# US 5,345,941 A · Contour mapping of spectral diagnostics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,941 A - Document ID: US5345941A - Status: Granted - Kind: A - Application number: 08/024,674 - Filed: 1993-03-01 - Granted: 1994-09-13 - Earliest claimed: 1989-04-24 - Assignees: Massachusetts Institute of Technology - Inventors: Richard P. Rava; Rebecca Richards-Kortum; Michael S. Feld; Joseph J. Baraga - Web page: https://patentgrep.com/patent/US5345941A ## CPC - G01J 3/4406: {Fluorescence spectrometry} - A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)} - G01N 21/6456: {Spatial resolved fluorescence measurements; Imaging} - G01N 2021/6417: {Spectrofluorimetric devices} - G01N 2021/6419: {Excitation at two or more wavelengths} - G01N 2021/6484: {Optical fibres} - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## 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 ### Claim 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. ### Claim 2 (depends on 1) The method of claim 1 wherein the tissue comprises an artery such that fluorophores of atherosclerotic material within the artery are identified. ### Claim 3 (depends on 1) The method of claim 1 further comprising directing the light to the tissue with a fiber optic cable. ### Claim 4 (depends on 1) The method of claim 1 wherein a data processor identifies the plurality of fluorophores. ### Claim 5 (depends on 1) The method of claim 1 wherein the tissue comprises colon tissue. ### Claim 6 (depends on 1) The method of claim 1 wherein the tissue comprises bladder tissue. ### Claim 7 (depends on 1) The method of claim 1 wherein the tissue comprises gastrointestinal tissue. ### Claim 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. ### Claim 9 (depends on 8) The method of claim 8 wherein a data processor identifies the plurality of fluorophores. ### Claim 10 (depends on 8) The method of claim 8 wherein the tissue comprises arterial tissue. ### Claim 11 (depends on 8) The method of claim 8 wherein the tissue comprises atherosclerotic tissue. ### Claim 12 (depends on 8) The method of claim 8 further comprising inserting a fiber optic probe into a vascular lumen. ### Claim 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. ### Claim 14 (depends on 13) The method of claim 13 wherein a data processor identifies the plurality of fluorophores. ### Claim 15 (depends on 13) The method of claim 13 wherein the tissue comprises colon tissue to identify the presence of adenomatous. ### Claim 16 (depends on 13) The method of claim 13 wherein the tissue comprises bladder tissue. ### Claim 17 (depends on 13) 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. ### Claim 18 (depends on 13) The method of claim 13 further comprising comparing the contoured representation with a reference contour representation.