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Title: Optimizing the use of capsule endoscopy in the detection of small-bowel pathology
Author: Koulaouzidis, Anastasios
ISNI:       0000 0004 6425 3373
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2014
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Background: Wireless capsule endoscopy (CE) was introduced in clinical practice just over a decade ago; it has since established a new era in the investigation and diagnosis of small-bowel diseases. Nevertheless, the detection of small-bowel pathology can be limited by issues related to the current level of CE technology. Furthermore, the clinical validity of the use of surrogate markers of diagnostic yield such as the ampulla of Vater (AoV), or that of various prokinetics, to increase the completion rate - and theoretically, the diagnostic yield - have not been clearly established. Other factors that could optimize the rate of detection of small-bowel pathology in CE are: 'speedy' video sequence review, chromoendoscopy and/or the application of three-dimensional (3-D) image-reproduction software. Threedimensional imaging in CE is not currently feasible due to hardware limitations. However, software algorithms (shape-from-shading, SfS) that enable 3-D reconstruction in CE are available. Methods: The database of capsule endoscopy examinations of our centre includes procedures performed with two different models of capsule endoscopes. The detection rate of the duodenal papilla was examined in the largest - to date - cohort of small-bowel capsule endoscopy videos obtained with two different capsule endoscopy systems. Using meta-analysis software, the impact of various prokinetics was analysed. Furthermore, the validity and safety of QuickView pre-read was examined. In regard to proprietary chromoendoscopy software, Blue Mode filter offers better image enhancement when compared with Fujinon Intelligent Chromoendoscopy (FICE). Out of four publicly available SfS algorithms, Tsai's method is the one that gives the better results. Tested on still-capsule endoscopy images, the application of a 3-D reconstruction software leads to image enhancement for a significant proportion of vascular, but less so for inflammatory and protruding, lesions. Furthermore, the adjunct of 3-D reconstruction to the standard two-dimensional video reading software significantly improves the performance of novice small-bowel CE readers in distinguishing masses from mucosal bulges, thus potentially shortening their learning curve. Results: This thesis demonstrates that the selective and judicious use of prokinetics - and specifically that of metoclopramide with purgative and/or real-time viewer - in capsule endoscopy improves the completion rate. My results also show that the persistently low rate of AoV detection using two different smallbowel CE systems underlines the weakness of non-steerable CE. Although the benefits of QuickView are outweighed to some extent by a decrease in the overall detection rate, this mode can be used confidently in overt obscure gastrointestinal bleeding in an urgent inpatient setting and in outpatients with occult obscure gastrointestinal bleeding or suspected Crohn's disease. FICE (especially I) and Blue Mode is useful for the characterization of small-bowel findings. Conclusion: There are limitations in the current commercially available software for CE review. The inclusion of a 3-D representation algorithm may be of training and diagnostic benefit. Until optics technology allows hardware-enabled threedimensional reconstruction, it seems a plausible alternative. Further clinical and development work is required in order to optimize the currently available reading software.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available