There are several types of disorders that affect our colon’s ability to function properly such as colorectal cancer, ulcerative colitis, diverticulitis, irritable bowel syndrome and colonic polyps. Automatic detection of these diseases would inform the endoscopist of possible sub-optimal inspection during the colonoscopy procedure as well as save time during post-procedure evaluation. But existing systems only detects few of those disorders like colonic polyps. In this dissertation, we address the automatic detection of another important disorder called ulcerative colitis. We propose a novel texture feature extraction technique to detect the severity of ulcerative colitis in block, image, and video levels. We also enhance the current informative frame filtering methods by detecting water and bubble frames using our proposed technique. Our feature extraction algorithm based on accumulation of pixel value difference provides better accuracy at faster speed than the existing methods making it highly suitable for real-time systems. We also propose a hybrid approach in which our feature method is combined with existing feature method(s) to provide even better accuracy. We extend the block and image level detection method to video level severity score calculation and shot segmentation. Also, the proposed novel feature extraction method can detect water and bubble frames in colonoscopy videos with very high accuracy in significantly less processing time even when clustering is used to reduce the training size by 10 times.

Inflammatory bowel disease (IBD) is associated with lifetime morbidity and the onset of disease frequently occurs in early life. Although IBD manifests throughout all ethnic groups, there has been marked heterogeneity in its incidence, prevalence, manifestation, and outcome. We sought to study the incidence, prevalence, and survival of ulcerative colitis (UC) and to examine the evolution and prognostic predictors of Crohn's disease (CD) and UC among Hong Kong Chinese. A total of 4 studies were performed to address these issues. One longitudinal cohort study examined the incidence, prevalence, survival and phenotypic changes of UC. Two other longitudinal cohort studies evaluated the phenotypic evolution of CD. One of them specifically compared the course of disease between patients with and patients without upper gastrointestinal tract phenotype. The final retrospective study identified clinical factors that predicted the occurrence of corticosteroid dependency and refractoriness in patients with IBD. The annual age-standardized incidence rate and point prevalence of UC per 100,000 Hong Kong Chinese in 2006 were 2.1 (95% CI: 1.1-3.7) and 26.5 (95% CI: 22.6-30.9), respectively. Incidence of UC has increased 6 times over the past two decades. The overall survival of UC patients was similar to the expected survival of the Hong Kong population. Phenotypic changes in CD also occurred in Chinese patients in the same way as the white patients with respect to disease behavior, though at a slower rate. Similar to the white CD patients, the location of disease remained relatively stable over the course of disease. Chinese CD patients had more upper gastrointestinal tract phenotype which predicted the need of surgery and subsequent hospitalization. On the other hand, the rate of proximal extension of UC was less than 25% after 10 years. In CD, thrombocytosis predicted, whereas colonic disease negatively predicted corticosteroid dependency. Stricturing CD was associated with corticosteroid refractoriness. In UC, thrombocytosis and extensive colitis predicted corticosteroid dependency, whereas anemia predicted corticosteroid-refractory disease. The results of these studies are important in the planning of health service and they also assist in the formulation of treatment strategy. / Chow, Kai Lai. / "May 2009." / Advisers: Francis KL Chan; Joseph JY Sung. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 193-235). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

Pacientes com retocolite ulcerativa inespecífica,quando submetidos à colectomia, apresentam aumento na freqüência de cálculos vesiculares de colesterol. A hipomotilidade da vesícula biliar tem sido apontada como um importante fator na formação dos cálculos vesiculares de colesterol, ao lado da supersaturação biliar de colesterol e da nucleação dos cristais de colesterol (fatores nucleantes e antinucleantes). A estase vesicular aumenta o tempo de reabsorção de água pela mucosa da vesícula biliar com conseqüente superconcentração dos solutos, além de gerar o tempo necessário para a nucleação do colesterol, retenção e fusão dos cristais e,finalmente,formação dos cálculos. Embora a composição biliar já tenha sido estudada em pacientes colectornizados, não há informações sobre o comportamento da motilidade da vesícula biliar em pacientes com retocolite ulcerativa inespecífica com e sem colectomia. No presente trabalho,o esvaziamento vesicular foi estudado através do método ultra-sonográfico e após ingestão de dieta líqüida gordurosa em indivíduos controles (n=40), pacientes com retocolite ulcerativa inespecífica sem (n=30) e com colectomia (n =20). Como o esvaziamento gástrico pode interferir no vesicular, o tempo de esvaziamento gástrico, medido por método ultra-sonográfico, foi calculado nos três grupos. O esvaziamento vesicular foi significantemente diminuído nos pacientes com retocolite ulcerativa inespecífica com colectomia e após estímulo alimentar: esta alteração não foi conseqüência de esvaziamento gástrico retardado pois o tempo de esvaziamento gástrico foi semelhante nos três grupos. Ademais, a redução da motilidade vesicular nos pacientes colectomizados relacionou-se com a colectomia propriamente dita, uma vez que indivíduos controles e pacientes com retocolite ulcerativa inespecífica sem colectomia apresentaram esvaziamentos vesiculares semelhantes. Além disso,os resultados desta investigação reforçam a relevância do papel da motilidade vesicular na colelitíase e sua participação, juntamente com a diminuição do \"pool\" de ácidos biliares,na patogênese da calculo se vesicular de colesterol em pacientes com retocolite ulcerativa inespecífica submetidos à colectomia. / Patients with ulcerative colitis, who have their colon removed, are at increased risk of developing cholesterol gallstones. Gallbladder hypomotility has been quoted as being an important factor for cholesterol gallstone formation, together with biliary supersaturation of cholesterol and nucleation of cholesterol crystals (nucleating and antinucleating factors). Gallbladder stasis increases the time for water reabsorption by the gallbladder mucosa with ensuing solute superconcentration; moreover, gallbladder stasis renders enough time for cholesterol nucleation. crystal retention and fusion, and finally, stone formation. Although bile composition, in these patients, has already been studied, there is no information concerning the nature of gallbladder motility in patients with ulcerative colitis with or without colectomy. ln the present work, gallbladder emptying was studied by means of ultrasound examination, and after ingestion of a standard liquid fatty meal in controls (n=40), ulcerative colitis patients without colectomy (n=30) and with colectomy (n=20). Also, in order to rule out the influence of gastric emptying on gallbladder motility, the gastric emptying time was calculated, in the three groups, using the ultrasound method. Gallbladder emptying was significantly impaired in patients with ulcerative colitis with colectomy after a fatty-meal stimulus. and this abnormality was not a consequence of delayed gastric ernptying. since gastric emptying time was similar in the three groups. Furthermore. impaired gallbladder motility in ulcerative colitis patients with colectomy was related to the colectorny itself, since controls and ulcerative colitis

