JP2005131020A - Medical image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to easily and surely carry out proper gray-scale processing even to a medical image with various gray-scale style. <P>SOLUTION: An image processing means 20 stores gray-scale style identifying information for identifying the gray-scale style of a medical image data in a predetermined pixel area within the medical image data made in a modality 10 and transmitting the medical image data to a management server 40. The management server 40 stores the medical image data in an image DB 30, and thereafter transmits the medical image data in which the gray-scale style identifying means is written stored in the image DB 30 according to the request from an image output means 50. The image output means 50 receives the medical image data, thereafter identifies the gray-scale style by referring the gray-scale style identifying information, converting it data for output by carrying out gray-scale processing according to the gray-scale style, and carries out image output such as monitor display and print. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a medical image processing method for creating medical image data such as an X-ray image and displaying an image represented by the medical image data on a monitor or printing on a film or the like.

(01750)
In recent years, with the development of CR (Computed Radiography) equipment, the spread of monitor diagnosis using monitors such as CRT (Cathode Ray Tube) and LCD (Liquid Crystal Display), and the progress of intra-hospital / inter-hospital networks, the same medical image However, a plurality of types (for example, a plurality of manufacturers) of image output means (for example, including a monitor, a printer, etc., the same shall apply hereinafter) are displayed on a monitor or printed on a film, etc. For example, there are cases where a plurality of medical images photographed by an image photographing device (manufactured by a plurality of manufacturers) (including various modalities; hereinafter the same) are displayed on a monitor or printed on a film or the like by the same image output means. It is increasing.

  For this reason, in any of the above cases, an image processing technique for matching the expression gradation and preventing the difference in the appearance of the medical image has attracted widespread attention (see, for example, Patent Document 1). ). In Patent Document 1, information indicating an environment for displaying an image is recorded as supplementary information of the image data. When this image is displayed at a later date, an image display is performed based on the environment information recorded in the supplementary information. Techniques for performing are disclosed.

On the other hand, as the image processing technique, for example, a technique using GSDF (Grayscale Standard Display Function) based on DICOM (Digital Imaging and Communication in Medicine) standard is known. According to the image processing technique using GSDF, the pixel value of image data is converted into a linear value (P value) for visual characteristics, and the expression gradation is matched in any of the above cases. It is possible to prevent a difference in the appearance of the medical image.
JP-A-10-134166

In the DICOM standard, gradation formats such as density values and P values can be recorded on a tag compliant with the standard. By referring to the gradation format recorded on the tag, each medical image can be recorded. Appropriate gradation processing can be performed.
However, in addition to the gradation format based on the DICOM standard (P value, etc.), the gradation format based on the conventionally used relative density value (D value), the gradation linear to the logarithmic value of the luminance value When a plurality of medical images based on various gradation formats such as a linear gradation format and a logarithmic value of the X-ray dose are mixed and transmitted to the image output means, the gradation format is the medical image It is not recorded in the tag, or the tag content cannot be referred to depending on the type of the image output means. For this reason, it is difficult to accurately specify the gradation format for such individual medical images, and as a result, gradation processing based on the same gradation format is performed. Therefore, it is difficult to output an image such as a monitor display or a print with an appropriate expression gradation corresponding to each medical image.

  An object of the present invention is to enable easy and reliable execution of appropriate gradation processing even for medical images in various gradation formats.

In order to solve the above problem, the invention according to claim 1
A recording step of recording discrimination information for discriminating the gradation format for the medical image generated based on a predetermined gradation format in the medical image;
When outputting the medical image, a gradation processing step of reading the determination information recorded in the image and performing gradation processing on the medical image based on the determination information;
It is characterized by including.

Further, as in the invention according to claim 2, in the invention according to claim 1,
In the recording step,
It is preferable that a new pixel having the discrimination information as a pixel value is added to the medical image.

Further, as in the invention according to claim 3, in the invention according to claim 1,
In the recording step,
It is preferable to update the pixel value of a predetermined pixel or pixels among the pixels constituting the medical image to discrimination information for discriminating the gradation format of the medical image.

