pixel of the medical moving image. A periodic motion region extracting means for extracting a periodic motion region based on the change; and an average for calculating an average density value of a plurality of pixels including at least pixels existing in the periodic motion region extracted by the periodic motion region extracting device. It comprises a density value calculating means and a change cycle calculating means for calculating a change cycle of the average density value obtained by the average density value calculating means as a motion cycle of the periodic motion area.

According to a third aspect of the present invention, in the medical motion image motion cycle calculating apparatus according to the second aspect, the average density value calculating means includes a plurality of the plurality of microscopic areas existing in a minute area within the periodic motion area. The average density value of the pixel is calculated as an average density value.

[Operation] Next, a motion cycle calculating apparatus for medical moving images of the present invention (hereinafter abbreviated as "cycle calculating apparatus").
The operation at the time of the execution of the period finding by will be described. In the case of the cycle finding device of the present invention, by means for finding the motion cycle,
A motion cycle of a medical moving image in which an image includes a periodic motion region that performs a periodic motion is calculated based on a temporal change of a density value of a pixel of the medical moving image. In other words, in the case of a medical moving image which is a target for periodic calculation according to the present invention, the density value of the pixel in the periodic motion area changes with time in synchronization with the motion cycle of the periodic motion area. The movement period of the periodic movement region is obtained from the target change.

Further, when the motion cycle of the medical moving image is calculated by the cycle calculating device according to the second aspect, first, a periodic motion area for performing a periodic motion in the medical moving image is determined by the periodic motion area extracting means. The extraction is performed based on a change in the density value of the pixel. The periodic motion region is a region in which the image itself changes with the periodic motion, and if the image itself changes, the density value of each pixel naturally changes. In contrast, in the non-motion area, the image itself does not change, and the density value of each pixel does not substantially change. Therefore, the periodic motion region extracting means can extract and define the periodic motion region in the medical moving image based on the change in the density value of each pixel.

When the extraction of the periodic motion area is completed, the average density value obtaining means obtains the average density value of a plurality of pixels included in the periodic motion area. When several (a certain number) of the density values of the pixels present in the periodic motion area are included, the average density value indicates the remarkable time of substantially the same cycle as the motion cycle of the periodic motion area. Changes can be clearly seen. Therefore, by the change period finding means,
When the change cycle of the average density value of the pixel is calculated, the calculated cycle is the motion cycle of the periodic motion area. Since the temporal change in the average density value is remarkable, the change cycle of the average density value, which is the motion cycle of the periodic motion area, can be accurately obtained.

According to the third aspect of the present invention, the average value of the respective density values of a plurality of pixels existing in a minute area within the periodic motion area is determined by the average density value obtaining means. Calculated as a value. Since each pixel in the micro-area tends to have a uniform density value change tendency, the calculated average density value changes very greatly in the motion cycle of the periodic motion area, and the motion cycle of the moving image is further increased. In addition to being accurately obtained, the number of pixels to be processed is small and necessary processing is easy.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to an embodiment in which a period finding device according to an embodiment of the present invention is incorporated, and FIG. 2 is a schematic ultrasonic wave obtained by the ultrasonic diagnostic apparatus according to the embodiment. It is a top view showing a tomographic image.

As shown in FIG. 1, the ultrasonic diagnostic apparatus of the embodiment creates an ultrasonic tomographic image (moving image) of a so-called B-mode display for displaying a slice section of a site of interest in a patient M in a non-invasive and real-time manner. The diagnostic apparatus includes a diagnostic apparatus main body 1 configured to be able to perform the calculation, and a cycle determining unit 2 configured to determine a motion cycle in an ultrasonic tomographic image that is a medical moving image. Hereinafter, the configuration of each unit in the ultrasonic diagnostic apparatus of the embodiment will be specifically described.

The diagnostic apparatus main body 1 is an electronic linear scanning type probe (probe) applied to a site of interest of the patient M.
3, a transmission / reception unit 4 for transmitting and receiving ultrasonic waves by a probe (probe) 3, and a DSC (digital scan converter) 5 for performing ultrasonic diagnostic image creation processing in accordance with a received signal. After a part of the ultrasonic wave transmitted from the probe 3 is reflected in the body of the patient M and received by the probe 3 at the start of the process, the digital signal is further converted by the DSC 53 after being subjected to processing such as amplification by the transmitting and receiving unit 4. After that, necessary processing is performed, and an ultrasonic tomographic image in B-mode display is completed and stored in the image memory 6.

