JPH10305015A - Image displaying method utilizing after-image effect and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image displaying method and its device easily judging a lesion part or an abnormal part through the use of an after-image effect by displaying images from different medical image diagnostic device on the same screen by respectively switching every prescribed time. SOLUTION: The image display device 1 is provided with an image memory A43 housing medical images from a first image diagnostic device, an image memory B45 housing medical images from a second image diagnostic device, an image switching switch 47 selecting one of the memories A43 and B45 according to a display switching register 29, and CPU 27 executing the program of respectively switching display between the memories A43 and B45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display method and apparatus, and more particularly to an image display method and apparatus capable of easily detecting an abnormal part from two medical images by using an afterimage effect.

[0002]

2. Description of the Related Art Conventionally, subtraction between two images is performed.
Image subtraction for generating the difference image is performed. For example, by subtracting an image (contrast image) after injection of a contrast agent from a mask image before injection of a contrast agent, digital subtraction angiography (DSA) that obtains an image of only a blood vessel that cannot be obtained by a normal X-ray imaging method is available. Is being done.

There is also known an image synthesizing method in which coordinate points corresponding to two or more types of images are added to obtain a synthesized image. Japanese Patent Application Laid-Open No. Sho 59-46944 discloses a technique in which addition between two images is omitted and two types of image data are alternately switched for each field and displayed on the same screen.

[0004]

However, in the conventional DSA, a display image is obtained by performing subtraction between a plurality of images acquired at a time difference by the same medical image diagnostic apparatus. There is a problem in that only a difference due to a time difference, such as before and after administration of a contrast agent, is displayed, and no further information can be obtained.

In the technique disclosed in Japanese Patent Application Laid-Open No. S59-46944, two types of image data are alternately switched and displayed for each field, so that two types of images, a reference image and a comparison image, are displayed. There is a problem that a combined image that is uniformly combined is displayed, and it is difficult to read the difference between the two images.

Further, in the above-mentioned conventional techniques, a nuclear medicine diagnostic apparatus (hereinafter abbreviated as NM), an X-ray CT apparatus (hereinafter abbreviated as CT)
However, there is a problem in that it is not possible to compare and examine the medical images collected by different inspection methods such as a magnetic resonance imaging apparatus (hereinafter abbreviated as MR) by the afterimage effect.

[0007] In view of the above problems, an object of the present invention is to provide an image display method and apparatus capable of displaying images from different medical image diagnostic apparatuses superimposed on the same screen.

It is another object of the present invention to provide an image display method capable of easily judging a lesion or an abnormal part by efficiently using a residual image effect by switching the display of a reference image and a comparative image at an optimum display time ratio. And equipment.

It is a further object of the present invention to provide an image display method and apparatus which can easily compare and examine medical images collected by different kinds of medical image diagnostic apparatuses using a general-purpose image display apparatus. .

[0010]

To achieve the above object, the first invention of the present application is a first step of displaying a first medical image collected by a first medical image diagnostic apparatus on a display screen, A second step of displaying a second medical image collected by a second medical image diagnostic apparatus on the display screen;
And a third step of switching and repeating the second step for each designated duration time, and a third step.

In the first invention of the present application, the first invention
The ratio of the duration of the second step to the duration of the second step can be any value from 1: 3 to 1: 8.

Further, the second invention of the present application is directed to a first and second image storage means, and a selection means for selecting and outputting one of the images stored in the first or second image storage means, respectively. An afterimage effect comprising: display means for displaying an image selected by the selection means on a display screen; and selection control means for switching selection by the selection means for a predetermined time for each image. This is an image display device utilizing the above.

In the second invention of the present application, the first invention
The first medical image stored in the image storage means of the
And a second medical image stored in the image storage means of the present invention can be further provided with a positioning means for performing positioning so as to be displayed at the same position on the display screen.

In the second invention of the present application, the first invention
The first medical image stored in the image storage means of the
May be further provided with a bit width adjusting means for adjusting displayable gradation or density resolution with the second medical image stored in the image storage means.

Further, in the second invention of the present application, the first invention
The first medical image stored in the image storage means of the
May be further provided with a brightness adjustment unit that matches the brightness with the second medical image stored in the image storage unit.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an image display device according to the present invention. In the figure, an image display device 1 has an interface unit 3 (I /
F), an internal bus 21, an image memory write address register 23, an image memory write data register 25, and a CPU 2 which is a microprocessor for controlling the entire image display device.
7, display switching control register 29 in which a control command is set from CPU 27, main storage device 31, large-capacity storage device 3
3, input device 35, address changeover switches 37, 39,
An image changeover switch 47 for selecting one of the image memory A43 and the image memory B45 according to the contents of the display address register 41, the image memory A43, the image memory B45, and the display changeover register 29; a digital / analog converter (D / A) 49; It comprises a TV synchronizing signal generation circuit 51, a CRT 53 for image display, and a VTR 55 for recording an image displayed on the CRT.

The main storage device 31 stores various program subroutines for the CPU 27 to perform image display control.
B31b, brightness adjustment SUB31c, timekeeping SUB31
d, switching control SUB31e, input / output control SUB31f, and the like.

