Multiple choice as formative assessment in dental education.

INTRODUCTION: The effectiveness of multiple-choice questions (MCQs) in dental education is pivotal to student performance and knowledge advancement. However, their optimal implementation requires exploration to enhance the benefits. MATERIALS AND METHODS: An educational tool incorporating MCQs was administered from the 5th to the 10th semester in a dental curriculum. The students filled out a questionnaire after the MCQ, which was linked to the learning management system. Four cohorts of four semesters generated 2300 data points analysed by Spearmen correlation and mixed model regression analysis. RESULTS: Demonstrated a significant correlation between early exam preparation and improved student performance. Independent study hours and lecture attendance emerged as significant predictors, accounting for approximately 10.27% of the variance in student performance on MCQs. While the number of MCQs taken showed an inverse relationship with study hours, the perceived clarity of these questions positively correlated with academic achievement. CONCLUSION: MCQs have proven effective in enhancing student learning and knowledge within the discipline. Our analysis underscores the important role of independent study and consistent lecture attendance in positively influencing MCQ scores. The study provides valuable insights into using MCQs as a practical tool for dental student learning. Moreover, the clarity of assessment tools, such as MCQs, remains pivotal in influencing student outcomes. This study underscores the multifaceted nature of learning experiences in dental education and the importance of bridging the gap between student expectations and actual performance.

Assessing generalisability of deep learning-based polyp detection and segmentation methods through a computer vision challenge.

Polyps are well-known cancer precursors identified by colonoscopy. However, variability in their size, appearance, and location makes the detection of polyps challenging. Moreover, colonoscopy surveillance and removal of polyps are highly operator-dependent procedures and occur in a highly complex organ topology. There exists a high missed detection rate and incomplete removal of colonic polyps. To assist in clinical procedures and reduce missed rates, automated methods for detecting and segmenting polyps using machine learning have been achieved in past years. However, the major drawback in most of these methods is their ability to generalise to out-of-sample unseen datasets from different centres, populations, modalities, and acquisition systems. To test this hypothesis rigorously, we, together with expert gastroenterologists, curated a multi-centre and multi-population dataset acquired from six different colonoscopy systems and challenged the computational expert teams to develop robust automated detection and segmentation methods in a crowd-sourcing Endoscopic computer vision challenge. This work put forward rigorous generalisability tests and assesses the usability of devised deep learning methods in dynamic and actual clinical colonoscopy procedures. We analyse the results of four top performing teams for the detection task and five top performing teams for the segmentation task. Our analyses demonstrate that the top-ranking teams concentrated mainly on accuracy over the real-time performance required for clinical applicability. We further dissect the devised methods and provide an experiment-based hypothesis that reveals the need for improved generalisability to tackle diversity present in multi-centre datasets and routine clinical procedures.

Impact of AI-aided colonoscopy in clinical practice: a prospective randomised controlled trial.

OBJECTIVE: Colorectal cancer (CRC) has a significant role in cancer-related mortality. Colonoscopy, combined with adenoma removal, has proven effective in reducing CRC incidence. However, suboptimal colonoscopy quality often leads to missed polyps. The impact of artificial intelligence (AI) on adenoma and polyp detection rate (ADR, PDR) is yet to be established. DESIGN: We conducted a randomised controlled trial at Sahlgrenska University Hospital in Sweden. Patients underwent colonoscopy with or without the assistance of AI (AI-C or conventional colonoscopy (CC)). Examinations were performed with two different AI systems, that is, Fujifilm CADEye and Medtronic GI Genius. The primary outcome was ADR. RESULTS: Among 286 patients, 240 underwent analysis (average age: 66 years). The ADR was 42% for all patients, and no significant difference emerged between AI-C and CC groups (41% vs 43%). The overall PDR was 61%, with a trend towards higher PDR in the AI-C group. Subgroup analysis revealed higher detection rates for sessile serrated lesions (SSL) with AI assistance (AI-C 22%, CC 11%, p=0.004). No difference was noticed in the detection of polyps or adenomas per colonoscopy. Examinations were most often performed by experienced endoscopists, 78% (n=86 AI-C, 100 CC). CONCLUSION: Amidst the ongoing AI integration, ADR did not improve with AI. Particularly noteworthy is the enhanced detection rates for SSL by AI assistance, especially since they pose a risk for postcolonoscopy CRC. The integration of AI into standard colonoscopy practice warrants further investigation and the development of improved software might be necessary before enforcing its mandatory implementation. TRIAL REGISTRATION NUMBER: NCT05178095.

