US 4,905,703 AGranted

Liver function testing apparatus and method

AssigneeSumitomo Electric Industries, Ltd.

InventorsMasahiko Kanda, Kunio Awazu

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Abstract

In a liver function testing apparatus, light sources (11, 12) expose vital tissue (15) to a first light of a wavelength absorbed by specific dye dosed into blood of the vital tissue, whereby the dye is to be taken in and removed by a liver and a second light of a wavelength not absorbed by the dye. Optical pulses obtained from the vital tissue are received by a light receiving element (13) providing an output signal which is sampled by an A-D converter (30) for converting the output signal into digital sampling signals. Variable components in the blood represented by the sampling signals are determined as coefficients of linear functions, to perform a biocalibration. A value correlated with a specific dye concentration in the blood is processed on the basis of the digital sampling signals during a prescribed period after injection of a defined dose of the specific dye and on the basis of the determined coefficients, so that a coefficient of a simulation function which is a function of time is obtained by using the method of least squares. Additionally a blood plasma disappearance rate and a retention rate are obtained on the basis of the coefficient.

Claims32

Dependent claims

An apparatus for testing the function of a liver, comprising light source means for exposing vital tissue to a first light of a wavelength absorbed by a specific dye injected as a dose into blood of said vital tissue, said specific dye to be taken in and removed by the liver, and to a second light of a wavelength not absorbed by said specific dye;

photoelectric conversion means for outputting first and second photoelectric conversion signals corresponding to said first light and to said second light applied to said vital tissue by said light source means and obtained from said vital tissue as said first and second light has passed through said vital tissue;
sampling means for sampling said first and second photoelectric conversion signals to provide sampling signal outputs;
decision means for deciding a coefficient of a regression line expression between said first and second photoelectric conversion signals on the basis of variable components in said blood included in said first and second photoelectric conversion signals sampled by said sampling means;
and arithmetic means connected to receive a value correlated to a specific dye concentration in said blood on the basis of said sampling signal output of said sampling means during a prescribed period of time from an injection of a dose of said specific dye, and connected to receive said coefficient of said regression line expression decided by said decision means for calculating a liver test result based on said sampling signal outputs and on said coefficient.

1 more element

A method for testing the function of a liver, comprising the steps of exposing vital tissue to a first light of a wavelength absorbed by a specific dye injected into blood of said vital tissue said specific dye to be taken in and removed by the liver, and to a second light of a wavelength not absorbed by said dye;

sampling photoelectric conversion signals corresponding to said first light and to said second light applied to said vital tissue and obtained from said vital tissue in a biocalibration mode as said first and second light has passed through said vital tissue;
deciding a coefficient of a regression line expression between said first and second photoelectric conversion signals on the basis of variable components in said blood included in respective sampling outputs obtained in said biocalibration mode;
injecting said specific dye into said blood and thereafter sampling said first and second photoelectric conversion signals during a prescribed period of time in a measurement mode;
and calculating a value correlated with a specific dye concentration in said blood on the basis of respective sampling outputs and on the basis of said coefficient of said regression line expression in said measurement mode for providing a calculated liver test result based on said sampling outputs and on said coefficient.

1 more element

Dependencies are inferred from the claim text.