Detection Of Colonic Polyps Research Articles

Applications of Colon Capsule Endoscopy.

This is a review of colon capsule endoscopy (CCE) with a focus on its recent developments, technological improvements, and current and potential future indications. Based on the current literature, CCE II demonstrates comparable polyp detection rates as optical colonoscopy and CT colonography, and improved cost-effectiveness. The main limitation to patient acceptance is the requirement of a rigorous bowel preparation. Preliminary studies show good correlation between CCE and optical colonoscopy for assessment of colonic disease activity in inflammatory bowel disease (IBD). CCE II is currently FDA, approved as an adjunctive test in patients with prior incomplete colonoscopy, and in the evaluation of patients with suspected lower gastrointestinal bleeding. The test is approved in Europe as one of the options for average-risk colorectal cancer screening, and high-risk screening in patients with contraindications or unwilling to undergo colonoscopy. CCE has a potential role in the evaluation and monitoring of colonic disease activity in IBD. Future technological advances should focus on minimizing bowel preparation, improvement in reading times, and development of therapeutic capabilities. • With technological improvements, the second-generation colon capsule has a significantly higher sensitivity than the first-generation capsule for detection of colon polyps. • Colon capsule endoscopy has been approved in Europe as an option for average-risk colorectal cancer screening, and high-risk screening in patients with contraindications or unwilling to undergo colonoscopy. • Colon capsule endoscopy has received FDA approval as an option for colorectal cancer screening in patients with prior incomplete colonoscopy, and in evaluation of patients with suspected lower gastrointestinal bleeding. • Colon capsule endoscopy may have a role in evaluation and monitoring of inflammatory bowel disease. • Colon capsule endoscopy currently requires a bowel preparation that is more rigorous than colonoscopy.

Comparison of colon polyp detection rate with full-spectrum endoscopy versus forward-viewing colonoscopy

Comparison of colon polyp detection rate with full-spectrum endoscopy versus forward-viewing colonoscopy

Timed colonoscopy withdrawal, a mandatory quality measure in the era of national screening?

A minimum recommended withdrawal time for screening colonoscopy is recommended for by both the US Multi-Society Task Force on Colorectal Cancer and European Society of Gastrointestinal Endoscopy. To characterize the relationship between endoscopists withdrawal time at colonoscopy and polyp detection in a symptomatic cohort of patients as compared to previously untimed withdrawal. Three experienced medical endoscopists prospectively performed 1079 colonoscopies during a 24-month period in an Irish hospital. Mean withdrawal time and individual polyp detection rate were noted. Introduction of mandatory withdrawal time which was monitored and documented was associated with higher polyp detection rate (33 versus 21%, p < 0.005) as compared to previously untimed withdrawal. Our findings support a monitored colonoscopy withdrawal time of at least 6min, which correlates with higher colon polyp detection rates in a symptomatic cohort.

Update on Bowel Preparation for Colonoscopy.

Colonoscopy is the gold standard for visualization and diagnosis of conditions involving the colon and terminal ileum. It also facilitates screening and prevention of colorectal cancer, which is the second leading cause of cancer death in the USA. Adequate cleansing is essential for thorough visualization of the colon with successful detection of colon polyps. While the original large-volume polyethylene glycol preparations are still commonly used, several lower volume regimens are widely available and selected based on provider and patient preferences. There remains a strong urge from patients for an even lower volume and more palatable regimen. Split-dose preparation is strongly recommended and additional data has come to support same-day preparation regimens as well. Despite extensive research and comparison of various preparation regimens, between 10 and 25% of patients continue to have inadequate colon cleansing on the day of colonoscopy. Several patient factors have been associated with poor preparation and this chapter will touch on scoring systems, which may be used to predict colon cleansing. Documentation of preparation quality is essential to guide the practitioner in timing of follow-up examination. We recommend the use of the Boston Bowel Preparation Scale (BBPS) which is a validated and reliable scale for evaluation of cleansing. In patients with an inadequate preparation, we emphasize the importance of repeat examinations with consideration of a more aggressive preparation regimen. We predict that dietary liberalization prior to colonoscopy will be more commonly practiced in the future as it improves both patient satisfaction and adherence. Thorough bowel cleansing is essential for visualization of the colon with successful detection of colon polyps. While polyethylene glycol regimens are still the most commonly used for preparation, recommendations regarding dose timing and volume continue to evolve to optimize patient satisfaction and success of bowel cleanse. As the patients presenting for colonoscopy are evermore complex with medical comorbidities and extensive medication lists, a patient-centered approach to colonoscopy preparation will likely yield the highest rates of success.

