JP2019181204A - Mammography image reading apparatus and mammography image reading method - Google Patents

Abstract

To make it possible to raise throughput of reading work while securing high reading accuracy, and mitigate a load on labor of the reading work.SOLUTION: A mammography reading apparatus is provided as a workstation for reading. The workstation displays on a monitor (13) a two-dimensional X-ray image of a human body's mamma imaged by an X-ray mammography apparatus. On a screen of the monitor of the workstation is set a simulated region (R) that has a specific shape and size and simulatively shows an assumed lesion. A plurality of pixels forming the simulated region are identified on the screen. A plurality of original degrees of brightness of at least some of the identified plurality of pixels are combined with degrees of brightness obtained by performing processing for characterizing an expanse of the simulated region on the at least some of the plurality of pixels. The simulated region having the combined degrees of brightness is superposed and displayed on the monitor screen.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a workstation including a display and an input device for reading a mammography image of a breast collected by X-ray mammography.

  In recent years, breast cancer screening by X-ray mammography has become increasingly important. This is because the incidence of breast cancer and the number of deaths are increasing not only in Japan but worldwide, and breast cancer is the leading cause of death in women aged 30 to 64 years.

  Among them, the incidence of breast cancer has increased in Europe and the United States, but the mortality rate has decreased. This is due to the introduction of breast cancer screening by mammography and early detection of breast cancer with a high screening rate of 60-80%. It is believed that On the other hand, in Japan, although the government recommends regular medical examinations, the breast cancer screening rate is low and the mortality rate is increasing year by year.

  Japanese have a higher percentage of high-concentration mammary gland than Westerners, and with the recent spread of breast cancer screening by mammography, the problem of high-density mammary gland, that is, the lesion is hidden in the high-density mammary gland, and mass lesions are discovered. The issue of difficulty is highlighted. In other words, mammography differs in the risk that the lesion is hidden in the normal mammary gland due to the composition of the mammary gland (fatty, scattered mammary glands, heterogeneous high concentration, extremely high concentration), especially for mass lesions compared to calcified lesions. Becomes higher.

  In recent years, imaging devices compatible with tomosynthesis have appeared, and tomographic images with less overlap of mammary glands can be obtained, making it possible to determine whether the mammary gland is more accurate and normal. However, a device compatible with tomosynthesis is expensive, and the burden on the patient, such as an increase in imaging time and exposure dose, is increased. Further, the number of tomographic images generated is large, and the burden of interpretation work on the interpretation doctor is high.

  In such a situation, a medical image display device and a mammography device described in Patent Document 1 have been proposed for the purpose of improving the efficiency of interpretation of mammography images. The medical image display device of Patent Document 1 is provided integrally with a mammography device. Thereby, the mammography apparatus displays graph information indicating the correspondence between the tomographic position for each tomographic image and the amount of mammary gland, and displays the graph marker GM indicating the tomographic position of the displayed tomographic image on the graph information G1. For this reason, an image reference person such as an interpretation doctor can perform interpretation while visually recognizing the position where the graph marker GM is displayed and easily grasping the mammary gland amount of the displayed tomographic image. As a result, the interpretation efficiency is improved.

JP 2017-047080

  However, in the medical image display device described in Patent Document 1 described above, the graph marker GM indicating the tomographic position of the displayed tomographic image is superimposed and displayed on the graph information G1, but the interpreting doctor has a tumor or tumor in the shadow of the mammary gland. In view of whether the lesions such as the above are not mixed in or hidden, it is not involved in the efficiency and facilitation of the interpretation of visual observation of each mammography image one by one.

  Of course, “improvement and efficiency of interpretation” here means not only shortening the interpretation process but also reliably interpreting lesions of a smaller size to improve diagnostic accuracy. . For this reason, it is desirable to have a marking mechanism so as not to miss “a lesion of at least a size”. For this reason, it is desirable to have a mechanism that can ensure higher interpretation accuracy and to increase the throughput of the interpretation work to reduce the labor burden of the interpretation doctor.

  Accordingly, the present invention can ensure higher interpretation accuracy in view of the situation of the above-described conventional interpretation work of mammography images, and can improve the throughput of interpretation work for the interpretation doctor and interpret the interpretation. It is an object of the present invention to provide an interpretation device and interpretation method for mammography that can reduce the labor burden of work.

In order to achieve the above object, a mammography interpretation apparatus according to the present invention provides:
A monitor, image display means for displaying a two-dimensional X-ray image of a human breast imaged by an X-ray mammography apparatus on the screen of the monitor, and the monitor on which the X-ray image is displayed by the image display means. A simulation area setting unit that sets a simulation area having a specific shape and size and simulating the size (and spread) of an assumed lesion is formed on the screen, and the simulation area is formed on the screen. A pixel specifying means for specifying a plurality of pixels, a plurality of original luminances of at least a part of the plurality of pixels specified by the pixel specifying means, and the presence of the simulated region in the at least a part of the plurality of pixels. A luminance synthesis unit that synthesizes the luminance obtained by performing the characteristic processing, and a screen displayed on the monitor is superimposed on the simulated area having the luminance synthesized by the luminance synthesis unit. Characterized in that and a superimposed display means for displaying.

  In this way, a simulated area simulating a lesion is superimposed and displayed on the X-ray image of the breast with a brightness that characterizes the spread of the simulated area. For this reason, by moving the simulated region to the site of interest, the size of the simulated region, that is, the size (spread) that the lesion such as a tumor does not want to be overlooked is compared with the spread of the region of interest in the mammary gland tissue. Can be observed. Specifically, the lesion is not hidden behind the region of interest of the mammary gland tissue, or a state equivalent to a rule is obtained easily and quickly on the image. For this reason, it is possible to perform interpretation of a mammography image with higher accuracy and speed, contribute to an improvement in interpretation throughput, and contribute to a reduction in interpretation labor of an interpreter.