The external bus 5 has an X-ray CT apparatus (C
T) 7, a magnetic resonance imaging device (MR) 9, a nuclear medicine diagnostic device (NM) 11, and other various medical image diagnostic devices are connected, and supplies a medical image displayed by the image display device 1.

Next, the operation of the image display device of FIG. 1 will be described with reference to the flowcharts of FIGS.

First, information for specifying an image group of an examination unit, such as a patient code, an examination date, an image diagnostic apparatus that has collected examination images, and a diagnosis site, is input from the input device 35 (step S11).

Next, from among the various diagnostic imaging devices 7, 9, 11,... Connected to the external bus 5, step S11 is performed.
The image group A of the designated examination is taken in via the I / F 3 from the first image diagnostic apparatus (hereinafter referred to as the image diagnostic apparatus A) selected in accordance with the specification and stored in the mass storage device 33 (step). S13).

Next, similarly, a second image diagnostic apparatus (which is selected from the various image diagnostic apparatuses 7, 9, 11,... Connected to the external bus 5 in accordance with the designation in step S11). The image group B of the inspection specified by the apparatus B) is fetched via the I / F 3 and stored in the mass storage device 33 (step S15).

Next, the inspection image group A is displayed on the CRT 53, and one image serving as a reference image is selected and designated from the inspection image group A (step S17). Either the image memory A43 or the image memory B45 may be used for display from the display of the inspection image group A in step S17 to step S27 described later. In this case, the image switch 47 is controlled so as to always select the image memory in which the image data is stored.

Next, similarly, the inspection image group B is displayed on the CRT 53.
Is displayed, and one comparison image to be compared is selected and designated from the inspection image group B (step S19). It is preferable that the respective inspection parts of the reference image and the comparison image are matched by, for example, referring to information accompanying the image data and selecting an image having the same distance from the top of the subject.

Next, bit matching is performed by the bit matching SUB 31a to match the density resolution of the reference image (bit width of image data for each pixel) with the density resolution of the comparison image (step S21). As the density resolution of the medical image, 8 bits, (256 gradations), 12 bits, 16 bits, and the like are used, and the density resolution does not always match between different medical image diagnostic apparatuses. Let it. The density represented by each pixel may be converted and matched by image tone conversion, or if processing is to be performed at high speed, upper bits or lower bits are added (the data range displayed simply at the white or black level). May be expanded) or deleted and matched. Normally, it is matched to an image having a larger number of bits.

Next, the positioning of the reference image and the comparison image is performed by the positioning SUB 31b (step S2).
3).

In this positioning step, if the enlargement ratio between the reference image and the comparison image is different on the display screen,
First, by referring to the accompanying information of each image, one of the images is enlarged or reduced so that the size of the area represented by one pixel is made equal, so that the enlargement ratios of the two images are made to match.

The alignment SUB 31b for aligning the two images calculates the center of gravity of both images and aligns them so that the two centers of gravity overlap, or as a medical image around the subject. A method of moving and positioning the area without information so that the distance from the edge of each image becomes equal may be used.

Next, the brightness adjustment of the reference image and the comparison image is performed by the brightness adjustment SUB 31c (step S2).
5). The brightness matching SUB 31c matches the brightness of at least a region without information as a medical image around the subject in both images. As a result, flicker in the background area of the medical image is eliminated, and the difference between the subject in the reference image and the subject in the comparative image is effectively recognized as an afterimage.

Next, the reference image is stored in the image memory A43 (step S27), and the comparison image is stored in the image memory B45.
(Step S29). In the process before this, if these steps are already stored in the image memory, these steps do not need to be performed again and can be omitted.

Next, the contents of the image memory A43 are stored in the CRT.
53 is displayed (step S31). This operation is performed by writing a command for selecting the image memory A43 from the CPU 27 to the display switching control register 29 by the switching control SUB 31e. Display switching control register 29
Decodes the written command, and generates a signal for selecting the image memory A43 to the image changeover switch 47.

At the start of the display of the contents of the image memory A43, the timing SUB 31d starts monitoring the time, and when a certain time t1, for example, the time for displaying the contents of the image memory A43 for four frames has elapsed (the determination in step S33 is YES).
ES), control is transferred to step S35.

Next, in step S35, the contents of the image memory B45 are displayed on the CRT 53. This operation is performed by writing a command for selecting the image memory B45 from the CPU 27 to the display switching control register 29 by the switching control SUB 31e. Display switching control register 29
Decodes the written command and generates a signal for selecting the image memory B45 to the image changeover switch 47.

When the display of the contents of the image memory B45 is started, the timer SUB 31d starts monitoring the time, and when a certain time t2, for example, the time for displaying the contents of the image memory B45 for one frame has elapsed (the determination in step S37 is YES).
ES), control is transferred to step S39.

In step S39, as long as the display end command has not been input from the input device, the process returns to step S31 to continue displaying the reference image and the comparison image.

As described above, the reference image and the comparative image are repeatedly displayed on the same screen for the designated time until the display end command is input from the input device. The image is observed as if it were raised.