Automatic Colon Polyp Detection Using Region Based Deep CNN and Post Learning Approaches

Automatic detection of colonic polyps is still an unsolved problem due to the large variation of polyps in terms of shape, texture, size, and color, and the existence of various polyp-like mimics during colonoscopy. In this study, we apply a recent region based convolutional neural network (CNN) approach for the automatic detection of polyps in images and videos obtained from colonoscopy examinations. We use a deep-CNN model (Inception Resnet) as a transfer learning scheme in the detection system. To overcome the polyp detection obstacles and the small number of polyp images, we examine image augmentation strategies for training deep networks. We further propose two efficient post-learning methods such as, automatic false positive learning and off-line learning, both of which can be incorporated with the region based detection system for reliable polyp detection. Using the large size of colonoscopy databases, experimental results demonstrate that the suggested detection systems show better performance compared to other systems in the literature. Furthermore, we show improved detection performance using the proposed post-learning schemes for colonoscopy videos.

Comparison of Quality of Bowel Preparation With Different Regimens of Polyethylene Glycol in Inner City Minority Population

Introduction: A good bowel preparation that ensures adequate colonic mucosal visualization during colonoscopy is essential to detect colon polyps and other colon pathologies. Suboptimal bowel preparation leads to lower adenoma detection rate (ADR), a key quality indicator and crucial component for the prevention of colorectal cancer. Polyethylene glycol with electrolytes (Golytely) is the commonest formulation used for bowel preparation at our hospital center. A few studies have shown that split administration of Golytely is superior to previous day administration. However, studies comparing the three regimens of Golytely administration, the previous day, split, and same day regimens are scarce. Methods: This is a retrospective study of patients who underwent screening colonoscopies at our hospital between October 1, 2014, and July 31, 2016, were included. The patients were divided into three groups based on the regimen of PEG solution administered. Demographic data, social history, medical comorbidities, HbA1C, colonoscopy findings and polyp pathology were collected and Adenoma detection rate (ADR) was calculated. Data between the three groups were compared and analyzed using SAS software and a two-sided p-value < 0.05 was considered statistically significant. Results: A total of 810 patients were included in the study, 42.4% males and 57.6% females. They were divided into Group-A, split regimen (n=308); Group B, same day regimen (n= 252); and Group C, previous day regimen (n =250). The average age in the three groups were 57, 57.3 and 59.3 years respectively. The average BMI was 29.6, 29.7 and 28.7 in Group A, B, and C respectively. Comparison of quality of bowel preparation between the three groups showed that the split day regimen had the higher percentage of adequate (adequate = excellent + good) preparation (83%) compared to same day (74%) and previous day regimens (64%). The Adenoma Detection Rate (ADR) was significantly higher in the split day regimen group (18%) compared to the previous day group (11.5%), p = 0.03. Conclusion: Our study shows that split administration of PEG solution provided the higher percentage of adequate (excellent and good) bowel preparation compared to other regimens of PEG administration. It also provided statistically significant higher Adenoma Detection Rate compared to previous day regimen (p= 0.03). The split regimen was observed to provide a higher quality of bowel preparation in people with BMI >30 (Obese) compared to the other regimens of PEG.Table: Table. Comparison of general factors between bowel preparation regimens

Clinical application of simethicone emulsion on bowel preparation for colonoscopy

