Near-infrared raman spectroscopy for in vitro and in vivo detection of cervical precancers

• US 5,991,653 A
• Filed: 06/19/1996
• Issued: 11/23/1999
• Est. Priority Date: 03/14/1995
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Ramanujam, Nirmala, Mahadevan-Jansen, Anita, Richards-Kortum, Rebecca, Mitchell, Michele Follen
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US08/667,993
• Time in Patent Office: 1,252 Days
• Field of Search: 600/473, 600/475, 250/341.1, 250/339.01, 250/339.06, 356/301, 436/63, 436/64, 436/171
• US Class Current: 600/475
• 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: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0086 using infrared radiation
• CPC Class Codes: A61B 5/4331 of the cervix A61B5/435 takes precedence
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G01N 2021/656 Raman microprobe
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

Early diagnosis of cervical precancer is an important clinical goal. Optical spectroscopy has been suggested as a new technique to overcome limitations of current clinical practice. Herein, NIR Raman spectroscopy is applied to the diagnosis of cervical precancers. Using algorithms based on empirically selected peak intensities, ratios of peak intensities and a combination of Principal Component Analysis (PCA) for data reduction and Fisher Discriminant Analysis (FDA), normal tissues, inflammation and metaplasia were distinguishable from low grade and high grade precancers. The primary contributors to the tissue spectra appear to be collagen, nucleic acids, phospholipids and glucose 1-phosphate. These results suggest that near infrared Raman spectroscopy can be used effectively for cervical precancer diagnosis.

Claims

1. A method of detecting tissue abnormality in a tissue sample, comprising:

(i) illuminating said tissue sample with an illumination wavelength of electromagnetic radiation selected to cause said tissue sample to emit a Raman spectrum comprising a plurality of wavelengths shifted from said illumination wavelength;

(ii) detecting peak intensities of said Raman spectrum wherein said emission wavelengths are shifted about 1070 cm^-1 and about 1656 cm^-1 from said illumination wavelength;

(iii) comparing each of said detected peak intensities at said wavelength shifts with intensities of a Raman spectrum from known normal tissue at corresponding wavelength shifts; and

(iv) detecting abnormality of said tissue sample, as a function of said comparison, wherein said abnormality detecting step comprises distinguishing precancerous and not precancerous tissue.

2. A method of detecting tissue abnormality in a tissue sample, comprising:

(i) illuminating said tissue sample with an illumination wavelength of electromagnetic radiation selected to cause said tissue sample to emit a Raman spectrum comprising a plurality of wavelengths shifted from said illumination wavelength;

(ii) detecting peak intensities of said Raman spectrum wherein said emission wavelengths are shifted about 1330 cm^-1 and about 1656 cm^-1 from said illumination wavelength;

(iii) calculating a ratio of peak intensities; and

(iv) detecting abnormality of said tissue sample, as a function of said ratio, wherein said abnormality detecting step comprises distinguishing precancerous and not precancerous tissue.

3. A method of detecting tissue abnormality in a tissue sample, comprising:

(i) illuminating said tissue sample with an illumination wavelength of electromagnetic radiation selected to cause said tissue sample to emit a Raman spectrum comprising a plurality of wavelengths shifted from said illumination wavelength;

(ii) detecting peak intensities of said Raman spectrum wherein said emission wavelengths are shifted about 1454 cm^-1 and about 1656 cm^-1 from said illumination wavelength;

(iii) calculating a ratio of peak intensities; and

(iv) detecting abnormality of said tissue sample, as a function of said ratio, wherein said abnormality detecting step comprises distinguishing low grade precancerous and high grade precancerous tissue.

4. A method of detecting tissue abnormality in a tissue sample, comprising:

(i) illuminating said tissue sample with an illumination wavelength of electromagnetic radiation selected to cause said tissue sample to emit a Raman spectrum comprising a plurality of wavelengths shifted from said illumination wavelength;

(ii) detecting a plurality of peak intensities of said Raman spectrum at wavelength shifts selected by their ability to distinguish normal tissue from abnormal tissue;

(iii) calculating a first ratio between at least two of said plurality of peak intensities of said Raman spectrum; and

(iv) detecting, as a function of said first ratio, whether the abnormal tissue is SIL or non-SIL.

5. The method of claim 4, further comprising:

(i) calculating a second ratio between at least two of said plurality of peak intensities of said Raman spectrum; and

(ii) detecting, as a function of said second ratio, whether the abnormal tissue is high grade SIL or low grade SIL.