Students' perceptions of post-exam feedback in oral radiology-A comparative study from two dental hygienist educational settings.

INTRODUCTION: The aim of this study was to investigate how students perceive the benefit of participating in a teacher-organised session providing feedback on exams, termed post-exam feedback, in two dental hygienist programmes. METHODS: The study was based on interviews with 22 participants, including 18 students and 4 faculty teachers. The data were approached on the basis of thematic analysis, allowing us to generate insights on how the participants reflected on their participation in the post-exam feedback sessions and how they perceived this arrangement as learners. RESULTS: The findings from the study suggest that motivated students consider post-exam feedback to be beneficial in clearing up uncertainties and deepening their understanding of issues not fully understood during the exam, as well as supporting their further learning. Less motivated students mainly consider post-exam feedback to be relevant for students who do not pass the exams. CONCLUSIONS: Organised in a student-centred way and with attentiveness to student learning preferences, the results suggest that post-exam feedback can be valuable for enhancing assessment and supporting student learning related to exams.

Diagnostic yield for video capsule endoscopy in gastrointestinal graft- versus -host disease: a systematic review and metaanalysis.

BACKGROUND: The gastrointestinal tract is the second most involved organ for graft-versus-host disease where involvement of the small intestine is present in 50% of the cases. Therefore, the use of a non-invasive investigation i.e., video capsule endoscopy (VCE) seems ideal in the diagnostic work-up, but this has never been systematically evaluated before. OBJECTIVE: The aim of this systematic review was to determine the efficacy and safety of VCE, in comparison with conventional endoscopy in patients who received hematopoietic stem cell transplantation. METHOD: Databases searched were PubMed, Scopus, EMBASE, and Cochrane CENTRAL. All databases were searched from their inception date until June 17, 2022. The search identified 792 publications, of which 8 studies were included in our analysis comprising of 232 unique patients. Efficacy was calculated in comparison with the golden standard i.e., histology. Risk of bias assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. RESULTS: The pooled sensitivity was higher for VCE at 0.77 (95% CI: 0.60-0.89) compared to conventional endoscopy 0.62 (95% CI: 0.47-0.75) but the difference was not statistically significant (p = 0.155, Q = 2.02). Similarly, the pooled specificity was higher for VCE at 0.68 (95% CI: 0.46-0.84) than for conventional endoscopy at 0.58 (95% CI: 0.40-0.74) but not statistically significant (p = 0.457, Q = 0.55). Moreover, concern for adverse events such as intestinal obstruction or perforation was not justified since none of the capsules were retained in the small bowel and no perforations occurred in relation to VCE. A limitation to the study is the retrospective approach seen in 50% of the studies. CONCLUSION: The role of video capsule endoscopy in diagnosing or dismissing graft-versus-host disease is not yet established and requires further studies. However, the modality appears safe in this cohort.

A multi-centre polyp detection and segmentation dataset for generalisability assessment.

Polyps in the colon are widely known cancer precursors identified by colonoscopy. Whilst most polyps are benign, the polyp's number, size and surface structure are linked to the risk of colon cancer. Several methods have been developed to automate polyp detection and segmentation. However, the main issue is that they are not tested rigorously on a large multicentre purpose-built dataset, one reason being the lack of a comprehensive public dataset. As a result, the developed methods may not generalise to different population datasets. To this extent, we have curated a dataset from six unique centres incorporating more than 300 patients. The dataset includes both single frame and sequence data with 3762 annotated polyp labels with precise delineation of polyp boundaries verified by six senior gastroenterologists. To our knowledge, this is the most comprehensive detection and pixel-level segmentation dataset (referred to as PolypGen) curated by a team of computational scientists and expert gastroenterologists. The paper provides insight into data construction and annotation strategies, quality assurance, and technical validation.

The use of post-exam feedback in oral radiology: A survey study of dental and dental hygienist schools in Europe.