The image memory 6 is a known frame memory having a large number of memory cells addressed by a two-dimensional address system corresponding to electronic linear scanning. Each memory cell (not shown) of the image memory 6 stores the density value of each pixel of the ultrasonic tomographic image.

Further, the diagnostic apparatus main unit 1 includes a display monitor 7 for displaying an ultrasonic diagnostic image on a screen and a control unit 8 for performing control for executing necessary processing, and is stored in the image memory 6. The ultrasonic tomographic image is read out and displayed on the screen of the display monitor 7, and under the control of the control unit 8, necessary parts from transmission of ultrasonic waves by the probe (probe) 3 to image display by the display monitor 7. Are configured so that the cooperative operation proceeds properly and orderly. When displaying a moving image of the heart on the screen of the display monitor 7, the diagnostic apparatus main body 1 updates the screen of the display monitor 7 by repeating electronic linear scanning and successively creating ultrasonic tomographic images. It has a configuration. Of course, each time a new ultrasonic tomographic image is created, the memory image in the image memory 6 is updated to the next image.

On the other hand, the period finding section 2 performs a periodic motion in the ultrasonic tomographic image based on the temporal change of the density value of each pixel of the image signal of the ultrasonic tomographic image stored in the image memory 6. A periodic motion area extracting unit 9 for extracting a periodic motion area, and an average density value obtaining for calculating an average density value of a plurality of pixels existing in a minute area of the periodic motion area extracted by the periodic motion area extracting unit 7. Unit 10 and average density value calculating unit 1
And a change cycle calculating unit 11 for calculating a change cycle of the average density value obtained by the zero as a motion cycle of the periodic motion area. The motion cycle T in the image is determined. Hereinafter, the configuration of each unit of the cycle finding unit 2 will be described in detail.

FIG. 2 is a plan view showing a schematic ultrasonic tomographic image of the heart of the patient M obtained by the diagnostic apparatus main body 1, and the ultrasonic tomographic image P of FIG. 7) (see FIG. 6). That is, in the ultrasonic tomographic image P, since the myocardium moves with the heartbeat, as shown in FIG. 2A, the state where the myocardial external Pa is maximally contracted and the blood flow Pb is retreated is shown in FIG. (B)
As shown in FIG. 7, the moving image is a moving image in which the image periodically changes during a state in which the outside of the myocardium Pa expands to the maximum and the blood flow Pb advances. Accordingly, in the case of the ultrasonic tomographic image P, as shown in FIG. 3, a periodic motion region that moves at a period synchronized with the heartbeat period due to the periodic change of the image portion of the myocardial outside Pa and the blood flow Pb. PA and PB exist in the image.
The periodic motion area PA is generated by an image change of the outside of the myocardium Pa, and the periodic motion area PB is generated by an image change of the blood flow Pb.

The periodic motion areas PA and PB of the ultrasonic tomographic image P are extracted by the periodic motion area extracting unit 9 of the cycle finding unit 2 as follows. As shown in FIG.
Pixels A existing outside the periodic motion region of the ultrasonic tomographic image P,
The density values of C and E do not change with time as shown in FIG. On the other hand, the density values of the pixels B and D existing in the periodic motion area of the ultrasonic tomographic image P have a temporal change corresponding to the motion cycle of the periodic motion areas PA and PB, as shown in FIG. The periodic motion region extraction unit 9 first executes an integration process of integrating the absolute value of the time derivative (temporal change) of the density value of each pixel of the image signal of the ultrasonic tomographic image P obtained one after another in real time. To obtain an integral value I. It goes without saying that the integration time in this integration process is set longer than the interval between image frames. The result of the integration process is 1
When viewed along the horizontal scanning line, the result is as shown in FIG. That is, as seen above, the periodic motion areas PA, P
Outside B, there is substantially no temporal change in the density value of each pixel, so that the integrated value I is very small, but within the periodic motion areas PA and PB, there is no temporal change in the density value of the pixel. Therefore, the integrated value I has a certain value or more.

