Catheter based mid-infrared reflectance and reflectance generated absorption spectroscopy
First Claim
1. A method of characterizing subsurface conditions in a tissue, comprising (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-infrared (IR) spectrum;
- (b) emitting light in said selected wavenumbers within the range of mid-IR spectrum and directing the light in said selected wavenumbers within the range of mid-IR spectrum from the catheter to an area of tissue at a subsurface location at or below the tunica intima of a blood vessel of a subject;
(c) collecting light reflected from the subsurface location and generating a reflectance spectra; and
(d) comparing said reflectance spectra to a reference spectra of normal tissue, whereby a subsurface location having an increased number of absorbance peaks at said selected wavenumbers indicates a subsurface tissue inside said blood vessel containing a physiological marker for atherosclerosis, wherein the comparing step comprises that increased numbers of absorbance peaks at said selected wavenumbers are within at least one range of mid-infrared wavenumbers selected from the group of;
about 3800-3000 cm−
1, about 3500-3000 cm−
1, and about 3020-3000 cm−
1.
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Accused Products
Abstract
A method of characterizing conditions in a tissue, by (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-IR spectrum; (b) directing the light from the catheter to an area of tissue at a location inside a blood vessel of a subject; (c) collecting light reflected from the location and generating a reflectance spectra; and (d) comparing the reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a tissue inside the blood vessel containing a physiological marker for atherosclerosis.
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Citations
21 Claims
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1. A method of characterizing subsurface conditions in a tissue, comprising (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-infrared (IR) spectrum;
- (b) emitting light in said selected wavenumbers within the range of mid-IR spectrum and directing the light in said selected wavenumbers within the range of mid-IR spectrum from the catheter to an area of tissue at a subsurface location at or below the tunica intima of a blood vessel of a subject;
(c) collecting light reflected from the subsurface location and generating a reflectance spectra; and
(d) comparing said reflectance spectra to a reference spectra of normal tissue, whereby a subsurface location having an increased number of absorbance peaks at said selected wavenumbers indicates a subsurface tissue inside said blood vessel containing a physiological marker for atherosclerosis, wherein the comparing step comprises that increased numbers of absorbance peaks at said selected wavenumbers are within at least one range of mid-infrared wavenumbers selected from the group of;
about 3800-3000 cm−
1, about 3500-3000 cm−
1, and about 3020-3000 cm−
1. - View Dependent Claims (2, 3)
- (b) emitting light in said selected wavenumbers within the range of mid-IR spectrum and directing the light in said selected wavenumbers within the range of mid-IR spectrum from the catheter to an area of tissue at a subsurface location at or below the tunica intima of a blood vessel of a subject;
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4. A method of characterizing conditions in a subsurface tissue, comprising (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-infrared (IR) spectrum;
- (b) emitting light in in said selected wavenumbers within the range of mid-IR spectrum and directing the light in said selected wavenumbers within the range of mid-IR spectrum from the catheter to an area of tissue at a subsurface tissue location in or below the tunica intima of a blood vessel of a subject;
(c) collecting light reflected from the subsurface tissue location and generating a reflectance spectra; and
(d) comparing said reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a subsurface tissue in or below the tunica intima of said blood vessel containing a physiological marker for atherosclerosis, wherein the comparing step comprises that increased numbers of absorbance peaks at said selected wavenumbers is in the range of wavenumbers 4000 to 400 cm−
1, wherein at least one peak is at about 3300 cm−
1, or about 3005 cm−
1.
- (b) emitting light in in said selected wavenumbers within the range of mid-IR spectrum and directing the light in said selected wavenumbers within the range of mid-IR spectrum from the catheter to an area of tissue at a subsurface tissue location in or below the tunica intima of a blood vessel of a subject;
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5. An apparatus for characterizing subsurface tissue conditions, comprising:
- (a) a single or multiple source of mid-IR light covering a range of mid-infrared wavenumbers;
(b) a catheter coupled to said source and a detector to detect light reflected by subsurface tissue in or below the tunica intima of a blood vessel of a subject;
(c) a computer means for generating the reflectance generated spectra at selected wavenumbers detected by said detectors and containing the generated spectra to a reference reflectance spectra of normal tissue, to determine whether the subject has atherosclerosis, wherein the selected wavenumbers are about 3800-3000 cm−
1, about 3500-3000 cm−
1, and about 3020-3000 cm−
1 and wherein said computer means has stored therein the reference wavenumber range of 4000-400 cm−
1. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
- (a) a single or multiple source of mid-IR light covering a range of mid-infrared wavenumbers;
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13. A method of characterizing atherosclerosis in the subsurface of a biological material that has enhanced reflectance and/or spectral features, comprising the steps of:
- (a) providing light in selected mid-IR wavenumbers between about 4000 to about 400 cm−
1;
(b) directing the light through a probe to a subsurface area in or below the tunica intima of said biological material;
(c) measuring reflected light returning through the probe over a range of selected wavenumbers to generate a pattern of spectral signals representative of said area; and
(d) comparing spectral signals from a reference spectra to the spectral signals from said area for enhanced reflectance and/or spectral features, wherein said range of selected wavenumbers is selected from the group of;
about 3800-3000 cm−
1, about 3500-3000 cm−
1, about 3020-3000 cm−
1 wherein enhanced reflectance and/or spectral features at the selected wavenumbers characterizes said area of said biological material as atherosclerotic.
- (a) providing light in selected mid-IR wavenumbers between about 4000 to about 400 cm−
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14. A method of spectroscopic diagnosis of tissue comprising:
- irradiating a subsurface portion of tissue at a target area at or below the tunica intima in the blood vessel of a subject with radiation having a frequency within the mid-infrared range, transmitted through a fiber optic cable;
detecting light reflected by the subsurface area of tissue in or below the tunica intima response to the radiation, the light having a range of 4000 cm−
1 to 400 cm−
1; and
analyzing the detected reflectance light to diagnose whether the tissue is atherosclerotic including the step of comparing the detected light with reference data, wherein said detected reflectance light is analyzed in at least one of the following wavenumber ranges;
about 3800-3000 cm−
1, about 3500-3000 cm−
1, and about 3020-3000 cm−
1. - View Dependent Claims (15, 16, 17, 18, 19, 20)
- irradiating a subsurface portion of tissue at a target area at or below the tunica intima in the blood vessel of a subject with radiation having a frequency within the mid-infrared range, transmitted through a fiber optic cable;
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21. A method of detecting vulnerable plaques in a blood vessel tissue of a subject comprising the steps of:
- delivering mid-infrared light to a subsurface tissue to be diagnosed, irradiating said blood vessel tissue with said light, detecting any delivered light reflected by any vulnerable plaque within the same range as the mid-infrared delivered light, and determining the chemical composition and cellular conditions in the subsurface tissue that indicate vulnerable plaque in a blood vessel in or below the tunica intima, wherein the reflected light is detected in at least one of the following wavenumber ranges;
about 3800-3000 cm−
1, about 3500-3000 cm−
1 and about 3020-3000 cm−
1.
- delivering mid-infrared light to a subsurface tissue to be diagnosed, irradiating said blood vessel tissue with said light, detecting any delivered light reflected by any vulnerable plaque within the same range as the mid-infrared delivered light, and determining the chemical composition and cellular conditions in the subsurface tissue that indicate vulnerable plaque in a blood vessel in or below the tunica intima, wherein the reflected light is detected in at least one of the following wavenumber ranges;
Specification