INTRODUCTION: A combination of summative assessments and post-exam feedback can create a formative environment to support student learning. It remains unknown to what extent feedback sessions are conducted after exams in oral radiology courses for dental and dental hygienist students in Europe. This survey study aimed to explore whether post-exam feedback sessions were conducted, and if so, in what format. MATERIALS AND METHODS: A questionnaire was distributed to 76 dental schools in 26 countries and 34 dental hygienist schools in 14 countries in Europe. The questions addressed whether feedback was provided after exams in oral radiology, the feedback format, and whether feedback sessions were formalised or performed for other reasons. RESULTS: Questionnaire responses were received from 33 dental schools in 18 countries, and 20 dental hygienist schools in 11 countries. Information about grades was provided in 23-30% of the schools. Post-exam feedback sessions including opportunities for discussion was provided at 39% of the schools, all with guidelines stating that these sessions should be carried out. The remaining schools provided feedback either on request by individual students or as written examples of correct answers. CONCLUSION: Almost one third of the dental schools announced grades without providing any post-exam feedback that could support learning. Two fifth utilised feedback sessions to assist students in gaining knowledge and sorting out misconceptions, all according to guidelines. Given the possible learning potential in post-exam feedback with opportunity to discuss, further studies of this format would be valuable, including the role and use of feedback guidelines.

Colonoscopy quality improvement after initial training: A cross-sectional study of intensive short-term training.

Background and study aims High-quality is crucial for the effectiveness of colonoscopy and can be achieved by high-quality training and verified with assessment of key performance indicators (KPIs) for colonoscopy such as cecum intubation rate (CIR), adenoma detection rate (ADR) and adequate polyp resection. Typically, trainees achieve adequate CIR after 275 procedures, but little is known about learning curves for KPIs after initial training. Methods This cross-sectional study includes work-up colonoscopies after a positive screening test with fecal occult blood testing (FIT) or sigmoidoscopy, performed by either trainees after 300 training colonoscopies or by consultants. Outcome measures were KPIs. We assessed inter-endoscopist variation in trainees and learning curves for trainees as a group. We also compared KPIs for trainees and consultants as a group.  Results Data from 6,655 colonoscopies performed by 21 trainees and 921 colonoscopies performed by 17 consultants were included. Most trainees achieved target standards for main KPIs. With time, trainees shortened cecum intubation time and withdrawal time without decreasing their ADR, reduced the proportion of painful colonoscopies, and increased the adequate polyp resection rate (all P  < 0.01). Compared to consultants, trainees had higher CIR (97.7 % vs. 96.3 %, P  = 0.02), ADR after positive FIT (57.6 % vs. 50.3 %, P  < 0.01), and proximal ADR after sigmoidoscopy screening (41.1 % vs. 29.8 %; P  < 0.01), higher adequate polyp resection rate (94.9 % vs. 93.1 %, P  = 0.01) and fewer serious adverse events (0.65 % vs. 1.41 %, P  = 0.02). Conclusions Trainees performed high-quality colonoscopies and achieved international target standards. Several KPIs continuously improved after initial training. Trainees outperformed consultants on several KPIs.

Type and Severity of Mental Illness and Participation in Colorectal Cancer Screening.

INTRODUCTION: The effectiveness of colorectal cancer screening programs depends on the participation rate. This study examined the association between type and severity of mental illness and colorectal cancer screening participation. METHODS: Between 2012 and 2017, a total of 46,919 individuals were invited to sigmoidoscopy screening in Norway, and 70,019 were invited to fecal immunochemical testing. In 2022, logistic regression was used to evaluate the association between the use of antipsychotics, anxiolytics, hypnotics, and antidepressants in the year preceding the screening invitation and screening participation, adjusted for demographic and socioeconomic factors. Defined daily doses of individual drugs were used to assess dose‒response relationships. RESULTS: Overall, 19.2% (24.8% of women, 13.4% of men) of all invitees used at least 1 psychotropic medication. Nonparticipation in the 2 arms combined was associated with the use of anxiolytics (60.7% in users vs 43.2% in nonusers; OR=1.53; 95% CI=1.45, 1.62) and antipsychotics (64.3% vs 43.8%; OR=1.41; 95% CI=1.30, 1.53) and increased with higher doses for both drugs. Hypnotics and antidepressants were only weakly associated with nonparticipation in higher doses. Participation rates were 57.3%, 52.3%, 42.9%, and 35.4% in those prescribed 0, 1, 2, and 3-4 classes of psychotropic medications, respectively. The associations between the use of psychotropic medications and nonparticipation were similar for the 2 screening tests. CONCLUSIONS: These findings show significant disparities in colorectal cancer screening participation for individuals with mental illness, independent of the screening method. Moreover, screening participation varied depending on the type and severity of mental illness. Targeted interventions are warranted to ensure that people with mental illness are supported to access the benefits of colorectal cancer screening.

