New technologies and techniques to improve adenoma detection in colonoscopy

Adenoma detection rate (ADR) is a key component of colonoscopy quality assessment, with a direct link between itself and future mortality from colorectal cancer. There are a number of potential factors, both modifiable and non-modifiable that can impact upon ADR. As methods, understanding and technologies advance, so should our ability to improve ADRs, and thus, reduce colorectal cancer mortality. This article will review new technologies and techniques that improve ADR, both in terms of the endoscopes themselves and adjuncts to current systems. In particular it focuses on effective techniques and behaviours, developments in image enhancement, advancement in endoscope design and developments in accessories that may improve ADR. It also highlights the key role that continued medical education plays in improving the quality of colonoscopy and thus ADR. The review aims to present a balanced summary of the evidence currently available and does not propose to serve as a guideline.     

Sessile serrated adenomas in the proximal colon are likely to be flat,large and occur in smokers

AIM:To examine the epidemiology and the morphology of the proximal sessile serrated adenomas(SSAs).METHODS:We conducted a retrospective study to identify patients with SSAs using a university-based hospital pathology database query from January 2007to April 2011.Data collected included:age,gender,ethnicity,body mass index,diabetes,smoking,family history of colorectal cancer,aspirin,and statin use.We collected data on morphology of SSAs including site(proximal or distal),size,and endoscopic appearance(flat or protuberant).We also compared proximal SSAs to proximal tubular adenomas detected during same time period.RESULTS:One hundred and twenty patients with SSAs were identified:61%were distal and 39%were proximal SSAs.Proximal SSAs were more likely to be flat than distal(100%vs 78%respectively;P=0.0001).Proximal SSAs were more likely to occur in smokers(OR=2.63;95%CI:1.17-5.90;P=0.02)and in patients with family history of colorectal cancer(OR=4.72;95%CI:1.43-15.55;P=0.01)compared to distal.Proximal SSAs were statistically more likely to be≥6 mm in size(OR=2.94;P=0.008),and also more likely to be large(≥1 cm)(OR=4.55;P=0.0005)compared to the distal lesions.Smokers were more likely to have proximal(P=0.02),flat(P=0.01)and large(P=0.007)SSAs compared to non-smokers.Compared to proximal tubular adenomas,proximal SSAs were more likely to be large and occur in smokers.CONCLUSION:Proximal SSAs which accounted for two-fifths of all SSAs were more likely to present as flat lesions,larger SSAs,and were more likely to occur in smokers and in patients with family history of colorectal cancer.Our data has implications for colorectal cancer screening.     

Technological advances for improving adenoma detection rates: The changing face of colonoscopy

Worldwide, colorectal cancer is the third commonest cancer. Over 90% follow an adenoma-to-cancer sequence over many years. Colonoscopy is the gold standard method for cancer screening and early adenoma detection. However, considerable variation exists between endoscopists’ detection rates. This review considers the effects of different endoscopic techniques on adenoma detection. Two areas of technological interest were considered: (1) optical technologies and (2) mechanical technologies. Optical solutions, including FICE, NBI, i-SCAN and high definition colonoscopy showed mixed results. In contrast, mechanical advances, such as cap-assisted colonoscopy, FUSE, EndoCuff and G-EYE™, showed promise, with reported detections rates of up to 69%. However, before definitive recommendations can be made for their incorporation into daily practice, further studies and comparison trials are required.     

Interendoscopist variability in proximal colon polyp detection is twice higher for serrated polyps than adenomas

AIMTo assess the interendoscopist variability in the detection of colorectal polyps according to their location and histological type.METHODSThis study was a retrospective analysis of prospectively collected data from a regional colorectal cancer (CRC) screening program; 2979 complete colonoscopies from 18 endoscopists were included. Variability in performance between endoscopists for detection of at least one adenoma (A), one proximal adenoma (PA), one distal adenoma (DA), and one proximal serrated polyp (PSP) was assessed by using multilevel logistic regression models.RESULTSThe observed detection rates among the 18 endoscopists ranged from 24.6% to 47.6% (mean = 35.7%) for A, from 19.1% to 39.0% (mean = 29.4%) for DA, from 6.0% to 22.9% (mean = 12.4%) for PA, and from 1.3% to 19.3% (mean = 6.9%) for PSP. After adjusting for patient-level variables (sex, age), the interendoscopist detection rates variability achieved a significant level for A, PA, and PSP but not for DA (P = 0.03, P = 0.02, P = 0.02 and P = 0.08, respectively). This heterogeneity, as measured by the variance partition coefficient, was approximately threefold higher for PA (6.6%) compared with A (2.1%), and twofold higher for PSP (12.3%) compared with PA.CONCLUSIONThese results demonstrate significant interendoscopist variability for proximal polyp particularly for serrated polyps, but not for distal adenoma detection. These findings contribute to explain the decreased effectiveness of complete colonoscopies at preventing proximal CRCs and the need to carefully assess the proximal colon during scope procedure.     

