Introdução: O sangramento colorretal é considerado um sinal de alarme e não deve ser ignorado. A perda de sangue pode não ser identificada pelo paciente, o que caracteriza a presença de sangue oculto. Este diagnóstico pode ser confirmado por testes de Pesquisa de Sangue Oculto nas Fezes (PSOF), através de métodos químicos ou imunoquímicos de identificação da hemoglobina. O resultado positivo de um teste de PSOF requer investigação complementar com colonoscopia, exame invasivo, de alto custo e que exige preparo intestinal. Justifica-se, portanto, a aplicação de um teste diagnóstico mais sensível e específico. No presente estudo, foram avaliados quatro diferentes testes de PSOF em 176 pacientes submetidos à colonoscopia e seus resultados foram comparados. Objetivos: 1) avaliar o grau de concordância entre os testes de PSOF e a colonoscopia. 2) avaliar a sensibilidade, a especificidade e os valores de predição dos testes químico e imunoquímico de PSOF, em pacientes submetidos à colonoscopia. Métodos: Pacientes com indicação de realizar colonoscopia foram submetidos também à PSOF pelo método químico (o-toluidina) e pelo método imunoquímico, empregando três kits comerciais disponíveis no mercado. Os pacientes foram avaliados quanto à indicação do exame colonoscópico, resultado da colonoscopia e uso de alimentos e medicamentos que pudessem interferir no resultado dos testes fecais. Fundamentado nos achados endoscópicos, a colonoscopia foi categorizada em positiva ou negativa, de acordo com a possível fonte de sangramento colorretal. O grau de concordância entre os testes de PSOF foi avaliado pelo índice Kappa. Resultados: Dos 176 pacientes, houve predomínio do sexo feminino (64,8%), com média de idade de 55,5 anos. As indicações clínicas mais frequentes para realização de colonoscopia foram alteração do hábito intestinal, doença inflamatória intestinal, dor abdominal e anemia. Os principais achados foram pólipos < 1 cm, doença diverticular não complicada do cólon e exame normal. Quarenta e quatro (25%) colonoscopias foram categorizadas como positivas quanto à fonte de sangramento colorretal. Observou-se concordância (p<0,05) entre todos os testes avaliados e a colonoscopia. O teste da o-toluidina apresentou concordância pobre (Kappa 0,03), enquanto os demais testes apresentaram concordância moderada (Kappa entre 0,43-0,48). O teste da o-toluidina revelou menor sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo em comparação aos testes imunoquímicos. Conclusões: Os testes imunoquímicos apresentaram melhores índices de concordância com a colonoscopia, quando comparados ao teste da o-toluidina. Os testes imunoquímicos revelaram maior sensibilidade, especificidade e valores de predição na detecção de sangramento colorretal / Introduction: Colorectal bleeding is considered an alarm sign and should not be ignored. Blood loss can not be identified by the patient, which characterizes the presence of occult blood. This diagnosis can be confirmed by Faecal Occult Blood Testing (FOBT), through chemical or immunochemical methods. The positive outcome of a test requires complementary research FOBT with colonoscopy, an examination of invasive, costly and requires bowel preparation. It is justifiable, therefore, the application of diagnostic tests with better sensitivity and specificity. In the present study, we evaluated four different tests of PSOF in 176 patients undergoing colonoscopy and their results were compared. Objectives: 1) evaluate the degree of concordance between the PSOF tests and colonoscopy 2) assess the sensitivity, the specificity and the prediction values of the chemical and immunochemical FOBTs, in patients undergoing colonoscopy. Methods: Patients with indication of perform colonoscopy were subjected also to FOBT by the chemical method (toluidine test) and by the immunochemical method employing three commercial kits available in the market. Patients were evaluated regarding the indication of the colonoscopic examination, colonoscopy result, and use of foods and drugs that could interfere in the results of the faecal tests. Based on the endoscopic findings, the colonoscopy was rated as positive or negative, according to the possible colorectal bleeding source. The degree of accordance between FOBTs was evaluated by the Kappa index. Results: Among the 176 patients, there was a predominance of female gender (64.8%) with an average age of 55.5 years old. The most frequent clinical indication for colonoscopy were bowel habit changes, inflammatory bowel disease, abdominal pain and anemia. The main findings of colonoscopy were polyps <1 cm, uncomplicated colonic diverticular disease and normal exam. Forty-four (25%) colonoscopies were categorized as positive as to the possible source of colorectal bleeding. There was agreement (p<0.05) between all tests evaluated and the colonoscopy. The toluidine test presented poor accordance (Kappa 0.03), while the others showed moderate concordance (Kappa 0.43-0.48). The toluidine test showed less sensitivity, specificity, positive predictive value and negative predictive value compared to immunochemical tests. Conclusions: Immunochemical tests showed the best indexes of agreement with colonoscopy, when compared to the toluidine test. The immunochemical tests have shown greater sensitivity, specificity and predictive values in detecting colorectal bleeding

<p>Sve veća potreba za izvođenjem kolonoskopije u dijagnostičke ili terapijske svrhe nameće potrebu za usavr&scaron;avanjem ove endoskopske procedure. Izvođenje kolonoskopije u op&scaron;toj, intravenskoj anesteziji, moglo bi u značajnoj meri olak&scaron;ati njeno izvođenje, pobolj&scaron;ati podno&scaron;enje ove procedure od strane ispitanika i omogućiti otkrivanje većeg broja pacijenata sa potencijalno malignim bolestima debelog creva. Cilj ispitivanja je bio utvrditi da li primena op&scaron;te intravenske anestezije tokom kolonoskopije povećava broj totalnih kolonoskopija i skraćuje vreme intubacije cekuma, povećava broj viđenih patolo&scaron;kih procesa i smanjuje osećaj bola i učestalost neželjenih reakcija. Primena op&scaron;te intravenske anestezije značajno je povećala broj totalnih kolonoskopija u 94.3% ispitanika u odnosu na 78.7% totalnih kolonoskopija kontrolne grupe i skratila vreme intubacije cekuma, značajno je povećala broj viđenih patolo&scaron;kih promena u 46.7% ispitanika u odnosu na broj viđenih patolo&scaron;kih promena u 28.8% ispitanika kontrolne grupe i značajno je smanjila intenzitet bola i učestalost neželjenih reakcija. U kontrolnoj grupi ispitanika skalom bola nakon kolonoskopije ustanovljen je značajno veći intenzitet bola u poređenju sa ispitanicima ekperimentalne grupe. Na Likertovoj skali zadovoljstva ustanovljena je značajno bolja kontrola bola i lični stav lekara u ekperimentalnoj grupi, dok su poseta ustanovi i procedura, razumevanje procedure, tehnička ve&scaron;tina lekara, lični stav medicinskih sestara i drugog tehničkog osoblja značajno bolje ocenjeni u kontrolnoj grupi. Od svih ispitivanih faktora na zadovoljstvo obe grupe pacijenata značajno su uticali: način izvođenja procedure, bol, uočene patolo&scaron;ke promene i intubacija cekuma. U kontrolnoj grupi ispitanika između skale zadovoljstva i skale bola ustanovljena je značajna negativna korelacija. U kontrolnoj grupi se 80,1% pacijenata izjasnilo da bi ponovnu kolonoskopiju uradili u op&scaron;toj intravenskoj anesteziji u poređenju sa svim pacijentima eksperimentalne grupe koji ne bi menjali način izvođenja ponovne procedure. Primena op&scaron;te intravenske anestezije tokom kolonoskopije povećava broj totalnih kolonoskopija i uočenih patolo&scaron;kih promena, smanjuje učestalost i intenzitet neželjenih reakcija povećavajući zadovoljstvo pacijenata, &scaron;to bi prevashodno moglo imati značaja u skriningu karcinoma debelog creva. Potrebno je pro&scaron;iriti ispitivanje primene op&scaron;te intravenske anestezije u drugim endoskopskim procedurama kako bi bila uvedena u svakodnevnoj kliničkoj praksi.