  As a preferred example, the simulated area is set to a desired size for an operator to prevent oversight of a lesion on the X-ray image.

  As another preferred example, the simulated area setting means includes area changing means capable of changing at least one of the size and shape of the simulated area displayed on the monitor screen.

  Further, the mammography interpretation method according to the present invention displays a two-dimensional X-ray image of a human breast imaged by an X-ray mammography apparatus on a monitor screen, and the screen of the monitor on which the X-ray image is displayed. In addition, a simulation region having a specific shape and size and simulating the size (and spread) of the assumed lesion is set to be movable for searching the X-ray image, and the simulation region is A plurality of pixels to be formed are specified, and at least a part of the plurality of specified pixels is subjected to a process for characterizing the presence of the simulated region on at least a part of the plurality of original luminances. The simulated area having the synthesized luminance is superimposed and displayed on the screen displayed on the monitor.

  Also by this interpretation method, the same operational effects as the operational effects that can be provided by the above-described interpretation apparatus can be exhibited.

In the accompanying drawings,
FIG. 1 is a configuration diagram including a partial functional block of a workstation that implements a mammography interpretation apparatus and a mammography interpretation method according to the first embodiment. FIG. 2 is a block diagram for explaining the outline of the arithmetic device mounted on the workstation according to the embodiment. FIG. 3 is a diagram for explaining the position of the simulated region placed on the X-ray mammography image. FIG. 4 is a screen diagram for explaining a comparison between the size of the simulated region and a part of the mammary tissue (whether the simulated region is hidden in the mammary tissue). FIG. 5 is a screen diagram illustrating an example of a simulated area generated based on luminance synthesis using the first synthesis pattern. FIG. 6 is a screen diagram illustrating an example of a simulated area generated based on luminance synthesis using the second synthesis pattern. FIG. 7 is a screen diagram illustrating an example of a simulated area generated based on luminance synthesis using the third synthesis pattern. FIG. 8 is a graph for explaining the use of the synthesis formula with the threshold as the boundary according to the third synthesis pattern. FIG. 9 is a screen diagram for explaining the relationship between the luminance synthetic pseudo lesion, the mammary gland tissue, and the display, which are encountered when the fourth synthetic pattern is used. FIG. 10 is a schematic flowchart illustrating an example of an image interpretation process with a simulated area, which is executed by the arithmetic unit (CPU). FIG. 11 is a configuration diagram including a partial functional block of a workstation that implements the mammography interpretation apparatus according to the second embodiment. FIG. 12 is an explanatory diagram for explaining interlocked display of simulated areas of two mammography images that are pair images according to the second embodiment. FIG. 13 is a diagram illustrating various examples of the shape of a specific region (simulated region) that simulates a lesion.

  Hereinafter, a mammography interpretation apparatus and a mammography interpretation method according to embodiments of the present invention will be described with reference to the accompanying drawings.

[First Embodiment]
A mammography interpretation apparatus and a mammography interpretation method according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the mammography interpretation apparatus and the mammography interpretation method are performed by an interpretation workstation (hereinafter simply referred to as a workstation) 3 that receives a mammography image captured by the mammography apparatus 1 via an image server 2. It has been implemented.

  The workstation 3 includes a computing device 11 that performs various predetermined program computations by a computer, and an input device 12 and a display device 13 that are communicably connected to the computing device 11 and function as a man-machine interface.

  The mammography apparatus 1 has a well-known configuration and collects X-ray transmission images obtained by performing X-ray irradiation and X-ray detection in the compression direction in a state where the human breast is compressed with a compression plate. Is configured to do. This X-ray transmission image is a two-dimensional image in which the degree of attenuation of X-rays exhibited by various tissues in the breast is expressed by, for example, gray level gradation. This X-ray transmission image is not only a simple two-dimensional image, but also shift-added multiple frame data acquired by tomosynthesis imaging (multiple imaging at different X-ray incidence angles with the breast pressed). Reconstructed images that are reconstructed using techniques such as shift and add and Filtered Back Projection, and focus on a region of a certain thickness at that position are also included.

  In general, mammography imaging is often performed in two directions, MLO (Medio-Lateral Oblique) and CC (Cranio-Caudal), in order to minimize the blind area of the breast. In the case of two-directional imaging, the direction in which the mammary gland tissue is pressed and expanded differs, so that the possibility that the lesion site is hidden behind the mammary gland tissue during interpretation can be reduced to some extent. Further, at the time of interpretation, an abnormality can be detected by comparing left and right mammary gland structures.

  As an example, the mammography image photographed by the mammography apparatus 1 is sent to the image server 2 together with examination information (patient name, patient ID, photographing date and time, photographing conditions, etc.) via the communication network CM1 (Internet etc.). Stored in the server 2. The image server 2 is configured, for example, as a PACS (picture archiving and communication system), in which examination information and mammography images are similarly received from one or more medical facilities. As an example of this transmission and storage, DICOM (Digital Imaging and Communications in Medicine) standard is adopted.

  The workstation 3 is communicably connected to the image server 2 via a communication network CM2 (for example, the Internet). Therefore, the workstation 3 can download the mammography image that matches the search condition from the image server 2 together with the inspection information by transmitting the search condition to the image server 2.