Use of the Endocuff during routine colonoscopy examination improves adenoma detection: A meta-analysis

AIM To perform meta-analysis of the use of Endocuff during average risk screening colonoscopy.METHODS Scopus, Cochrane databases, MEDLINE/Pub Med, and CINAHL were searched in April 2016. Abstracts from Digestive Disease Week, United European Gastroenterology, and the American College of Gastroenterology meeting were also searched from 2004-2015. Studies comparing EC-assisted colonoscopy(EAC) to standard colonoscopy, for any indication, were included in the analysis. The analysis was conducted by using the Mantel-Haenszel or DerS imonian and Laird models with the odds ratio(OR) to assess adenoma detection, cecal intubation rate, and complications performed. RESULTS Nine studies(n = 5624 patients) were included in the analysis. Compared to standard colonoscopy, procedures performed with EC had higher frequencies for adenoma(OR = 1.49, 95%CI: 1.23-1.80; P = 0.03), and sessile serrated adenomas detection(OR = 2.34 95%CI: 1.63-3.36; P 0.001). There was no significant difference in cecal intubation rates between the EACgroup and standard colonoscopy(OR = 1.26, 95%CI: 0.70-2.27, I2 = 0%; P = 0.44). EAC was associated with a higher risk of complications, most commonly being superficial mucosal injury without higher frequency for perforation.CONCLUSION The use of an EC on colonoscopy appears to improve pre-cancerous polyp detection without any difference in cecal intubation rates compared to standard colonoscopy.     

Retrograde inspection vs standard forward view for the detection of colorectal adenomas during colonoscopy: A back-to-back randomized clinical trial

BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.     

Seeing better- Evidence based recommendations on optimizing colonoscopy adenoma detection rate

Colorectal cancer is one of the three most frequent causes of cancer deaths in men and women in Europe and North America. Diagnosis and resection of adenomas has convincingly demonstrated its utility in diminishing colorectal cancer incidence. Therefore, colonoscopy is now the gold standard for colorectal cancer screening. But it is also known that colonoscopy effectiveness varies among endoscopists. Among different quality indicators, the most used is the adenoma detection rate(ADR) which is the percentage of average-risk patients for colorectal cancer who are found to have at least one adenoma or adenocarcinoma during a screening colonoscopy. There is compelling evidence supporting an inverse correlation between ADR and interval colorectal cancer(cancer found after a screening colonoscopy). Many factors such as quality of precolonoscopy preparation, additional observers, manoeuvres with the endoscope(second view, retroflexion, water inflation rather than air), time spent during withdrawal, changes in patient position, foldflattener devices, new imaging or endoscopic modalities and use of intravenous or through the scope sprayed drugs, have been studied and developed with the aim of increasing the ADR. This reviews discusses these factors, and the current evidence, to "see better" in the colon and optimize ADR.     

Conscious or unconscious: the impact of sedation choice on colon adenoma detection

AIM: To determine if anesthesiologist-monitored useof propofol results in improved detection of adenomaswhen compared with routine conscious sedation. METHODS: This retrospective study was conductedat two separate hospital-based endoscopy units whereapproximately 12 000 endoscopic procedures are permed annually, with one endoscopy unit exclusivelyusing anesthesiologist-monitored propofol. Three thousand two hundred and fifty-two patients underwent initial screening or surveillance colonoscopies. Our primary...     

