CERVICAL PRECANCER DETECTION USING A MULTIVARIATE STATISTICAL ALGORITHM-BASED ON LASER-INDUCED FLUORESCENCE-SPECTRA AT MULTIPLE EXCITATION WAVELENGTHS

A portable fluorimeter was developed and utilized to acquire fluoresce nce spectra from 381 cervical sites in 95 patients at 337, 380 and 460 nm excitation immediately prior to colposcopy, A multivariate statist ical algorithm was used to extract clinically useful information from tissue spectra acquired in vivo. Two full-parameter algorithms were de veloped using tissue fluorescence emission spectra at all three excita tion wavelengths (161 excitation-emission wavelength pairs) for cervic al precancer (squamous intraepithelial lesion [SIL]) detection: a scre ening algorithm that discriminates between SIL and non-SIL with a sens itivity of 82 +/- 1.4% and specificity of 68 +/- 0.0%, and a diagnosti c algorithm that differentiates high-grade SIL from non-high-grade SIL with a sensitivity and specificity of 79 +/- 2% and 78 +/- 6%, respec tively, Multivariate statistical analysis was also employed to reduce the number of fluorescence excitation-emission wavelength pairs needed to redevelop algorithms that demonstrate a minimum decrease in classi fication accuracy, Two reduced-parameter algorithms that employ fluore scence intensities at only 15 excitation-emission wavelength pairs wer e developed: the screening algorithm differentiates SIL from non-SIL w ith a sensitivity of 84 +/- 1.5% and specificity of 65 +/- 2% and the diagnostic algorithm discriminates high-grade SIL from non-high-grade SIL with a sensitivity and specificity of 78 +/- 0.7% and 74 +/- 2%, r espectively, Both the full-parameter and reduced-parameter screening a lgorithms discriminate between SIL and non-SIL with a similar specific ity (+/-5%) and a substantially improved sensitivity relative to Pap s mear screening. A comparison of the full-parameter and reduced-paramet er diagnostic algorithms to colposcopy in expert hands indicates that all three have a very similar sensitivity and specificity for differen tiating high-grade SIL from non-high-grade SIL.