</p> / <p>An increasing need to perform colonoscopy for diagnostic or therapeutic purposes imposed the need for mastering this endoscopic procedure. Performing colonoscopy in general intravenous anesthesia could greatly ease the procedure, make it more comfortable for patients and it could enable detecting a higher number of patients with occult malignant diseases of the colon. The aim of this paper was to determine if the implementation of general intravenous anesthesia during colonoscopy increases the number of total colonoscopies and shortens the time of cecum intubation, increases the number of familiar pathological processes and decreases the sensation of pain as well as the frequency of side reactions. The implementation of general intravenous anesthesia has significantly increased the number of total colonoscopies in 94.3% of examined patients in relation to 78.7% of total colonoscopies of the control group and shortened the time of cecum intubation. It has significantly increased the number of familiar pathological changes in 46.7% of the patients in relation to the number of familiar pathological changes in 28.8% patients of the control group and significantly decreased pain intensity and the frequency of side reactions. A statistically greater pain intensity after colonoscopy was determined by the pain scale in the control group in comparison to the examinees of the experimental group. Likert satisfaction scale has shown that the experiment group assessed pain control and doctors&rsquo; opinion as significantly better, while the institution visits and the procedure, understanding the procedure, doctors&rsquo; technical skills, nurses&rsquo; and technical personnel&rsquo;s personal opinions were assessed as significantly better in the control group. Out of all the examined factors on the satisfaction of both groups, the following ones had a significant inluence: the way the procedure was done, the level of pain, detected pathological changes and cecum intubation. A significanlty negative correlation was determined between the scale of satisfaction and the scale of pain in the control group. 80.1% of the control group patients stated that they would undergo a general anesthesia colonoscopy again in comparison to all the patients of the experimental group who would not change the way the procedure was previously done. The implementation of general intravenous anesthesia in the course of colonoscopy increases the number of total colonoscopies and detected pathological changes, decreases the frequency and intensity of side-effects therefore it enhances patients&#39; sastisfaction, which could play a major role in colon cancer screening. It is necessary to extend the implementation of general intravenous anesthesia in other endoscopic procedures in order to introduce it in everyday clinical practice.</p>

Aim To determine that carbon dioxide (CO2), instead of air, insufflated during colonoscopy reduces pain experienced by patients post colonoscopy. Method A randomised, double blinded, controlled trial with 205 consecutive consented patients referred for elective colonoscopy was undertaken at MidCentral Health Gastroenterology Department between July 2008 and January 2009. Patients were randomised to colonic insufflation with either air or CO2. A comparison of reported pain was undertaken using a 0 -10 point numeric rating scale at several time periods; intra procedure, 10, 30, and 60 minutes post procedure. Results The results were analysed using the SPSS programme. CO2 insufflation was used in 108 patients and air in 97 patients. Pain scores 10 minutes after were 0.43 ± 1.20 for CO2 and 1.61 ± 2.40 for air (P < .0001). 30 minutes after the procedure 90% of patients in the CO2 group reported no pain, compared to 61% of the air group. CO2 significantly reduced the amount of discomfort post colonoscopy at 10, 30 and 60 minutes. Conclusion Those receiving CO2 during colonoscopy experienced less post colonoscopy pain than those who received air insufflation. Carbon dioxide should be considered as the insufflating gas during colonoscopy.

Although it is not a new method endoscopy has undergone incredible development in recent years. The examination is however very unpleasant for a patient, which is why health care staff should be well trained, particularly for child patients. The aim of the thesis was to map the specifics of nursing care for children undergoing endoscopic examination of the gastrointestinal tract. We approached the whole issue from the point of view of caring staff ? nurses. In the theoretical part we first described the gastrointestinal tract anatomy, endoscopy development and types of endoscopic examination. Then we dealt with the role of a nurse in the care for child patients undergoing these examinations. We formed three goals for the research. Goal 1: To find out how nurses prepare child patients for the individual endoscopic examinations. Goal 2: To verify whether nurses caring about a child patient undergoing gastrointestinal tract endoscopy are specifically trained. Goal 3 served as the output of the work: To elaborate recommendation for nurses preparing child patients for the individual endoscopic examinations. We chose quantitative research for collection of the necessary information. A questionnaire designed for nurses caring for child patients was the data collection technique. The questionnaire was anonymous, distributed at paediatric clinics of faculty hospitals of Moravian region. 104 questionnaires suitable for processing returned from 140 issued. The research has shown that nurses working at the clinics where the research was performed master the correct nursing care for child patients undergoing endoscopic examination of the gastrointestinal tract. Nevertheless the fact that most information is gained upon practical experience, with low emphasis on initial and repeated training of nurses also results from the research. A recommendation was elaborated upon the gathered information in the form of a standard nursing procedure proposal.

