JP2001170035A - Method and instrument image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display at least two images of the same object to be comparatively read with improved performance for comparative reading images. SOLUTION: The structural relation among corresponding positions of three images displayed on an image display screen 11 are previously found by a corresponding position calculating means 14. Then the same structure/ organization as that indicated and displayed by a first marker C1 in a subtraction diachronic image Su among the displayed three images is indicated and displayed by a second marker C2 in a first original image P1 or by a third marker C3 in a second original image P2.

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 an image display apparatus, and more particularly to an improvement in display of two or more images of the same subject.

[0002]

2. Description of the Related Art Conventionally, it has been practiced in various fields to compare and read two or more images of the same subject, check the difference between the two images, and inspect the subject based on the difference. ing.

[0003] For example, in the field of manufacturing industrial products, an image of a certain product photographed in a new condition and an image photographed after a durability test of the product are compared and read to find a part where the difference between the two is large. Attention has been paid to studying areas where product durability should be improved.In the medical field, physicians use multiple radiographic images taken in chronological order of a patient's diseased area. By performing comparative image interpretation, the progress of the disease and the healing status of the disease are grasped to examine a treatment policy.

[0004] As described above, comparative reading of two or more images is routinely performed in various fields. When the two or more images are displayed on an image display device or the like for the comparative reading. There is. That is, the image is converted into a density signal or a luminance signal and then displayed on an image display device or the like.

[0005]

When displaying two or more images to be compared, it is common to simply display those images side by side. Of most interest is the difference between these images. However, as described above, for example, 2
It is difficult to find the difference by simply displaying two images side by side, and the smaller the difference is, the more difficult it is.

In order to meet this demand, the present applicant has proposed various types of image display methods and image display devices for improving the performance of comparative image interpretation (Japanese Patent Application No. 11-34).
No. 2900).

[0007] However, even with these proposed image display methods and devices, the corresponding portions between two or more images are not directly indicated, so that the corresponding portions between the images are not necessarily compared with high accuracy. Not exclusively.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and improves the image interpretation performance of two or more images of the same subject to be compared and interpreted by increasing the contrast accuracy of the comparison object portion compared to the related art. It is an object of the present invention to provide an image display method and an image display device that can be improved.

[0009]

SUMMARY OF THE INVENTION An image display method and an image display apparatus according to the present invention provide an image display method using a marker or a pointer on one of two or more images displayed for the same subject, which are to be compared and interpreted. When a part is designated, a different marker or pointer is used to display a different marker or pointer at a part (structurally corresponding position) corresponding to the image part designated by a marker or the like on another displayed image. The comparison accuracy of the portion to be compared is improved.

That is, according to the image display method of the present invention, there is provided an image display method for displaying two or more images of the same subject, which is a subject of comparative image interpretation, wherein a structural correspondence positional relationship is previously determined for the two or more images. Based on the previously determined structural correspondence positional relationship, a structural correspondence positional relationship portion in another image corresponding to an image portion designated in one of the two or more displayed images is displayed. It is characterized by displaying an instruction.

[0011] Here, the subject includes animals and plants, plants and animals in addition to the human body and the like.
Everything including industrial products, terrain, celestial bodies, landscapes, etc. is included.

The structural correspondence positional relationship means a positional relationship when a structural element of a subject recorded as an image is associated with the structural element, and ignores the structural element on the image to the left edge of the image. ○ cm from the top edge, and × cm from the upper edge. Note that the structure is not limited to an appearance structure on an image, but may be, for example, an anatomical structure (eg, lung field, sternum, neck, etc.). This is because it is the most interesting part in comparative reading in the medical field.

An instruction for an image portion on one image is:
As described above, the marker and the pointer may be displayed together with the image, and the reader may move the marker or the like arbitrarily using an interface such as a mouse.

As the two or more images of the same subject to be compared and interpreted, a medical radiation image can be applied. In this case, the two or more images of the same subject to be compared and interpreted may be original images (original images) or at least one of the two or more original images.
And at least one or more subtraction images, which is the difference between the two images selected from the two or more original images after the two images are aligned, or selected from the three or more original images. Two or more subtraction images, which are the differences between the two images after the two images are aligned, may be used as the subtraction images. Energy subtraction images obtained based on one original image (= original image; high-pressure image (normal radiographic image), low-pressure image (high-pressure suppression image)) (simple subtraction or weight subtraction), taken at different times in time series Subtraction images obtained based on the two original images obtained before and after the injection of the contrast agent Obtained on the basis of the two original images obtained vascular Te DSA can be applied (digital subtraction angiography) images and the like.