Impact of looping on premalignant polyp detection during colonoscopy

BACKGROUNDThe presence of premalignant polyps on colonoscopy is an indicator of metachronous colorectal cancer. Looping during colonoscopy is associated with old age, female sex, and colonoscopy insertion time. However, the clinical significance of looping is not fully understood. We aimed to clarify the effect of looping on colorectal premalignant polyp detection.AIMTo assess the effects of looping on premalignant polyp detection using logistic regression analyses.METHODSWe retrospectively investigated patients who underwent colonoscopy at Toyoshima Endoscopy Clinic between May, 2017 and October, 2020. From the clinic’s endoscopy database, we extracted data on patient age, sex, endoscopist-assessed looping, colonoscopy duration, endoscopist experience, detection rate, and number of premalignant polyps.RESULTSWe assessed 12259 patients (mean age, 53.6 years; men, 50.7%). Looping occurred in 54.3% of the patients. Mild and severe looping were noted in 4399 and 2253 patients, respectively. The detection rates of adenomas, advanced adenomas, high-risk adenomas, clinically significant serrated polyps (CSSPs), and sessile serrated lesions (SSLs) were 44.7%, 2.0%, 9.9%, 8.9% and 3.5%, respectively. The mean numbers of adenomas and SSLs were 0.82 and 0.04, respectively. The detection rates of adenomas, high-risk adenomas, and CSSPs increased with looping severity (all P < 0.001). The number of adenomas increased with looping severity (P < 0.001). Multivariate analyses found that detection of adenomas, high-risk adenomas, and CSSPs was associated with severe looping (P < 0.001, P < 0.001, and P = 0.007, respectively) regardless of age, sex, time required for colonoscope insertion and withdrawal, and endoscopist experience.CONCLUSIONLooping severity was independently associated with high detection rates of premalignant polyps. Therefore, looping may predict the risk of metachronous colorectal cancer. Endoscopists should carefully examine the colorectum of patients with looping.     

Endoscopic innovations to increase the adenoma detection rate during colonoscopy

Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope^® may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.     

Use of artificial intelligence in improving adenoma detection rate during colonoscopy: Might both endoscopists and pathologists be further helped

Colonoscopy remains the standard strategy for screening for colorectal cancer around the world due to its efficacy in both detecting adenomatous or precancerous lesions and the capacity to remove them intra-procedurally. Computeraided detection and diagnosis(CAD), thanks to the brand new developed innovations of artificial intelligence, and especially deep-learning techniques, leads to a promising solution to human biases in performance by guarantying decision support during colonoscopy. The application of CAD on real-time colonoscopy helps increasing the adenoma detection rate, and therefore contributes to reduce the incidence of interval cancers improving the effectiveness of colonoscopy screening on critical outcome such as colorectal cancer related mortality. Furthermore, a significant reduction in costs is also expected. In addition, the assistance of the machine will lead to a reduction of the examination time and therefore an optimization of the endoscopic schedule. The aim of this opinion review is to analyze the clinical applications of CAD and artificial intelligence in colonoscopy, as it is reported in literature, addressing evidence, limitations, and future prospects.     

A simple method to improve adenoma detection rate during colonoscopy: Altering patient position

BACKGROUND:

Colonoscopy is currently considered to be the gold standard method for detecting and removing adenomatous polyps. However, tandem colonoscopy studies reveal a pooled polyp miss rate of 22%.

OBJECTIVE:

A prospective randomized trial was conducted to assess whether alteration of patient position during colonoscopy withdrawal increases the adenoma detection rate (ADR).

METHOD:

The study group included 120 patients who presented for elective colonoscopic examination. After reaching the cecum, patients were randomly assigned in a 1:1 ratio to examination in either the left lateral position or other positions (left lateral position for the cecum, ascending colon and hepatic flexure; supine for transverse colon; and supine and right lateral position for splenic flexure, descending and sigmoid colon) first. Examination of the colon was performed segment by segment. The size, morphology and location of all polyps were recorded. Polyps were removed immediately after examination of a colon segment when all positions were completed. ADR and polyp detection rates (PDR) were calculated.

RESULTS:

A total of 102 patients completed the study. Examination in the left lateral position revealed 66 polyps in 31 patients (PDR 30.3%) and 42 adenomas in 24 patients (ADR 23.5%). PDR increased to 43.1% (81 polyps in 44 patients) and the ADR to 33.3% (53 adenomas in 34 patients) after the colon was examined in the additional positions (P<0.001 and P=0.002, respectively). The increase in the number of adenomas detected was statistically significant in the transverse and sigmoid colon. The addition of position changes led to a 9.8% increase in the ADR in the transverse colon, splenic flexure, and descending and sigmoid colon. The frequency of surveillance interval was shortened in nine (8.8%) patients after examination of the colon in dynamic positions.

CONCLUSION:

Alteration of patient position during colonoscopy withdrawal is a simple and effective method to improve ADR.     

Comparison of adenoma detection rate and adenoma per colonoscopy as a quality indicator of colonoscopy

Background: Although adenoma detection rate (ADR) has been proposed as a quality indicator of colonoscopies, adenomas per colonoscopy (APC) is a promising alternative to ADR, as it reflects inspection over the entire length of the colon. This study investigated the correlation between ADR and APC, and compared the efficacy of ADR and APC based on the correlation of each with the advanced adenoma detection rate (AADR).

