Noninvasive blood analyzer

• US 6,061,583 A
• Filed: 06/11/1998
• Issued: 05/09/2000
• Est. Priority Date: 12/27/1995
• Status: Expired due to Term

• Current Assignee: Sysmex Corporation
• Original Assignee: Sysmex Corporation and KEN Ishihara
• Inventors: Ishihara, Ken, Kouchi, Yasuhiro, Kusuzawa, Hideo, Asano, Kaoru
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US09/077,743
• Time in Patent Office: 698 Days
• Field of Search: 600/310, 600/322, 600/473, 600/476, 600/479, 356/39
• US Class Current: 600/322
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B

Abstract

A noninvasive blood analyzer is provided which comprises: a light source for illuminating a part of tissues of a living body including a blood vessel; an image pickup section for picking up an image of the illuminated blood vessel and tissues; and an analyzing section for analyzing the picked image; the analyzing section including an extracting section for extracting image density distribution across the blood vessel in the image as an image density profile, a quantifying section for quantifying configurational characteristics of the image density profile, a computing section for computing the concentration of a blood constituent on the basis of the quantified characteristics, and an outputting section for outputting a computation result. The blood analyzer can measure the concentration of blood hemoglobin and the hematocrit in real time with an improved repeatability without blood sampling.

Claims

1. A noninvasive blood analyzer comprising:

a light source for illuminating part of a tissue of a living body including a blood vessel;

an image pickup section for picking up an image of the illuminated blood vessel and tissue; and

an analyzing section for analyzing the image, wherein the analyzing section includes;

an extracting section for extracting an image density distribution across the blood vessel in the image as an image density profile;

a quantifying section for quantifying configurational characteristics of the image density profile;

a computing section for computing an amount of a blood constituent on the basis of the quantified characteristics; and

an outputting section for outputting the computed amount.

2. A noninvasive blood analyzer as set forth in claim 1, wherein the amount of the blood constituent is at least one of hemoglobin concentration and hematocrit.

3. A noninvasive blood analyzer as set forth in claim 2, wherein the image pickup section includes an object lens, a focusing lens, a space filter disposed between the lenses and having two-dimensionally variable transmittances, and filter controlling means for two-dimensionally varying the transmittance of the space filter.

4. A noninvasive blood analyzer as set forth in claim 3, wherein the image pickup section further includes adjusting means for adjusting the position of a focal point of the object lens with respect to the blood vessel.

5. A noninvasive blood analyzer as set forth in claim 4, wherein the quantifying section normalizes the image density profile, and computes a peak value h and a distribution width w corresponding to the diameter of the blood vessel from the normalized image density profile.

6. A noninvasive blood analyzer as set forth in claim 5, wherein the quantifying section computes a depth L defined between a surface of the body tissues and the blood vessel on the basis of the position of the focal point of the object lens which is adjusted by the adjusting means such that the sharpest image is picked up, and corrects the peak value h and the distribution width w on the basis of the depth L.

7. A noninvasive blood analyzer as set forth in claim 3, wherein the quantifying section normalizes the image density profile, and computes a peak value h and a distribution width w corresponding to the diameter of the blood vessel from the normalized image density profile.

8. A noninvasive blood analyzer as set forth in claim 7, wherein the quantifying section corrects the peak value h and the distribution width w on the basis of a plurality of images picked up every time the transmittance of the space filter is two-dimensionally varied.

9. A noninvasive blood analyzer as set forth in claim 1, wherein the light source comprises a light emitting device which is adapted to selectively emit light beams of first and second wavelengths, which are substantially isosbestic for oxidized and reduced hemoglobins.

10. A noninvasive blood analyzer as set forth in claim 1, wherein the extracting section searches for an area in the image where a blood vessel image stands in the sharpest contrast and extracts the image density profile from the area thus searched for.

11. A noninvasive blood analyzer as set forth in claim 1, wherein the quantifying section normalizes the image density profile, and computes a peak value h and a distribution width w corresponding to the diameter of the blood vessel from the normalized image density profile.

12. A noninvasive blood analyzer as set forth in claim 11,

wherein the light source comprises a light emitting device which is adapted to selectively emit light beams of first and second wavelengths;

wherein the quantifying section computes peak values h1 and h2 and distribution widths w1 and w2 of first and second profiles respectively obtained by picking up images of the same part of the body tissues at the first and second wavelengths; and

wherein the computing section computes the concentration of hemoglobin and hematocrit on the basis of the computed peak values h1 and h2 and distribution widths w1 and w2.

13. A noninvasive blood analyzer as set forth in claim 12, wherein the quantifying section estimates a depth L at which the blood vessel is located on the basis of the distribution widths w1 and w2 of the first and second image density profiles obtained by picking up images of the same part of the body tissues at the first and second wavelengths, and corrects the peak values h1 and h2 on the basis of the depth L.

14. A noninvasive blood analyzer as set forth in claim 1, further comprising a fixing member for relatively fixing the living body to the light source and the image pickup section.

15. A noninvasive blood analyzer as set forth in claim 1, wherein the image pick up section picks up a transmitted light image of the blood vessel and the tissue.

16. A noninvasive blood analyzer as set forth in claim 1, wherein the image pick up section picks up a reflected light image of the blood vessel and the tissue.

17. A noninvasive blood analyzer comprising:

a light source for illuminating part of a tissue of a living body including a blood vessel;

an image pickup section for picking up an image of the illuminated blood vessel and the tissue; and

an analyzing section for analyzing the image, the analyzing section analyzing an image of the blood vessel in the image to compute an amount of a blood constituent and output a computation result;

wherein the light source comprises a light emitting device which is adapted to selectively emit light beams of first and second wavelengths, which are within a range between 600 and 950 nm.

18. A noninvasive blood analyzer as set forth in claim 17, wherein the amount of the blood constituent is at least one of hemoglobin concentration and hematocrit.

19. A noninvasive blood analyzer as set forth in claim 17, further comprising a fixing member for relatively fixing the living body to the light source and the image pickup section.

20. A noninvasive blood analyzer as set forth in claim 17, wherein the image pickup section-picks up a transmitted light image of the blood vessel and the tissue.

21. A noninvasive blood analyzer as set forth in claim 17, wherein the image pickup section picks up a reflected light image of the blood vessel and the tissue.

22. A noninvasive blood analyzer comprising:

a light source for illuminating part of a tissue of a living body including a blood vessel;

an image pickup section for picking up an image of the illuminated blood vessel and the tissue; and

an analyzing section for analyzing the image, the analyzing section analyzing an image of the blood vessel in the image to compute an amount of a blood constituent and output a computation result;

wherein the image pickup section includes an object lens, a focusing lens, a space filter disposed between the lenses and having two-dimensionally variable transmittances, and filter controlling means for two-dimensionally varying the transmittance of the space filter.

23. A noninvasive blood analyzer as set forth in claim 22, wherein the image pickup section further includes adjusting means for adjusting the position of a focal point of the object lens with respect to the blood vessel.