Cette thèse, consacrée à la mesure endoscopique de formes tridimensionnelle, se place dans un double contexte applicatif : tout d'abord industriel, avec l'inspection endoscopique de pièces mécaniques en milieu contraint (notamment tubulaire) à des résolutions micrométriques. Le second contexte est médical avec la détection de formes tridimensionnelle lors de coloscopies pour l'aide au diagnostic. L'endoscopie souple est obtenue par l'utilisation de guides optiques, la méthode de mesure tridimensionnelle est basée sur la stéréovision active avec la génération de lumière structurée par une matrice de micro-miroirs. Après avoir établi l'état de l'art, une méthode de conception et d'évaluation optique appliquée à la stéréovision en endoscopie souple est décrite. C'est ensuite la réalisation instrumentale, son évaluation métrologique, et une méthode innovante de basculement de modes dynamique entre stéréovision active et passive qui sont détaillées. Des méthodes algorithmiques de reconstruction tridimensionnelle adaptées à ce type d'instrument sont enfin proposées. Les contributions scientifiques de cette étude sont multiples. Une méthode d'analyse optique basée sur l'utilisation de fonctions de transfert de modulation pour la conception d'un endoscope mesurant par stéréovision est proposée. Des méthodes de traitement d'image pour un étalonnage robuste malgré une défocalisation optique ainsi qu'un nouvel algorithme à décalage de phase constituent également des contributions de l'étude. L'association de ces méthodes a permis d'extraire un principe de réalisation permettant la mesure tridimensionnelle par endoscopie souple. / This thesis aims at developing a tri-dimensional measurement endoscopic device in a double context: the first one is industrial with endoscopic inspection of mechanical pieces (tubular inspection, for example) at micrometric resolution. The second context is medical with tri-dimensional shape detection during colonoscopy to help the surgeon diagnosis. In this study, flexible endoscopy is made possible by using image guides and the tri-dimensional reconstruction method is based on active stereovision where a digital micro-mirror device is used to spatially structure the incoming light. After developing the state of the art, an optical conception and evaluation method, applied to stereovision for flexible endoscopic devices is described. The instrumental realization is then detailed and metrologically evaluated. An innovative method that allows to switch dynamically between active and passive stereovision is then detailed. Finally, 3D reconstruction algorithms adapted to this endoscopic instrument are proposed. The scientific contributions of this study are multiple. Firstly, an optical analysis method based on the modulation transfer function to design an endoscopic stereovision system is proposed. An image processing method for robust calibration in a defocused optical environment and a new phase-shifting algorithm for 3D reconstruction are proposed. Finally, a realization principle for 3D measurement in flexible endoscopy was extracted from the combination of all these methods.

Introdução: O sangramento colorretal é considerado um sinal de alarme e não deve ser ignorado. A perda de sangue pode não ser identificada pelo paciente, o que caracteriza a presença de sangue oculto. Este diagnóstico pode ser confirmado por testes de Pesquisa de Sangue Oculto nas Fezes (PSOF), através de métodos químicos ou imunoquímicos de identificação da hemoglobina. O resultado positivo de um teste de PSOF requer investigação complementar com colonoscopia, exame invasivo, de alto custo e que exige preparo intestinal. Justifica-se, portanto, a aplicação de um teste diagnóstico mais sensível e específico. No presente estudo, foram avaliados quatro diferentes testes de PSOF em 176 pacientes submetidos à colonoscopia e seus resultados foram comparados. Objetivos: 1) avaliar o grau de concordância entre os testes de PSOF e a colonoscopia. 2) avaliar a sensibilidade, a especificidade e os valores de predição dos testes químico e imunoquímico de PSOF, em pacientes submetidos à colonoscopia. Métodos: Pacientes com indicação de realizar colonoscopia foram submetidos também à PSOF pelo método químico (o-toluidina) e pelo método imunoquímico, empregando três kits comerciais disponíveis no mercado. Os pacientes foram avaliados quanto à indicação do exame colonoscópico, resultado da colonoscopia e uso de alimentos e medicamentos que pudessem interferir no resultado dos testes fecais. Fundamentado nos achados endoscópicos, a colonoscopia foi categorizada em positiva ou negativa, de acordo com a possível fonte de sangramento colorretal. O grau de concordância entre os testes de PSOF foi avaliado pelo índice Kappa. Resultados: Dos 176 pacientes, houve predomínio do sexo feminino (64,8%), com média de idade de 55,5 anos. As indicações clínicas mais frequentes para realização de colonoscopia foram alteração do hábito intestinal, doença inflamatória intestinal, dor abdominal e anemia. Os principais achados foram pólipos < 1 cm, doença diverticular não complicada do cólon e exame normal. Quarenta e quatro (25%) colonoscopias foram categorizadas como positivas quanto à fonte de sangramento colorretal. Observou-se concordância (p<0,05) entre todos os testes avaliados e a colonoscopia. O teste da o-toluidina apresentou concordância pobre (Kappa 0,03), enquanto os demais testes apresentaram concordância moderada (Kappa entre 0,43-0,48). O teste da o-toluidina revelou menor sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo em comparação aos testes imunoquímicos. Conclusões: Os testes imunoquímicos apresentaram melhores índices de concordância com a colonoscopia, quando comparados ao teste da o-toluidina. Os testes imunoquímicos revelaram maior sensibilidade, especificidade e valores de predição na detecção de sangramento colorretal / Introduction: Colorectal bleeding is considered an alarm sign and should not be ignored. Blood loss can not be identified by the patient, which characterizes the presence of occult blood. This diagnosis can be confirmed by Faecal Occult Blood Testing (FOBT), through chemical or immunochemical methods. The positive outcome of a test requires complementary research FOBT with colonoscopy, an examination of invasive, costly and requires bowel preparation. It is justifiable, therefore, the application of diagnostic tests with better sensitivity and specificity. In the present study, we evaluated four different tests of PSOF in 176 patients undergoing colonoscopy and their results were compared. Objectives: 1) evaluate the degree of concordance between the PSOF tests and colonoscopy 2) assess the sensitivity, the specificity and the prediction values of the chemical and immunochemical FOBTs, in patients undergoing colonoscopy. Methods: Patients with indication of perform colonoscopy were subjected also to FOBT by the chemical method (toluidine test) and by the immunochemical method employing three commercial kits available in the market. Patients were evaluated regarding the indication of the colonoscopic examination, colonoscopy result, and use of foods and drugs that could interfere in the results of the faecal tests. Based on the endoscopic findings, the colonoscopy was rated as positive or negative, according to the possible colorectal bleeding source. The degree of accordance between FOBTs was evaluated by the Kappa index. Results: Among the 176 patients, there was a predominance of female gender (64.8%) with an average age of 55.5 years old. The most frequent clinical indication for colonoscopy were bowel habit changes, inflammatory bowel disease, abdominal pain and anemia. The main findings of colonoscopy were polyps <1 cm, uncomplicated colonic diverticular disease and normal exam. Forty-four (25%) colonoscopies were categorized as positive as to the possible source of colorectal bleeding. There was agreement (p<0.05) between all tests evaluated and the colonoscopy. The toluidine test presented poor accordance (Kappa 0.03), while the others showed moderate concordance (Kappa 0.43-0.48). The toluidine test showed less sensitivity, specificity, positive predictive value and negative predictive value compared to immunochemical tests. Conclusions: Immunochemical tests showed the best indexes of agreement with colonoscopy, when compared to the toluidine test. The immunochemical tests have shown greater sensitivity, specificity and predictive values in detecting colorectal bleeding