  Further, in the workstation 3, as shown in FIG. 2, the arithmetic unit 11 specifically includes a central processing unit (CPU) 21 and a non-volatile ROM (read-only ROM) that form the central configuration of the computer. memory), a second storage device 23 composed of volatile RAM (random access memory), etc., and examination information and image data such as patient information and examination information Are connected to each other via a bus 25. An input / output interface (I / O) 26 is connected to the bus 25, and the input / output interface is connected to the bus 25. In addition, as described above, the communication device 26 is communicably connected to the input device 12, the image interpretation observation display device 13, and the image server 2 operated by an operator (such as an image interpretation doctor). .

  The CPU 21 can call an application program stored in the first storage device 22 in advance in its work area, and sequentially execute the instructions along the steps of the program. It is configured to be able to communicate with the outside via the input / output interface 26. The second storage device 23 is used for temporary writing and reading of data accompanying the operation of the CPU 21.

  Here, the first storage device 22 is provided as a non-transitory computer-readable recoding medium. For this reason, when the arithmetic unit 11 (specifically, the CPU 21) executes an interpretation program stored in the first storage device 22 in advance, functionally, the region setting unit 11A, the pixel specifying unit 11B, and the luminance A combining unit 11C, a display control unit 11D, and a movement control unit 11E are obtained. These functional units will become apparent from the description of the flowchart of FIG. 10 described later.

  The input device 12 includes devices such as a mouse and a keyboard that are operated by an operator (such as an interpreting physician; hereinafter simply referred to as an operator). As an example, the display unit 13 includes a normal color monitor and a high-definition monitor.

  Therefore, the inspection information stored in the image server 2 can be accessed at the request of the operator, and a list of inspection information can be displayed on the color monitor. Further, the operator can select the desired inspection information on the displayed inspection information list, thereby acquiring the mammographic image data of the inspection from the image server 2 and displaying it on the high-definition monitor of the display unit 13. Has been.

In this workstation 3, as schematically shown in FIG. 3, a two-dimensional mammography image IM _m collected by the mammography apparatus 1 is displayed on a display device 13 (particularly, a high-definition monitor: hereinafter referred to as a display device). Occasionally, its mammography images IM _m, the first feature to be displayed by superimposing the region R _sp specific shape in a position in accordance with the desired operator.

Furthermore, the particular shape R _sp plurality of pixels Pn respective luminance forming the region (i.e., pixel values) for its original brightness: and (original luminance collected mammographic image as luminance), the spread of its original brightness The luminance obtained from the synthesized pattern that defines the characterizing process (or determined in advance by default) is synthesized, and the region _Rsp having the specific shape is superimposed and displayed on the mammography image IM _m according to the synthesized luminance. This is the second feature.

This display on the mammographic image IM _m, so that the region R _sp specially processed to specific shape is superimposed. The region R _sp having a specific shape can be freely moved on the screen of the display 13 in accordance with an instruction via the input device 12 of the operator. Since the mammography image IM _m is fixedly displayed on the screen, only the region R _sp having a specific shape is moved in accordance with the movement instruction, and the combined luminance is calculated based on the pixel of the movement destination. It can be updated and displayed according to the display synchronization.

<Features of this embodiment>
Here, features useful for the interpretation work performed at the workstation 3 according to the present embodiment will be described.

<About the first feature>
The shape of the region R _{sp having} the specific shape is set, for example, as a circle, but may not be a circle, and various other shapes can be adopted. For example, the region _Rsp may be a polygon such as a pentagon or a hexagon, or may be an ellipse. A modification of this shape will be described later.

The operator can be used to against the region R _sp at a site lesion mammographic image is suspected, to determine whether it is possible lesion is hidden at the site. On the mammography image, for example, since the display brightness of a part of the structure of the mammary gland is high, if there is a part that looks like a tumor by visual observation, a region R _sp having a specific shape is applied to that part. This is to confirm whether or not the local region R _sp is large enough to hide the lesion. In other words, to shed the region R _sp, since it is determined by a ruler to determine the amount of such suspect part, hereinafter referred to as "simulated region R _sp" region R _sp specific shape from the functional surface I will decide. Note that this “simulated region R _sp ” can be said to be a region of interest (ROI) from the viewpoint of an interpreting doctor.

As an example of the use of this "simulated region R _sp" when shed "simulated region R _sp" on the screen of the mammographic image IM _m, from the portion where it is determined from its initial position or now, through the input unit 12 by the operator In response to the instruction, the “simulated region R _sp ” is moved to the next (suspected) part that the user wants to see.

Since the simulation region R _sp has a rule function as described above, the size of the simulation region R _sp is extremely important. This size is desirably set to a minimum value of a lesion (for example, a mass) to be found in interpretation, that is, “Do not miss anything larger than this”. Furthermore, the size of the simulated region _Rsp is also the minimum size of a lesion that needs to be found.

For this reason, as an example, the simulated region _Rsp is set as a circular region having a diameter of 1 cm. In the case of this example, it can be visually determined whether or not a 1 cm diameter tumor lesion can be hidden in the mammary gland structure, and interpretation can be supported.

Expressing this schematically, the case in FIG. 4 (A), since a portion of the mammary gland NS is smaller than the simulated region R _sp, mass lesion diameter of more than 1cm in this part can be determined that it is impossible to hide . On the other hand, as shown in FIG. 5B, another part of the mammary gland structure NS to which the simulated region R _sp is applied is larger than the region R _sp , so that a mass lesion is hidden in that portion in terms of brightness. Can be determined to exist or possibly exist. For this reason, the operator moves the simulated region _Rsp from the same figure (A) to the same figure (B), and whether or not there is a tumor lesion at the position of each movement destination, and is hidden in the mammary gland structure NS there. Interpretation is possible while paying attention to whether there is any.

