KR100458088B1 - A volume calculation method for the target internal organs using computed tomography - Google Patents

Abstract

Converting image information included in a digital medical image file provided by a CT into a PGM file; Finding pixels having the value of the organ to be extracted from the PGM image and outputting the pixels through the display device as colors according to the GUI; The number and proportion of pixels corresponding to the CT value (256 gray level) of the pixel of the target to be shown which differs according to the mixing ratio between the target and the other components in each slice Calculating and storing the data in an arbitrary storage location; Calculating the volume and ratio of the organ to be extracted using the information stored in the memory; A method of calculating a volume of an object to be extracted using CT image information, comprising outputting the calculated information through a display device so that a user can recognize the information through a display device.

Description

A volume calculation method for the target internal organs using computed tomography

The present invention relates to a method for extracting a volume of a specific organ from an image of an organ photographed by a computerized imaging device.

Medical images include X-ray, CT (Computed Tomography), MRI (Magnetic Resonance Imaging), Ultrasound (Ultra Sound), and other imaging materials are used depending on the part of the human body and the purpose of observation. Medical imaging is a non-invasive view of the inside of the human body, so it is an important data for determining plans or methods for diagnosis, treatment, and surgery.

However, the use of such image information still depends on the visual judgment of medical professionals, and there is no special way to find out the volume of organs. Under such circumstances, visual recognition or reading of each organ may not be easy depending on various conditions of the image. Thus, until now, the administration of a substance such as contrast enhancement medium has been performed to observe a particular organ highlighted by it, and a method of calculating the volume of an organ through autopsy of a corpse has been used.

The body consists of four main components: body water, protein, body fat, and minerals. In general, obesity refers to a state in which a person is overweight, but precisely, a state in which a relatively large amount of body fat is broken because a balance is broken between energy-using muscle components and body fat emitting energy. Obesity is often diagnosed as the ratio of body fat mass to body weight, ie body fat percentage. Excluding body fat, body weight is mostly determined by skeletal and muscle mass, so body fat percentage is determined by the ratio of muscle mass and body fat mass.

If the amount of body fat is higher than the standard value or the muscle mass is lower than the standard value, the body fat rate increases. Obesity is not just determined by weight alone, and a slim young woman may be determined to be obese if she lacks muscle mass despite her underweight. Therefore, it is also used as a means of quantitatively measuring the components constituting such a body and measuring the mutual ratio of them repeatedly to determine the therapeutic effect.

Physiologists have different views, and the following study uncovered a set of conflicting data. However, based on data from the National Institutes of Health and the American College of Sports Medicine, the optimal percentage of body fat is 11-15% for adults under 30 and 18-25% for women of the same age group. However, checking your weight on a regular basis only tells you how many kilograms have been swollen or lost, and you don't know if those kilograms are fat or muscle. And if you lose weight too quickly (0.5-1 pounds of fat loss per week, or about 1 percent of weight loss per month, the most, according to most experts), your body goes into a deficiency mode. It is. Here, it is believed that the first muscle is wasted and fat is accumulated for the less greasy time. In fact, research shows that the first 10 days of intensive diet lose 65% of self-loss weight from muscle and only 35% of fat. Keeping track of your weight and body fat is the only way to know if your training and diet plan is working.

In order to know how fat you are in the sense of percentage, more sophisticated experimentation is required, which can be done in several ways. Keep in mind, though, that fat testing is not an exact science, and the only sure way to know how much fat you have is to analyze it in the carcass, and perhaps anyone wants to avoid it.

Hydrodynamic experiments by soaking in a water tank are a way of measuring your own fat. Fat is more buoyant than muscle and is easy to float. So the amount of water you remove with respect to your weight indicates how much you've blown. It is precisely these lockout advocates that their method is about 98-99% accurate, although if they do not release all the air in their lungs, the room for error increases. It is also a skill that requires hard practice.

Another fat test, called bioimpedance (biological voltage / current ratio), measures how many volts a meter takes before the current passes from wrist to ankle. It is based on the principle that a slim person has a greater difference in electric charge than a healthy person. According to the Diet Center, the results of this method are 98% accurate, although if your body is dehydrated, you just drink water or ate meat, the water can change because it affects the current. Although both methods require expensive equipment and go to a gym or sports center, this is a measure you can get.

