JP2003310601A - Calcification degree measurement device, calcification degree measurement method, calcification degree measurement program, computer-readable recording medium recorded with calcification degree measurement program and prediction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quantitatively measure a calcification degree of an artery. <P>SOLUTION: This calcification degree measurement device has: an input means (S01) inputting a CT image by reading the CT image; an area reception means (S03) receiving specification of an area of the artery included in the inputted CT image; a specification range reception means (S04) receiving specification of a range of a luminance value of a pixel; and calculation means (S07) calculating the calcification degree on the basis of the number of the pixels having the luminance values in the specified range among the pixels included in the specified area. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calcification degree measuring device, a calcification degree measuring method, a calcification degree measuring program, a computer-readable recording medium recording the calcification degree measuring program, and a prediction method, and more particularly to a tomographic image. A calcification degree measuring device for measuring calcification degree using an image, a calcification degree measuring method, a calcification degree measuring program, a computer-readable recording medium recording the calcification degree measuring program, and a calcification degree were used. Regarding prediction method.

[0002]

2. Description of the Related Art As a method for diagnosing arteriosclerosis, there is known a method of diagnosing the degree of arterial calcification from X-ray photographs. In recent years, X-ray CT has been used to observe organs.
(Computed Topography) equipment is used. In an X-ray CT apparatus, an X-ray tube and a detector rotate and scan each section of a human body, and an X-ray absorption value obtained by the detector is digitally processed by a computer. Then, the X-ray absorption value of one pixel on the matrix-shaped cross section is reconstructed as the CT value (Hounsfield value). CT value is usually +100 for calcium
0, water is 0, air is -1,000, CT image is C
It is imaged in gray scale based on the T value. A qualitative diagnostic method is performed in which the cross section of the abdominal aorta shown in a tomographic image of the abdomen taken by using this X-ray CT apparatus is divided into 12 and the number of divisions having calcification is used as the calcification degree (dialysis. Vol.32 (9): p.1233-1238, 1999, Clinical dialysis
Vol.4 (2), p.233-238,1988).

[0003]

[Problems to be Solved by the Invention] Since vascular calcification does not cause pain even if it progresses, the patient does not feel subjective symptoms. However, as vascular calcification progresses, it causes restenosis after PTCA (percutaneous transluminal coronary angioplasty),
It is said to be deeply involved in the development of myocardial infarction, arteriosclerosis obliterans (ASO), cerebrovascular accidents and the like. Therefore, a method for quantitatively measuring the degree of vascular calcification has been desired.

However, the degree of calcification of the abdominal aorta has not been quantitatively measured, and an accurate diagnosis can be made only by an experienced doctor in order to diagnose arteriosclerosis. There wasn't.

The present invention has been made to solve the above problems, and one of the objects of the present invention is to provide a calcification degree measuring device capable of quantitatively measuring the calcification degree of an artery, A calcification degree measuring method, a calcification degree measuring program, and a computer-readable recording medium recording the calcification degree measuring program.

Another object of the present invention is to predict the risk of developing restenosis, myocardial infarction, arteriosclerosis obliterans (ASO) or cerebrovascular accident after PTCA (percutaneous transluminal coronary vasodilation). It is to provide a prediction method.

[0007]

According to one aspect of the present invention for achieving the above object, a calcification degree measuring device is included in input means for inputting a tomographic image, and the input tomographic image. A region receiving unit that receives the designation of the region of the artery, a designated range receiving unit that receives the designation of the range of the luminance value of the pixel, and the number of pixels having the luminance value of the designated range among the pixels included in the designated region And a calculating means for calculating the calcification degree.

According to the invention, the area of the artery included in the input tomographic image is specified, the range of the brightness value of the pixel is specified, and the brightness of the specified range of the pixels included in the specified area is specified. The degree of calcification is calculated based on the number of pixels having a value. Therefore, it is possible to provide a calcification degree measuring device capable of quantitatively measuring the calcification degree of an artery.