O uso do propofol em sedação para colonoscopia e outros procedimentos endoscópicos é cada vez mais frequente, devido ao seu rápido início de efeito e curto período de recuperação, com poucos efeitos residuais, o que o torna um anestésico ideal para o uso em condutas médicas realizadas em regime ambulatorial. Seu perfil farmacológico o posiciona como um anestésico adequado a métodos de administração endovenosa contínuos ou titulados, possibilitando maior controle na sua concentração plasmática. Devido à sua alta lipossolubilidade, o propofol difunde-se rapidamente ao sistema nervoso e outros tecidos aonde exercerá seu efeito clínico, intimamente ligado à propofolemia, com diminuição da atividade do sistema nervoso central, que determinará tanto a sedação nos seus diversos níveis, quanto os indesejados efeitos depressores do sistema cardiovascular e respiratório, podendo levar a uma diminuição importante do débito cardíaco e pressão arterial e também a uma depressão central do sistema regulatório da respiração, que pode gerar apneia ou hipoventilação significativas. O presente estudo teve como objetivo avaliar clinicamente, e com dosagem sérica, o propofol em três esquemas diferentes de infusão endovenosa. Foram avaliados aleatoriamente 50 pacientes submetidos à colonoscopia nos Serviços de Endoscopia do Hospital Ana Costa (Santos - SP) e no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (São Paulo-SP). Os pacientes foram divididos em três grupos, conforme o esquema de sedação que foi utilizado. O Grupo 1 recebeu fentanil no início, uma dose inicial de propofol de um miligrama por quilo em um minuto na indução, posteriormente recebeu propofol em infusão intermitente de doses fracionadas de 30 mg (bolus) conforme necessidade clínica durante o exame. O Grupo 2 recebeu fentanil no início, uma dose inicial de propofol de 1 mg/kg em um minuto na indução, após essa, recebeu propofol contínuo em uma solução diluída a 0,2% em solução glicosada a 5%, em uma dose inicial de 1 gota/kg de peso do paciente, o que equivale a aproximadamente 100 ug/kg/min, controlada manualmente e alterada conforme a necessidade clínica do exame. O Grupo 3 recebeu fentanil no início do exame, e propofol com dose calculada e administrada por bomba eletrônica computadorizada (Diprifusor®) em esquema de infusão contínua alvo controlada, numa dose inicial de indução de 4 ug/mL administrada em um minuto, baixada a 2 ug/mL após a dose inicial completada, e alteradas para mais ou para menos conforme a necessidade clínica do exame. Os pacientes foram monitorizados com eletrocardiografia contínua, pressão arterial não invasiva medida de dois em dois minutos, oximetria de pulso, capnografia de aspiração lateral e índice bispectral (BIS). As dosagens séricas de propofol foram feitas em três amostras de sangue colhidas por paciente. A primeira amostra, cinco minutos após a indução, a segunda ao endoscopista alcançar o ceco durante o exame e a terceira a cinco minutos após a última dose de propofol administrada ou ao término da infusão contínua, no final do exame. Não houve diferença estatística significativa entre os Grupos em relação às características físicas pessoais dos pacientes como: sexo (p = 0,976), estado físico de acordo com a American Society of Anestesiology (ASA) (p = 0,945), idade (p = 0,896), peso (p = 0,340), altura (p = 0,947), índice de massa corpórea (IMC) (p = 0406), nos parâmetros clínicos observados como menor valor de índice BIS (p = 0,871) e o tempo para alcançá-lo (p = 0,052), tempo médio do exame (p = 0,123) e efeitos adversos observados como a queda da saturação de oxigênio abaixo de 90% (p = 0,054). Houve diferença estatisticamente significativa nas pressões arteriais iniciais dos Grupos 2 e 3, que foram ligeiramente elevadas em relação ao Grupo 1 a sistólica (p = 0,008), diastólica (p = 0,018) e média (p = 0,008), porém após a indução, a média das pressões arteriais sistólica (p = 0,440), diastólica (p = 0,960) e média (p = 0,815), e as menores pressões alcançadas não foram estatisticamente diferentes: sistólica (p = 0,656), diastólica (p = 0,783) e média (p = 0,993). Não houve diferença estatística em relação à frequência cardíaca inicial (p = 0,453), média após indução (p = 0,702), e menor frequência cardíaca alcançada (p = 0,788). Houve diferença entre o número de agitações médias entre os Grupos (p = 0,001), sendo maior no Grupo 1, porém este número foi relacionado ao esquema de administração do propofol no Grupo 1, que foi administrado após a indução quando o paciente apresentou algum grau de agitação que necessitou aprofundamento anestésico. Houve queda de saturação de oxigênio em seis pacientes (12%) da amostra avaliada, revertidas em tempo menor que cinco minutos com manobras de elevação da mandíbula do paciente ou utilização de cânula de Guedel para desobstrução das vias aéreas. Antes das quedas na saturação de oxigênio, foram percebidas alterações típicas de obstrução de vias aéreas, hipopneia ou apneia nas ondas de capnografia em 16 pacientes (32%), sendo que, em alguns pacientes por mais de uma vez, demonstrando esse ser um bom parâmetro de monitorização para prevenir hipóxia, não houve diferença entre os Grupos no parâmetro de obstrução de vias aéreas/apneia (p = 0,543). Em relação à propofolemia, o comportamento médio dos pacientes dos três Grupos foi estatisticamente igual ao longo dos momentos de avaliação (p = 0,830), não havendo diferença média estatisticamente significativa entre os Grupos (p = 0,964). Não houve diferença entre o consumo do propofol médio por minuto de exame (p = 0,748). Em relação à análise de custos com a administração do propofol, o Grupo 1 apresentou o menor valor médio para as colonoscopias avaliadas com gasto médio de R$ 7,00, o Grupo 2 gastou em média R$ 17,50 e o Grupo 3 gastou em média R$ 112,70 com diferença estatisticamente significativa entre eles (p < 0,001). A conclusão é que os esquemas de administração do propofol testados foram seguros, e houve semelhança entre os Grupos nos parâmetros avaliados incluindo a propofolemia, porém com custos diferenciados entre eles. Em relação ao Grupo 1, devido ao maior número de agitações por minuto este pode ser um bom método para procedimentos mais curtos, para procedimentos mais longos os Grupos 2 e 3 se mostraram mais confortáveis para o responsável pela sedação / The use of propofol sedation for colonoscopies and other endoscopic procedures is increasing due to the rapid onset of effect and short recovery time with few residual effects, which makes it an ideal anesthetic for usingin outpatient medical procedures. Its pharmacological profile places it as a suitable anesthetic to continuous or titred intravenous administration, providing increased control in its plasma levels. Due to its high liposolubility, propofol diffuses rapidly to the central nervous system and other tissues where it shall perform its clinical effects, closely related to plasma concentration, and providing sedation at different levels, as much as the unwanted depressant effects of the cardiovascular and respiratory system, it may lead to a significant reduction in cardiac output and blood pressure and also a central regulatory breathing system depression, that can result in significant apnea or hypoventilation. This study aimed to evaluate clinically and serum, propofol in three different regimens of intravenous infusion. 