The two or more images displayed simultaneously may be displayed on different display areas on the same image display surface, or may be displayed on different image display surfaces (different image display surfaces). (A display device).

Further, in addition to two or more images displayed simultaneously, a plurality of images to be observed and interpreted may be switched and displayed.

An image display apparatus according to the present invention is an apparatus for implementing the above-described image display method according to the present invention, and includes an image display means for displaying an image, and is an object of comparative image interpretation.
In an image display apparatus displaying two or more images of the same subject, a corresponding position calculating means for previously obtaining a structural corresponding positional relationship for the two or more images, and based on the previously obtained structural corresponding positional relationship, An instruction marker means for instructing and displaying a desired image portion in any one of the displayed two or more images, and a correspondence based on the structural correspondence positional relationship obtained by the correspondence position calculation means. And a follow-up marking means for instructing and displaying a portion of the structural correspondence positional relationship in another image.

For two or more images of the same subject to be compared and interpreted, as in the case of the image display method of the present invention, the original image, the subtraction image, and the combination of the original image and the subtraction image are used. There may be. Further, the two or more original images may be time-series images having different imaging time points, or may be medical radiation images.

[0019]

According to the image display method and the image display apparatus of the present invention, a marker, a pointer or the like (indicating marker) is displayed on one of two or more images displayed for the same subject, which is a target of comparative image interpretation. ), When an image portion is designated, a portion (structurally corresponding position) corresponding to the image portion designated by a marker or the like on another displayed image,
By displaying instructions with different markers, pointers, etc. (follow-up signs), the accuracy of comparison of the comparison target part is increased, so that image readers such as doctors can accurately grasp differences between images. In addition, the comparative image reading performance can be improved.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an image display method and an image display device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a medical image network 100 including an image display device 10 which is an embodiment of the image display method and the image display device of the present invention.

The network 100 shown in FIG.
T image (computer tomography apparatus), MRI apparatus (magnetic resonance image apparatus), CR apparatus (computer radiography) 50, and other medical image generating apparatuses, and various types of medical image generating apparatuses generated by these medical image generating apparatuses. A database 70 for storing and storing diagnostic medical images, an image display device 10 for displaying images once stored in the database 70 and images directly sent from the image generation device, and the like are connected. The network 100 is also connected to a printer or the like that outputs an image distributed on the network 100 to a film or the like, but is not shown in the figure including the CT apparatus and the MRI apparatus.

The CR device 50 irradiates radiation transmitted through the subject onto a sheet-shaped stimulable phosphor sheet having a stimulable phosphor layer, thereby accumulating a transmitted radiation image of the subject on the stimulable phosphor sheet. Recording, then irradiating the stimulable phosphor sheet with a laser beam, and photoelectrically reading the stimulated emission light emitted in an amount corresponding to the radiation energy stored and recorded on the sheet, thereby transmitting the object through the stimulable phosphor sheet. It is a device that acquires a radiation image as a digital image, and is widely used in medical institutions such as hospitals.

A QA-WS (work station for image quality check) 60 interposed between the CR device 50 and the network 100 checks a diagnostic image generated by an image generating device such as the CR device 50 described above. The workstation has a function of requesting the image generating apparatus to reacquire an image when necessary. The QA-WS 60 according to the present embodiment displays the digital image P generated by the CR device 50 before storing the digital image P in the database 70 and checks the image quality such as image density and contrast, and checks the shooting range and the like. It is provided as a thing.