Therefore, if a pixel having an integral value I equal to or greater than a certain value is determined, the periodic motion regions PA and PB can be extracted. A pixel that is equal to or greater than It is detected (the address of the memory cell corresponding to the pixel) is stored. In this case,
Only pixels located at the end of the section where the integral value I is equal to or greater than a certain value are stored (that is, only the outlines of the periodic motion areas PA and PB are stored)
You may make it. In this manner, the extraction of the periodic motion areas PA and PB by the periodic motion area extraction unit 9 is performed. As the threshold value It serving as a criterion in the periodic motion region extraction unit 9, a value obtained by the following equation is used, for example. It = minimum integral value Imin + (maximum integral value Imax−minimum integral value Imin) × 0.9 Of course, the threshold value It is not limited to the above expression, and an appropriate threshold value can be set according to the type and state of the medical moving image. Needless to say,

The average density value calculation unit 10 of the cycle calculation unit 2
A minute area Ps is set in the extracted and defined periodic motion area PA, and an average density value Q of a plurality of (for example, 20) pixels existing in the minute area Ps is calculated. Specifically, a pixel in the middle of the micro area Ps and one pixel
The average of the density values is calculated for the nine pixels. As shown in FIG. 6, the density value of each pixel in the micro area Ps mostly shows a temporal density change corresponding to the motion cycle of the periodic motion area PA, that is, the heart beat cycle.
The average density value Q of the pixels also changes temporally at substantially the same cycle as the motion cycle of the periodic motion area A. The setting of the minute area Ps may be performed on the periodic movement area PB.

Therefore, when the change cycle of the average density value Q is calculated by the change cycle calculating section 11 of the cycle calculating section 2, this becomes the motion cycle T of the periodic motion areas PA and PB. Specifically, as shown in FIG. 6, the interval between the peaks PK appearing one after another in the average density value Q over time is determined by the change period determining unit 11 as the change period. In the case of the change period calculating unit 11 of the embodiment, after the movement period T in seconds is obtained, the heart rate N is finally obtained by a simple calculation of 60 / T. Exercise cycle T
Is determined, the heart rate N is also determined in real time.
In this manner, the heart rate N determined by the cycle determining unit 2 is sequentially transmitted to the display monitor 7 and is transmitted to the ultrasonic tomographic image P.
Is displayed on the screen of the display monitor 7 together with the
The periodical motion region extraction unit 9 and the average density value calculation unit 10 and the change period calculation unit 11 of the period calculation unit 2 are mainly composed of a computer and its operation program (software). is there.

Next, a series of processing operations when the motion period in the ultrasonic tomographic image is calculated by the period calculating unit of the embodiment device having the above-described configuration will be described with reference to the drawings. FIG. 7 is a flow chart showing the progress of the period finding by the embodiment device over time. The diagnostic apparatus main body 1 of the embodiment apparatus repeatedly generates a so-called B-mode display ultrasonic tomographic image P of the heart of the patient M in parallel with the period determination and updates and stores the ultrasonic tomographic image P in the image memory 2. At the same time, the operation state in which the ultrasonic tomographic image P is displayed on the screen of the display monitor 7 continues.

[Step S1] The periodic motion area extracting section 9 of the cycle finding section 2 obtains an integral value I for extracting the periodic motion area based on the image signals of the ultrasonic tomographic image P repeatedly obtained one after another. At the same time, a threshold value It as a reference for extracting the periodic motion region is obtained.

[Step S2] The periodic motion areas PA and PB are extracted by detecting pixels whose integral value I is equal to or larger than the threshold value It by the periodic motion area extracting section 9.

[Step S3] The average density value calculating section 10 sets a small area Ps in the periodic motion area PA.

[Step S4] The average density value calculating section 10 calculates an average density value Q of 20 pixels in the minute area Ps.

[Step S5] After the change cycle calculating section 11 calculates the change cycle of the average density value Q as the exercise cycle T, the heart rate N is further calculated.

[Step S6] The determined heart rate N of the patient M is sent to the display monitor 7 and displayed on the screen of the display monitor 7 together with the ultrasonic tomographic image P.

[Step S7] If it is necessary to continuously calculate and display the heart rate N, the steps from step S1 are repeated. If this is not necessary, the cycle finding operation by the cycle finding unit 2 ends.

As described above, in the apparatus of the embodiment, the motion cycle T of the periodic motion areas PA and PB in the ultrasonic tomographic image P is obtained based on the moving image even without the ECG apparatus. In addition, in the case of the embodiment apparatus, since the average density value Q of the pixels that are fixed in the minute area Ps in the extracted periodic motion area is used, the average density value Q is the motion cycle of the periodic motion area. As a result, the change period of the average density value Q can be determined very accurately, so that the movement period T of the periodic movement region can be determined very accurately.
The number of pixels to be processed is small, and necessary processing is easy.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) In the case of the embodiment, the minute area Ps is set to be completely within the periodic motion area.
s may be set to straddle both inside and outside the periodic motion region. Furthermore, the average density value Q may be a value obtained by averaging the density values of all pixels without extracting the periodic motion region.