In addition, the pliers caliper measurement method is a traditional fat measurement experiment. Caliper experiments are a method of measuring the thickness of skin in certain parts of the body where fat is accumulated, such as the waist or chest. Scientists study how thick your skin should be and to estimate the percentage of percentage of body fat by adding and subtracting 2 to 3%, although the room for mistakes actually varies greatly depending on the skill of the measurement technician. Reduce the thickness of fat

An object of the present invention is to provide a method for calculating the volume of an organ from tomography image data without using a contrast enhancer.

Another object of the present invention is to provide a method for calculating the volume of body fat from tomography information.

In order to achieve the above object, a volume calculation method of a target to be extracted using CT image information is provided using a digital tomography (CT) digital medical image (Digital Imaging and Communications in). Medicine: process of converting image information included in DICOM file into PGM (Portable GreyMap) file; Finding pixels having a CT value of a target to be extracted from the PGM image and outputting them through a display device as colors according to a user's setting (Graphic User Interface); Arbitrary memory by calculating the CT value (256 gray level) of the pixel of the target organ which appears differently according to the mixing ratio of the target organ and other components in each slice. Storing in a place; Calculating the volume and ratio of the organ to be extracted using the information stored in the memory; And outputting the calculated information through the display device so that the user can recognize the calculated information through the display device.

A detailed feature of the present invention is to provide a GUI (Graphic User Interface) function to change the CT output color of the object to be extracted according to the user's setting in the image provided through the CT image information.

A feature of the volume calculation method of a blood extraction target using CT image information according to another embodiment of the present invention is that the blood extraction target is body fat.

1 is a flow chart showing a volume calculation method according to the present invention,

2 is an exemplary diagram provided in accordance with the present invention;

3a to 3b is an exemplary view of the extraction of abdominal and leg body fat,

4 is an exemplary diagram for calculating liver volume from a CT image of a pig.

5 is a liver image of a real pig.

Hereinafter, a method for calculating a volume of an object to be extracted using CT image information according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a method for calculating the volume of internal organs from a CT image, which will be described using body fat as an example.

Accurately measuring the location, volume and ratio of body fat is important not only for aesthetic reasons but also for health reasons. Until now, accurate measurement of body fat is known to use CT or MRI. However, MRI is more expensive than CT in spite of the advantages of no risk of radiation, and it is difficult to measure body fat accurately because the value of image data representing body fat can be changed depending on the situation. However, because CT technology has advanced and greatly reduced the amount of radiation in a single measurement, experts say there is little harm to the human body. In addition, CT measures the position, volume, and ratio of body fat accurately because the body fat value is constant even when measuring a person under any circumstances. Therefore, in the present invention, an image photographed using the CT is used.

By using the method according to the invention it is possible to accurately measure the body fat of the abdomen and legs from the image taken through the CT. Of course, other sites can also measure body fat accurately using CT.

1 is a flowchart illustrating a process of calculating a volume of an object to be extracted using CT information according to the present invention.

Digital Imaging and Communications in Medicine (DICOM) files obtained by using CT (Computed Tomography) are composed of header information and image information. The dual image information is converted into a PGM (Portable GreyMap) file. The header contains information such as the unique number, gender, age, size of each pixel, and interval between slices. The image information converted into PGM file is composed of several slices. A slice is composed of pixels in two dimensions. When the CT image is a film, it is converted into a PGM file using a film scanner. In this case, the header information must be found in the film and input through the input device such as a keyboard (S11).

In the PGM image, pixels with body fat values are found and displayed in a specific color. In this case, the CT value of the pixel of the body fat is represented by 256 gray levels, which is 79 to 87, and a graphic user interface function is provided as shown in FIG. In addition, the color of the body fat is determined in advance in yellow, but this also provides a GUI that can be changed by the user if necessary (S12 process).

Body fat pixel values appear differently depending on the blended ratio when body fat is mixed with other components (eg, muscles). Therefore, if you know the pixel value of pure body fat and the pixel value of pure muscle, you can know the relationship between the value of body fat and the ratio of body fat. For example, if the value of pure body fat is 81 and the value of pure muscle is 91, the pixel value of 80% body fat and 20% muscle is 83. The pixel value of pure body fat and the pixel value of pure muscle can be seen in the corresponding part of the leg that is determined to have pure body fat and pure muscle. The number of pixels corresponding to the CT value (256 gray level) of pixels of the body fat, which differs according to the mixing ratio of body fat and other components in each slice, is stored in an arbitrary storage location. S13 process).