<About the second feature>
When the “simulation region R _sp ” is applied (set) to a local part of interest on the screen of the mammography image IM _m and a synthesis process to be described later is instructed, the luminance synthesis pattern is used to synthesize the luminance of the local part. Processing is done. Thus, in addition to the ruler functions described above, the original luminance of the pixels constituting the simulated region R _sp (original pixel value of mammography images) can be replaced with a composite luminance in accordance with the characteristics. Therefore, the simulated area R _sp in accordance with the characteristics of the original brightness is displayed on the display unit 13 in a state of being superimposed on the mammographic image IM _m. This display is also updated in synchronization with the screen display of the display 13.

The synthesis process is performed in accordance with one or more synthesis patterns (luminance synthesis mode) that can be selected by the operator or determined by default settings. The synthesis process is based on the properties exhibited by the original brightness of the pixels constituting the simulated region R _sp, lesion corresponding to the simulated region R _sp is to visually demonstrate whether or not hidden mammary tissue It is processing. Therefore, since the lesion is hidden determination of the target corresponding to the simulated region R _sp, likened the simulated area R _sp full moon, mammary tissue can be assumed that a cloud reflected in the full moon. For this reason, if the full moon is covered with a cloud, the full moon behind the cloud will not be visible. In order to clearly show this hidden state, four types of synthesis patterns (luminance synthesis mode) are used in this embodiment. ) Based processing is prepared to be selectable.

<4 types of composite patterns>
· First combined pattern first combined pattern synthesizes luminance only marginal pixels of the simulated area R _sp, inside the pixel values of the mammographic image itself, i.e., to output the original pixel values. This first synthesis pattern is effective when it is desired to accurately check the original pixel value inside the simulation region _Rsp .

  When synthesizing the output luminance of the edge pixels, it may be output at a constant luminance, or a value obtained by XORing the original luminance and the intermediate luminance so as not to be buried in the surrounding display luminance may be used as the output value.

FIG. 5 shows an example of the simulation region _Rsp based on the first composite pattern. As shown in the figure, only the line L _sp indicating the margins of simulated region R _sp is depicted.

A synthetic process by the first combined pattern, the mammographic image IM _m, simulated region simulated manner is equivalent to the tumor mass region R _sp is a mammary gland of determining whether or not Shimawa hiding mammary gland region Effective for interpretation.

Second Synthesis Pattern The second synthesis pattern uses the original luminance as the alpha value for the pixels in the simulated region _Rsp , and outputs the original luminance and the specific value by alpha blending. Thereby, the inside of the region can be expressed with a sense of sheer corresponding to the luminance.

  When this second synthesis pattern is used, its synthesis formula can be provided in the following two ways.

Synthesis formula (1): out = r * org + (1-r) * a
Synthesis formula (2): our = r * org + (1-r) * a * δ _{i, j}
here,
Org: Original pixel brightness,
r = org / gradation width,
a: Constant (for example, a = 128)
δ _{i, j} is a coefficient that simulates the gradation of a sphere depending on the position (i, j) of the simulation region _Rsp . Thereby, based on the synthesis formula (1), for example, as shown in FIG. 6A, the simulated region _Rsp is superimposed on the mammography image IM _m , and on the basis of the synthesis formula (2), for example, FIG. as shown in B), the simulated area R _sp is superimposed on the mammographic image IM _m.

- third each pixel constituting the combined pattern simulated region R _sp of, depending on the whether the original brightness is whether a threshold value or more is less than a threshold, by switching the two types of synthetic equation calculates the synthetic luminance. The threshold is set to 108, for example, when the original luminance of the pixel is expressed by 256 gradations. This threshold can be changed.

As an example, if the original luminance of each pixel is less than the threshold,
Synthesis formula (3): out = (1-r _u ) * org + r _u * 192 + 128
r _u = org / 255
And the original luminance of each pixel is greater than or equal to the threshold,
Is used. Where org: original luminance, a, b, c: changeable synthesis parameters. Among these parameters, a is a parameter that forms a prescribed luminance value of the pseudo lesion and controls basic brightness (this parameter depends on the position of the above-mentioned δ _{i, j} : simulated region R _sp . B may be a parameter), b is a parameter for controlling the position of convergence by the gain of the sigmoid function, and c is a parameter for controlling the degree of convergence by the offset of the sigmoid function. For example, a = 32, b = 5, c = 0.

  The setting of the threshold value used in the third combined pattern has a great influence on the combined luminance display result. The main purpose of this function is to support the determination of whether or not a mass lesion can be hidden in the mammary gland structure, so that the threshold value is specified as the initial value that separates mammary and adipose tissue. ing. Of course, this threshold value can be changed by the operator in advance or during interpretation.

  For this reason, in this embodiment, the threshold initial value used for the third composite pattern is automatically determined using the Otsu method, which is a binarization discrimination method based on the histogram in the breast region. It is comprised so that. The threshold value determined by this method is generally set to a value that separates mammary gland tissue and adipose tissue. Of course, the automatically set threshold value can be changed by an operator's operation (mouse wheel operation or the like).

FIG. 7 shows a similar mammography image IM _m (shown in FIG. 7A) when the threshold value is reduced from the mammography image IM _m (FIG. 9A) in which the simulation region R _sp based on the automatically set threshold value is superimposed and displayed. B)) and a similar mammography image IM _m (FIG. 5C) when the threshold value is increased are illustrated. By increasing the threshold value, the number of pixels calculated by the synthesis formula (3) increases, so that the display luminance of the original pixel having a luminance less than the threshold value is increased, and the visual effect is enhanced ((C) in the figure). ).

  8A and 8B show the output luminance (synthetic luminance) and the pseudo lesion (pseudo) for the input luminance (original luminance: original luminance = 108 = threshold) based on the synthesis formulas (3) and (4). An example of characteristics of each luminance of the pixel in the region is shown.

