The Usefulness of Raman Spectroscopy for the Differential Diagnosis of Colonic Polyps

Abstract

BACKGROUND/AIMS: Narrow band imaging (NBI) systems consist of sequential electronic endoscopes and light sources equipped with modern narrow band filters, and yield very clear images of microvessels on mucosal surfaces. The aim of this study was to assess the relationships between images obtained with an NBI system and histological findings, especially vascular patterns, to distinguish adenoma from early gastric cancer (EGC) type IIa. PATIENTS AND METHODS: We postoperatively confirmed and evaluated 39 elevated lesions, 32 adenomas and seven type IIa early gastric cancers (EGC IIa) in patients who had undergone endoscopic submucosal dissection. We selected three sites per adenoma and four sites per EGC IIa for NBI. The selected sites were classified as four conventional superficial structures (SSs) or irregular microvascular patterns (IMVPs). In addition, the selected sites were divided into two groups based on the presence of corkscrew (CS) vascular patterns over 10% of the field. RESULTS: Regarding IMVP subcategories, (1) slight intrastructural irregular microvascular patterns (ISIMVPs) accounted for 84%, (2) severe ISIMVPs accounted for 6%, (3) fine networks (FNs) accounted for 10%, and (4) corkscrews accounted for 0% of cases in the adenomas. The corresponding proportions in the EGC IIa were (1) 25%, (2) 25%, (3) 50%, and (4) 0%. Slight ISIMVPs, severe ISIMVPs, and FNs reliably distinguished the two diseases: P=0.000 for slight ISMVPs; P=0.010 for severe ISIMVPs; P=0.000 for FNs. Corkscrew vascular patterns were observed in 46% of EGC IIa and 7% of adenoma cases (P=0.000). CONCLUSIONS: NBI can be used to differentiate EGC IIa from gastric adenoma based on IMVP classifications and the presence of corkscrew vascular patterns. Irregular microvascular patterns of adenoma and EGC IIa