Endoscopic imaging: emerging optical techniques for the detection of colorectal neoplasia.

PURPOSE OF REVIEW: Advances in bioengineering have spawned various imaging modalities which have revolutionized endoscopy. Some of these technologies provide real-time, high-resolution, subcellular imaging. This review provides an update on these technologies and their role in the evaluation of colorectal neoplasia. RECENT FINDINGS: Narrow band imaging has been shown to visualize capillary patterns in early cancer and is complementary to magnification endoscopy. Optical coherence tomography has been used to evaluate neoplastic progression and distinguish Crohn's from ulcerative colitis. Confocal endomicroscopy has been shown to accurately predict neoplastic changes in polyps and identify areas of neoplasia in patients with colitis. Among the spectroscopic techniques, autofluorescence is best studied in the colon and has been used to identify adenomas and dysplasia in inflammatory bowel disease. Endocytoscopy is a relatively new technology but shows promise in distinguishing neoplastic lesions. SUMMARY: Recently a number of imaging technologies have arisen that have the potential to enhance our detection of colorectal neoplasia. Several of these, such as autofluorescent imaging and narrow band imaging, are 'red flag' techniques which enhance our visualization of mucosal change(s). Complementary technologies, such as confocal endomicroscopy and endocytoscopy, provide subcellular imaging. Combined with a 'red flag' technique, these may transform our approach to colonoscopy, allowing the real-time detection and diagnosis of neoplasia.     

New technologies

Colonoscopy with polypectomy is currently the standard of practice for detecting and removing superficial neoplastic lesions from the colon that may be precursors of colorectal cancer. The technique of colonoscopy is challenging to learn and perform, and may demonstrate a variable and at times suboptimal rate of procedure completion (colonoscope insertion to the level of the cecum) and adenoma (neoplastic polyp) detection rate. In recent years, many alternative but similar techniques have been developed to overcome these issues. Many of them still remain under clinical evaluation even after several years of development and assessment, as they have not yet been accepted into routine practice, whereas others were soon abandoned, even prior to their introduction into clinical practice. Other procedures that provide a complete and thorough examination of the entire large bowel are currently available and have already entered routine clinical practice (computed tomography colonography and magnetic resonance colonography), whereas some are in the early phase of clinical investigation (colon capsule endoscopy), while others are already in use but require standardization (water-aided colonoscopy).     

Magnifying colonoscopy as a non-biopsy technique for differential diagnosis of non-neoplastic and neoplastic lesions

AIM: To clarify whether mucosal crypt patterns observed with magnifying colonoscopy are feasible to distinguish non-neoplastic polyps from neoplastic polyps. METHODS: From June 1999 through March 2000, 180 consecutive patients with 210 lesions diagnosed with a magnifying colonoscope (CF-200Z, Olympus Optical Co., Ltd., Tokyo, Japan) were enrolled. Magnification and chromoendoscopy with 0.2% indigo-carmine dye was applied to each lesion for mucosal crypt observation. Lesions showing typesⅠandⅡcrypt patterns were considered non-neoplastic and examined histologically by biopsy, whereas lesions showing typesⅢtoⅤcrypt patterns were removed endoscopically or surgically. The correlation of endoscopic diagnosis and histologic diagnosis was then investigated. RESULTS: At endoscopy, 24 lesions showed a typeⅠorⅡpit pattern, and 186 lesions showed typeⅢtoⅤpit patterns. With histologic examination, 26 lesions were diagnosed as non-neoplastic polyps, and 184 lesions were diagnosed as neoplastic polyps. The overall diagnostic accuracy was 99.1% (208/210). The sensitivity and specificity were 92.3% (24/26) and 99.8% (184/186), respectively. CONCLUSION: Magnifying colonoscopy could be used as a non-biopsy technique for differentiating neoplastic and non-neoplastic polyps.     

Magnifying colonoscopy in differentiating neoplastic from nonneoplastic colorectal lesions

OBJECTIVE: Because the medical management of persons with adenomatous colorectal polyps differs from that of those with hyperplastic polyps, accuracy of diagnosis is essential. This study reports our experience using a magnifying colonoscope combined with indigocarmine dye to diagnose colorectal polyps, emphasizing its ability to differentiate neoplastic from nonneoplastic lesions. METHODS: The materials consisted of 175 polyps. A 0.2% indigocarmine solution was sprayed, and the colonoscope zoom apparatus performed a magnified observation after an ordinary colonoscopy identified the lesions. The pit patterns were classified into six categories: I, II, III(L), IIIs, IV, and V according to Kudo's modified classification. RESULTS: The percentages of neoplastic changes in the lesions with pit pattern I, II, III(L), IIIs, IV, and V were 0, 12.2, 69.7, 80, 84.4, and 100%, respectively. The diagnostic sensitivity of neoplastic lesions was 93.8% and specificity was 64.6% when types I and II represented the pit pattern of nonneoplastic lesions and types III(L), IIIs, IV, and V represented neoplastic lesions. The overall diagnostic accuracy in differentiating neoplastic from nonneoplastic lesions was 80.1%. The diagnostic accuracy is not influenced by the size and shape of the lesions. The six neoplastic lesions that were misjudged to be nonneoplastic were histologically adenoma with only mild atypia. CONCLUSIONS: The pit pattern analysis of colorectal lesions by magnifying colonoscopy is a useful and objective tool for differentiating neoplastic from nonneoplastic lesions of the large bowel. In its current state of development, however, this technique is not a substitute for histology.     