Preferably, the calculating means calculates, as the degree of calcification, a ratio of pixels having a luminance value in the designated range to the area designated by the area receiving means.

According to the present invention, since the ratio of the pixels having the luminance value in the designated range to the designated region is taken as the calcification degree, it is not affected by the difference in the thickness of the artery. The degree of calcification can be calculated.

The arteries include abdominal aorta, thoracic aorta,
Examples include cerebral blood vessels, coronary arteries, and limb arteries, and preferably the abdominal aorta. Further, as the tomographic image, a tomographic image obtained from an X-ray CT apparatus is used in the embodiment, but a tomographic image obtained from an MRI (magnetic resonance imaging) apparatus, a blood vessel echo apparatus, or the like can also be used.

According to another aspect of the present invention, a calcification degree measuring method includes a step of inputting a tomographic image, a step of accepting designation of an artery region included in the input tomographic image, and a luminance value of a pixel. And a step of calculating the degree of calcification based on the number of pixels having a luminance value in the designated range among the pixels included in the designated area.

According to the invention, the area of the artery included in the input tomographic image is specified, the range of the brightness value of the pixel is specified, and the brightness of the specified range of the pixels included in the specified area is specified. The degree of calcification is calculated based on the number of pixels having a value. Therefore, it is possible to provide a calcification degree measuring method capable of quantitatively measuring the calcification degree of an artery.

According to another aspect of the present invention, the calcification degree measuring program inputs a tomographic image, accepts designation of an artery region included in the input tomographic image, and pixel brightness. The computer is caused to execute a step of accepting designation of a range of values and a step of calculating a degree of calcification based on the number of pixels having a luminance value in the designated range among the pixels included in the designated area.

According to the present invention, the area of the artery included in the input tomographic image is specified, the range of the brightness value of the pixel is specified, and the brightness of the specified range of the pixels included in the specified area is specified. The degree of calcification is calculated based on the number of pixels having a value. Therefore, it is possible to provide a calcification degree measurement program capable of quantitatively measuring the calcification degree of an artery and a computer-readable recording medium recording the calcification degree measurement program.

[0016] According to still another aspect of the present invention, a predicting method is to calculate the degree of calcification measured by the above-mentioned method for measuring calcification, restenosis and myocardium after PTCA (percutaneous transluminal coronary vasodilation). It is used as an index for predicting the risk of developing infarction, arteriosclerosis obliterans (ASO), cerebrovascular accident, etc.

According to the present invention, since quantitative calcification degree is used for prediction, restenosis, myocardial infarction, and arteriosclerosis obliterans (AS) after PTCA (percutaneous transluminal coronary vasodilation) are performed.
O) or the risk of developing cerebrovascular disease can be easily predicted.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

FIG. 1 is an external view of a calcification degree measuring device 1 according to one of the embodiments of the present invention. Referring to FIG. 1, a calcification degree measuring device 1 is a CD-ROM (Compact Di
sk-Read-Only Memory) drive 110 and FD (Fle
xible Disk) Computer 10 with drive 112
0, a display 102, a printer 104, an image reader 105, a keyboard 106, and a mouse 10.
8 and. The computer 100 may have a general configuration.

FIG. 2 is a block diagram showing the structure of the calcification degree measuring apparatus 1 according to this embodiment. As shown in FIG. 2, the computer 100 includes a CPU (Central Processing) connected to a bus 126 in addition to a CD-ROM drive 110 and an FD drive 112.
Unit) 116 and a ROM (Read Only Me) that stores an operating system boot-up program and the like.
mory) 118, a RAM (Random Access Memory) 120 for loading a program to be executed and for storing data during execution of the program, and a hard disk 114 for storing the created program in a non-volatile manner. And a network interface 130 for connecting the computer 100 to the network 132. CD-ROM drive 110
A CD-ROM 122 is mounted on the. FD drive 1
An FD 124 is attached to the device 12.