Pacientes com retocolite ulcerativa inespecífica,quando submetidos à colectomia, apresentam aumento na freqüência de cálculos vesiculares de colesterol. A hipomotilidade da vesícula biliar tem sido apontada como um importante fator na formação dos cálculos vesiculares de colesterol, ao lado da supersaturação biliar de colesterol e da nucleação dos cristais de colesterol (fatores nucleantes e antinucleantes). A estase vesicular aumenta o tempo de reabsorção de água pela mucosa da vesícula biliar com conseqüente superconcentração dos solutos, além de gerar o tempo necessário para a nucleação do colesterol, retenção e fusão dos cristais e,finalmente,formação dos cálculos. Embora a composição biliar já tenha sido estudada em pacientes colectornizados, não há informações sobre o comportamento da motilidade da vesícula biliar em pacientes com retocolite ulcerativa inespecífica com e sem colectomia. No presente trabalho,o esvaziamento vesicular foi estudado através do método ultra-sonográfico e após ingestão de dieta líqüida gordurosa em indivíduos controles (n=40), pacientes com retocolite ulcerativa inespecífica sem (n=30) e com colectomia (n =20). Como o esvaziamento gástrico pode interferir no vesicular, o tempo de esvaziamento gástrico, medido por método ultra-sonográfico, foi calculado nos três grupos. O esvaziamento vesicular foi significantemente diminuído nos pacientes com retocolite ulcerativa inespecífica com colectomia e após estímulo alimentar: esta alteração não foi conseqüência de esvaziamento gástrico retardado pois o tempo de esvaziamento gástrico foi semelhante nos três grupos. Ademais, a redução da motilidade vesicular nos pacientes colectomizados relacionou-se com a colectomia propriamente dita, uma vez que indivíduos controles e pacientes com retocolite ulcerativa inespecífica sem colectomia apresentaram esvaziamentos vesiculares semelhantes. Além disso,os resultados desta investigação reforçam a relevância do papel da motilidade vesicular na colelitíase e sua participação, juntamente com a diminuição do \"pool\" de ácidos biliares,na patogênese da calculo se vesicular de colesterol em pacientes com retocolite ulcerativa inespecífica submetidos à colectomia. / Patients with ulcerative colitis, who have their colon removed, are at increased risk of developing cholesterol gallstones. Gallbladder hypomotility has been quoted as being an important factor for cholesterol gallstone formation, together with biliary supersaturation of cholesterol and nucleation of cholesterol crystals (nucleating and antinucleating factors). Gallbladder stasis increases the time for water reabsorption by the gallbladder mucosa with ensuing solute superconcentration; moreover, gallbladder stasis renders enough time for cholesterol nucleation. crystal retention and fusion, and finally, stone formation. Although bile composition, in these patients, has already been studied, there is no information concerning the nature of gallbladder motility in patients with ulcerative colitis with or without colectomy. ln the present work, gallbladder emptying was studied by means of ultrasound examination, and after ingestion of a standard liquid fatty meal in controls (n=40), ulcerative colitis patients without colectomy (n=30) and with colectomy (n=20). Also, in order to rule out the influence of gastric emptying on gallbladder motility, the gastric emptying time was calculated, in the three groups, using the ultrasound method. Gallbladder emptying was significantly impaired in patients with ulcerative colitis with colectomy after a fatty-meal stimulus. and this abnormality was not a consequence of delayed gastric ernptying. since gastric emptying time was similar in the three groups. Furthermore. impaired gallbladder motility in ulcerative colitis patients with colectomy was related to the colectorny itself, since controls and ulcerative colitis