Contour mapping of spectral diagnostics

• US 5,345,941 A
• Filed: 03/01/1993
• Issued: 09/13/1994
• Est. Priority Date: 04/24/1989
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Baraga, Joseph J., Rava, Richard P., Richards-Kortum, Rebecca, Feld, Michael S.
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US08/024,674
• Time in Patent Office: 561 Days
• Field of Search: 128/664, 128/665, 128/633, 128/666
• US Class Current: 600/476
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 2021/6417 Spectrofluorimetric devices
• CPC Class Codes: G01N 2021/6419 Excitation at two or more wavelengths
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/6456 Spatial resolved fluorescence measurements; Imaging

Abstract

The present invention relates to a method of generating and processing spectral information arising from the laser induced fluorescence of tissue. The intensity of fluorescence is recorded as a function of both excitation and emission wavelengths and contour maps of tissue fluorescence are generated which are useful in the diagnosis of condition of the tissue under examination.

Claims

1. A method of optically measuring tissue comprising:

directing light from a broadband light source having a multiplicity of excitation wavelengths onto tissue to induce autofluorescence at a multiplicity of emission wavelengths

measuring intensities of the induced autofluorescence at the multiplicity of emission wavelengths to produce intensity data;

generating a contoured electronic representation of the intensity data, the contoured representation being a function of both excitation wavelengths and emission wavelengths;

correcting the contoured representation by removing a component of the representation correlated with a spectrally absorbing material within the tissue; and

identifying the presence of a plurality of fluorophores within the tissue from the corrected contoured representation.

2. The method of claim 1 wherein the tissue comprises an artery such that fluorophores of atherosclerotic material within the artery are identified.

3. The method of claim 1 further comprising directing the light to the tissue with a fiber optic cable.

4. The method of claim 1 wherein a data processor identifies the plurality of fluorophores.

5. The method of claim 1 wherein the tissue comprises colon tissue.

6. The method of claim 1 wherein the tissue comprises bladder tissue.

7. The method of claim 1 wherein the tissue comprises gastrointestinal tissue.

8. A method of optically measuring vascular tissue comprising:

directing light from a broadband light source having a multiplicity of excitation wavelengths onto vascular tissue to induce autofluorescence at a multiplicity of emission wavelengths;

measuring intensities of the induced autofluorescence at the multiplicity of emission wavelengths to produce intensity data;

generating a contoured electronic representation of the intensity data, the contoured representation being a function of both excitation wavelengths and emission wavelengths; and

identifying the presence of a plurality of fluorophores within the tissue from the contoured representation.

9. The method of claim 8 wherein a data processor identifies the plurality of fluorophores.

10. The method of claim 8 wherein the tissue comprises arterial tissue.

11. The method of claim 8 wherein the tissue comprises atherosclerotic tissue.

12. The method of claim 8 further comprising inserting a fiber optic probe into a vascular lumen.

13. A method of optically measuring tissue comprising:

inserting a fiber optic probe into a body lumen;

directing light from a broadband light source having a multiplicity of excitation wavelengths through the probe and onto tissue within the lumen to induce autofluorescence at a multiplicity of emission wavelengths;

collecting induced autofluorescence radiation from the tissue with the fiber optic probe and coupling the collected radiation at a proximal end of the probe to a detector;

measuring intensities of the induced autofluorescence at the multiplicity of emission wavelengths to produce intensity data;

generating a contoured electronic representation of the intensity data, the contoured representation being a function of both excitation wavelengths;

forming a displayed image from the contoured electronic representation; and

identifying the presence of a plurality of fluorophores within the tissue from the contoured representation.

14. The method of claim 13 wherein a data processor identifies the plurality of fluorophores.

15. The method of claim 13 wherein the tissue comprises colon tissue to identify the presence of adenomatous.

16. The method of claim 13 wherein the tissue comprises bladder tissue.

17. The method of claim 13 wherein the tissue comprises gastrointestinal tissue and the one of the plurality of identified fluorophores is selected from the group consisting of collagen and pyridoxic acid.

18. The method of claim 13 further comprising comparing the contoured representation with a reference contour representation.