The image reader 105 reads a tomographic photograph (hereinafter referred to as "CT image") output from the X-ray CT apparatus and sends it to the CPU 116. In this way, the CT image is input to the calcification degree measuring device 1. Further, in the present embodiment, the CT using the image reader 105 is used.
Although it is configured to read an image, the X connected to the network interface 130 via the network 132
The CT image data may be received from the line CT apparatus. Further, the CT image data may be read from the CD-ROM 122 or the FD 124 in which the CT image data read by another image reader or the CT image data output by the X-ray CT apparatus is recorded.

As described above, this calcification degree measuring device 1
Are realized by computer hardware and software executed by the CPU 116. Generally, such software includes CD-ROM 122, FD1.
CD-ROM stored in a recording medium such as 24 and distributed.
The data is read from the storage medium by the drive 110 or the FD drive 112 and is temporarily stored in the hard disk 114. Furthermore, from the hard disk 114 to the RAM 120
And is executed by the CPU 116. The hardware itself of the calcification degree measuring device shown in FIG. 1 and FIG. 2 is general. Therefore, the most essential part of the present invention is the software stored in the recording medium such as the CD-ROM 122, the FD 124, and the hard disk 114.

Since the operation of the computer itself shown in FIGS. 1 and 2 is well known, its detailed description will not be repeated here.

The software is a concept including not only a program directly executable by the CPU 116 but also a program in a source program format, a compressed program, an encrypted program and the like.

The recording medium in which such software is stored is a magnetic tape, a cassette tape, an optical disc, an IC card (including a memory card), an optical card, a mask RO, in addition to the CD-ROM 122, the FD 124 and the like.
It may be a medium that fixedly carries the program, such as a semiconductor memory such as M, EPROM, EEPROM, or flash memory.

FIG. 3 is a flow chart showing the flow of calcification degree measurement processing executed by the calcification degree measurement device 1 according to the present embodiment. Referring to FIG. 3, in the calcification degree measuring apparatus 1, the CT image is read by the image reader 105,
CT image data is acquired (step S01). The CT image read in this case is a tomographic image of the abdomen of a person. CT output by X-ray CT system
The image is imaged in grayscale. Therefore, the CT image read by the image reader 105 is 1
This is data in which pixels are represented by density data of 256 gradations.

Next, calibration processing is performed using the scale included in the read CT image data (step S02). The X-ray CT apparatus usually outputs a CT image including a reference scale. That is, it includes a scale for indicating how large the distance between the parts represented in the CT image is actually.

FIG. 4 is a diagram showing an example of CT image data read by the calcification degree measuring device 1 according to the present embodiment. Referring to FIG. 4, CT image data 200 includes a tomographic image region 201 of a human abdomen and a scale 206. The scale 206 is a scale for indicating how long the length of each part shown in the area 201 is actually. In addition, the region 201 includes a region 203 of the abdominal aorta and a region 205 of the spinal cord.

Returning to FIG. 3, in the calibration process, the length of the scale 206 is designated by using the mouse 108 or the like, and the actual length value of the designated length is entered by using the keyboard 106. By doing so, the actual length corresponding to a predetermined number of pixels (for example, one pixel) of the CT image data 200 is acquired. As a result, the actual size can be measured by counting the number of pixels in the CT image data 200.

The calibration process is performed by the X-ray C
Unless the photographing condition of the T device and the setting of the magnification of the image reader are changed, once it is performed, it is not necessary to repeat it. Therefore, if the imaging condition of the X-ray CT apparatus and the setting of the image reader are not changed, once the calibration process is performed, it is not necessary to repeat it. In this case, the scale obtained by once performing the calibration process is the hard disk 114.
The scales in the image are determined by reading the stored scales stored in the.

In the next step S03, the designation of the abdominal aortic region in the CT image data 200 is accepted (step S03). The region may be specified by designating two points of the abdominal aorta, that is, a start point and an end point corresponding to the diameter, or a circular region 203, or by designating two points on a diagonal of a quadrangle. The area may be designated by. Further, the area is not limited to a circle or a quadrangle, and an ellipse may be used to specify the area.
Further, an arbitrary area in the displayed CT image data 200 may be designated by drawing a free curve with the mouse 108. In this way, CT image data 2
The designation of region 203 of the abdominal aorta in 00 is accepted.

