Automatic View-Point Selection for Inter-Operative Endoscopic Surveillance

International audienceAbstract. Esophageal adenocarcinoma arises from Barrett’s esophagus, which is the most serious complication of gastroesophageal reflux disease. Strategies for screening involve periodic surveillance and tissue biopsies. A major challenge in such regular examinations is to record and track the disease evolution and re-localization of biopsied sites to provide targeted treatments. In this paper, we extend our original inter-operativerelocalization framework to provide a constrained image based search for obtaining the best view-point match to the live view. Within this context we investigate the effect of, (a) the choice of feature descriptors and color-space, (b) filtering of uninformative frames, (c) endoscopic modality, for view-point localization. Our experiments indicate an improvement in the best view-point retrieval rate to [92%, 87%] from [73%, 76%] (in our previous approach) for NBI and WL

Video Synchronization: An Approach to Biopsy Site Re-localization

International audienceBarrett’s esophagus (Barrett’s esophagus) is the pre-malignant lesion for the majority of patients with esophageal adenocarcinoma. The sequence of events from Barrett’s esophagus to adenocarcinoma has several steps, encompassing low grade intra-epithelial Neoplasia (LGIN), and high grade intra-epithelial neoplasia (HGIN). As it seems that this evolution spans many years, endoscopic surveillance for patients with Barrett’s esophagus has been advocated, to detect neoplasia at early and curable stages. In recent years endoscopic imaging techniques have improved greatly. However, even using sophisticated imaging techniques, the standard approach of comprehensive endoscopic biopsy protocol includes direct sampling from suspicious areas in combination with systematic random four quadrant biopsies (4QBs) every 1±2 cm along the length of the Barrett’s segment, according to the Seattle protocol, is recommended as the gold standard for surveillance. The approach is labor-intensive but iscurrently considered to be the state of the art. However, the primary problem is the inter-operative re-localization of these biopsy sites to guide the treatment. Often re-localization is performed using the markings made on the endoscope which are highly unreliable and prevent targeted treatments

Inter-Operative Biopsy Site Relocalization in Endoluminal Surgery

International audienceBarrett's oesophagus, a pre-malignant condition of the oesophagus has been on a rise in the recent years. The standard diagnostic protocol for Barrett's involves obtaining biopsies at suspicious regions along the oesophagus. The localization and tracking of these biopsy sites " inter-operatively " poses a significant challenge for providing targeted treatments and tracking disease progression. This paper proposes an approach to provide guided navigation and relocalization of the biopsy sites using an electromagnetic tracking system. The characteristic of our approach over existing ones is the integration of an EM sensor at the flexible endoscope tip, so that the endoscopic camera depth inside the oesophagus can be computed in real-time, allowing to retrieve and display an image from a previous exploration at the same depth. We firstly describe our system setup and methodology for inter-operative registration. We then propose three incremental experiments of our approach. First, on synthetic data with realistic noise model to analyze the error bounds of our system. The second on in-vivo pig data using an optical tracking system to provide a pseudo ground-truth. Accuracy results obtained were consistent with the synthetic experiments despite uncertainty introduced due to breathing motion, and remain inside acceptable error margin according to medical experts. Finally, a third experiment designed using data from pigs to simulate a real task of biopsy site relocalization, and evaluated by 10 GI experts. It clearly demonstrated the benefit of our system towards assisted guidance by improving the biopsy site retrieval rate from 47.5% to 94%

Développement d’un système de relocalisation endoscopique de sites de biopsie dans le suivi de l’endobrachyoesophage : Résultats préliminaires d’un prototype de synchronisation video

International audienceEtude de faisabilité de l'u/lisa/on d’un prototype endoscopique comprenant un système électromagné/que de repérage associé à un logiciel de synchronisa/on video pour la relocalisa/on des sites de biopsie, chez l’animal. Première u/lisa/on chez deux pa/ents présentant un endobrachyoesophag