Diagnostic Utility Of Magnifying Endoscopy With Narrow Band Imaging And Correlation Of Vascular Pattern With Underlying Histopathology In Early Gastric Cancer

Background:Narrow-band imaging (NBI) is a novel endoscopic technique that may enhances the accuracy of diagnosis by using narrow-bandwidth filters in a red-green-blue (R/G/B) sequential illumination system. This results in different images at distinct levels of the mucosa and increases the contrast between the epithelial surface and the subjacent vascular pattern thus yielding very clear images of microvessels on mucosal surfaces. The aim of our study was to measure correlation of vascular patterns with histopathological findings in early adenocarcinoma by using magnifying endoscopy combined with narrow band imaging. In this study we also focused to access the utility of this technique in diagnosis of early gastric cancer.Methods:In this study,28 patients with depressed and elevated type early stage gastric carcinoma were enrolled. (19 well-differentiated adenocarcinoma and 9 poorly differentiated adenocarcinoma). The mixed type with well and poorly differentiated adenocarcinoma recognized in 5 cases was classified into one of the types according to the prominent histological characteristic. The lesions were observed carefully without magnification, with magnification, and with magnification using NBI system. The images of lesions and the pathological characteristics of the lesions were observed and analyzed carefully. Microvascular patterns on the mucosal surface were classified into three patterns:(a) fine network pattern (b) corkscrew pattern and (c) Unclassified Pattern. And these findings of endoscopic images were compared with histological findings. Sensitivity, specificity and diagnostic accuracy of each endoscopic modality were assessed with reference to histopathology.Results:Fine network pattern was observed in 12 cases (63.16%) of 19 well-differentiated adenocarcinomas. Among 9 cases of poorly differentiated adenocarcinoma, corkscrew pattern was observed in 6 cases (66.7%) (P<0.05).Our results showed that differentiated-type adenocarcinomas mainly exhibited fine-network pattern, while undifferentiated type adenocarcinomas mainly exhibited corkscrew pattern. Out of all 28 cases of early adenocarcinoma,2 cases (7.14%) were misdiagnosed as non cancerous lesion on NBI which didn't match with histological results, where as in 26 cases (92.8%) the surface microstructure and microvascular patterns observed in magnified images obtained with NBI system corresponded well with the histological findings of resected specimens. The diagnostic accuracy of NBI remained up to 92.8%.Conclusions:NBI is capable of enhancing the diagnostic ability of endoscopes in charactering tissues by using narrow bandwidth filters in an R/G/B sequential illumination system. The combination of NBI magnification and conventional endoscopy assist in the formulation of a more objective and precise diagnosis.In early gastric cancer, surface capillary patterns and minute surface structures exhibit characteristic features when visualized using magnifying endoscopy with NBI. With regard to the surface capillary patterns, well-differentiated adenocarcinoma and undifferentiated adenocarcinoma specifically show FNP and CSP vascular patterns, respectively. It is possible to diagnose minute gastric cancer before biopsy based on these NBI-visualized patterns. Thus Narrow band Imaging combined with Magnifying endoscopy appears to be an excellent tool for making early and better diagnosis by predicting the histopathological characteristics of lesions in Adenocarcinoma before biopsy. It can help in better screening and early diagnosis of gastric cancers that can lead to early and appropriate treatment with better prognosis.