Claims
- 1. A method for detecting a fibrous cap in a blood vessel wall, the method comprising(a) illuminating the blood vessel wall with near-infrared light at a range of wavelengths from about 1200 to 2400 nm; (b) detecting light reflected from the blood vessel wall having a range of wavelengths from about 1200 to 2400 nm to obtain a sample reflectance spectrum; and (c) comparing the sample reflectance spectrum to a known reflectance spectrum of a fibrous cap as set forth in FIG. 3, wherein a sample reflectance spectrum that substantially matches the known reflectance spectrum of a fibrous cap indicates the presence of a fibrous cap in the blood vessel wall.
- 2. The method of claim 1, wherein the comparing is done using analytical software.
- 3. The method of claim 1, wherein the comparing is done using pattern recognition software.
- 4. The method of claim 1, wherein the sample spectrum is normalized by subtraction of a mean absorbance at each wavelength at each pixel to obtain a subtraction spectrum, and dividing the subtraction spectrum by a standard deviation of absorbances of each wavelength.
- 5. The method of claim 1, wherein the blood vessel wall is in vivo.
- 6. The method of claim 1, wherein the blood vessel is an artery.
- 7. The method of claim 1, wherein the blood vessel is a coronary artery.
- 8. A method of detecting a vulnerable plaque in a blood vessel wall, the method comprisinglocating a fibrous cap in a blood vessel wall by the method of claim 11; and determining the thickness of the fibrous cap based on the sample reflectance spectrum, wherein the presence of a fibrous cap that is less than 65 microns in thickness indicates that the blood vessel wall contains a vulnerable plaque.
- 9. A method for detecting cholesterol in a blood vessel wall, the method comprising(a) illuminating the blood vessel wall with near-infrared light at a range of wavelengths from about 1200 to 2400 nm; (b) detecting light reflected from the blood vessel wall having a range of wavelengths from about 1200 to 2400 nm to obtain a sample reflectance spectrum; and (c) comparing the sample reflectance spectrum to a known reflectance spectrum of cholesterol as set forth in FIG. 1, wherein a sample reflectance spectrum that substantially matches the known reflectance spectrum of cholesterol indicates the presence of cholesterol in the blood vessel wall.
- 10. The method of claim 9, wherein the blood vessel is a coronary artery.
- 11. A method for detecting lysophosphatidylcholine (LPC) in a blood vessel wall, the method comprising(a) illuminating the blood vessel wall with near-infrared light at a range of wavelengths from about 1200 to 2400 nm; (b) detecting light reflected from the blood vessel wall having a range of wavelengths from about 1200 to 2400 nm to obtain a sample reflectance spectrum; and (c) comparing the sample reflectance spectrum to a known reflectance spectrum of LPC as set forth in FIG. 2, wherein a sample reflectance spectrum that substantially matches the known reflectance spectrum of LPC indicates the presence of LPC in the blood vessel wall.
- 12. The method of claim 11, wherein the blood vessel is a coronary artery.
- 13. A method for detecting a lipid pool in a blood vessel wall, the method comprising(a) illuminating the blood vessel wall with near-infrared light at a range of wavelengths from about 1200 to 2400 nm; (b) detecting light reflected from the blood vessel wall having a range of wavelengths from about 1200 to 2400 nm to obtain a sample reflectance spectrum; and (c) comparing the sample reflectance spectrum to a known reflectance spectrum of a lipid pool as set forth in FIG. 12, wherein a sample reflectance spectrum that substantially matches the known reflectance spectrum of a lipid pool indicates the presence of a lipid pool in the blood vessel wall.
- 14. The method of claim 13, wherein the blood vessel is a coronary artery.
- 15. A method of determining whether a plaque containing a lipid pool in a blood vessel wall is vulnerable to rupture, the method comprisinglocating a lipid pool in a blood vessel wall by the method of claim 13; and determining the cross-sectional area of the lipid pool as a percentage of a total cross-sectional area of a plaque associated with the lipid pool; wherein a lipid pool greater than 30 percent of the total plaque indicates that the plaque is vulnerable to rupture.
Parent Case Info
This application is a continuation (and claims the benefit of priority under 35 USC 120) of U.S. application Ser. No. 09/169,621, filed Oct. 8, 1998 now abandoned. The disclosure of the prior application is considered part of (and incorporated by reference in) the disclosure of this application.
US Referenced Citations (18)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0 467 459 |
Jan 1992 |
EP |
0467 459 |
Jan 1992 |
EP |
649410 |
Feb 1979 |
SU |
Non-Patent Literature Citations (1)
Entry |
Lodder, Robert A. et al. “Assessment of the Feasibility of Determination of Cholesterol and Other Blood Constituents by Near-Infrared Reflectance Analysis” The University of Georgia and International Business Machines Corporation, 1992. |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/169621 |
Oct 1998 |
US |
Child |
09/768920 |
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US |