As a result, for example, as shown in FIG. 7, a simulated region _Rsp is superimposed and displayed on the mammography image IM _m, and a part of the full moon (a part simulating a tumor part) that looks out from between the clouds is a predetermined threshold value. Since it has a luminance of less than that, it is displayed with a high luminance value so that it is clearly depicted that it is less than the threshold. On the other hand, the remaining part of the full moon covered by the cloud (mammary gland tissue) is a pixel having a luminance equal to or higher than a threshold value. Therefore, based on the synthesis formula (4), a sigmoid function is used, and a pseudo lesion term whose output value converges as the luminance becomes higher is added to the original luminance. As a result, the combined luminance is calculated and displayed so that a lesion (simulated region R _sp ) exists behind the mammary gland structure (cloud).

  As a result, it is possible to draw a transparent feeling that the full moon is hidden behind the clouds, and to exhibit the visual effect of converting the density of the mammary gland structure into a depth-like appearance.

· In the fourth combined pattern fourth combined pattern of the simulated area from the original luminance of each pixel of R _sp estimate the average linear absorption coefficient of the pixel, when the pseudo lesion embedded simulation model (simulating region) The composite line absorption coefficient is calculated, and the luminances are combined and output.

Specifically, a value obtained by synthesizing the average line absorption coefficient estimated from the original luminance in each pixel constituting the simulation region _Rsp and the line absorption coefficient of the tumor is calculated, and the combined luminance is calculated using the value as a parameter.

  FIGS. 9A, 9B, and 9C show examples of phantom mammography images in which a pseudo lesion model is embedded and the ratio of fat / mammary gland is changed. (A), (B), and (C), from adipose tissue (100% fat), average breast tissue (50% fat, 50% mammary gland), and dense breast tissue ( As an example, as the ratio of the mammary gland increases to 30% fat and 70% mammary gland), the synthetic component of the pseudo-lesion decreases and is displayed by being melted by the mammary gland region.

  For this reason, the linear absorption coefficient synthesized by embedding the pseudo lesion is inversely transformed and used as the output luminance to obtain the pseudo lesion output. The inverse transformation becomes an exponential function approximated from a combination of a specific display luminance and a linear absorption coefficient. For this reason, it is necessary to appropriately cope with variations in image quality due to differences in photographing apparatuses and image processing.

  In order to cope with variations in image quality due to differences in imaging devices and image processing, a synthetic component of a pseudo lesion is calculated using the synthesized linear absorption coefficient as a parameter and added to the original display luminance to synthesize the output luminance.

  The synthesized linear absorption coefficient is converted into a normalized parameter of 0 to 1.0 and applied to a formula for calculating the synthetic component of the pseudo lesion, and the output luminance is calculated.

  The effect of the breast thickness on the synthetic component of the pseudo lesion is reduced by adjusting the offset amount of the exponential function. Further, in order to simulate the sphere shadow of the pseudo lesion, the combined linear absorption coefficient is calculated by a cylindrical shape having a uniform thickness, and the sphere shape parameter is applied to the display correction amount of the composite component.

  In the workstation 3 according to the present embodiment, the fourth synthesis pattern is omitted, only the first to third synthesis patterns described above are employed, and the first to third synthesis patterns are used. It may be configured to be selectable or switchable as appropriate.

  Next, an example of image interpretation processing executed by the workstation 3 will be described with reference to FIG. This interpretation process is executed by the CPU 21 of the arithmetic unit 11.

  In step S10, the CPU 21 sends patient information and examination information together with an image transmission request to the image server 2 through the interface 26 interactively with the operator. In response to this, since the corresponding mammography image is transmitted from the image server 2, this image data is stored in, for example, a dedicated image storage device 24.

  Next, in step S11, the CPU 21 interactively determines the display mode of the received mammography image with the operator. As this display mode, one mammography image (single display of either left or right breasts or juxtaposed display of left and right breasts (in this juxtaposed display, a display mode in which left and right pair images are juxtaposed in the same direction, Select a display mode for juxtaposing left and right symmetrically).

  Next, in step S12, the CPU 21 causes the display device 13 to display a mammography image in the determined display mode. Now, it is assumed that a mammographic image of either the left or right breast is displayed on the screen of the display unit 13 alone.

When this display is completed, the CPU 21 determines the initial position of the simulation region _Rsp described above according to an instruction of an operator (such as a doctor) who is viewing the display screen of the display device 13 or by automatic setting based on an image recognition calculation. (Step S13).

Further, CPU 21 is the shape and / or size of the simulated area R _sp, determined interactively in response to a command from the operator (step S14). For this reason, this step S14 bears an area change means functionally.