Study: Two prospectively collected databases, including the 1142 subjects who underwent screening colonoscopies by 28 colonoscopists, were retrospectively reviewed. AADR1 were definded as the proportion of participants having advanced neoplasms, and AADR2 were definded as the proportion of participants having advanced neoplasms or three or more adenomas. Pearson correlation and Steiger’s z-test was used to evaluate the relationship between ADR-APC, ADR-AADR and APC-AADR.

Results: The ADRs ranged from 16.67 to 66.67% (mean, 37.29%) and APCs ranged from 0.22 to 1.28 (mean, 0.65). The ADR and APC showed a significant correlation (R?=?0.82; p?R?=?0.60; p?=?0.001 and R?=?0.64; p?R?=?0.65; p?R?=?0.77; p?p?=?0.04).

Conclusions: Colonoscopists’ ADRs and APC were significantly correlated. Moreover, as the correlation coefficient for AADR was higher with APC than it was with ADR, APC might be a better quality indicator of colonoscopy than ADR.     

Risk of proximal colorectal neoplasia among asymptomatic patients with distal hyperplastic polyps

PURPOSE: Many guidelines on colorectal cancer screening do not consider distal hyperplastic polyps to be a marker for proximal neoplasia. However, 11 of 17 published studies have shown an increased risk of proximal neoplasia in patients with distal hyperplastic polyps. Our goal is to assess the risk of proximal neoplasia in asymptomatic patients with distal hyperplastic polyps, compared to those with distal tubular adenomas or no distal polyps. METHODS: We assessed proximal (cecum, ascending, transverse colon and splenic flexure) and distal polyps in patients undergoing screening colonoscopy, classifying them into 3 groups: distal hyperplastic polyps only; distal adenomas with or without hyperplastic polyps; no distal polyps. The prevalence of proximal neoplasia and advanced neoplasia (polyps > or =1 cm, villous adenomas, or cancer) was compared among these groups. RESULTS: Of 2357 patients, 427 (18%) had neoplasia, including 103 (4%) with advanced neoplasia. Proximal neoplasia occurred in 175 (9%) of 1896 patients with no distal polyps, compared with 28 (12%) of 237 with distal hyperplastic polyps (P = 0.20) and 64 (29%) of 224 with distal adenomas (P <0.0001). Proximal advanced neoplasia occurred in 39 (2%) patients with no distal polyps, compared with 4 (2%) with distal hyperplastic polyps (P = 0.70) and 9 (4%) with distal adenomas (P = 0.13). CONCLUSIONS: Patients with distal hyperplastic polyps, unlike those with distal adenomas, do not exhibit an increased risk for proximal neoplasia or proximal advanced neoplasia compared to those with no distal polyps. The discovery of hyperplastic polyps on screening sigmoidoscopy should not prompt colonoscopy.     

Rectosigmoid findings are not associated with proximal colon cancer： Analysis of 6 196 consecutive cases undergoing total colonoscopy

AIM: To review the risk of proximal colon cancer in patients undergoing colonoscopy. METHODS: We estimated the risk of advanced proximal adenomas and cancers in 6 196 consecutive patients that underwent colonoscopy (mean age 60 years, 65% males, without prior history of colorectal examination). Neoplasms were classified as diminutive adenoma (5 mm or less), small adenoma (6-9 mm), advanced adenoma (10 mm or more, with villous component or high-grade dysplasia) and cancer (invasive adenocarcinoma). The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal colon (from cecum to descending colon). RESULTS: The trend of the prevalence of advanced proximal adenoma was to increase with severe rectosigmoid findings, while the prevalence of proximal colon cancer did not increase with severe rectosigmoid findings. Among the 157 patients with proximal colon cancer, 74% had no neoplasm in the rectosigmoid colon. Multivariate logistic-regression analysis revealed that age was the main predictor of proximal colon cancer and existence of rectosigmoid adenoma was not a predictor of proximal colon cancer. CONCLUSION: Sigmoidoscopy is inadequate for colorectal cancer screening, especially in older populations.     

Inter-centre variability of the adenoma detection rate: A prospective,multicentre study

Background

Suboptimal colonoscopy quality is related to a higher risk of interval cancer. Aim of our study was to explore the variability in detection rate of neoplasia among different endoscopic centres in an unselected population.

Methods

Consecutive patients referred for colonoscopy in 28 Italian centres were included. Detection rate for polyp, neoplasia and advanced neoplasia was assessed at both the individual and centre level. Inter-centre variability in detection rate of colorectal lesions was explored after adjusting for patient-related factors at multivariate analysis.