Outcome of self-expandable metal stents placement for obstructive colorectal cancer: 7 years' experience from a Swedish tertiary center.

BACKGROUND AND STUDY AIMS: Self expandable metal stents (SEMS) is an alternative to emergency surgery to treat malignant large bowel obstruction. It can be used either for palliation or as a bridge to curative surgery. Our study aims to review the outcomes of SEMS treatment in a tertiary center and to find predictors for the clinical outcome. PATIENT AND METHODS: We retrospectively analyzed data from SEMS insertion at Sahlgrenska University Hospital, a referral center in Western Sweden (1.7 million inhabitants), between 2014 and 2020. Data collected were age, the intent of intervention, tumor localization, complication rate, technical and clinical success, 30- and 90-days mortality as well as long-term survival for the indication bridge to surgery. RESULTS: We identified 265 SEMS insertions (mean age 72, female 49.4%). Most SEMS were used for palliation (90.2%). The malign obstruction was most often located in the left colon (71.7%). Technical success was achieved in 259 (97.7%) cases and clinical success in 244 (92.1%) cases. Post-operative complications occurred in 11 cases (4.2%). The 30-days mortality rate was 11.7% and the 90-day was 31.7%. In our analysis the tumor site was not associated with adverse outcomes and bridge to surgery indication was a positive prognostic factor for the 90-day mortality. CONCLUSIONS: We found that SEMS is an effective and safe treatment for patients with acute obstructive colorectal cancer.

Key research questions for implementation of artificial intelligence in capsule endoscopy.

Background: Artificial intelligence (AI) is rapidly infiltrating multiple areas in medicine, with gastrointestinal endoscopy paving the way in both research and clinical applications. Multiple challenges associated with the incorporation of AI in endoscopy are being addressed in recent consensus documents. Objectives: In the current paper, we aimed to map future challenges and areas of research for the incorporation of AI in capsule endoscopy (CE) practice. Design: Modified three-round Delphi consensus online survey. Methods: The study design was based on a modified three-round Delphi consensus online survey distributed to a group of CE and AI experts. Round one aimed to map out key research statements and challenges for the implementation of AI in CE. All queries addressing the same questions were merged into a single issue. The second round aimed to rank all generated questions during round one and to identify the top-ranked statements with the highest total score. Finally, the third round aimed to redistribute and rescore the top-ranked statements. Results: Twenty-one (16 gastroenterologists and 5 data scientists) experts participated in the survey. In the first round, 48 statements divided into seven themes were generated. After scoring all statements and rescoring the top 12, the question of AI use for identification and grading of small bowel pathologies was scored the highest (mean score 9.15), correlation of AI and human expert reading-second (9.05), and real-life feasibility-third (9.0). Conclusion: In summary, our current study points out a roadmap for future challenges and research areas on our way to fully incorporating AI in CE reading.

Characteristics of nonparticipants in a randomised colorectal cancer screening trial comparing sigmoidoscopy and faecal immunochemical testing.

Public health systems should guarantee universal access to health care services, including cancer screening. We assessed whether certain population subgroups were underrepresented among participants in colorectal cancer screening with sigmoidoscopy and faecal immunochemical testing (FIT). Between 2012 and 2019, about 140 000 individuals aged 50 to 74 years were randomly invited to once-only sigmoidoscopy or first round of FIT screening. Our study included 46 919 individuals invited to sigmoidoscopy and 70 019 to FIT between 2012 and 2017. We used logistic regression models to evaluate if demographic and socioeconomic factors and use of certain drugs were associated with participation. Twenty-four thousand one hundred and fifty-nine (51.5%) individuals attended sigmoidoscopy and 40 931 (58.5%) FIT screening. Male gender, young age, low education and income, being retired or unemployed, living alone, being an immigrant, long driving time to screening centre, and use of antidiabetic and psychotropic drugs were associated with low participation in both screening groups. Many of these factors also predicted low acceptance of colonoscopy after positive FIT. While male gender, young age and living alone were more strongly associated with nonparticipation in FIT than sigmoidoscopy, low education and income, being retired or immigrant and long driving time were more strongly associated with nonparticipation in sigmoidoscopy than FIT. In conclusion, participation was lower in sigmoidoscopy than FIT. Predictors of nonparticipation were similar between arms. However, low socioeconomic status, being an immigrant and long driving time affected participation more in sigmoidoscopy screening, suggesting that FIT may guarantee more equal access to screening services than sigmoidoscopy.