The image display device 10 includes a network 100
Not only as a visible image, but also as a subtraction process for two or more images P taken in time series for the same affected part of the same patient. A temporal subtraction image creating unit 15 for producing such temporal subtraction images Su, an image display surface (image display means) 11 for displaying images, and a memory 16 for temporarily storing the images.
And a corresponding position calculating unit 14 for previously obtaining a structural (anatomical) corresponding positional relationship for the three images displayed on the image display surface 11, and an anatomical corresponding positional relationship previously obtained by the corresponding position calculating unit 14. , One of the three displayed images (in the present embodiment, the first original image P1 and the second original image P2 are obtained by subtraction processing in which pixels correspond to each other). The desired image portion 14 in the subtraction time-lapse image Su) is designated by the mouse 1
7 (the arrow-shaped first sign)
Instruction marker means 13 for displaying an instruction at marker C1;
On the basis of the anatomical corresponding positional relationship obtained by the corresponding position calculating means 14, other remaining display images (in the present embodiment, the first original image P1 and the first original image P1) corresponding to the designated position of the first marker C1. A portion corresponding to the structural correspondence positional relationship in the second original image P2) is designated as a follow-up marker (the second marker C2 and the third marker C3).
And a follow-up marking means 12 for indicating and displaying with the marker C3).

Next, the operation of the image display device 10 according to the present embodiment will be described.

The radiographic images P1 and P2 of the chest of a specific patient are previously taken by the CR device 50 at different imaging times, and after these images P1 and P2 have been checked for image quality and the like by the QA-WS60. It is stored in the database 70 via the network 100. Each of the stored and stored images P1 and P2 includes, as header information, an ID number unique to the patient who has been photographed, a sign indicating a photographed region (in the present description, the chest), a photographing position, and a photographing date. are doing.

First, the network 1 is connected to the image display device 10.
00, two original images P1 and P2 to which the same ID number, the same imaging part symbol, and header information of different imaging dates are attached are input. The two original images P1 and P2 are chest front images of the same patient with different imaging dates, and are images to be compared in time series (FIGS. 2A and 2B). Note that the first original image P
The second original image P2 has a newer shooting time than the first original image P1, and the first original image P1 can be called a past image and the second original image P2 can be called a current image.

Here, the two input time-series images P
1 and P2 are input to the temporal subtraction image creating unit 15. The temporal subtraction image creating unit 15 performs a subtraction process of calculating a difference by associating pixels between the two input original images P1 and P2. As shown in FIG. 2, both images P1 and P2 are processed. The arrangement positions of the subject (the chest of the patient) in the above are not exactly the same. Therefore, if the subtraction processing is performed by associating pixels between the two as it is, there is a high possibility that processing is performed between different tissues, such as the subtraction is performed between the bone and the soft part.

The temporal subtraction image creating unit 1
5 performs a subtraction process after performing a positioning process as shown in FIG. Hereinafter, the processing content of the temporal subtraction image creation unit 15 will be described.

First, a first original image P1 and a second original image P
2 (global matching). This is a process of performing affine transformation (rotation, parallel shift) on the first original image P1 so that the first original image P1 matches the second original image P2.
By this processing, the first original image P1 is converted into a first image P1 'as shown in FIG.

Next, the temporal subtraction image creating unit 15
Is obtained by combining the entire second original image P2 with a number of regions of interest (RO).
I) Divide into T, and represent the center pixel of each ROI (T) by an xy coordinate system (x, y) (see FIG. 5). In addition, the temporal subtraction image creation unit 15 outputs the first image P
The search ROI (R) is set to 1 '. This search ROI
(R) is set corresponding to each ROI (T) of the second original image P2, has the same center coordinates (x, y), and
This is an area four times as large as (T) (both vertically and horizontally).

The temporal subtraction image creation unit 15
By moving the corresponding ROI (T) of the second original image P2 among the respective search ROIs (R) set in the first image P1 ', the two images P2, A position (ROI center position (x ′, y ′)) where the degree of matching of P1 ′ is high is calculated (shift amount calculation for each ROI by local matching). As the index value indicating the degree of the matching degree, for example, an index value based on cross-correlation can be used.

The shift value (Δx, Δy) (where Δx = x′−x, Δy = y′−y) for each center pixel (x, y) of each ROI thus obtained is Image P
As shown in FIG. 6, between P2 and P1 '. Then, each shift value (Δx, Δx) for each central pixel (x, y)
Using y), an approximation process using a two-dimensional tenth-order polynomial is performed in order to obtain shift values (Δx, Δy) for all pixels of the first image P1 ′. Then, based on the obtained shift value (Δx, Δy) for each pixel, a nonlinear distortion conversion process (warping) for shifting each pixel (x, y) of the first image P1 ′ is performed on the first image P1. '.