Objective To assess the clinical effects of simethicone emulsion combined with polyethylene glycol on bowel preparation for colonoscopy. Methods Two hundred out-patients, who underwent colonoscopy, were randomly divided into the study group and the control group. The study group was given simethicone in addition with polyethylene glycol, and the control group was given polyethylene glycol only. The differences on bowel preparation scores, air bubble reduction rate, colon lens sharpness, ileocecal region arrival time, colon polyp detection rate, the number of colon poly detection, and adverse event rate between the two groups were compared. Results The air bubble reduction rate, colon lens sharpness score and ileocecal region arrival time of the study group was 1(0-3) score, 1.0(0-2) score, and 9 (5-21) min, respectively, which was 2 (1-3) score, 1.5 (0-2) score and 12 (6-22) min, respectively in the control group. Differences between the two groups were statistically significant(Z=-9.490, P=0.000; Z=-6.768, P=0.000; Z=-5.521, P=0.000). For the bowel preparation score, colonoscopy polyp detection rate, the detection rate of colon polyp of diameter less than 5 mm, and number of colonoscopy polyp detection, there was no statistical difference between the two groups (P>0.05). No adverse events were observed in the both two groups. Conclusion The bowel preparation using simethicone combined with polyethylene glycol could effectively decrease the number of air bubble, enhance colon lens sharpness and shorten operation time, which contributes significant improvement for colonoscopy quality. Key words: Colonoscopy; Bowel preparation; Simethicone; Polyethylene glycol

The Detection of Proximal Colon Polyps and Its Importance in Screening Colonoscopy

Abstract Background: Colon polyps are precursors of colorectal cancer (CRC), therefore their endoscopic detection is very important. A shift of in the localization of colorectal polyps toward the proximal colon has been recently observed in Western countries. Aim: The aim of this paper was to establish the most important clinical and endoscopic aspects of right colon polyps and to correlate them with their histopathological types, with an emphasis on sessile serrated adenomas/polyps (SSA/Ps). Material and method: We perfomed a retrospective study on a series of consecutive patients who underwent colonoscopy in the Gastroenterology and Endoscopy Unit of the County Emergency Clinical Hospital of Tîrgu Mureș between January 1, 2010 – December 31, 2014, comparing the results with those of patients who underwent colonoscopy between January 1, 2005 – December 31, 2009. In all cases with abnormal aspects at endoscopy, multiple biopsies were taken for histopathological examination. Only cases where the diagnosis of colon polyp was confirmed by the Histopathology Department were included in the study. Results: In the 2010–2014 period there were 871 patients diagnosed with colon polyps (1,038 polyps), with a mean age of 62.28 years. The most frequent histopathological form was tubular adenoma in 55.97% of cases (n = 581). SSA/Ps were found in 66 patients (75 polyps). Considering all polyps, the most frequent localization was in the sigmoid colon in 32.36% of cases (n = 336), but for SSA/Ps the most common localization was the ascending colon in 24% of cases (n = 18), followed by the sigmoid colon in 21.33% of cases (n = 16). Compared with patients investigated between 2005 and 2009, we found an increasing localization in the right colon, from 10.43% (n = 67) in 2005–2009 to 15.41% (n = 160) in 2010–2014. SSA/Ps were found in the right colon in 5.97% of cases (n = 4) in the first period compared with 11.25% of cases (n = 18) in the second period. Conclusions: In the last years we found an increasing localization of colon polyps in the right colon. These findings underscore the importance of high quality colonoscopy to maximize protection against colorectal cancer.

Clinical Significance of Preoperative Virtual Colonoscopy for Evaluation of the Proximal Colon in Patient With Obstructive Colorectal Cancer.

PurposeVirtual colonoscopy is the most recently developed tool for detecting colorectal cancers and polyps, but its effectiveness is limited. In our study, we compared the result of preoperative virtual colonoscopy to result of preoperative and postoperative colonoscopy. We evaluated also the accuracy of preoperative virtual colonoscopy in patients who had obstructive colorectal cancer that did not allow passage of a colonoscope.MethodsA total of 164 patients who had undergone preoperative virtual colonoscopy and curative surgery after the diagnosis of a colorectal adenocarcinoma between November 2008 and August 2013 were pooled. We compared the result of conventional colonoscopy with that of virtual colonoscopy in the nonobstructive group and the results of preoperative virtual colonoscopy with that of postoperative colonoscopy performed at 6 months after surgery in the obstructive group.ResultsOf the 164 patients, 108 were male and 56 were female patients. The mean age was 62.7 years. The average sensitivity, specificity, and accuracy of virtual colonoscopy for all patients were 31.0%, 67.2%, and 43.8%, respectively. In the nonobstructive group, the average sensitivity, specificity, and accuracy were 36.6%, 66.2%, and 48.0%, respectively, whereas in the obstructive group, they were 2%, 72.4%, and 25.4%. Synchronous cancer was detected via virtual colonoscopy in 4 of the 164 patients.ConclusionVirtual colonoscopy may not be an effective method for the detection of proximal colon polyps, but it can be helpful in determining the therapeutic plan when its results are correlated with the results of other studies.