Women require routine opioids to prevent painful colonoscopies: a randomised controlled trial.

BACKGROUND: Women are at high risk for painful colonoscopy. Pain, but also sedation, are barriers to colorectal cancer (CRC) screening participation. In a randomised controlled trial, we compared on-demand with pre-colonoscopy opioid administration to control pain in women at CRC screening age. METHODS: Women, aged 55-79 years, attending colonoscopy at two Norwegian endoscopy units were randomised 1:1:1 to (1) fentanyl on-demand, (2) fentanyl prior to colonoscopy, or (3) alfentanil on-demand. The primary endpoint was procedural pain reported by the patients on a validated four-point Likert scale and further dichotomized for the study into painful (moderate or severe pain) and non-painful (slight or no pain) colonoscopy. Secondary endpoints were: willingness to repeat colonoscopy, adverse events, cecal intubation time and rate, and post-procedure recovery time. RESULTS: Between June 2017 and May 2020, 183 patients were included in intention-to-treat analyses in the fentanyl on-demand group, 177 in the fentanyl prior to colonoscopy group, and 179 in the alfentanil on-demand group. Fewer women receiving fentanyl prior to colonoscopy reported a painful colonoscopy compared to those who were given fentanyl on-demand (25.2% vs. 44.1%, p < .001). There was no difference in the proportion of painful colonoscopies between fentanyl on-demand and alfentanil on-demand (44.1% vs. 39.5%, p = .40). No differences were observed for adverse events or any of the other secondary endpoints between the three groups. CONCLUSIONS: Fentanyl prior to colonoscopy provided better pain control than fentanyl or alfentanil on-demand. Fentanyl before colonoscopy should be recommended to all women at screening age. Trial registration: Clinicaltrials.gov (NCT01538550). Norwegian Medicines Agency (16/16266-13). EU Clinical Trials Register (EUDRACTNR. 2016-005090-13).

The CRCbiome study: a large prospective cohort study examining the role of lifestyle and the gut microbiome in colorectal cancer screening participants.

BACKGROUND: Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, current screening methods are either hampered by invasiveness or suboptimal performance, limiting their effectiveness as primary screening methods. To aid in the development of a non-invasive screening test with improved sensitivity and specificity, we have initiated a prospective biomarker study (CRCbiome), nested within a large randomized CRC screening trial in Norway. We aim to develop a microbiome-based classification algorithm to identify advanced colorectal lesions in screening participants testing positive for an immunochemical fecal occult blood test (FIT). We will also examine interactions with host factors, diet, lifestyle and prescription drugs. The prospective nature of the study also enables the analysis of changes in the gut microbiome following the removal of precancerous lesions. METHODS: The CRCbiome study recruits participants enrolled in the Bowel Cancer Screening in Norway (BCSN) study, a randomized trial initiated in 2012 comparing once-only sigmoidoscopy to repeated biennial FIT, where women and men aged 50-74 years at study entry are invited to participate. Since 2017, participants randomized to FIT screening with a positive test result have been invited to join the CRCbiome study. Self-reported diet, lifestyle and demographic data are collected prior to colonoscopy after the positive FIT-test (baseline). Screening data, including colonoscopy findings are obtained from the BCSN database. Fecal samples for gut microbiome analyses are collected both before and 2 and 12 months after colonoscopy. Samples are analyzed using metagenome sequencing, with taxonomy profiles, and gene and pathway content as primary measures. CRCbiome data will also be linked to national registries to obtain information on prescription histories and cancer relevant outcomes occurring during the 10 year follow-up period. DISCUSSION: The CRCbiome study will increase our understanding of how the gut microbiome, in combination with lifestyle and environmental factors, influences the early stages of colorectal carcinogenesis. This knowledge will be crucial to develop microbiome-based screening tools for CRC. By evaluating biomarker performance in a screening setting, using samples from the target population, the generalizability of the findings to future screening cohorts is likely to be high. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01538550 .

Detection of cancers and advanced adenomas in asymptomatic participants in colorectal cancer screening: a cross-sectional study.