According to the present invention, even when a plurality of medical images based on various gradation formats are transmitted in a mixed state to an image output means for outputting an image to a monitor or a printer, the tag By analyzing the image itself without referring to incidental information such as information, the gradation format of each medical image can be easily and accurately determined. For this reason, gradation processing can be performed in accordance with various gradation formats, so that appropriate image output (monitor display, printing, etc.) is possible.
In addition, since the discrimination information for discriminating the gradation format can be recorded in the first or last predetermined pixel of the medical image, an image portion necessary for interpretation or diagnosis is lost due to the discrimination information. The situation is avoided.
That is, appropriate gradation processing can be easily and reliably performed for medical images in various gradation formats.

  Hereinafter, an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration of a medical image processing system 100 to which the present invention is applied. As shown in FIG. 1, the medical image processing system 100 includes a modality 10, an image processing unit 20, an image DB 30, a management server 40, and an image output unit 50.

  The modality 10 is a film digitizer, angiography device, CT (Computed Tomography) scanner device, MRI (Magnetic Resonance Imaging) device, nuclear medicine diagnostic device, ultrasonic diagnostic device, electronic endoscope device, CR (Computed Radiography), etc. Yes, medical image data is created as digital data.

  The modality 10 includes an image processing unit 20. The image processing means 20 updates the medical image data to a predetermined expression gradation, and writes gradation format determination information for determining the gradation format of the expression gradation in the medical image data.

  Here, as the gradation format of the expression gradation, the gradation format based on the DICOM standard P value (referred to as P value gradation format), the gradation format based on the relative density value (D value) (D value scale). The tone format), a linear gradation format (referred to as luminance value gradation format) for the logarithmic value of the luminance value, a linear gradation format (referred to as X dose gradation format) for the logarithmic value of the X-ray dose, and the like. .

  The gradation format determination information is a pixel value corresponding to a predetermined pixel in the medical image data. For example, in the case of a 12-bit pixel value, the gradation format determination information takes a predetermined integer value from 0 to 4095.

  Hereinafter, in the present embodiment, assuming 12-bit pixel values, gradation format discrimination information (P value gradation format, D value gradation format, luminance value gradation format, and X dose gradation format). Each of the pixel values) is, for example, 511 (corresponding to a substantially intermediate value of 0 or more and 1023 or less), 1535 (corresponding to a substantially intermediate value of 1024 or more and 2047 or less), 2559 (substantially intermediate values of 2048 or more and 3071 or less). ), 3583 (corresponding to a substantially intermediate value of 3072 or more and 4095 or less), but is not limited thereto.

  Here, setting examples (two examples) of gradation format discrimination information for medical image data will be described with reference to FIG. In the following description of the present embodiment, for example, the number of pixels is 1000 (vertical) × 1000 (horizontal).

  First, the medical image data illustrated in FIG. 2A corresponds to the first to Nth pixels (N is a natural number) at the top of the data that is outside the effective image (corresponding to the determination pixel region A1). ), Common tone format discrimination information (pixel value 511) is recorded.

  In addition, in the medical image data illustrated in FIG. 2B, N pixels (corresponding to the determination pixel area A2) outside the effective image are added to the medical image data at the end of the data. Common gradation format discrimination information (pixel value 511) is recorded in each pixel of the added discrimination pixel area A2. In this case, the total number of pixels of the medical image data is 1000000 + N.

  In particular, at the time of film output, the pixel value of the border portion outside the effective image is 0 or 4095, so the gradation format discrimination information (pixel value 511, etc.) recorded in the border portion can be easily obtained. It becomes.

  Therefore, the gradation format of the medical image data can be easily determined by referring to the pixel value of each pixel in the determination pixel area A1 or A2. In the medical image processing system 100, one of the discrimination pixel areas A1 and A2 is used as a pixel area for recording gradation format discrimination information.

Returning to FIG.
The image DB 30 stores medical image data, and the management server 40 performs input / output (recording / reading) management of medical image data with respect to the image DB 30.

  The image output means 50 includes a monitor such as a CRT or LCD or a printer, and acquires medical image data stored in the image DB 30 via the management server 40.

  Further, the image output means 50 determines the gradation format of the acquired medical image data by referring to the gradation format determination information recorded in the determination pixel area A1 or A2 of the medical image data. The gradation processing according to the gradation format is performed to change to output data, and image output such as monitor display or printing on a film or the like is performed.