Development and Validation of a High-Throughput Mass Spectrometry Based Urine Metabolomic Test for the Detection of Colonic Adenomatous Polyps.

Background: Colorectal cancer is one of the leading causes of cancer deaths worldwide. The detection and removal of the precursors to colorectal cancer, adenomatous polyps, is the key for screening. The aim of this study was to develop a clinically scalable (high throughput, low cost, and high sensitivity) mass spectrometry (MS)-based urine metabolomic test for the detection of adenomatous polyps. Methods: Prospective urine and stool samples were collected from 685 participants enrolled in a colorectal cancer screening program to undergo colonoscopy examination. Statistical analysis was performed on 69 urine metabolites measured by one-dimensional nuclear magnetic resonance spectroscopy to identify key metabolites. A targeted MS assay was then developed to quantify the key metabolites in urine. A MS-based urine metabolomic diagnostic test for adenomatous polyps was established using 67% samples (un-blinded training set) and validated using the remaining 33% samples (blinded testing set). Results: The MS-based urine metabolomic test identifies patients with colonic adenomatous polyps with an AUC of 0.692, outperforming the NMR based predictor with an AUC of 0.670. Conclusion: Here we describe a clinically scalable MS-based urine metabolomic test that identifies patients with adenomatous polyps at a higher level of sensitivity (86%) over current fecal-based tests (<18%).

Přínos CT kolografie v klinické praxi

CT colonography is a CT examination focused on the detection of colonic polyps and masses. Its most common indications include incomplete optical colonoscopy and generally personal preference in symptomatic or frail patients. CT colonography has a diagnostic yield similar to optical colonoscopy. It is less demanding for the patient, has shorter examination times, lower rates of adverse effects (including bowel perforation) and allows limited evaluation of extracolonic structures. In 10-15 % of asymptomatic patients, optical colonoscopy is needed if either a colonic polyp or mass is detected. CT colonography requires bowel prior preparation, including laxatives and stool tagging with contrast material. Stool tagging can be completed for same-day CT colonography after an incomplete colonoscopy. Evaluation of extracolonic structures in CT colonography is limited, but CT colonography can be combined with other CT examinations (eg. CT of abdomen). C-RADS classification has been established for a more straightforward interpretation of findings on CT colonography. CT colonography and optical colonoscopy complement each other but do not compete.Key words: colonoscopy - colorectal carcinoma - CT colonography - polyp - screening - virtual colonoscopy.

Abstract IA16: Current and emerging molecular diagnostic assays for colorectal cancer

Abstract IA16: Current and emerging molecular diagnostic assays for colorectal cancer

A CAD of fully automated colonic polyp detection for contrasted and non-contrasted CT scans.

Computer-aided detection (CAD) systems are developed to help radiologists detect colonic polyps over CT scans. It is possible to reduce the detection time and increase the detection accuracy rates by using CAD systems. In this paper, we aimed to develop a fully integrated CAD system for automated detection of polyps that yields a high polyp detection rate with a reasonable number of false positives. The proposed CAD system is a multistage implementation whose main components are: automatic colon segmentation, candidate detection, feature extraction and classification. The first element of the algorithm includes a discrete segmentation for both air and fluid regions. Colon-air regions were determined based on adaptive thresholding, and the volume/length measure was used to detect air regions. To extract the colon-fluid regions, a rule-based connectivity test was used to detect the regions belong to the colon. Potential polyp candidates were detected based on the 3D Laplacian of Gaussian filter. The geometrical features were used to reduce false-positive detections. A 2D projection image was generated to extract discriminative features as the inputs of an artificial neural network classifier. Our CAD system performs at 100% sensitivity for polyps larger than 9 mm, 95.83% sensitivity for polyps 6-10 mm and 85.71% sensitivity for polyps smaller than 6 mm with 5.3 false positives per dataset. Also, clinically relevant polyps ([Formula: see text]6 mm) were identified with 96.67% sensitivity at 1.12 FP/dataset. To the best of our knowledge, the novel polyp candidate detection system which determines polyp candidates with LoG filters is one of the main contributions. We also propose a new 2D projection image calculation scheme to determine the distinctive features. We believe that our CAD system is highly effective for assisting radiologist interpreting CT.