Then, in the next step S04, the brightness value of the region designated in step S03, that is, the region in which the abdominal aorta is represented, in which the calcified region is represented, is designated in the range. It As mentioned above, CT
In the image data 200, one pixel is represented by density data of 256 gradations. Therefore, the brightness value of the calcified region can be specified within the range of 0 to 255. To simplify this designation, for example, 0 to 1
It is also possible to divide the brightness value into 15 ranges, such as 4, 15 to 29, and select the brightness value in the separated range. Alternatively, the minimum value and the maximum value of the brightness values to be selected may be directly input. Usually, in a CT image, the brightness value of hydroxyapatite is high. Therefore, when the luminance value of the hydroxyapatite region is set to 255, it is preferable that the region having a luminance value of 80% or more of the luminance value of hydroxyapatite is a calcified region. For example, when the luminance value of the hydroxyapatite region is 255, 80% or more of 255, that is, pixels having a luminance value of 204 or more are included in the calcified region. By doing so, even if the luminance value of hydroxyapatite included in the CT image differs due to the difference in X-ray CT apparatus, the difference in imaging environment, etc., the region of the spine clearly included in the abdominal tomographic image Can be specified to obtain the luminance value of hydroxyapatite.
As a result, even if the CT images have different imaging environments,
The degree of calcification can be measured accurately.

In the next step S05, step S04
Pixels having luminance values in the range designated by are extracted and displayed on the display 102. In this case, step S
In the area designated by 03, the color of the pixel having the luminance value designated by step S04 is displayed differently from the colors of the other pixels.

FIG. 5 is a diagram schematically showing an example of an image of the abdominal aorta displayed by the calcification degree measuring apparatus 1 according to the present embodiment. Referring to FIG. 5, a region 203 designated as an abdominal aorta and a region 207 considered to be calcified
A, 207B and 207C are displayed. The calcified regions 207A, 207B, 207C in the region 203 are
It is displayed with a different color from other pixels. In this case,
By displaying the image shown in (1) and the image of the region 203 of the CT image data side by side, it is possible to determine up to which density of the CT image data is selected as the calcified region.

Thus, it is possible to determine up to which density to extract as a calcified region while observing the CT image data. Therefore, the degree of calcification can be measured more accurately.

Returning to FIG. 3, in step S06, the user is requested whether or not the image of the abdominal aorta displayed on the display 102 and the calcified area are correct,
It is determined whether or not there is an input as to whether or not the designation of the range of the brightness value is corrected (step S06). Depending on the user
If it is determined that the range specification of the brightness value is to be corrected, the process proceeds to step S04, and if not, the process proceeds to step S07.

In the next step S07, the degree of calcification is calculated. The degree of calcification is represented by the ratio of the area of the calcified region to the area of the abdominal aorta. In the present embodiment, it is obtained from the number of pixels of the area 203 designated as the abdominal aorta and the total sum of the pixels of the areas 207A, 207B, 207C extracted with the luminance value designated as the calcified area.

Although the degree of calcification is defined here as the ratio of the area of the calcified region to the area of the abdominal aorta, this is merely an example and may be expressed by the calcified area.

As described above, in the calcification degree measuring device according to the present embodiment, the calcification degree is calculated from the area of the calcified region with respect to the area of the abdominal aorta shown in the CT image. Therefore, the degree of calcification can be measured more accurately.

In this embodiment, one C sheet is used.
Although the T image is read to calculate the degree of calcification, a plurality of CT images obtained by tomography at a plurality of sites, for example, every 1 cm, or a plurality of CT images obtained at every 5 mm are used, and each CT is used. You may make it obtain | require a calcification degree by averaging the calcification degree measured from the image.

