Effects of biographical variables on cervical fluorescence emission spectra

Abstract

Diagnostic algorithms can classify tissue samples as diseased or nondiseased based on fluorescence emission collected from the intact cervix. Such algorithms can distinguish high-grade squamous intraepithelial lesions from low-grade squamous intraepithelial lesions. An understanding of the effects of the values of biographical covariates, such as age, race, smoking, or menopausal status on the emission spectra for each patient could improve diagnostic efficiency. The analysis described was performed using data collected from two previously published clinical trials; one study measured spectra from 395 sites in 95 patients referred to a colposcopy clinic with abnormal Pap smears, and the second study measured spectra from 204 sites in 54 patients self-referred for screening and expected to have a normal Pap smear. For this analysis, data about age, race, menstrual cycle, and smoking were collected. The principal components from normalized data were compared. There are clear intensity differences observed with age and menopausal status; postmenopausal patients exhibit higher emission intensities. Differences associated with biographical variables need to be tested in larger studies, which stratify adequately for these variables. The addition of these biographical variables in the preprocessing of data could dramatically improve algorithm performance and applicability.

Comparative evaluation of differential laser-induced perturbation spectroscopy as a technique to discriminate emerging skin pathology

“…As for the control skin, this region of higher variability could be due to the aging-related remodeling of skin or the natural turnover of skin ECM proteins. 13,17 In this regard, DLIPS serves as a convenient probe for ECM structure that was previously inaccessible when exciting natural fluorescence at 355 nm, as it has been noted that at this excitation wavelength it is not possible to resolve collagen fluorescence from that of NADH. 43 Our component-loading plots for the laser-induced fluorescence spectra and the post-perturbation spectra [ Fig.…”

“…This sensitivity to signal intensity highlights an important limitation of traditional in vivo fluorescence techniques; namely, that subjectto-subject variability can often obscure the relatively much smaller variability due to changes in tissue autofluorescence. 13 Finally, Fig. 7(g) through 7(i) shows the same technique applied to the spectra collected after the perturbation laser pulse.…”

“…13, 21 Brookner, 13 for example, reported variations in peak fluorescence intensities varying by more than a factor of five between patients while the intra-patient coefficient of variation was less than 25%. While fluorescence signals are directly linked to the local molecular structure of the targeted system, there clearly remains a need for further improvement in optical-based sensing schemes to specifically address the variations realized with absolute fluorescence intensity.…”

“…However, the largest hurdle to surmount in translating these spectral strategies to the clinic has been the significant patient-to-patient variation in fluorescent properties. 13,14 This has been shown to be associated with race, age, sex, air temperature, and even deformation of the tissue when applying the probe. 13,[15][16][17][18][19][20][21] The results of this patient and sampling variability include fluctuations in absolute emission intensity, emission peak shifts, and changes in the scattering and absorption properties of the tissue, among other effects.…”

Fluorescence spectroscopy of an in vitro model of human cervical precancer identifies neoplastic phenotype

“…7,8 However, the clinical applicability of in vivo systems is limited by the significant variation in cervical fluorescence properties that occurs between patients. 9 The combination of reflectance and fluorescence approaches has some benefits in improving the discrimination between normal and neoplastic tissues, 8 and the incorporation of biomarkers into optical strategies may help to improve the detection of cervical precancers. 10 Nevertheless, a better understanding of the changes that occur in the physical and biochemical properties of the cervix during the development of neoplastic disease is necessary to develop better diagnostic algorithms.…”