Clinical validation of a novel urine-based metabolomic test for the detection of colonic polyps on Chinese population

Colorectal cancer is the fifth leading cause of cancer-related deaths in China. When detected early, with the removal of adenomatous polyps, precursors of colorectal cancer, it is preventable. The aim of this study was to evaluate a novel urine-based metabolomic diagnostic test for the detection of adenomatous polyps, PolypDx™, that was originally developed and validated using 1000 samples from Canadian Cohort, on Chinese population. Prospective urine samples were collected from 1000 participants undergoing colonoscopy examination, from March 2013 to July 2014 at Minhang District, Shanghai Centre for Disease Control and Prevention. One-dimensional nuclear magnetic resonance spectra of urine metabolites were analyzed to determine the concentrations of three key metabolites used in PolypDx™. The predicted results were then compared to the gold standard for colorectal cancer diagnostic, colonoscopy. Area under curve (AUC) was calculated specifically for the Chinese population and compared with the Canadian dataset. Sensitivity and specificity of this urine-based metabolomic diagnostic test were also compared with three commercially available fecal-based tests. An AUC of 0.717 for PolypDx™ was calculated on Chinese dataset which is slightly lower than the AUC on the Canadian dataset. A sensitivity of 82.6% and a specificity of 42.4% were achieved on Chinese dataset. Here, we validated a novel urine-based metabolomic diagnostic test for the detection of adenomatous polyps, PolypDx™, on Chinese population through a sample size of 1000 participants with a greater level of sensitivity than fecal-based tests.

Abdominal obesity as the colorectal adenomas risk factor

Obesity is a risk factor for many diseases, including colorectal cancer. Aim: to study association of the constitutional features (height, weight, waist circumference) with detection of colon polyps on the screening colonoscopy. Materials and methods: Constitutional features (height, weight, waist circumference) of 145 patients were assessed with detection of colon polyps on the screening colonoscopy for the period from 2013to 2015. Exclusion criteria were: cancer of any location in history, surgery within the past two years, the inflammatory bowel diseases (Crohn's disease, ulcerative colitis), autoimmune diseases (rheumatoid arthritis, HIV, AIDS, SLE), diabetes, chronic liver or kidney disease, family polyposis. Results: the presence of adenomas (OR = 6.0 CI: 2,2-16,7); multiplicity of polyps (the possibility that there will be ≥ 3 polyps was 6.4, CI: 1,4-29,9) were significantly higher in obese patients than in those with normal weight. Subjects with a waist circumference in the highest tertile (>115 cm), were 4.6 times more likely to identify ≥ 3 polyps than those with waist circumference in the lowest tertile (<96 cm) . The probability of detection of adenomas in patients with a waist circumference in the highest tertile were 6.2 times higher than in the lowest tertile. Conclusions. Visceral obesity is associated with a morphological type and number of colon polyps. The presence of visceral obesity significantly increases the risk of colon adenomas. Increased visceral fat layer is an indication for colonoscopy especially of the right half of the colon examination. Screening colonoscopy should be recommended for the obese patients after 50 y.o. in order to diagnose adenomas of the colon and colorectal cancer.

Endoscopy Lower.

Endoscopy Lower.

