PTU-028 Linked colour imaging increases the diagnostic yield and accuracy of type 1 gastric carcinoids

Abstract

Introduction Type 1 Gastric carcinoid tumours (GCTs) are the most common neuroendocrine tumours arising from enterchromaffin cell hyperplasia and hypergastrinaemia on a background of atrophic gastritis. Endoscopic diagnosis of Type 1 GCTs remains a challenge. White light endoscopy (WLE) and Narrow Band Imaging (NBI) have failed to demonstrate reliable endoscopic signs of carcinoid which are often misdiagnosed as hyperplastic, adenomatous or neoplastic lesions, warranting histopathological diagnosis. Furthermore, microcarcinoids are usually an incidental diagnosis during routine gastric biopsy. Here we evaluate the use of Linked Colour Imaging (LCI); the latest Fujifilm post- processing digital technology for the endoscopic diagnosis of Type 1 GCTs. Methods Consecutive patients undergoing endoscopic surveillance of Type 1 GCTs were included. Patient baseline demographics were recorded. Endoscopic examination was performed using Fujifilm ELUXEOTM EG-760Z gastroscopes and simethicone/saline irrigation with imaging performed in the following sequence; WLE, blue laser imaging (BLI) and finally LCI. Lesion number, visibility using a known endoscopic scale (1–4; poor-excellent), endoscopic diagnosis were recorded for each imaging modality. Lesion demarcation and surface pattern features using LCI were recorded. High quality images of histopathologically confirmed Type 1 GCTs were selected for independent review by 2 further endoscopists blinded to histopathological diagnosis and inter-observer agreement calculated. Results 3 patients (2 F), mean age 51.6 years were included. The total number of gastric lesions identified by WLE, BLI and LCI were 14, 8 and 24 respectively. LCI identified an additional 10 and 16 gastric lesions compared to WLE and BLI respectively. Mean lesion size was 6.5 (2–15) mm. Atrophic gastritis was confirmed histopathologically in all patients. Nine lesions with optimal image quality were selected for further review (Figure.1). Endoscopic features included, villous/inflammatory surface pattern (n=9, 100%), dense vasculature (n=9, 100%) and an amber hue (n=9,100%). Diagnostic accuracy for Type 1 GCTs using WLE, BLI, and LCI were 22%, 22% and 100% respectively. Median visibility of all lesions for both WLE and BLI were 2 (1–4) and 4 (3–4) using LCI. All lesions were well demarcated using LCI, 44% with WLE and 22% with BLI. Inter-observer agreement for the LCI diagnosis of Gastric NET was 100%. Conclusions LCI increases diagnostic yield and accuracy compared to both WLE and BLI and provides consistent endoscopic features;a novel feature over the challenges of prior imaging modalities. Lesion demarcation is clearer using LCI;an important factor to guide successful and complete endoscopic resection.