50 patients submitted to colonoscopy in the endoscopy centers at Hospital Ana Costa (Santos - SP), and Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (São Paulo-SP), have been randomly assessed. Such patients were divided into three groups, according to the sedation scheme that was used for them. Group 1 received fentanyl at first, then a one milligram per kilogram propofol dose, at induction, in a minute, later they received intermittent infusion of propofol in fractionated doses of 30 mg (Bolus) according to clinical needs during the test. Group 2 received fentanyl in the beginning, a starting dose of propofol 1 mg/kg at induction in one minute, after that received propofol in a 0.2% solution diluted in 5% glucose solution at an initial 1 drop/kg of patient weight dose, equivalent to about one 100 u100/min, manually controlled and changed according to clinical need of the examination. Group 3 received in the beginning of the examination fentanyl and propofol calculated by target controlled continuous infusion electronic device (Diprifusor®), an initial loading dose of 4 ug/mL was administered in one minute, reduced at 2 ug/mL after the initial dose, changed up or down according to clinical needs of examination. Patients were monitorized with continuous electrocardiography, non-invasive blood pressure measured every two minutes, pulse oximetry, side suction capnography and bispectral index (BIS). Serum levels of propofol were performed on three samples of blood taken by each patient. The first sample, five minutes after the induction, the second when the endoscopist reached the cecum during the examination and the third sample five minutes after the last administered dose or the end of continuous infusion of propofol, at the end of the test. No statistically significant difference between groups with respect to personal physical characteristics of patients as: sex (p = 0.976), physical state according to the American Society of Anesthesiology (ASA) (p = 0.945), age (p = 0.896), weight (p = 0.340), height (p = 0.947), body mass index body (BMI) (p = 0.406) in clinical parameters observed as a minor reached bispectral index value (BIS) (p = 0.871) and time to reach it (p = 0.052), mean procedure time (p = 0.123) and adverse effects observed as a drop in oxygen saturation below 90% (p = 0.054). There was a difference between the number of averages agitations between groups (p = 0.001), being higher in Group 1, but that number was related to propofol administration scheme in Group 1, as this was administered after induction when the patient had some agitation that required deeper anesthesia. There was a statistically significant difference in initial blood pressures of groups 2 and 3, which were slightly higher compared to Group 1: systolic (p = 0.008), diastolic (p = 0.018) and mean (p=0.008), but after induction, the average systolic (p = 0.440), diastolic (p = 0.960) and average (p = 0.815), and lower pressures achieved: systolic (p = 0.656) and diastolic (p = 0.783) and average (p = 0.993), were not statistically different. There was no statistical difference from the initial heart rate (p = 0.453), average heart rate after induction (p=0.702), and lower heart rate achieved (p = 0.788). There was oxygen dessaturation below 90% in six patients (12%) of the study sample, reversed in less than five minutes with patient jaw thrust maneuver or use of Guedel cannula, for airway clearance. Before the declines in oxygen saturation, typical tract obstruction, hypopnea or apnea wave changes were noted in capnography in sixteen patients (32%), and in some patients for more than once, showing this to be a good monitoring parameter to prevent hypoxia in patients, there was no difference between Groups in the airway obstruction/apnea parameter (p = 0.543). Regarding serum propofol, the average behavior of patients in the three Groups were statistically similar over the time (p = 0.830), with no statistically significant mean difference between groups (p = 0.964). There was no difference between the average propofol consumption per minute examination (p = 0.748). Regarding cost analysis with the administration of propofol, Group 1 had the lowest average value for colonoscopies evaluated with an average expense of R$ 7.00, Group 2 spent on average R$ 17.50 and the Group spent 3 on average R$ 112.70 with a statistically significant difference (p < 0.001). The conclusion is that propofol administration schemes tested were safe and there was similarity between the Groups in the evaluated parameters including propofolemia, but with different costs among them. With respect to Group 1 due to the larger number of agitations per minute, this is a good method for shorter procedures, for longer procedures groups 2 and 3 were more comfortable for the person responsible for sedation

[pt] O câncer de cólon é atualmente a segunda principal causa de morte por câncer no mundo. Nos últimos anos houve um aumento do interesse em pesquisas voltadas para o desenvolvimento de métodos automáticos para detecção de pólipos e os resultados mais relevantes foram alcançados por meio de técnicas de aprendizado profundo. No entanto, o desempenho destas abordagens está fortemente associado ao uso de grandes e variados conjuntos de dados. Amostras de imagens de colonoscopia estão disponíveis publicamente, porém a quantidade e a variação limitada podem ser insuficientes para um treinamento bem-sucedido. O trabalho de pesquisa desta tese propõe uma estratégia para aumentar a quantidade e variação de imagens de colonoscopia, melhorando os resultados de segmentação e detecção de pólipos. Diferentemente de outros trabalhos encontrados na literatura que fazem uso de abordagens tradicionais de aumento de dados (data augmentation) e da combinação de imagens de outras modalidades de exame, esta metodologia enfatiza a criação de novas amostras inserindo pólipos em imagens de colonoscopia publicamente disponíveis. A estratégia de inserção faz uso de pólipos gerados sinteticamente e também de pólipos reais, além de aplicar técnicas de processamento para preservar o aspecto realista das imagens, ao mesmo tempo em que cria automaticamente amostras mais diversas com seus rótulos apropriados para fins de treinamento. As redes neurais convolucionais treinadas com estes conjuntos de dados aprimorados apresentaram resultados promissores no contexto de segmentação e detecção. As melhorias obtidas indicam que a implementação de novos métodos para aprimoramento automático de amostras em conjuntos de imagens médicas tem potencial de afetar positivamente o treinamento de redes convolucionais. / [en] Nowadays colorectal cancer is the second-leading cause of cancer death worldwide. In recent years there has been an increase in interest in research aimed at the development of automatic methods for the detection of polyps and the most relevant results have been achieved through deep learning techniques. However, the performance of these approaches is strongly associated with the use of large and varied datasets. Samples of colonoscopy images are publicly available, but the amount and limited variation may be insufficient for successful training. Based on this observation, a new approach is described in this thesis with the objective of increasing the quantity and variation of colonoscopy images, improving the results of segmentation and detection of polyps. Unlike other works found in the literature that use traditional data augmentation approaches and the combination of images from other exam modalities, the proposed methodology emphasizes the creation of new samples by inserting polyps in publicly available colonoscopy images. The insertion strategy makes use of synthetically generated polyps as well as real polyps, in addition to applying processing techniques to preserve the realistic aspect of the images, while automatically creating more diverse samples with their appropriate labels for training purposes. Convolutional neural networks trained with these improved datasets have shown promising results in the context of segmentation and detection. The improvements obtained indicate that the implementation of new methods for the automatic improvement of samples in medical image datasets has the potential to positively affect the training of convolutional networks.