Calcification degree measuring device 1 in the present embodiment
According to the method, the calcification degree is measured by using the CT image data obtained by reading the CT image taken by the X-ray CT apparatus with the image reader 105. Therefore, the degree of calcification can be measured easily and quickly.

The calcification degree measured by the calcification degree measuring device 1 is used as restenosis, myocardial infarction, arteriosclerosis obliterans (ASO) or cerebral blood vessel after PTCA (percutaneous transluminal coronary vasodilation). It can be used as an index for predicting the risk of developing disorders and the like. This makes it possible to predict quantitative calcification degree as an index. Therefore, it is possible to easily predict the risk of developing restenosis, myocardial infarction, arteriosclerosis obliterans or cerebrovascular accident after PTCA. You can

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[Brief description of drawings]

FIG. 1 is an external view of a calcification degree measuring device according to one of the embodiments of the present invention.

FIG. 2 is a block diagram of a calcification degree measuring device according to the present embodiment.

FIG. 3 is a flowchart showing a flow of calcification degree measurement processing executed by the calcification degree measurement device according to the present embodiment.

FIG. 4 is a diagram showing an example of CT image data read by a calcification degree measuring device according to the present embodiment.

FIG. 5 is a diagram schematically showing an example of an image of an abdominal aorta displayed by the calcification degree measuring device according to the present embodiment.

[Explanation of symbols]

1 calcification degree measuring device, 100 computer, 102
Display, 104 printer, 105 image reader, 106 keyboard, 108 mouse, 110
CD-ROM drive, 112 FD drive, 11
4 hard disk, 126 bus, 130 network interface, 132 network, 200
Image data, 206 scale.

Continued front page    (72) Inventor Junichiro Tanaka             2-8 Doshomachi, Chuo-ku, Osaka-shi, Osaka Prefecture               Sumitomo Pharmaceutical Co., Ltd. F-term (reference) 4C093 AA22 AA26 DA02 FF08 FF09                       FF16 FF19 FF22 FF23 FF28                       FG05 FG12 FG13                 4C096 AA20 AB41 AB50 AC10 AD14                       DC20 DC22 DC27                 4C301 DD11 EE11 EE14 FF09 JB23                       JB27 JC14 JC16 KK02 KK12                       KK26 KK30                 5B057 AA09 BA07 CA08 CA12 CA16                       CB20 CH01 CH11 DA13 DC22

Claims (7)

[Claims] 1. An input unit for inputting a tomographic image, a region receiving unit for receiving designation of a region of an artery included in the input tomographic image, and a designated range receiving unit for receiving designation of a range of pixel brightness values. A calcification degree measuring device, comprising: a calculator that calculates the calcification degree based on the number of pixels having a luminance value in the specified range among the pixels included in the specified area. 2. The calcification degree according to claim 1, wherein the calculating unit calculates, as the calcification degree, a ratio of a pixel having a luminance value in the designated range to a region designated by the region receiving unit. Calcification degree measuring device. 3. The calcification degree measuring device according to claim 1, wherein the artery is an abdominal aorta. 4. A step of inputting a tomographic image, a step of accepting designation of a region of an artery included in the input tomographic image, a step of accepting designation of a range of brightness values of pixels, the designated region Calculating a calcification degree based on the number of pixels having a luminance value in the specified range among the pixels included in the calcification degree. 5. A step of inputting a tomographic image, a step of accepting designation of a region of an artery included in the input tomographic image, a step of accepting designation of a range of pixel luminance values, the designated region A calcification degree measurement program that causes a computer to calculate a calcification degree based on the number of pixels having a brightness value in the specified range among the pixels included in the. 6. A computer-readable recording medium in which the calcification degree measuring program according to claim 5 is recorded. 7. Restenosis, myocardial infarction, occlusive artery after PTCA (percutaneous transluminal coronary artery vasodilation) using the calcification degree measured by the calcification degree measurement method according to claim 4 as an index. A method for predicting the risk of developing sclerosis (ASO) or cerebrovascular disorder.