Near-infrared-excited confocal Raman spectroscopy advancesin vivodiagnosis of cervical precancer

Abstract

Abstract. Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes of biomolecules associated with tissue premalignant transformation. This study evaluates the clinical utility of confocal Raman spectroscopy over near-infrared (NIR) autofluorescence (AF) spectroscopy and composite NIR AF/ Raman spectroscopy for improving early diagnosis of cervical precancer in vivo at colposcopy. A rapid NIR Raman system coupled with a ball-lens fiber-optic confocal Raman probe was utilized for in vivo NIR AF/ Raman spectral measurements of the cervix. A total of 1240 in vivo Raman spectra [normal (n ¼ 993), dysplasia (n ¼ 247)] were acquired from 84 cervical patients. Principal components analysis (PCA) and linear discriminant analysis (LDA) together with a leave-one-patient-out, cross-validation method were used to extract the diagnostic information associated with distinctive spectroscopic modalities. The diagnostic ability of confocal Raman spectroscopy was evaluated using the PCA-LDA model developed from the significant principal components (PCs) [i.e., PC4, 0.0023%; PC5, 0.00095%; PC8, 0.00022%, (p < 0.05)], representing the primary tissue Raman features (e.g., 854, 937, 1095, 1253, 1311, 1445, and 1654 cm −1 ). Confocal Raman spectroscopy coupled with PCA-LDA modeling yielded the diagnostic accuracy of 84.1% (a sensitivity of 81.0% and a specificity of 87.1%) for in vivo discrimination of dysplastic cervix. The receiver operating characteristic curves further confirmed that the best classification was achieved using confocal Raman spectroscopy compared to the composite NIR AF/Raman spectroscopy or NIR AF spectroscopy alone. This study illustrates that confocal Raman spectroscopy has great potential to improve early diagnosis of cervical precancer in vivo during clinical colposcopy. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Raman spectroscopy in cervical cancers: An update

“…More recent confocal studies have demonstrated great potential of in vivo RS to improve early diagnosis of cervical precancers. [49] Confocal RS coupled with PCA-LDA modeling yielded a sensitivity and specificity of 81 and 87%, respectively, for in vivo discrimination of dysplastic cervix. It is also concluded that the best classification can be achieved using confocal RS compared to the composite near infrared autofluorescence (NIR AF)/RS or NIR AF spectroscopy alone.…”

“…[32,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] In 1998, a fiberoptic in vivo Raman study of cervix to delineate precancer lesions from the normal cervix was reported. [39] In this study, in vivo Raman spectra of cervix could be acquired in 90 s. Authors concluded that the increase in the laser power could reduce the integration time to less than 20 s for measuring in vivo Raman spectra of cervix.…”

The Use of a Novel Optical Algorithm in the Diagnosis of Cervical Pre-Invasive Pathology - A Preliminary Proof of Principal Study

“…Also, tissue auto-fluorescence background further obscures part of the Raman signal. When comparing several spectroscopic modalities for the diagnosis of cervical dysplasia, Duraipandian et al [16] found that near infra-red confocal Raman spectroscopy is the preferred method when used as an adjunct with colposcopy. This system of spectroscopy is still under development and not widely available or accepted.…”

“…Among the different optical spectroscopic techniques, near infrared Raman spectroscopy has been found to have high specificity for diagnosis of malignancies in various organs, including the cervix. Also, LUMA was approved by the US FDA as an adjunct to colposcopy to map the cervix and identify high risk lesions with spectroscopy [9,10,11,12,13,14,15,16]. …”

Diagnostic aids in detection of oral precancer and cancer: Past to present

“…It is sensitive and real-time imaging at the molecular level and has high biomolecular specificity for in vitro and in vivo diagnosis of malignancies in various organs. [41,42] …”