Contexte  Le cancer colorectal, deuxième par ordre de fréquence chez les femmes françaises, se développe principalement à partir de lésions précancéreuses, des adénomes. Les facteurs associés à l’obésité sont multiples, incluant des événements de début de vie, le niveau socio-économique et le comportement alimentaire ; l’obésité a aussi été associée de façon assez constante au risque de cancer colorectal. Cependant les associations entre des facteurs anthropométriques spécifiques ou au cours de la vie et le risque de tumeurs colorectales selon la filiation adénome-cancer ou selon le site sont moins claires. La ménopause est un événement de vie majeur et est associée à des modifications anthropométriques, tandis que le traitement hormonal de la ménopause (THM) est susceptible d’interagir avec les aspects anthropométriques mais aussi directement avec le risque de tumeur. De plus, la prescription du THM dépend de plusieurs paramètres, dont l’importance du suivi médical. Enfin, si le dépistage des tumeurs colorectales est conseillé à partir de 50 ans (soit aux environs de la ménopause) les attitudes vis-à-vis du dépistage varient selon de nombreux paramètres incluant les antécédents familiaux de cancer, le niveau socio-économique et les comportements de santé. Objectif  Le risque de tumeurs colorectales dépend ainsi de nombreux facteurs étroitement liés, parmi lesquels nous avons choisi d’étudier les relations complexes entre facteurs anthropométriques au cours de la vie, utilisation de THM et antécédents personnels de coloscopie, et le risque d’adénomes et de cancers colorectaux. Population  Les analyses ont été effectuées sur les données de la cohorte de femmes françaises E3N, comportant environ 1400 cas d’adénomes diagnostiqués parmi 17000 femmes ayant passé une coloscopie au cours du suivi (1993-2002) et 690 cas de cancers diagnostiqués parmi 92000 femmes au cours du suivi (1990-2008). Résultats  Notre étude a mis en évidence plusieurs aspects originaux. Tout d’abord, nous avons mis en évidence que les trois facteurs d’exposition principaux étudiés étaient associés au risque de tumeurs colorectales de façon significativement hétérogène en fonction du site, renforçant l’hypothèse selon laquelle il existe trois entités bien distinctes le long du cadre colorectal. Les caractéristiques anthropométriques typiquement occidentales (IMC et tour de taille élevés) étaient associées à un risque accru de tumeurs du côlon gauche, tandis que les associations originales que nous avons décrites entre taille assise et risque d’adénomes du côlon droit, et entre corpulence dans l’enfance et plus faible risque d’adénomes du rectum suggèrent de nouvelles pistes de recherche pour ces sites à l’étiologie mal connue. La mise en évidence d’une association positive entre prise de THM de type estrogènes seul (habituellement prescrit aux femmes hystérectomisées) et risque d’adénomes, en particulier du côlon gauche, et d’une association inverse entre le même type de THM et le risque de cancer, en particulier du côlon gauche, n’étant pas cohérentes avec les associations décrites dans la littérature, nous a conduit a explorer un éventuel biais de dépistage. La pratique de coloscopie était effectivement plus fréquente chez les femmes utilisant des estrogènes seuls (et donc aux antécédents d’hystérectomie), tandis que les antécédents de fibrome utérin étaient associés à un risque accru d’adénomes. De leur côté, les antécédents personnels de coloscopie étaient associés à une diminution de risque de cancer, surtout du côlon gauche, tandis que la réduction de risque des cancers du rectum devenait semblable à celle observée pour le côlon gauche dans la période la plus récente. Conclusion  En conclusion, nos résultats suggèrent qu’il existe des moyens efficaces de prévention des tumeurs distales, mais que la prévention des tumeurs du côlon droit demande des études spécifiques et peut-être de nouveaux paradigmes. / Background  Colorectal cancer, the second most common cancer in French women, mostly develops from precancerous lesions, the adenomas. Factors associated with adult obesity are multiple, including early life events, the socio-economic level, and eating habits; obesity has also been, in turn, quite consistently associated with colorectal cancer risk. However, associations between specific anthropometric components or lifetime anthropometry and colorectal tumours according to the adenoma-carcinoma sequence or to tumour site are less clear. Menopause is a major event in women, and is associated with changes in anthropometric features, while menopausal hormone therapy (MHT) may interact with post-menopausal anthropometry but also with tumour risk per se. In addition, prescription of this MHT depends on various parameters including quality of medical follow-up. Finally, while screening for colorectal tumours is advocated after the age of 50 (thus around menopausal age), attitudes towards colorectal screening differ according to many factors including family history of cancer, the socio-economic level, and attitudes towards a healthy behaviour. Objective  Thus colorectal tumour risk depends on many interrelated factors, among which we chose to investigate the complex relationship between lifetime anthropometric features, MHT use and personal history of colonoscopy, and colorectal adenoma and cancer risk. Population  This study was based on data from the French E3N cohort, including approximately 1400 adenoma cases diagnosed among 17000 women who underwent a colonoscopy during follow-up (1993-2002), and 690 cancer cases diagnosed among 92000 women (1990-2008).Results  Our study brought out several original findings. First our findings regarding all three major studied exposures displayed significant heterogeneity between sites, thus enforcing the hypothesis of separate entities according to site along the large bowel. Typical Western anthropometric features (high BMI and high waist circumference) were associated with left colon tumours, while the original findings of sitting height associated with risk of right colon tumours and of a large silhouette in childhood inversely associated with rectal tumours may bring out new hypotheses regarding these less understood sites. The findings of a positive association between estrogens only MHT use (usually prescribed in hysterectomised women) and adenoma risk, especially left colon adenomas, and an inverse association between the same MHT and cancer risk, especially left colon cancer, which are not consistent with associations generally described in the literature, led us to explore potential screening biases. Indeed, colonoscopy screening was more common in women who used estrogens alone (so with a history of hysterectomy), while colorectal adenomas were more common in women with uterine leiomyoma. Colonoscopy screening in turn was associated with a reduced risk of colorectal cancer, especially left colon cancer, while the risk reduction for rectal cancers became similar to that of left colon cancer in the most recent years. Conclusion  Altogether, our findings suggest efficient ways to prevent distal tumours, while prevention of right colon tumours requires further specific investigations and new paradigms.