(2) In the case of the apparatus of the embodiment, the averaging target pixel of the average density value calculating section 10 is a pixel which is present in a small area called a small area Ps. May be pixels that are widely scattered throughout the periodic motion region.

(3) In the case of the ultrasonic diagnostic apparatus of the embodiment, the electronic linear scanning method is used. However, the ultrasonic diagnostic apparatus according to the present invention employs another method such as a mechanical scanning method, a sector scanning method, or a convex scanning method. A scanning type device may be used.

(4) In the case of the embodiment, the medical moving image of which period is to be determined is an ultrasonic tomographic image. However, the medical moving image of which period is to be determined according to the present invention is not limited to an ultrasonic tomographic image.
For example, it may be an X-ray fluoroscopic image obtained by an X-ray fluoroscopic apparatus.

(5) In the case of the embodiment, the period finding device is incorporated in the ultrasonic diagnostic apparatus, but the period finding device of the present invention is a single form which is not incorporated in other devices. Is also good.

[0039]

As described above in detail, according to the medical moving image motion cycle calculating apparatus of the first aspect of the present invention, the medical moving image based on the temporal change of the density value of the pixel of the medical moving image. ECG is provided with means for finding the motion cycle in
The motion cycle in the medical moving image can be obtained based on the density value of the image without using a device.

According to the medical moving image motion cycle calculating device of the second aspect of the present invention, a plurality of pixels including a pixel existing in the periodic motion area extracted based on the change in the density value of the pixel. Since it is equipped with a configuration that calculates the change cycle of the average density value as the motion cycle, the change cycle of the average density value is accurately obtained from the remarkable temporal change in the average density value, and the motion cycle of the moving image is more accurately determined. You can ask.

According to the third aspect of the present invention, the average value of the density values of a plurality of pixels existing in a small area within the periodic motion area is determined by the average density value obtaining means. Calculated as a value. Since each pixel in the micro-area tends to have a uniform density value change tendency, the calculated average density value changes very greatly in the motion cycle of the periodic motion area, and the motion cycle of the moving image is further increased. In addition to being accurately obtained, the number of pixels to be processed is small and necessary processing is easy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an ultrasonic diagnostic apparatus according to an embodiment.

FIG. 2 is a plan view showing a schematic ultrasonic tomographic image obtained by the apparatus according to the embodiment.

FIG. 3 is a schematic diagram showing a periodic motion region in the ultrasonic tomographic image of FIG. 2;

FIG. 4 is a graph showing a temporal change of a density value of a pixel of an ultrasonic tomographic image.

FIG. 5 is a graph showing an integrated value relating to a density value of a pixel in an ultrasonic tomographic image.

FIG. 6 is a graph showing a time change of an average density value of a plurality of pixels in a periodic motion region.

FIG. 7 is a flowchart showing the progress of periodical calculation by the embodiment device over time.

FIG. 8 is a block diagram showing the overall configuration of a conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

 2 ... period finding section 9 ... periodical movement area extracting section 10 ... average density value finding section 11 ... change period finding section P ... ultrasonic tomographic image PA, PB ... periodical movement area Ps ... minute area

Claims (3)

[Claims] An apparatus for calculating a motion cycle of a periodic motion region of a medical moving image in which a periodic motion region performing a periodic motion exists in an image, the temporal motion of a density value of a pixel of the medical moving image being obtained. An apparatus for calculating a motion cycle of a medical moving image, comprising: means for calculating a motion cycle of a periodic motion area based on a change. 2. The medical motion image motion cycle calculating apparatus according to claim 1, wherein the means for calculating the motion cycle determines the periodic motion area based on a temporal change in the density value of each pixel of the medical moving image. A periodic motion region extracting means for extracting, and an average density value calculating means for calculating an average density value of a plurality of pixels including at least a pixel present in the periodic motion region extracted by the periodic motion region extracting means, A motion cycle calculating apparatus for medical moving images, comprising: a change cycle calculating means for calculating a change cycle of the average density value calculated by the average density value calculating means as a motion cycle of a periodic motion area. 3. An apparatus according to claim 2, wherein said average density value calculating means is configured to calculate an average density value of a plurality of pixels present in a minute area within the periodic motion area. Is obtained as an average density value.