For example, the simulated region _Rsp is hidden in the mammary gland tissue and avoids the situation that it cannot be detected visually. Therefore, the width and size of the mammary tissue on the screen and the lesion such as a tumor that is to be interpreted without overlooking it. It can be selected and set in consideration of the shape and / or size of the part. As an example, these shapes and / or sizes are stored in advance in a table (for example, the first storage device 22), and the operator may select them with reference to them. Of course, the operator may specify an arbitrary size on the spot.
For example, considering the ruler function to be given to the simulated region R _sp as the shape first, a round simulated region R _sp-1 is appropriate as shown in FIG. 13 (FIG. 13A). reference). Considering the interpretation that additionally considers the shape of the lesion, the oval simulated region R _sp-2 (see FIG. 13B) and the polygonal simulated region R _{sp- 3} (see FIG. 13C), lobular simulated region R _sp-4 (see FIG. 13D), irregular simulated region R _sp-5 (see FIG. 13E) One or a plurality of shapes may be selectably set. These simulated areas are “Mamography Guidelines, 3rd Supplement, Edition, Japan Radiological Society / Japan Radiological Society, Medical School”, “Chapter 6, Mammogram Finding Terminology, page 40, figure This is a basic shape region based on “6-1 Schema of the shape of a tumor”. Actually, this basic shape collapses and deforms, and there are also spiculas that protrude from the periphery.
In the present invention, even the simulated regions R _sp (R _sp-1 , R _sp-2 , R _sp-3 , R _sp-4 , R _sp-5 ) of these various shapes are, for example, the longest. It is only necessary to retain the diameter as a known size (diameter R1 in the case of a circle) (see diameters R2, R3, R4, and R5 in FIG. 13), thereby obtaining a ruler function.
For this reason, these simulated regions _Rsp are stored as data indicating the shape and / or size in advance in the first storage device 22 for each shape and / or size (diameter), for example. In this case, regarding the size (diameter), an interpreter may be able to interactively set an arbitrary value at the time of interpretation.
Of course, only the circular simulation region R _sp-1 may be held so that it can be set, and only its size (diameter) may be set continuously or stepwise within a certain range (for example, 5 mm to 15 mm).

For example, as such shape and size, the circular simulated region R _sp diameter 1cm as a physical (real space) dimensions of the actual in the breast is set. Of course, other shapes and sizes may be used. In order to interpret a small lesion, that is, a smaller lesion, for example, a circle or a polygon having a diameter of 8 mm or 5 mm may be set. This means that the smaller the simulated region _Rsp is set in the real space, the smaller the size of the lesion to be simulated is. Therefore, how much shape and size is selected depends on the amount of interpretation work, etc. It is determined by the operator in consideration of balance.

Then, CPU 21 selects a synthetic pattern to be used for the synthesis of required when to superimpose the simulated region R _sp mammography image IM _m, the luminance of the pixels of the mammographic image IM _m (pixel value) (step S15 ). For example, since the first to third types of synthesis patterns described above are prepared as the synthesis pattern, the operator can specify any synthesis pattern by interactively selecting them.

  Note that the various preparation steps described above are not necessarily limited to the illustrated order, and may be performed in a different order, or a desired order or determination content may be set in advance as a default.

With such ready, CPU 21 waits for whether the command performs interpretation is moved while specifying a simulated area R _sp (step S16). When the operator instructs the image reading start (step S16, YES), CPU 21 is first simulated region R _sp is placed in the initial position of the mammographic image IM _m, mammographic image IM constituting the simulated region R _sp at its initial position A plurality of _m pixels Pn are determined (step S17). The plurality of pixels Pn are specified by positions (i, j) on vertical and horizontal x and y coordinates, as shown in FIG.

  After this, the CPU 21 designates the first target pixel among the plurality of pixels Pn with the coordinate value (step S18). Next, the CPU 21 performs luminance combining processing on the target pixel according to the processing method according to any of the selected first to third combining patterns, and temporarily stores the processing result in, for example, the second storage device 23. Store (step S19). The processing method is as described above according to each synthesis pattern.

Thereafter, the CPU 21 determines whether or not the target pixel to be subjected to luminance synthesis still remains (step S20). If it is determined that the target pixel still remains (step S20, YES), the process proceeds to step S18. The processes in steps S19 and S20 described above are repeated. This is repeated until all the target pixels constituting the simulation region _Rsp are processed.

For this reason, when the determination in step S20 is NO, all the target pixels constituting the simulation region _Rsp have been processed. Therefore, the CPU 21 creates display data by updating the display frame data (step S21). The display data is sent to the display 13 by the CPU 21 via the interface 26 and displayed on the screen (step S22).

Thereby, the simulated region _Rsp is superimposed and displayed on the initial position of the mammography image IM _{m on} the display device 13 instead of or as a part of the screen of the previous preparatory work (step S22). 5, 6, 7).

The superimposed simulated region R _sp each luminance (pixel) is the original luminance by the first to third synthetic pattern described above, by treatment of the composite pattern, little and also some of the pixel synthesis process ( Modulation), not simply replacing or overwriting the entire area with pixels of different brightness. That is, the simulated region _Rsp has region information simulating a lesion such as a tumor while having at least part of luminance information of the original pixel.

CPU21 further operator determines whether to move the simulated region R _sp on mammographic image IM _m (step S23). Further, when the determination result is NO, the process waits while determining the movement of the simulation region _Rsp until an end instruction is issued, and when there is an end instruction, the interpretation is ended (step S24). On the other hand, if YES is determined in step S23, the process is returned to step S17, and the process from the pixel determination at the updated simulated region position to the synthesis process and display is performed (steps S17 to S22). Thus, for example, from the state of the simulated area R _sp in in FIG. 4 (A), the process described above to move to the state of the simulated area R _sp of the (B) is performed. This series of processes is repeated until the operator issues a stop and the interpretation end command the movement of the simulated area R _sp.

  It should be noted that a processing procedure executed by the CPU 21 is set so that the display mode, the shape and size of the simulation area, the synthesis pattern to be used (that is, the luminance synthesis mode), and the like can be arbitrarily switched at any timing during interpretation. Of course you can.

  Here, functionally, step S14 corresponds to the region setting unit 11A, step S17 corresponds to the pixel specifying unit 11B, steps S18 to S20 correspond to the luminance synthesis unit 11C, and step S21 corresponds to the display control unit 11D. Step S23 corresponds to the movement control unit 11E, and step S11 serves as a part of the interlock control unit 11F.

  Functionally, step S22 corresponds to image display means, step S15 constitutes selection means, and step S23 constitutes area movement means.

