English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The assessment of the quality of the colonoscopic interventions arises as a most relevant issue once the number and the availability of these clinical procedures are increased day by day. The use of the latest computer visionbased techniques can provide the physician with both qualitative and, most important, objectively verifiable quantitative indicators of performance. In this paper we present a study in which we propose the automatic analysis of colonoscopy video for the quality assessment of the intervention from different points of view: 1) We propose the characterization of the different parts of the colon in order to obtain metrics of the time used for navigation, portion of gut analyzed, etc. 2) We analyze the image contents in order to automatically characterize the presence of polyps. 3) We use the information obtained by and eye-tracker in order to assess the physician’s skills. 1 COLON CANCER AND INTESTINAL SCREENING 1.1 Colon Cancer in Numbers The main lesions associated to the intestine are: bleeding, lump, ulcer, Crohn disease, and cancer. During the last 20 years, colon cancer has been the second leading cause of cancer deaths in the United States, behind lung cancer, with approximately 60,000 deaths per year as shown in O’Brien’s report (O’Brien et al., 1990), and also analyzed in other studies (U.S. Department of Health and Human Services, 2003). America Cancer Society’s 2007 report (American Cancer Society, 2007) provides an extended summary of facts and statistics about colon cancer prevalence and impact in the population. Colorectal cancer is the second leading cause of cancerrelated deaths in Singapore and Europe (Ministry of Health Singapore, 1990). Although colon screening has become the main alternative for prevention of colorectal cancer, recent data suggest that there is a significant miss-rate for the detection of even relatively large polyps and cancer (Pabby et al., 2005). For this reason, special efforts have been focused on the development of computer-aided systems for the detection of this type of pathologies. Nowadays, novel lines of research are oriented to widen this perspective by means of the implementation of objective indicators for the assessment of the procedures used in colon screening, since the miss rate of polyps is highly correlated to elements such as the quality of the preparation, the time consumed for the intervention, the amount of intestinal surface screened, the kills of the physician in the manipulation of the endoscope, etc. Moreover, this indicators present a potential value for the training of future endoscopists as reference values to measure abilities in and objective way. 1.2 Screening Technics Intestinal endoscopy is referred to as the technique for screening the intestinal lumen. For the case of large intestine, this technique receives the name of colonoscopy. Fiberoptic colonoscopy (FOC) is widely accepted as the definitive method for diagnosis of colonic polyps. FOC allows direct visualization of the intestinal surface and affords the possibility of obtaining a in-situ biopsy as well as cauteriza320 Vilariño F. and Lacey G. (2009). QUALITY ASSESSMENT IN COLONOSCOPY New Challenges Through Computer Vision-based Systems. In Proceedings of the International Conference on Biomedical Electronics and Devices, pages 320-325 DOI: 10.5220/0001780703200325 Copyright c © SciTePress tion and clinical intervention such as polyp removal (Winawer et al., 1997). FOC is a minimal invasive surgery (Hunter and Sackier, 1993), (Hulka and Reich, 1994) consisting of the introduction through the anus of a flexible probe which a camera and an illumination device on its tip. The probe consists of a flexible cable which can be controlled by the expert in order to reach every part on the intestinal wall. There exist several reference books regarding clinical colonoscopy for the reader interested in deepening in the specificities of colonoscopy, amongst which Kato’s textbook (Kato and Baron, 2003) can provide an insightful introductory view. Several authors have assessed that endoscopic images possess rich information (Nagasako et al., 1998), which facilitates the abnormality detection by multiple techniques (Zheng et al., 2005). The main drawbacks related with FOC can be enumerated as follows (Winawer et al., 1993), (Eddy, 1990): risks of perforation; costs of the intervention; difficulty in visualizing the 100% of the intestinal surface; high number of patients for a reduced number of specialists provide a stress and shrink in the intervention time; difficult visualization due to the intestinal content; preparation needed; imprecise localization of events for a subsequent interventions, and high rate of negative results in inspections looking for polyps (Gokturk and Tomasi, 2001). In the last years, other modalities for the visualization of the colon have arisen. One of the most relevant is virtual colonoscopy, a technique consisting of the construction of a virtual 3D model of the colon from computed tomography (CT) data (Liang et al., 2004), and for this reason several authors have proposed automatic techniques for the detection of lesions in this modality of images. On the other hand, Wireless Capsule Video Endoscopy (WCVE) (Iddan and Meron, 2000) has devoted particular attention, recently. WCVE (Fireman et al., 2002) consists of a capsule with a camera, a battery and a set of led lamps for illumination attached to it, which is swallowed by the patient, emitting a radio frequency signal which is received and stored in an external device. The result is a video movie which records the trip of the capsule along the intestinal tract with a rate of two frames per second, and that can be easily downloaded into a PC with the camera software installed. It is much less invasive, since the patient simply has to swallow the pill, which will be expelled in the normal cycle through defecation. Moreover, there is no need of hospitalization nor expert support through the process and the patient can lead an ordinary life, since the attached device is recording the video movie emitted by the camera in the capsule (Vilariño, 2006; Vilariño et al., 2009). However, although these new modalities provide new ways of clinical analysis, colonoscopy is the reference technique for clinical intervention in the case of colon screening and colon cancer. 2 COMPUTER VISION FOR QUALITY ASSESSMENT We state that computer vision-based techniques can be used in order to obtain objective indicators of the quality of the interventions in an automatic way. Our approach provides a framework for the quality assessment which is implemented in the following 3 areas in which we are developing our research, namely: 1) Computer-aided intervention: On-line detection and characterization of potential targets in interventiontime, 2) Post-interventional quality metrics: Automatic computation of the quality measures related to the intervention such as quality of preparation, amount of bowel surface visualized, time measures, etc. 3) Evaluation of skills: Analysis of 3D trajectories of the endoscopes and the screening behavior. For this final point, we propose to use the trajectories together with the information obtained from the tracking of the gaze position of trainees in order to assess their skills. The perspective presented in this paragraph is graphically depicted in Figure 1. Figure 1: Our framework for automatic quality assessment in colonoscopy. 3 COLON CANCER: CLINICAL CHARACTERIZATION Colon cancer has devoted wide attention in many studies in order to find proper descriptions and categorization (Rembacken et al., 2000), (Saitoh et al., 2001), (Paris Workshop Participants, 2003). Adenomatous polyps, particularly those larger than 1 cm in QUALITY ASSESSMENT IN COLONOSCOPY New Challenges Through Computer Vision-based Systems

QUALITY ASSESSMENT IN COLONOSCOPY - New Challenges Through Computer Vision-based Systems