Endoscope-based beveled and volume fiber-optic Raman probes for in vivo diagnosis of gastric dysplasia: A comparative study

Raman spectroscopy is a unique optical vibrational spectroscopic technique which is capable of probing biochemical and biomolecular structures and conformations associated with disease transformation. Raman probe is a key component to facilitate the in vivo tissue diagnosis by using Raman spectroscopy. The diagnostic performance of the two different endoscope-based fiber-optic Raman probe designs (i.e., beveled and volume Raman probes) were evaluated for real-time, in vivo diagnosis of gastric dysplasia at endoscopy. The beveled Raman probe provides approximately 2-fold improvements in tissue Raman to autofluorescence intensity ratios as compared to the use of volume Raman probe. The diagnostic accuracy of gastric dysplasia using beveled Raman probe is 93.0% (sensitivity of 92.5%; specificity of 93.1%), which is superior to the diagnostic performance (accuracy of 88.4%; sensitivity of 85.8%; specificity of 88.6%) using the volume Raman probe. Biomolecular modeling is finally employed to extract the different Raman active components interrogated by the two types of endoscope-based Raman probes.