  Here, when determining the gradation format, the image output means 50 determines that the medical image data is a P-value gradation format if the gradation format determination information is an integer value of 0 or more and 1023 or less, and 1024 If it is an integer value of 2047 or less, it is determined as a D value gradation format, if it is an integer value of 2048 or more and 3071 or less, it is determined as a luminance value gradation format, and if it is 3072 or more and 4095 or less, it is determined as an X-ray dose level. It is determined as a key form.

  In the medical image processing system 100 described above, the image processing unit 20 applies the medical image to a predetermined pixel region (such as the determination pixel region A1 or A2) outside the effective image in the medical image data created by the modality 10. The tone format discrimination information for discriminating the tone format of the data is recorded, and the medical image data in which the tone format discrimination information is recorded is transmitted to the management server 40. The management server 40 stores the medical image data in which the gradation format determination information is recorded in the image DB 30, and then writes the gradation format determination information stored in the image DB 30 in response to a request from the image output unit 50. The stored medical image data is transmitted. Upon receiving this medical image data, the image output means 50 determines the gradation format by referring to the gradation format determination information, performs gradation processing according to the gradation format, and outputs it. The data is changed to data, and image output such as monitor display or printing is performed.

Therefore, even when a plurality of medical image data based on various gradation formats such as the P value gradation format and the D value gradation format are mixedly transmitted to the image output means 50, the tag information or the like By analyzing the image data itself without referring to the accompanying information, it is possible to easily and accurately determine the gradation format of each medical image data. For this reason, the image output means 50 can perform gradation processing according to various gradation formats, so that appropriate image output (monitor display, print, etc.) is possible.
Further, the gradation format discrimination information corresponds to a predetermined pixel (for example, at the time of film output, a border portion) for the top (discrimination pixel region A1) or the end (discrimination pixel region A2) that is outside the effective image of the medical image data. ) Is very unlikely to be affected by image portions necessary for interpretation and diagnosis.
The gradation format discrimination information discriminated by the image output means 50 is, for example, an integer of 0 or more and 1023 or less in the case of each tone format discrimination information (pixel value) for the P value gradation format. Therefore, even if the numerical value of the gradation format discrimination information is slightly changed from the value set by the image processing means 20 during various image processing on the image data, the gradation format is correct. Discrimination becomes possible.
That is, appropriate gradation processing can be easily and reliably performed on medical image data in various gradation formats.

  Note that the description in the present embodiment shows an example of the image processing method according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of the medical image processing system 100 using the image processing method in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

  For example, the image processing unit 20 and the modality 10 are integrally provided, but the configuration is not limited thereto, and the modality 10 and the image processing unit 20 may be provided separately.

  Further, although the image output means 50 determines the gradation format of the medical image data based on the gradation format determination information, the present invention is not limited to this. For example, such a function of determining the gradation format may be made independent of the image output means 50. That is, a reception-side image processing means (not shown) may be provided in the preceding stage on the network N side of the image output means 50, and the reception-side image processing means may have the gradation format discrimination function.

  Further, it may be configured such that medical image data can be directly transmitted and received between the image processing unit 20 and the image output unit 50 without using the image DB 30 and the management server 40.

It is a figure which shows the structure of the medical image processing system to which this invention is applied. (A) is a figure which shows the data content of medical image data for every pixel, (b) is a figure which shows the other data content of medical image data for every pixel.

Explanation of symbols

10 modality 20 image processing means 30 image DB
40 management server 50 image output means 100 medical image processing system A1, A2 pixel area for discrimination

Claims (3)

A recording step of recording discrimination information for discriminating the gradation format for the medical image generated based on a predetermined gradation format in the medical image;
When outputting the medical image, a gradation processing step of reading the determination information recorded in the image and performing gradation processing on the medical image based on the determination information;
A medical image processing method comprising: In the recording step,
The medical image processing method according to claim 1, wherein a new pixel having the discrimination information as a pixel value is added to the medical image. In the recording step,
The medical value according to claim 1, wherein pixel values of one or more predetermined pixels of the pixels constituting the medical image are updated to discrimination information for discriminating a gradation format of the medical image. Image processing method.

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