In vivo , real-time, transnasal, image-guided Raman endoscopy: defining spectral properties in the nasopharynx and larynx

• Published in: Journal of biomedical optics Vol. 17; no. 7; pp. 770021 - 1-077002-7
• Main Authors: Bergholt, Mads Sylvest, Lin, Kan, Zheng, Wei, Lau, David Pang Cheng, Huang, Zhiwei
• Format: Journal Article
• Language: English
• Published: United States 01.07.2012
• Subjects: Algorithms; Biocompatibility; Biomedical materials; Computer Systems; Endoscopes; Humans; In vivo testing; In vivo tests; Larynx; Larynx - chemistry; Male; Molecular Imaging - instrumentation; Nasopharynx - chemistry; Reproducibility of Results; Sensitivity and Specificity; Spectra; Spectrum Analysis, Raman - instrumentation; Spectrum Analysis, Raman - methods; Surgical implants
• ISSN: 1083-3668; 1560-2281; 1560-2281
• DOI: 10.1117/1.JBO.17.7.077002

We report for the first time the implementation of transnasal, image-guided Raman endoscopy to directly assess Raman spectral properties of nasopharyngeal and laryngeal tissue in vivo during clinical endoscopic examinations. A rapid 785-nm excitation Raman endoscopy system, coupled with a miniaturized fiber-optic Raman probe, was utilized for real-time, in vivo Raman measurements of different anatomical locations in the head and neck. A total of 874 high-quality in vivo Raman spectra were successfully acquired from different anatomic locations of the nasopharynx and larynx [i.e., posterior nasopharynx (PN) (n=521), the fossa of Rosenmüller (FOR) (n=157), and true laryngeal vocal chords (LVC) (n=196)] in 23 normal subjects at transnasal endoscopy. Difference spectra and principal component analysis (PCA) were employed for tissue characterization, uncovering the tissue variability at the biomolecular level. The PCA-linear discriminant analysis (LDA) provides sensitivity of 77.0% and specificity of 89.2% for differentiation between PN and FOR, and sensitivity of 68.8% and specificity of 76.0% for distinguishing LVC and PN using the leave-one-subject-out, cross-validation method. This work demonstrates that transnasal, image-guided Raman endoscopy can be used to acquire in vivo Raman spectra from the nasopharynx and larynx in real time. Significant Raman spectral differences (p<0.05) identified as reflecting the distinct composition and morphology in the nasopharynx and larynx should be considered to be important parameters in the interpretation and rendering of diagnostic decision algorithms for in vivo tissue diagnosis and characterization in the head and neck.