Image-Guided Real-Time Raman Endoscopy for In Vivo Diagnosis of Gastric Precancer and Cancer During Clinical Gastroscopy

Abstract

Objective: Raman spectroscopy is a vibrational spectroscopic technique capable of probing the changes of biochemical compositions and conformations occurring in tissue. The main aims of this research are to develop a novel image-guided Raman endoscopic technique to conduct In Vivo optical biopsy and to evaluate its diagnostic potential for improving early diagnosis and detection of gastric precancer and cancer In Vivo. Methods: With our successful development of an integrated Raman endoscopy and multimodal wide-field imaging modalities (white-light reflectance (WLR), narrow-band imaging (NBI), autofluorescence imaging (AFI)) technique, a total of 427 In Vivo gastric sites have been measured from 61 gastric patients during clinical gastroscopy. Histopathological examination revealed that 281 Raman spectra were from normal mucosa, 17 spectra were from dysplasia and 129 spectra were from neoplasia. The partial least squares (PLS) discriminant analysis (DA) was employed to develop multi-class diagnostic algorithms for tissue diagnosis and classification. Results: High quality In Vivo Raman spectra can be acquired in real-time within 0.5 sec from the stomach during clinical endoscopic examination. Significant differences in Raman spectra between normal, dysplastic and neoplastic gastric tissue are observed reflecting the pathological transformation associated with cancer (e.g., increased mitotic activity and elevated DNA content). The PLS-DA modeling on the In Vivo gastric Raman spectra achieved the diagnostic sensitivities of 95.1%, 100.0%, and 89.8%; and specificities of 93.0%, 95.0%, and 93.8%; respectively, for identifying normal, dysplastic and neoplastic gastric tissue In Vivo. Conclusions: This study demonstrates that the image-guided Raman endoscopy technology has promising clinical potential for rapid In Vivo diagnosis and detection of gastric premalignancies and malignancies during routine gastroscopy. ________________________________ *Correspondence to: Dr. Zhiwei Huang, Department of Bioengineering, Faculty of Engineering, National University of Singapore. Tel: +656516-8856; Fax: +656872-3069; E-mail: biehzw@nus.edu.sg