Introduction: Le cancer colorectal demeure un grave problème de santé publique au Canada. Les programmes de dépistage pourraient réduire l'incidence du cancer colorectal et la mortalité qui lui est associée. Une coloscopie de haute qualité est considérée comme un moyen rentable de prévenir le cancer en identifiant et en éliminant les lésions précurseurs du cancer. Bien que la coloscopie puisse servir de mesure préventive contre le cancer, la procédure peut imposer un fardeau supplémentaire à la santé publique par l'enlèvement et l'évaluation histologique de polypes colorectaux diminutifs et insignifiants, qui présentent un risque minime d'histologie avancée ou de cancer. La technologie de l'amélioration de l'image permettrait aux médecins de réséquer et de rejeter les polypes diminutifs ou de diagnostiquer et de laisser les polypes rectosigmoïdiens diminutifs sans examen histopathologique. Malgré la disponibilité de systèmes informatiques de caractérisation des polypes, la pratique du diagnostic optique reste limitée en raison de la crainte d'un mauvais diagnostic de cancer, d'une mauvaise surveillance des patients et des problèmes médico-légaux correspondants. Il est donc indispensable d'élaborer des stratégies alternatives de résection et d'élimination non optiques pour améliorer la précision et la sécurité du diagnostic optique et l'adapter à la pratique clinique. Ces stratégies doivent répondre à des critères cliniques simples et ne nécessitent pas de formation supplémentaire ni de dispositifs d'amélioration de l'image. De plus, la pratique sûre du diagnostic optique, la prise de décision appropriée concernant la technique de polypectomie ou l'intervalle de surveillance dépendent de l'estimation précise de la taille des polypes. La variabilité inter-endoscopistes dans la mesure de la taille des polypes exige le développement de méthodes fiables et validées pour augmenter la précision de la mesure de la taille. Une balance virtuelle intégrée à un endoscope haute définition est actuellement disponible pour le calcul automatique de la taille des polypes, mais sa faisabilité clinique n'a pas encore été établie. En dehors des points susmentionnés, une coloscopie de haute qualité nécessite l'examen complet de la muqueuse colique, ainsi que la visualisation de la valve iléocæcale et de l'orifice appendiculaire. À ce jour, aucune solution informatique n'a été capable d'assister les endoscopistes pendant les coloscopies en temps réel en détectant et en différenciant les points de repère cæcaux de façon automatique. Objectifs: Les objectifs de cette thèse sont : 1) d'étudier l'effet de la limitation du diagnostic optique aux polypes de 1 à 3 mm sur la sécurité du diagnostic optique pour le traitement des polypes diminutifs et l'acceptation par les endoscopistes de son utilisation dans les pratiques en temps réel tout en préservant ses potentiels de temps et de rentabilité ; 2) élaborer et examiner des stratégies non optiques de résection et d'élimination qui peuvent remplacer le diagnostic optique tout en offrant les mêmes possibilités d'économie de temps et d'argent ; 3) examiner la précision relative d'un endoscope à échelle virtuelle pour mesurer la taille des polypes ; 4) former, valider et tester un modèle d'intelligence artificielle qui peut prédire la complétude d'une procédure de coloscopie en identifiant les points de repère anatomiques du cæcum (c'est-à-dire la valve iléo-cæcale et l'orifice appendiculaire) et en les différenciant les uns des autres, des polypes et de la muqueuse normale. Méthodes: Pour atteindre le premier objectif de cette thèse, une analyse post-hoc de trois études prospectives a été réalisée pour évaluer la proportion de patients chez lesquels des adénomes avancés ont été découverts et le diagnostic optique a entraîné une surveillance retardée dans trois groupes de taille de polypes : 1–3, 1–5, et 1–10 mm. Pour atteindre le second objectif de cette thèse, deux stratégies non optiques ont été développées et testées dans deux études prospectives: une stratégie de résection et d'élimination basée sur la localisation qui utilise la localisation anatomique des polypes pour classer les polypes du côlon en non-néoplasiques ou néoplasiques à faible risque et une stratégie de résection et d'élimination basée sur les polypes qui attribue des intervalles de surveillance en fonction du nombre et de la taille des polypes. Dans les trois études, la concordance de l'attribution d'intervalles de surveillance basée sur un diagnostic optique à haute confiance ou sur des stratégies non optiques avec les recommandations basées sur la pathologie, ainsi que la proportion d'examens pathologiques évités et la proportion de communications immédiates d'intervalles de surveillance, ont été évaluées. Le troisième objectif de cette thèse a été abordé par le biais d'une étude de faisabilité pilote prospective qui a utilisé la mesure de spécimens de polypes immédiatement après leur prélèvement, suite à une polypectomie par un pied à coulisse Vernier comme référence pour comparer la précision relative des mesures de la taille des polypes entre les endoscopistes et un endoscope à échelle virtuelle. Enfin, le quatrième objectif de cette thèse a été évalué par l'enregistrement et l'annotation prospective de vidéos de coloscopie. Des images non modifiées de polype, de valve iléo-caecale, d'orifice appendiculaire et de muqueuse normale ont été extraites et utilisées pour développer et tester un modèle de réseau neuronal convolutionnel profond pour classer les images pour les points de repère qu'elles contiennent. Résultats: La réduction du seuil du diagnostic optique favoriserait la sécurité du diagnostic optique en diminuant de manière significative le risque d'écarter un polype avec une histologie avancée ou la mauvaise surveillance d'un patient avec de tels polypes. En outre, les stratégies non optiques de résection et d'élimination pourraient dépasser le critère de référence d'au moins 90% de concordance dans l'attribution des intervalles de surveillance post-polypectomie par rapport aux décisions basées sur l'évaluation pathologique. De plus, il a été démontré que l'endoscope à échelle virtuelle est plus précis que l'estimation visuelle de la taille des polypes en temps réel. Enfin, un modèle d'apprentissage profond s'est révélé très efficace pour détecter les repères cæcaux, les polypes et la muqueuse normale, à la fois individuellement et en combinaison. Discussion: La prédiction histologique optique des polypes de 1 à 3 mm est une approche efficace pour améliorer la sécurité et la faisabilité de la stratégie de résection et d'écartement dans la pratique. Les approches non optiques de résection et d'élimination offrent également des alternatives viables au diagnostic optique lorsque les endoscopistes ne sont pas en mesure de répondre aux conditions de mise en œuvre systématique du diagnostic optique, ou lorsque la technologie d'amélioration de l'image n'est pas accessible. Les stratégies de résection et de rejet, qu'elles soient optiques ou non, pourraient réduire les coûts supplémentaires liés aux examens histopathologiques et faciliter la communication du prochain intervalle de surveillance le même jour que la coloscopie de référence. Un endoscope virtuel à échelle réduite faciliterait l'utilisation du diagnostic optique pour la détection des polypes diminutifs et permet une prise de décision appropriée pendant et après la coloscopie. Enfin, le modèle d'apprentissage profond peut être utile pour promouvoir et contrôler la qualité des coloscopies par la prédiction d'une coloscopie complète. Cette technologie peut être intégrée dans le cadre d'une plateforme de vérification et de génération de rapports qui élimine le besoin d'intervention humaine. Conclusion: Les résultats présentés dans cette thèse contribueront à l'état actuel des connaissances dans la pratique de la coloscopie concernant les stratégies pour améliorer l'efficacité de la coloscopie