OBJECTIVES: To assess detection rates for colorectal cancer (CRC) and advanced adenomas in asymptomatic CRC screening participants and bowel symptoms in association with CRC and advanced adenoma. DESIGN: Cross-sectional study. SETTING: Two screening centres. PARTICIPANTS: 42 554 men and women, aged 50-74 years, participating in a randomised CRC screening trial. 36 059 participants underwent a sigmoidoscopy (and follow-up colonoscopy if positive sigmoidoscopy) and 6495 underwent a colonoscopy after a positive faecal immunochemical test (FIT). PRIMARY AND SECONDARY OUTCOME MEASURES: Proportion of asymptomatic participants diagnosed with CRC or advanced adenomas. Prevalence of bowel symptoms (rectal bleeding, change in bowel habits, diarrhoea, constipation, bloating, alternating bowel habits, general symptoms, other bowel symptoms) recorded by the endoscopist and their association with CRC and advanced adenomas. RESULTS: Among sigmoidoscopy participants, 7336 (20.3%) reported at least one symptom. 120 (60%) out of 200 individuals with screen-detected CRC and 1301 (76.5%) out of 1700 with advanced adenoma were asymptomatic. Rectal bleeding was associated with detection of CRC and advanced adenoma (OR 4.3, 95% CI 3.1 to 6.1 and 1.8, 95% CI 1.5 to 2.1, respectively), while change in bowel habits only with CRC detection (OR 3.8, 95% CI 2.4 to 6.1). Among the FIT positives, 2173 (33.5%) reported at least one symptom. Out of 299 individuals with screen-detected CRC and 1639 with advanced adenoma, 167 (55.9%) and 1 175 (71.7%) were asymptomatic, respectively. Detection of CRC was associated with rectal bleeding (OR 1.8, 95% CI 1.4 to 2.3), change in bowel habits (OR 2.2, 95% CI 1.4 to 3.5) and abdominal pain (OR 1.8, 95% CI 1.2 to 2.7). CONCLUSIONS: Some bowel symptoms increased the likelihood of being diagnosed with CRC or advanced adenoma. However, the majority of individuals with these findings were asymptomatic. Asymptomatic individuals should be encouraged to participate in CRC screening. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov Identifier: NCT01538550.

Kvasir-Capsule, a video capsule endoscopy dataset.

Artificial intelligence (AI) is predicted to have profound effects on the future of video capsule endoscopy (VCE) technology. The potential lies in improving anomaly detection while reducing manual labour. Existing work demonstrates the promising benefits of AI-based computer-assisted diagnosis systems for VCE. They also show great potential for improvements to achieve even better results. Also, medical data is often sparse and unavailable to the research community, and qualified medical personnel rarely have time for the tedious labelling work. We present Kvasir-Capsule, a large VCE dataset collected from examinations at a Norwegian Hospital. Kvasir-Capsule consists of 117 videos which can be used to extract a total of 4,741,504 image frames. We have labelled and medically verified 47,238 frames with a bounding box around findings from 14 different classes. In addition to these labelled images, there are 4,694,266 unlabelled frames included in the dataset. The Kvasir-Capsule dataset can play a valuable role in developing better algorithms in order to reach true potential of VCE technology.

A comprehensive analysis of classification methods in gastrointestinal endoscopy imaging.

Gastrointestinal (GI) endoscopy has been an active field of research motivated by the large number of highly lethal GI cancers. Early GI cancer precursors are often missed during the endoscopic surveillance. The high missed rate of such abnormalities during endoscopy is thus a critical bottleneck. Lack of attentiveness due to tiring procedures, and requirement of training are few contributing factors. An automatic GI disease classification system can help reduce such risks by flagging suspicious frames and lesions. GI endoscopy consists of several multi-organ surveillance, therefore, there is need to develop methods that can generalize to various endoscopic findings. In this realm, we present a comprehensive analysis of the Medico GI challenges: Medical Multimedia Task at MediaEval 2017, Medico Multimedia Task at MediaEval 2018, and BioMedia ACM MM Grand Challenge 2019. These challenges are initiative to set-up a benchmark for different computer vision methods applied to the multi-class endoscopic images and promote to build new approaches that could reliably be used in clinics. We report the performance of 21 participating teams over a period of three consecutive years and provide a detailed analysis of the methods used by the participants, highlighting the challenges and shortcomings of the current approaches and dissect their credibility for the use in clinical settings. Our analysis revealed that the participants achieved an improvement on maximum Mathew correlation coefficient (MCC) from 82.68% in 2017 to 93.98% in 2018 and 95.20% in 2019 challenges, and a significant increase in computational speed over consecutive years.