As described above, according to the workstation 3 according to the present embodiment, an operator (such as a doctor) can determine a desired composite pattern from among a plurality of prepared composite patterns. For this reason, the luminance (pixel value) of at least a part of the pixels in the simulation region _Rsp is modulated based on the processing method defined by the synthesis pattern, and the modulated luminance is synthesized with the original original luminance and displayed. A simulated region _Rsp for use is created. This created simulated region R _sp, the operator has specified, are displayed superimposed on the image at a desired position on the mammographic image IM _m. This superimposition display is made at the changed position accompanying this movement every time the operator moves the simulation region _Rsp .

As can be seen from the simulation images illustrated in FIGS. 5, 6, and 7, the operator reads the mammography image IM _m displayed on the display unit 13 while viewing the screen. According to this screen, the desired position of the mammographic image IM _m, simulated region R _sp is displayed as a round moon-shaped region, moreover, at least its marginal is rendered. According to the second and third combined pattern, not only the edge of the simulated area R _sp, the region of its inside is displayed is processed luminance value. Furthermore, the luminance information of all or part of the mammary gland tissue that is created by the pixels on the mammography image IM _m corresponding to the simulation region R _sp is also left at least partially. As a result, the simulated region _Rsp simulating a lesion such as a tumor and the other mammary gland tissue, for example, are appropriately superimposed and displayed.

In other words, since this simulated region R _sp mimics the shape and size of the lesion, if this simulated region R _sp is hidden behind a part of the mammary gland tissue and cannot be seen, a part of the mammary gland tissue includes a tumor or the like. The lesion may be hidden. That is, the operator can quickly determine whether or not the portion hides the lesion by moving the simulated region _Rsp to a region of interest (suspect). In other words, the operator can obtain a rule function for searching for this simulated region R _sp , that is, a part that hides the lesion in terms of luminance or makes it difficult to see, while taking into account its intuition.

Therefore, the operator can quickly determine the size and spread state of the region while moving the simulated region _Rsp to the region of interest. Of course, when a part where the simulated region _Rsp is hidden is found, it is confirmed and diagnosed whether there is a lesion in the part by another method. Such as compared to ruler A traditional method which does not use a simulated area R _sp having, in this embodiment, the image interpretation work by the auxiliary means with the simulated region R _sp is much faster, it can be expected that the throughput is increased . In addition, the operator's interpretation work can be reduced.

Moreover, by moving the simulated area R _sp site of interest, of easy to Notes attention during operator visually observed at the site, as it were, pointing confirmatory secondary effects can be obtained.

[Second Embodiment]
Next, a workstation according to the second embodiment will be described with reference to FIGS. 11 and 12 and FIG. 10 described above. In the second embodiment, the same or similar components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  As shown in FIG. 11, the second workstation has an interlock control unit 11 </ b> F by program processing of interpretation processing given by the CPU 21 of the arithmetic device 11.

  Explaining this interlocking control, the position of the simulated region, which is a pseudo lesion, is schematically shown in FIGS. 12 (A) and 12 (B). Initial display is made at a symmetrical position. Thereafter, in accordance with the operation of the operator, the initial positional relationship is maintained, and the updated display is interlocked on the pair image. This function is obtained when the processing is performed in parallel with each of the pair images in steps S13 and S16 to S22 of FIG. Therefore, steps S13 and S16 to S23 are functionally equivalent to the interlock control unit shown in FIG.

Specifically, two mammography images IM _m acquired by imaging the left and right breasts with the X-ray mammography apparatus 1 are symmetrically displayed on the screen of the display 13 (see FIG. 12A) or in the same direction ( (See FIG. 12 (B)). Further, in each of the two displayed mammography images IM _m , the simulated region R _sp (R _{sp (L)} , R _{sp (R)} ) is an initial position having left-right symmetry or the same positional relationship in the same direction. Set to

Further, in the two mammography images IM _m , the two simulated areas whose luminance is combined between the images move and display in conjunction with each other while maintaining the same positional relationship in the left-right symmetry or in the same direction. The

  Thereby, the simulated areas are displayed symmetrically on the left and right mammography images. For this reason, in addition to the effects obtained in the first embodiment described above, the comparison of the display brightness of the same area on the opposite side is performed when evaluating the local asymmetric shadow (FAD). And can be judged on the basis of size. As a result, it can be expected that the interpretation accuracy is further improved.

  In the embodiment described above, an example of interpretation of a mammography image was shown as the present invention. However, the gist of the present invention is an X-ray image obtained by imaging other parts of a patient, such as the lung field and stomach. It is also possible to develop the apparatus and method for image interpretation.

DESCRIPTION OF SYMBOLS 1 Mammography apparatus 3 Interpretation workstation 11 Arithmetic apparatus 11A Area setting part 11B Pixel specific part 11C Luminance composition part 11D Display control part 11E Movement control part 11F Interlocking control part 12 Input device 13 Display _Rsp ( _Rsp-1 ... R _sp-5 ) Simulated region IM _m mammography image NS simulating lesion NS Breast tissue

Claims (12)