dans la prévention du cancer colorectal. Cette étude fournira des indications précieuses pour les futurs chercheurs intéressés par le développement de méthodes efficaces de traitement des polypes colorectaux diminutifs. Le diagnostic optique nécessite une formation complémentaire et une mise en œuvre à l'aide de modules de caractérisation informatisés. En outre, malgré la lenteur de l'adoption des solutions informatiques dans la pratique clinique, la coloscopie assistée par l'IA ouvrira la voie à la détection automatique, à la caractérisation et à la rédaction semi-automatique des rapports de procédure. / Introduction: Colorectal cancer remains a critical public health concern in Canada. Screening programs could reduce the incidence of colorectal cancer and its associated mortality. A high-quality colonoscopy is appraised to be a cost-effective means of cancer prevention through identifying and removing cancer precursor lesions. Although colonoscopy can serve as a preventative measure against cancer, the procedure can impose an additional burden on the public health by removing and histologically evaluating insignificant diminutive colorectal polyps, which pose a minimal risk of advanced histology or cancer. The image-enhance technology would enable physicians to resect and discard diminutive polyps or diagnose and leave diminutive rectosigmoid polyps without histopathology examination. Despite the availability of computer-based polyp characterization systems, the practice of optical diagnosis remains limited due to the fear of cancer misdiagnosis, patient mismanagement, and the related medicolegal issues. Thus, alternative non-optical resection and discard strategies are imperative for improving the accuracy and safety of optical diagnosis for adaptation to clinical practice. These strategies should follow simple clinical criteria and do not require additional education or image enhanced devices. Furthermore, the safe practice of optical diagnosis, adequate decision-making regarding polypectomy technique, or surveillance interval depends on accurate polyp size estimation. The inter-endoscopist variability in polyp sizing necessitates the development of reliable and validated methods to enhance the accuracy of size measurement. A virtual scale integrated into a high-definition endoscope is currently available for automated polyp sizing, but its clinical feasibility has not yet been demonstrated. In addition to the points mentioned above, a high-quality colonoscopy requires the complete examination of the entire colonic mucosa, as well as the visualization of the ileocecal valve and appendiceal orifice. To date, no computer-based solution has been able to support endoscopists during live colonoscopies by automatically detecting and differentiating cecal landmarks. Aims: The aims of this thesis are: 1) to investigate the effect of limiting optical diagnosis to polyps 1–3mm on the safety of optical diagnosis for the management of diminutive polyps and the acceptance of endoscopists for its use in real-time practices while preserving its time- and cost-effectiveness potentials; 2) to develop and examine non-optical resect and discard strategies that can replace optical diagnosis while offering the same time- and cost-saving potentials; 3) to examine the relative accuracy of a virtual scale endoscope for measuring polyp size; 4) to train, validate, and test an artificial intelligence-empower model that can predict the completeness of a colonoscopy procedure by identifying cecal anatomical landmarks (i.e., ileocecal valve and appendiceal orifice) and differentiating them from one another, polyps, and normal mucosa. Methods: To achieve the first aim of this thesis, a post-hoc analysis of three prospective studies was performed to evaluate the proportion of patients in which advanced adenomas were found and optical diagnosis resulted in delayed surveillance in three polyp size groups: 1‒3, 1‒5, and 1‒10 mm. To achieve the second aim of this thesis, two non-optical strategies were developed and tested in two prospective studies: a location-based resect and discard strategy that uses anatomical polyp location to classify colon polyps into non-neoplastic or low-risk neoplastic and a polyp-based resect and discard strategy that assigns surveillance intervals based on polyp number and size. In all three studies, the agreement of assigning surveillance intervals based on high-confidence optical diagnosis or non-optical strategies with pathology-based recommendations, as well as the proportion of avoided pathology examinations and the proportion of immediate surveillance interval communications, was evaluated. The third aim of this thesis was addressed through a prospective pilot feasibility study that used the measurement of polyp specimens immediately after retrieving, following a polypectomy by a Vernier caliper as a reference to compare the relative accuracy of polyp size measurements between endoscopists and a virtual scale endoscope. Finally, the fourth aim of this thesis was assessed through prospective recording and annotation of colonoscopy videos. Unaltered images of polyp, ileocecal valve, appendiceal orifice and normal mucosa were extracted and used to develop and test a deep convolutional neural network model for classifying images for the containing landmarks. Results: Reducing the threshold of optical diagnosis would promote the safety of optical diagnosis by significantly decreasing the risk of discarding a polyp with advanced histology or the mismanagement of a patient with such polyps. Additionally, the non-optical resect and discard strategies could surpass the benchmark of at least 90% agreement in the assignment of post-polypectomy surveillance intervals compared with decisions based on pathologic assessment. Moreover, the virtual scale endoscope was demonstrated to be more accurate than visual estimation of polyp size in real-time. Finally, a deep learning model proved to be highly effective in detecting cecal landmarks, polyps, and normal mucosa, both individually and in combination. Discussion: Optical histology prediction of polyps 1‒3 mm in size is an effective approach to enhance the safety and feasibility of resect and discard strategy in practice. Non-optical resect and discard approaches also offer feasible alternatives to optical diagnosis when endoscopists are unable to meet the conditions for routine implementation of optical diagnosis, or when image-enhanced technology is not accessible. Both optical and non-optical resect and discard strategies could reduce additional costs related to histopathology examinations and facilitate the communication of the next surveillance interval in the same day as the index colonoscopy. A virtual scale endoscope would facilitate the use of optical diagnosis for the detection of diminutive polyps and allows for appropriate decision-making during and after colonoscopy. Additionally, the deep learning model may be useful in promoting and monitoring the quality of colonoscopies through the prediction of a complete colonoscopy. This technology may be incorporated as part of a platform for auditing and report generation that eliminates the need for human intervention. Conclusion: The results presented in this thesis will contribute to the current state of knowledge in colonoscopy practice regarding strategies for improving the efficacy of colonoscopy in the prevention of colorectal cancer. This study will provide valuable insights for future researchers interested in developing effective methods for treating diminutive colorectal polyps. Optical diagnosis requires further training and implementation using computer-based characterization modules. Furthermore, despite the slow adoption of computer-based solutions in clinical practice, AI-empowered colonoscopy will eventually pave the way for automatic detection, characterization, and semi-automated completion of procedure reports in the future.