X-ray or gamma ray systems or devices – Specific application – Computerized tomography
Reexamination Certificate
1999-10-15
2001-08-21
Bruce, David V. (Department: 2882)
X-ray or gamma ray systems or devices
Specific application
Computerized tomography
C378S901000
Reexamination Certificate
active
06278761
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of establishing range of somatic fat by Gaussian function approximation in computerized tomography which can automatically establish the range of somatic fat, which is used at the time of measuring the somatic fat by using the computerized tomography, using Gaussian function approximation by least square method.
2. Information Disclosure Statement
The importance of measurement of somatic fat has increased day by day in connection with fatness, and various methods of measurement of somatic fat have been suggested and used.
Although a method of measuring fatness degree by using ratio of height and weight is well known, it has a disadvantage that the correlation of ratio of height and weight with the amount of actual somatic fat is not strong. In addition, there is a method of measuring the amount of somatic fat by measuring conductivity, however, it has a disadvantage that accuracy is low since a deviation of the conductivity is large according to the measurement method. Further, there is a method of measuring ratio of waist circumference and hip circumference, however, it has a disadvantage that the correlation of the ratio of waist circumference and hip circumference with the actual amount of somatic fat is not strong. Still further, there is a method of measuring thickness of subcutaneous fat by pliers, however it has a disadvantage that the degree of precision is low since the method itself is very simple and can not directly measure the amount of somatic fat.
Recently, ratio of subcutaneous fat and intra-abdominal cavity fat is used as an indication of disease connected with the fatness, and a method of separately measuring the subcutaneous fat and intra-abdominal cavity fat is required. The computerized tomography is a means which satisfies such requirement and can separately and directly measure through an image processing the amounts of subcutaneous fat and intra-abdominal fat from computerized tomography image.
The computerized tomography provides an image composed of Hounsfield values proportional to density. The Hounsfield value for the air is −1000 and that for the water is 0. Further, the Hounsfield value for a material of high density such as a bone is 1000.
The method of measuring the somatic fat from the image composed as described above is a method in which a range of Hounsfield values corresponding to the somatic fat is given and the number of pixels belonging to the range is counted.
However, there is no standard range since a reference for the range of somatic fat is vague and different ranges of somatic fat are used depending on person. In addition, since the characteristic of somatic fat varies with person and region, different range of somatic fat have to be given, however, up to now, the same value has been used in the measurement of various persons and various regions.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a method of establishing range of somatic fat by Gaussian function approximation in the computerized tomography which can solve the disadvantage described above by obtaining a histogram of Hounsfield value in computerized tomography image, approximating the histogram by Gaussian function by least square method and determining the range of somatic fat from a position and a width of a somatic fat histogram peak, to automatically establish the range of somatic fat by considering characteristics of persons and regions.
A method of establishing the range of somatic fat by Gaussian function approximation in the computerized tomography according to the present invention to accomplish the object described above comprises a step of separating an intra-abdominal cavity and an extra-abdominal cavity at the time of measuring amounts of subcutaneous fat and intra-abdominal cavity fat by using the computerized tomography, a step of preparing histograms of Hounsfield values of the separated intra-abdominal cavity and extra-abdominal cavity, a step of approximating the prepared histograms to Gaussian function by using least square method, and a step of establishing the range of somatic fat with a position and width of peak of the obtained Gaussian function.
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Kim Seung Hwan
Park Seon Hee
Pyo Hyeon Bong
Bruce David V.
Cohen & Pontani, Lieberman & Pavane
Electronics and Telecommunications Research Institute
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