When the display end command is input (the determination in step S39 is YES), it is determined whether or not an image change command is input (step S41).
If it has been input, the flow branches to step S17 to change the reference image and the comparison image from the respective inspection image groups A and B.

Next, it is checked whether or not a selection change command has been input (step S43). If the command has been input, the flow branches to step S11, and returns to the input stage of the patient code and the like. If the display ends and there is no image change or selection change, the process ends.

In this embodiment, the image memory A and the image memory B are provided. However, these memories are arranged in different address areas of the same address space, and the display image is switched by, for example, switching the address range. You may go.

In this embodiment, the reference image is CT
Although the comparison image was an NM image and the comparison image was an NM image, the present invention is not limited thereto, and an image acquired by an arbitrary image diagnostic apparatus such as CT, NM, and MR may be used as a reference image and a comparison image. It is still the same that different parts appear to be raised by the afterimage effect.

Further, in order to align images obtained from a plurality of medical image diagnostic apparatuses different from each other, a tube containing a contrast agent is fixed on the body surface of the subject with a belt or the like, and alignment is performed. After setting the marker, image data may be collected, and the position of the image may be adjusted by overlapping the marker. In this case, it is preferable that at least three markers are arranged so as to be projected on the image, so that the position of each cross section can be identified.

FIG. 4 is a diagram showing the concept of image display by the image display device of the present embodiment.
An image display method is shown in which a T image is displayed as a reference image, four frames are displayed, an NM image corresponding to this image is displayed as one frame as a comparison image, and display of a total of five frames is repeated to obtain an afterimage effect. The number of frames displayed in one second is, for example, 30 or 60.

Table 1 below shows the results of the subjective evaluation on the change in the display time ratio between the comparative image and the reference image. That is, for one frame of the comparative image, the afterimage effect of the display time ratio (image mixing ratio) for displaying the reference image in N frames is subjectively evaluated in three stages, 3 is preferable, 2 cannot be said or neither, and image interpretation is difficult. Indicated as 1.

[0045]

[Table 1] As is apparent from Table 1, the display time ratio between the comparative image and the reference image is preferably in the range of 1: 3 to 1: 8. Below this, the reference image and the comparative image are combined to form one image. As a result, the difference becomes difficult to read, and when the difference is larger, the comparison image is almost invisible.

[0046]

As described above, according to the present invention, one of the image data collected by the different types of image diagnostic apparatuses is used as a reference image and the other is used as a comparative image, and the display is switched at predetermined time intervals. Since the comparison image can be displayed on the same screen, a portion of the comparison image different from the reference image is observed as a result of the afterimage effect, and an effective image diagnosis can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an image display device according to the present invention.

FIG. 2 is the first half of a flowchart showing the operation of the image display device according to the present invention.

FIG. 3 is the second half of a flowchart showing the operation of the image display device according to the present invention.

FIG. 4 is a conceptual diagram of display by the image display device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image display device, 3 ... Interface (I / F), 5
... External bus, 7 ... X-ray CT apparatus (CT), 9 ... Magnetic resonance imaging apparatus (MR), 11 ... Nuclear medicine diagnostic apparatus (N
M), 21: internal bus, 23: image memory write address register, 25: image memory write data register, 27
... CPU, 29 ... Display switching control register, 31 ... Main storage device, 33 ... Large-capacity storage device, 35 ... Input device, 37,
39: Address changeover switch, 41: Display address register, 43: Image memory A, 45: Image memory B, 47
... Image changeover switch, 49 ... Digital / analog converter (D / A), 51 ... TV synchronization signal generation circuit, 53
... CRT, 55 ... VTR.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/262 G06F 15/62 390Z

Claims (6)

[Claims] 1. A first step of displaying a first medical image acquired by a first medical image diagnostic apparatus on a display screen, and a step of displaying a second medical image acquired by a second medical image diagnostic apparatus. A second step of displaying on the display screen; and a third step of switching and repeating the first and second steps for each designated duration. Image display method. 2. The method according to claim 1, further comprising the step of:
2. The method according to claim 1, wherein the ratio of the time to the duration of the process is any value from 1: 3 to 1: 8. 3. A first and second image storage unit, a selection unit for selecting and outputting one of the images stored in the first or second image storage unit, and a selection unit for selecting the image. Display means for displaying a selected image on a display screen, and selection control means for switching selection by the selection means according to a predetermined time for each image, an image display device using an afterimage effect, comprising: . 4. A first medical image stored in the first image storage and a second medical image stored in the second image storage are displayed at the same position on the display screen. 4. The image display device using the afterimage effect according to claim 3, further comprising a positioning means for performing positioning so as to perform the positioning. 5. A displayable gradation or density resolution of each of a first medical image stored in the first image storage unit and a second medical image stored in the second image storage unit. 4. The image display device using an afterimage effect according to claim 3, further comprising a bit width adjusting unit that joins. 6. A brightness adjusting means for adjusting the brightness of the first medical image stored in the first image storing means and the brightness of the second medical image stored in the second image storing means. The image display device using the afterimage effect according to claim 3.