A first converted image P1 "obtained by warping the first image P1 'is converted into a second original image P2 (FIG. 7).
(1)) is an image in which the structure / tissue matching at the corresponding pixel is very good ((2) in the figure), and the second original image P2 is converted from the first converted image P1 ″ to the corresponding pixel. (3), a temporal subtraction image Su with very few artifacts due to boundaries between tissues is acquired, as shown in Fig. 3 (3), and this temporal subtraction image Su is a first original image. The lesion K that is not present in P1 but is present in the left lung field of the second original image P2 is prominent.

The temporal subtraction image Su generated by the temporal subtraction image generating means 15 and the original images P1 and P2 read from the memory 16 are input to the corresponding position calculating means 14, respectively. The corresponding position calculating means 14 calculates the structural corresponding positions of the three input images P1, P2 and Su based on the result of the image alignment by the temporal subtraction image generating means 15. In other words, the subtraction image Su is composed of a second original image P1 that is a current image that has not been subjected to any conversion processing and a first converted image P1 that is a past image that has been subjected to the conversion processing.
1 ", the second original image P2 has exactly the same positional relationship of the structure / tissue. Therefore, the coordinate position (xsub, ysub) on the subtraction image is the same as the second original image P2. 2 on the original image (x
2, y2) (xsub = x2, ysub)
= Y2). On the other hand, the subtraction image Su has the same positional relationship with the structure / tissue as the first converted image P1 ″, but does not have the same positional relationship with the first original image P1 before the conversion. The coordinate position (xsub, ysub) on the subtraction image and the coordinate position (x1 , Y1).

As described above, since the coordinate position (xsub, ysub) on the subtraction image completely matches the coordinate position (x2, y2) on the second original image, the coordinate position (xsub, y2) on the subtraction image is xsub, ysub) and the coordinate position (x1, y1) on the first original image, the coordinate position (x
2, y2) and the coordinate position (x1, y1) on the first original image
Is also determined at the same time.

The corresponding positional relationship between the images obtained by the above operation is stored in the memory 16. Each of the images P1, P2, and Su is, as shown in FIG.
At the top, they are displayed in a horizontal line in order from the left.

Here, the first marker (arrow-shaped cursor) C1 linked to the movement of the mouse 17 is displayed on the subtraction image Su by the instruction marker means 13, and is displayed on the first original image P1. The second marker C2 linked to the movement of the first marker C1 is displayed on the second original image P2 by the second marker C12.
Thereby, the third markers C3 linked to the movement of the first markers C1 are displayed.

Each of the second marker C2 and the third marker C3 is controlled by the follow-up marker 12 based on the corresponding positional relationship stored in the memory.
Following the movement of the first marker C1 output from the third marker 3, the first and second originals having the same structure and organization as the image portion indicated by the first marker C1 on the first original image P1. The structure and organization in the images P1 and P2 are specified.

That is, as shown in FIG. 8, since the second original image P2 is an image shifted to the lower side of the subject relative to the first original image P1, the images are simultaneously displayed on the image display surface 11. Sometimes, even when the height position of a structure or a tissue in each image is deviated between the images, the radiologist reads the first marker C on the subtraction image Su by operating the mouse.
1 is moved, the other images (the first original image P1, the second
Of each marker C on the original image P2)
2 and C3 indicate structures / tissues indicated by the first marker C1 at each moment or positions where these structures and the like are assumed to be present.

Therefore, compared to the conventional case where the images are simply displayed side by side, the marker can be used to reliably indicate the comparison target portion in each image, so that the contrast accuracy can be improved. Accordingly, an image interpreter such as a doctor can accurately grasp the difference between the images.

In the description of the present embodiment, the temporal subtraction image creation unit 15 performs local matching after performing global matching on at least one image. However, the present invention is not limited to such an embodiment. Alternatively, local matching may be performed without global matching. Further, the processing (affine transformation, non-linear distortion transformation) is not performed only on the first original image P1, but also on the second original image P2 or the second original image P2.
The processing may be performed on only the second.