Therefore, the volume of body fat can be calculated more accurately by using the relationship between the value of body fat and the ratio of body fat. The calculation is as follows. Body fat volume formula a) is a formula that assumes that all pixels in the pixel value range of body fat are 100% body fat, and b) is a formula that assumes that each value of body fat contains a corresponding percentage of body fat (step S14). .

V: volume of specific organs

P _A : area of one pixel

Psi: Number of pixels in slice i )

Rj: The ratio of a specific organ to a specific organ pixel value j ( )

Psij: number of pixels of body fat pixel value j in slice i

Ds: spacing between slices

Fs: Start value of specific long-term pixel range

Fe: End value of specific long-term pixel range

end)

I)

To visually provide the user with a percentage of these body fats, choose the index yellow of the initial body fat or the saturation of the color of your choice to make the color with the highest saturation the color of 100% body fat, as the percentage of body fat decreases. Select a lower (step S15).

When the user selects specific organs or internal organs as a closed curve in the abdomen, the body fat contained in the specific organs or internal organs is distinguished from the remaining abdominal body fats, and the volume and ratio of each body fat are calculated to be shown in FIGS. 3A and 3B. Similarly, the volume and ratio of body fat in the abdominal and leg images are calculated and displayed for the user to recognize.

In the same way as body fat measurement, muscle volume and percentage can be calculated accurately from muscle pixel values. Therefore, even for the same weight, the result of calculating the ratio of body fat and muscle may be different, and this ratio indicates the degree of obesity.

As a result of calculating the volume of liver extracted through smoothing from the original image in the pig CT image as shown in FIG. 4 by the volumetric formula a), it was 1057.972 ml, and the volume was 1055 ml because the actual pig liver in FIG. 5 was 1055 ml. The accuracy of the calculation was confirmed.

As described above, the volume of a specific organ can be calculated from CT image information using the calculation method according to the present invention, and in particular, it can be applied to CT images obtained from other diseases to measure body fat, By monitoring the CT images and the volume and ratio of body fat in the database regularly to accurately represent changes in body fat, it is possible to know not only the aesthetic aspects but also the changes in long-term body fat that have a fatal effect on health. Can play a part in promotion.

Claims (3)

Converting image information included in a digital imaging and communications in medicine (DICOM) file provided by a computed tomography (CT) file into a portable gray map (PGM) file; Finding pixels having a target value in the PGM image and outputting them through a display device as colors according to a user's setting (Graphic User Interface); The number and proportion of pixels corresponding to the CT value (256 gray level) of the pixel of the target to be shown which differs according to the mixing ratio between the target and the other components in each slice Calculating and storing the data in an arbitrary storage location; Calculating a volume and a ratio of the object to be extracted using information stored in the memory; In order for the user to recognize the calculated information through the display device, the color of the object to be extracted is selected as the color of the object to be extracted by selecting the color of the object to be extracted initially or the color selected by the user through the display device. Including the process of lowering the saturation as the ratio decreases, The process of calculating the volume, Area of one pixel × (((Number of pixels with the first CT value of the CT value of the organ in the first slice × corresponding ratio of the organs + ... + Last CT value of the range of CT values of the organ in the first slice Number of pixels with × corresponding proportion of organs) + (number of pixels with first CT value in the range of CT values of organs in the last slice × corresponding ratio of organs + ... + long term CT values in last slice The number of pixels with the last CT value in the range of × the corresponding ratio of organs)) × ½ + The number of pixels with the first CT value in the CT value range of the organs for the last to second slice from the second slice × Long The corresponding ratio of + ... + the number of pixels with the last CT value in the range of CT values for the organ × the corresponding ratio of the organ) × interval between slice A volume calculation method for an object to be extracted using CT image information, characterized in that the volume of the organ is calculated from the equation. delete The method of claim 1, The method of calculating the volume of the object to be extracted using CT image information, characterized in that the object to be extracted is body fat.