Apparatus for evaluating biological function

• US 7,065,392 B2
• Filed: 08/11/2004
• Issued: 06/20/2006
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Toshinori Kato
• Original Assignee: Toshinori Kato
• Inventors: Kato, Toshinori
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/915,711
• Publication Number:
  US 20050080323A1
• Time in Patent Office: 678 Days
• Field of Search: 600/310, 600322-323, 600/473
• US Class Current: 600/323
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue

Abstract

The present invention provides an apparatus for evaluating biological function that, in differentiating as far as possible information from the capillaries, which reflects tissue metabolism, from information from outside the tissue (for example, the arteries and veins), has high speed and accuracy enabling it to compensate for the low spatial resolution of conventional near infrared spectroscopy methods, and that furthermore does not merely monitor changes in oxygen concentration and the like, but makes it possible to easily and conveniently distinguish between capillary reactions, metabolic reactions and the like; its configuration is characterized in that it provides a light irradiation means for irradiating light to a specified site of a living body, a light detection means for detecting light exiting from the living body, a calculation means for determining the respective changes in concentration of oxygenated hemoglobin and deoxygenated hemoglobin by performing calculations in near infrared spectroscopy with the intensity of the detected light as a parameter, and a display means for displaying information concerning the relative ratio “k” between both these data over time.

Claims

1. An apparatus for evaluating biological function comprising:

light irradiation means for irradiating light to a specified site of a living body;

light detection means for detecting light exiting from the living body;

calculation means for determining respective changes in concentration of oxygenated hemoglobin and deoxygenated hemoglobin by performing calculations in near infrared spectroscopy on the intensity of the light detected by said light detection means, and for calculating a parameter for deciding whether the concentration of oxygenated hemoglobin and deoxygenated hemoglobin of said specified site of the living body are predominantly capillary data, based on said respective changes in concentration of oxygenated hemoglobin and deoxyenated hemoglobin;

decision means for deciding whether the concentration of oxygenated hemoglobin and deoxygenated hemoglobin of said specified site of the living body are predominantly capillary data by means of said calculated parameter; and

display means for displaying information concerning said parameter over time.

2. An apparatus for evaluating biological function according to claim 1, wherein said light detection means detects light exiting from the living body at a plurality of detection sites, and said calculation means performs the function of determining the respective changes in concentration of oxygenated hemoglobin and deoxygenated hemoglobin for each detection site.

3. An apparatus for evaluating biological function according to claim 1, wherein said parameter is the oxygen exchange ratio “

k”

calculated according to the equation;

4. An apparatus for evaluating biological function according to claim 3, wherein said calculation means performs the function of calculating the angular velocity of said oxygen exchange ratio “

k”

as the differentials of said oxygen exchange ratio “

k,” and

the angular acceleration of said oxygen exchange ratio “

k”

as the differentials of the differentials of said oxygen exchange ratio “

k.”

5. An apparatus for evaluating biological function according to claim 4, wherein said display means performs the function of displaying a two-dimensional diagram plotted overtime, with the changes in concentration of oxygenated hemoglobin as the X-axis and the changes in concentration of deoxygenated hemoglobin as the Y-axis.

6. An apparatus for evaluating biological function according to claim 5, wherein said calculation means performs the function of calculating values for “

L,”

the differentials of said values “

L,” and

the differentials of the differentials of said values “

L,”

where “

L”

is the distance from the zero point to a plot on said two-dimensional diagram.

7. An apparatus for evaluating biological function according to claim 5, wherein said display means performs the function of displaying said two-dimensional diagram showing the relationship between changes in oxygenated hemoglobin concentration and changes in deoxygenated hemoglobin concentration rotated 45 degrees, converting said diagram into a two-dimensional diagram showing the relationship between changes in oxygen saturation and changes in total hemoglobin concentration.

8. An apparatus for evaluating biological function according to claim 7, wherein said display means performs the function of dividing said two-dimensional diagram into eight phases of 45 degrees each to display changes in phase.

9. An apparatus for evaluating biological function according to claim 8, wherein said calculation means performs the function of calculating changes in phase on said two-dimensional diagram.

10. An apparatus for evaluating biological function according to claim 1, further comprising selection means for invalidating detection sites for which the concentration of oxygenated hemoglobin and deoxygenated hemoglobin are determined not to be predominantly capillary data.