Further, a temporal subtraction image creating unit 1
The image display device 5 does not necessarily need to be provided in the image display device 10 itself, and may be provided as an independent temporal subtraction image creation device on the network 100 or provided as a part of the function of the QA-WS 60. You may.

In the image display apparatus of the present embodiment, the temporal subtraction image obtained by the processing disclosed in Japanese Patent Application Laid-Open No. 7-37074 is mainly displayed. The display device is not limited to such images, and two original images (high-voltage image, low-voltage image) having different energy distributions obtained by photographing at substantially the same time in time series, and the energy obtained based on these images. Subtraction image, two original images of blood vessels obtained before and after the injection of the contrast agent, and DS obtained based on these images
As long as two or more images of the same subject, such as the A image, to be compared and interpreted, any image can be applied irrespective of whether it is a living body or not.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing two original images displayed on the image display device shown in FIG.

FIG. 3 is a diagram showing an outline of a temporal subtraction process;

FIG. 4 is a diagram illustrating global matching.

FIG. 5 is a diagram illustrating local matching.

FIG. 6 is a diagram illustrating a nonlinear distortion conversion process.

FIG. 7 is a diagram showing a second original image P2, a first converted image P1 ″, and a subtraction image Su.

FIG. 8 is a diagram showing a state displayed on an image display surface.

[Explanation of symbols]

 10 Image display device 11 Image display surface (image display means) 12 Follow-up sign means (second and third markers) 13 Pointer sign means (first marker) 14 Corresponding position calculating means 15 Temporal subtraction image creating means 16 Memory 17 Mouse 50 CR device 60 QA-WS 70 Database server 100 Network P1, P2 Original image Su Subtraction image K Lesion R Search ROIT ROI C1, C2, C3 Marker

Claims (12)

[Claims] 1. An image display method for displaying two or more images of the same subject to be compared and interpreted, wherein a structural correspondence positional relationship is determined in advance for the two or more images, and the structural relationship determined in advance is determined. Instructing and displaying, based on the corresponding positional relationship, a portion of the structurally corresponding positional relationship in another image corresponding to the image portion designated in any one of the displayed two or more images. Image display method to be used. 2. The image display method according to claim 1, wherein each of the two or more images of the same subject to be compared and interpreted is an original image. 3. Two or more images of the same subject to be compared and interpreted are at least one of two or more original images and two selected images of the two or more original images. 2. The image display method according to claim 1, wherein the difference is at least one or more subtraction images, which is a difference between the two after the positioning. 4. A subtraction in which two or more images of the same subject to be compared and read are each a difference between two or more selected three or more original images after registration. The image display method according to claim 1, wherein the image is an image. 5. The image display method according to claim 2, wherein the two or more original images are time-series images whose photographing time points are different from each other. 6. The image according to claim 1, wherein two or more images of the same subject to be subjected to the comparative interpretation are medical radiation images. Display method. 7. An image display device comprising an image display means for displaying an image and displaying two or more images of the same subject, which is a subject of comparative image interpretation, wherein a structural correspondence positional relationship between the two or more images is determined. A corresponding position calculating unit that is determined in advance; and an indicating sign unit that indicates and displays a desired image portion in any one of the displayed two or more images based on the previously determined structural corresponding positional relationship. And a follow-up sign unit that indicates and displays a portion of the structural corresponding positional relationship in another corresponding image based on the structural corresponding positional relationship obtained by the corresponding position calculating unit. Image display device. 8. The image display apparatus according to claim 7, wherein each of the two or more images of the same subject to be compared and interpreted is an original image. 9. Two or more images of the same subject to be compared and interpreted are at least one of two or more original images and two selected images of the two or more original images. 8. The image display device according to claim 7, wherein at least one or more subtraction images, which are the differences between the two after the positioning, are performed. 10. A subtraction in which two or more images of the same subject to be compared and read are each a difference between two or more selected three or more original images after registration. The image display device according to claim 7, wherein the image display device is an image. 11. The image display device according to claim 8, wherein the two or more original images are time-series images at different photographing points. 12. The image according to claim 7, wherein two or more images of the same subject to be subjected to the comparative interpretation are medical radiation images. Display device.