Results

3150 patients were included. Median detection rates for polyp, neoplasia and advanced neoplasia were 35%, 26% and 13%. At multivariate analysis, patient-related factors associated with neoplasia detection were age, sex, alcohol and smoking history. After adjusting for these variables, a statistically significant difference in the observed/expected ratio among different centres was observed (Chi-squared test: p < 0.01). Among non-patient-related factors, documentation of withdrawal time was associated with neoplasia detection. However, a statistically significant inter-centre variability also remained after adjusting for this variable.

Conclusions

A wide variability was present in the detection rate of neoplasia and advanced neoplasia at the level of endoscopic centres in an unselected population. The adoption of a centre-related neoplasia detection rate could be suggested as a performance indicator.     

Hypertriglyceridemia is positively correlated with the development of colorectal tubular adenoma in Japanese men

AIM: To determine the real association between serum lipid levels and colonic polyp formation. METHODS: We performed a large scale retrospective study to analyze the correlation between the incidence of colorectal adenoma or carcinoma and the fasting serum levels of total cholesterol (TC) and triglycerides (TG) in patients who underwent total colonoscopy for screening for colon cancer. RESULTS: Both levels were significantly elevated in patients with adenomas as compared with patients without any neoplastic lesion (TC 207.6+/-29.5 vs 199.5+/-34.3, n=4883, P<0.001; TG 135.0+/-82.2 vs 108.7+/-71.5, n=4874, P<0.001). The difference was significant in patients with tubular adenoma but not in those with villous or serrated adenoma. Multiple logistic regression analysis including age and sex revealed that TG was an independent correlation factor in male (P<0.01), but not in female patients. The level of TG in patients with invasive carcinoma did not show a significant elevation from that in patients with adenoma. These findings suggest that hypertriglyceridemia is an independent risk factor for colonic adenoma in men. CONCLUSION: Although a high level of serum triglyceride does not appear to be mechanically involved in the development of carcinoma, reduction of serum TG and intensive surveillance with total colonoscopy may have benefit in men with hypertriglyceridemia.     

Narrow band imaging vs. high definition colonoscopy for detection of colorectal adenomas in patients with positive faecal occult blood test: A randomised trial

BackgroundThe impact of narrow band imaging in improving the adenoma detection rate in a screening scenario is still unclear.AimTo evaluate whether narrow band imaging compared with high definition white light colonoscopy can enhance the adenoma detection rate during screening colonoscopy.MethodsConsecutive patients presenting for screening colonoscopy were included into this study and were randomly assigned to the narrow band imaging group (Group 1) or standard colonoscopy group (Group 2). Primary end point was the adenoma detection rate and secondary aim was the detection rate of advanced adenomas.ResultsOverall, 117 patients were allocated to Group 1 and 120 to Group 2. Both the adenoma detection rate and the detection rate of advanced adenomas were not significantly different between the two groups (respectively, 52.1% vs. 55%, RR = 0.95, 95% CI 0.75–1.20; 32.5% vs. 44.2%, RR = 0.74, 95% CI 0.53–1.02). No significant difference between the proportions of polypoid and flat adenomas was found. Male gender, no prior history of screening, and endoscopist's adenoma detection rate were independent predictive factors of higher advanced adenoma detection rate.ConclusionsIn a screening scenario, narrow band imaging did not improve the adenoma nor advanced adenoma detection rates compared to high definition white light colonoscopy.     

基于不同肠段的结肠镜检查人群肠道准备失败现状及影响因素分析

目的研究不同肠段发生肠道准备失败的现状, 并分析其影响因素。方法选取2021年12月—2023年1月在北京协和医院消化内镜中心进行结肠镜检查的677例患者作为研究对象, 患者均采用3 L聚乙二醇电解质散分次剂量的标准化肠道准备方案, 以波士顿肠道准备评分量表对患者的肠道准备情况进行评估, 并通过Logistic回归模型分析不同肠段发生肠道准备失败的影响因素。结果结肠镜检查人群的肠道准备不合格率为31.5%(213/677), 在肠道准备失败人群中, 仅近端肠道失败占85.4%(182/213), 全肠道失败占14.1%(30/213), 仅远端肠道失败仅占0.5%(1/213)。将仅远端肠道失败与全肠道失败合并为发生远端肠道准备失败, Logistic回归分析结果显示:男性(P=0.001, OR=2.253, 95%CI:1.399～3.629)、门诊患者(P<0.001, OR=4.175, 95%CI:2.410～7.231)、无结直肠癌家族史(P=0.001, OR=2.117, 95%CI:1.365～3.284)以及因诊断行结肠镜检查(P=0.003, OR=1.97...