A monitor,
Image display means for displaying a two-dimensional X-ray image of the human breast imaged by the X-ray mammography device on the screen of the monitor;
A simulation area setting means for setting a simulation area having a specific shape and size and simulating an assumed lesion on the screen of the monitor on which the X-ray image is displayed by the image display means;
Pixel specifying means for specifying a plurality of pixels forming the simulated region on the screen;
Combining a plurality of original luminances of at least a part of the plurality of pixels specified by the pixel specifying unit and a luminance obtained by performing processing for characterizing the spread of the simulated area on the at least some of the pixels. Luminance synthesis means to
Superimposed display means for displaying the simulated area having the brightness synthesized by the brightness synthesis means by superimposing the screen displayed on the monitor;
A mammography interpretation device characterized by comprising:
The luminance synthesis means includes
The luminance is synthesized by synthesizing, for each pixel, the original luminance of the at least some of the plurality of pixels and the luminance obtained by processing the original luminance of the at least some of the plurality of pixels by a predetermined process. Being
The mammography interpretation apparatus according to claim 1.
The predetermined process includes a plurality of types of processes prepared in advance.
The luminance synthesis means is configured to be operable in a plurality of luminance synthesis modes corresponding to the plurality of types of processing,
The image interpretation device comprises:
A selection means that allows the user to arbitrarily select the plurality of luminance synthesis modes;
When an arbitrary luminance composition mode is selected by the selection means, the user can move the simulated area corresponding to the selected luminance composition mode to an arbitrary position on the screen; Prepared,
The superimposed display means is configured to update and display the simulated area moved by the area moving means on the monitor together with the X-ray image.
The mammography interpretation apparatus according to claim 2.
The plurality of types of treatment methods are:
A first luminance composite pattern that replaces the original luminance of only a plurality of pixels at the edge of the simulated region with luminance indicating the edge of the simulated region;
A second luminance composition pattern in which the original luminance of each pixel in the simulated region is alpha-blended with the original luminance and the given specific value by using the original luminance as an alpha value;
A third luminance synthesis pattern for switching processing for the synthesis based on a discrimination result by a predetermined threshold for the original pixel of each pixel inside the simulation region;
Having at least
The mammography interpretation apparatus according to claim 3.
The simulated area is set to a shape and size set by an operator to prevent oversight of a lesion on the X-ray image.
The mammography interpretation apparatus according to any one of claims 1 to 4, wherein
The simulated area setting means includes initial display setting means for initially displaying the simulated area on the screen of the monitor.
The mammography interpretation apparatus according to any one of claims 1 to 5, wherein
The simulated area setting means includes area changing means for giving an instruction to change at least one of the size and shape of the simulated area displayed on the monitor screen.
The mammography interpretation apparatus according to any one of claims 1 to 6, wherein
The image display means is configured to display two X-ray images acquired by imaging the left and right breasts with the X-ray mammography apparatus in a symmetrical manner or juxtaposed in the same direction on the monitor screen. ,
The simulated region setting means sets the simulated region to an initial position having the same positional relationship in the left-right symmetry or in the same direction for each of the two X-ray images displayed on the monitor screen. Configured as
In the two X-ray images, the superimposed display means maintains the same positional relationship in the left-right symmetry or in the same direction with respect to the two simulated areas synthesized by the brightness synthesis means for each image. Configured to display while interlocking,
The mammography interpretation apparatus according to any one of claims 1 to 7, characterized in that
A two-dimensional X-ray image of a human breast imaged by an X-ray mammography device is displayed on a monitor screen;
On the screen of the monitor on which the X-ray image is displayed, a simulation region having a specific shape and simulating an assumed lesion is set to be movable for searching the X-ray image,
Identifying a plurality of pixels forming the simulated region;
Combining a plurality of original luminances of at least some of the identified plurality of pixels and luminance obtained by performing processing for characterizing the spread of the simulated area on the at least some of the plurality of pixels;
Displaying the simulated area having the synthesized luminance superimposed on a screen displayed on the monitor;
A mammography interpretation method characterized by this.
The simulated area is set to a shape and size set by an operator to prevent oversight of a lesion on the X-ray image.
The mammography interpretation method according to claim 9.
A mammography interpretation apparatus provided with a computer capable of displaying a two-dimensional X-ray image of a human breast imaged by an X-ray mammography apparatus on a monitor screen and giving input information from an input device to the screen display A recording medium capable of prerecording a mammography interpretation program that can be read and executed by the computer,
When the computer reads and executes the program recorded on the recording medium, the computer:
Image display means for displaying a two-dimensional X-ray image of a human breast imaged by the X-ray mammography device on the screen of the monitor;
Simulated area setting means for setting a simulated area having a specific and size shape and movable to search for the X-ray image on the screen of the monitor on which the X-ray image is displayed by the image display means When,
Pixel specifying means for specifying a plurality of pixels forming the simulated region on the screen;
Combining a plurality of original luminances of at least a part of the plurality of pixels specified by the pixel specifying unit and a luminance obtained by performing processing for characterizing the existence of the simulated area on the at least some of the plurality of pixels. Luminance synthesis means to
Superimposed display means for displaying the simulated area having the brightness synthesized by the brightness synthesis means by superimposing the screen displayed on the monitor;
Functionally providing a recording medium.
A two-dimensional X-ray image of a human breast imaged by an X-ray mammography apparatus is displayed on a monitor screen, and input information can be read and executed by a computer capable of providing the screen display in advance. In the program for mammography interpretation recorded in
When the computer reads the program from the recording medium and executes it, the computer:
Image display means for displaying a two-dimensional X-ray image of a human breast imaged by the X-ray mammography apparatus on a monitor screen;
Simulation area setting means for setting a simulation area having a specific shape and size and movable to search for the X-ray image on the screen of the monitor on which the X-ray image is displayed by the image display means When,
Pixel specifying means for specifying a plurality of pixels forming the simulated region on the screen;
Combining a plurality of original luminances of at least a part of the plurality of pixels specified by the pixel specifying unit and a luminance obtained by performing processing for characterizing the existence of the simulated area on the at least some of the plurality of pixels. Luminance synthesis means to
Superimposed display means for displaying the simulated area having the brightness synthesized by the brightness synthesis means superimposed on the screen displayed on the monitor;
A program characterized by providing a function.