Computed Tomography Colonography: The Robley Rex VAMC Experience

Introduction: Computed tomography colonography (CTC) was introduced as a non-invasive option for colorectal cancer screening in the 1990's. In the past couple of decades, studies have shown this to be a highly sensitive and specific, minimally invasive diagnostic technique for the detection of colon polyps and cancers. This alternative means of screening has the potential to improve patient compliance and therefore could have a significant impact on the prevention of colorectal cancer. Methods: In January 2012 CT colonography was introduced at the Robley Rex VA in Louisville Kentucky. A chart review was performed on all patients who underwent CTC from 2012 to 2015 as a quality improvement project. 35 patient charts (demographics table 1) were reviewed to evaluate the indication for CTC (table 2), results of the diagnostic exam (table 3), comorbidities for colon cancer and any secondary outcome that resulted from this non-invasive examination (table 4). CTCs were performed by 320-row CT scan in both the supine and prone position without any intravenous contrast. Colonic and extracolonic findings were evaluated. Results: 33/35 patients underwent CTC evaluation between 2012 to 2015, with prior difficult colonoscopy being the most common indication (63.6%), followed by CTC being the patient's preferred method of surveillance (15%) and increased bleeding risk (12.1%). Diverticulosis was the most common finding (27.3% of CTCs), with only two CTCs showing polyps (6.1%). These patients had a variety of comorbidities, including tobacco abuse, diabetes, hyperlipidemia, obesity and hyperlipidemia. Only one patient used CTC as their initial screening method at age 50. All patients tolerated CTC diagnostic evaluation well without difficulty. No adverse effects were noted. Conclusion: Based on the results, CTC was primarily used when colonoscopy was difficult for the patient, or increased risk for bleeding or sedation as a result of patient comorbidities (table 4). CTC may become the method of choice for those patients that prefer not to have colonoscopy. The study number is small and is limited to one center's experience with CTC that was reviewed and interpreted by one radiologist. A head-to-head study assessing polyp detection in CTC interpreted by an expert radiologist and colonoscopy for initial screening may provide valuable information.Figure 1Figure 2Figure 3

Heterogeneous data analysis: Online learning for medical-image-based diagnosis

Heterogeneous Data Analysis (HDA) is proposed to address a learning problem of medical image databases of Computed Tomographic Colonography (CTC). The databases are generated from clinical CTC images using a Computer-aided Detection (CAD) system, the goal of which is to aid radiologists' interpretation of CTC images by providing highly accurate, machine-based detection of colonic polyps. We aim to achieve a high detection accuracy in CAD in a clinically realistic context, in which additional CTC cases of new patients are added regularly to an existing database. In this context, the CAD performance can be improved by exploiting the heterogeneity information that is brought into the database through the addition of diverse and disparate patient populations. In the HDA, several quantitative criteria of data compatibility are proposed for efficient management of these online images. After an initial supervised offline learning phase, the proposed online learning method decides whether the online data are heterogeneous or homogeneous. Our previously developed Principal Composite Kernel Feature Analysis (PC-KFA) is applied to the online data, managed with HDA, for iterative construction of a linear subspace of a high-dimensional feature space by maximizing the variance of the non-linearly transformed samples. The experimental results showed that significant improvements in the data compatibility were obtained when the online PC-KFA was used, based on an accuracy measure for long-term sequential online datasets. The computational time is reduced by more than 93% in online training compared with that of offline training.

PillCam colon capsule endoscopy (PCCE) in colonic diseases.

Diseases affecting the colon are common worldwide and can cause a major health problem. Colorectal cancer (CRC) as well as Inflammatory bowel diseases represent a major cause of morbidity and mortality in western countries. PillCam colon capsule endoscopy (PCCE) is a novel and promising technology that can be useful for the screening and monitoring of colonic diseases. In the recent years many articles examined the use of various versions of PCCE-the 1st and 2nd generation versus various other endoscopic or radiologic modalities both for detection of colonic polyps or cancer and in both ulcerative colitis (UC) and Crohn's disease. The aim of the current review is to provide up to date information regarding the use and usefulness of this method in these disease.

Exploring the clinical potential of an automatic colonic polyp detection method based on the creation of energy maps.

Polyp miss-rate is a drawback of colonoscopy that increases significantly for small polyps. We explored the efficacy of an automatic computer-vision method for polyp detection. Our method relies on a model that defines polyp boundaries as valleys of image intensity. Valley information is integrated into energy maps that represent the likelihood of the presence of a polyp. In 24 videos containing polyps from routine colonoscopies, all polyps were detected in at least one frame. The mean of the maximum values on the energy map was higher for frames with polyps than without (P < 0.001). Performance improved in high quality frames (AUC = 0.79 [95 %CI 0.70 - 0.87] vs. 0.75 [95 %CI 0.66 - 0.83]). With 3.75 set as the maximum threshold value, sensitivity and specificity for the detection of polyps were 70.4 % (95 %CI 60.3 % - 80.8 %) and 72.4 % (95 %CI 61.6 % - 84.6 %), respectively. Energy maps performed well for colonic polyp detection, indicating their potential applicability in clinical practice.