A Comprehensive Study on Colorectal Polyp Segmentation With ResUNet++, Conditional Random Field and Test-Time Augmentation.

Colonoscopy is considered the gold standard for detection of colorectal cancer and its precursors. Existing examination methods are, however, hampered by high overall miss-rate, and many abnormalities are left undetected. Computer-Aided Diagnosis systems based on advanced machine learning algorithms are touted as a game-changer that can identify regions in the colon overlooked by the physicians during endoscopic examinations, and help detect and characterize lesions. In previous work, we have proposed the ResUNet++ architecture and demonstrated that it produces more efficient results compared with its counterparts U-Net and ResUNet. In this paper, we demonstrate that further improvements to the overall prediction performance of the ResUNet++ architecture can be achieved by using Conditional Random Field (CRF) and Test-Time Augmentation (TTA). We have performed extensive evaluations and validated the improvements using six publicly available datasets: Kvasir-SEG, CVC-ClinicDB, CVC-ColonDB, ETIS-Larib Polyp DB, ASU-Mayo Clinic Colonoscopy Video Database, and CVC-VideoClinicDB. Moreover, we compare our proposed architecture and resulting model with other state-of-the-art methods. To explore the generalization capability of ResUNet++ on different publicly available polyp datasets, so that it could be used in a real-world setting, we performed an extensive cross-dataset evaluation. The experimental results show that applying CRF and TTA improves the performance on various polyp segmentation datasets both on the same dataset and cross-dataset. To check the model's performance on difficult to detect polyps, we selected, with the help of an expert gastroenterologist, 196 sessile or flat polyps that are less than ten millimeters in size. This additional data has been made available as a subset of Kvasir-SEG. Our approaches showed good results for flat or sessile and smaller polyps, which are known to be one of the major reasons for high polyp miss-rates. This is one of the significant strengths of our work and indicates that our methods should be investigated further for use in clinical practice.

Colorectal Cancer Screening With Repeated Fecal Immunochemical Test Versus Sigmoidoscopy: Baseline Results From a Randomized Trial.

BACKGROUND & AIMS: The comparative effectiveness of sigmoidoscopy and fecal immunochemical testing (FIT) for colorectal cancer (CRC) screening is unknown. METHODS: Individuals aged 50-74 years living in Southeast Norway were randomly invited between 2012 and 2019 to either once-only flexible sigmoidoscopy or FIT screening every second year. Colonoscopy was recommended after sigmoidoscopy if any polyp of ≥10 mm, ≥3 adenomas, any advanced adenomas, or CRC was found or, subsequent to, FIT >15 µg hemoglobin/g feces. Data for this report were obtained after complete recruitment in both groups and included 2 full FIT rounds and part of the third round. Outcome measures were participation, neoplasia detection, and adverse events. Age-standardized detection rates and age-adjusted odds ratios (ORs) were calculated. RESULTS: We included 139,291 individuals: 69,195 randomized to sigmoidoscopy and 70,096 to FIT. The participation rate was 52% for sigmoidoscopy, 58% in the first FIT round, and 68% for 3 cumulative FIT rounds. Compared to sigmoidoscopy, the detection rate for CRC was similar in the first FIT round (0.25% vs 0.27%; OR, 0.92; 95% confidence interval [CI], 0.75-1.13) but higher after 3 FIT rounds (0.49% vs 0.27%; OR, 1.87; 95% CI, 1.54-2.27). Advanced adenoma detection rate was lower in the first FIT round compared to sigmoidoscopy at 1.4% vs 2.4% (OR, 0.57; 95% CI, 0.53-0.62) but higher after 3 cumulative FIT rounds at 2.7% vs 2.4% (OR, 1.14; 95% CI, 1.05-1.23). There were 33 (0.05%) serious adverse events in the sigmoidoscopy group compared to 47 (0.07%) in the FIT group (P = .13). CONCLUSIONS: Participation was higher and more CRC and advanced adenomas were detected with repeated FIT compared to sigmoidoscopy. The risk of perforation and bleeding was comparable. Clinicaltrials.gov, Number: NCT01538550.