Role of chromoendoscopy in colon cancer surveillance in inflammatory bowel disease

Inflammation in the intestine is a well-known risk factor for neoplastic changes in the mucosa. In fact, it has been shown that long-standing ulcerative colitis and colonic Crohn's disease have a significantly increased risk for developing colorectal cancer, although the estimates vary widely between studies. Conventional colonoscopy is effective in detecting polypoid changes in the mucosa. However, it is now generally accepted that neoplastic changes in colitis are frequently flat and depressed, which are easily missed by use of routine colonoscopy. The introduction of chromoendoscopy, especially in combination with magnifying endoscopy, has greatly advanced our means to detect and differentiate neoplastic lesions in the colorectum. Accumulating evidence-based data indicate that implementation of chromoendoscopy into colon cancer surveillance protocols for patients with inflammatory bowel disease is effective. However, the introduction of chromoendoscopy into surveillance programs requires meticulous training and further studies to compare the value of chromoendoscopy to newer endoscopic devices and techniques, such as narrow band imaging.     

A comparison of magnifying and nonmagnifying colonoscopy for diagnosis of colorectal polyps: A prospective study

BACKGROUND: Discrimination between neoplastic and non-neoplastic colorectal polyps is essential for determining appropriate treatment. The mucosal crypt pattern of polyps can be observed with a nonmagnifying colonoscope; however, mucosal crypt patterns are better seen by magnifying colonoscopy, which can also be a noninvasive means for predicting histopathology. This study prospectively compared the ability to distinguish between neoplastic and non-neoplastic lesions by magnifying and nonmagnifying colonoscopy. METHODS: Six hundred sixty patients were randomly assigned to undergo magnifying or nonmagnifying colonoscopy (2 groups each of 330 patients). The mucosal crypt pattern of colorectal lesions was classified into types I through V after spraying with 0.2% Indigo carmine dye. The histopathology of all lesions was confirmed by evaluation of endoscopic resection specimens or biopsy specimens. Only lesions 10 mm or less in diameter were included in the study. RESULTS: The accuracy of magnifying colonoscopy in distinguishing neoplastic from non-neoplastic lesions (92%, 372/405) was significantly higher than for nonmagnifying colonoscopy (68%, 278/407). Insertion of magnifying and nonmagnifying colonoscopes to the cecum was successful in, respectively, 321 patients (97%) and 317 patients (96%), with no significant differences in the average time to reach the cecum or average total procedure time. No serious complication was observed during or immediately after the examinations. CONCLUSIONS: Observation of mucosal crypt pattern with magnifying colonoscopy is superior to nonmagnifying colonoscopy for distinguishing between neoplastic and non-neoplastic colorectal lesions.     

Endoscopic detection of early lower gastrointestinal cancer

The prognosis for patients with malignancies of the lower gastrointestinal tract is strictly dependent on early detection of premalignant and malignant lesions. What should an ideal screening and surveillance colonoscopy be able to accomplish? The technique should allow detection of large but also discrete mucosal alterations. Ideally, endoscopic discrimination between neoplastic and non-neoplastic lesions would be possible during the ongoing procedure. At present, endoscopy can be performed with powerful new endoscopes. Comparable to the rapid development in chip technology, the optical features of the newly designed endoscopes offer resolutions, which allow new surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool video colonoscopy is much easier and more impressive today than with the previously used fibre-optic endoscopes. Recently, new endoscopic technologies such as narrow band imaging, endocytoscopy, or confocal laser endoscopy have allowed the discovery of a whole new world of image details which will surely improve the diagnostic yield in the field of early malignancies. This review summarises newly available technologies and clinical data about the diagnosis of early lower gastrointestinal cancers.     

High-definition and filter-aided colonoscopy

New high-resolution colonoscopes and filter technologies are allowing us to visualize more lesions and better characterize lesions within the gastrointestinal tract. In light of recent findings that flat and serrated lesions are more likely to contain invasive cancer and that even small lesions (5-10 mm) may contain advanced histology, detecting these lesions earlier with improved optical technologies may help decrease the rate of interval cancers after colonoscopy. With the limited accuracy of white-light colonoscopy (59%-84%) in distinguishing non-neoplastic lesions from neoplastic lesions, these new technologies can help us improve our abilities to risk stratify patients and determine more precise surveillance intervals.     

Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps

AIM: To identify the feasibility of the narrow-band imaging (NBI) method compared with that of conventional colonoscopy and chromoendoscopy for distinguishing neoplastic and nonneoplastic colonic polyps. METHOD: This study enrolled consecutive patients who underwent colonoscopy using a conventional colonoscope between January and February 2006 at Chang-Gung Memorial Hospital, Linkou Medical Center, Taiwan. These 78 patients had 110 colorectal polyps. During the procedure, conventional colonoscopy first detected lesions, and then the NBI system was used to examine the capillary networks. Thereafter indigo carmine (0.2%) was sprayed directly on the mucosa surface prior to evaluating the crypts using a conventional colonoscope. The pit patterns were characterized using the classification system proposed by Kudo. Finally, a polypectomy or biopsy was performed for histological diagnosis. RESULTS: Of the 110 colorectal polyps, 65 were adenomas, 40 were hyperplastic polyps, and five were adenocarcinomas. The NBI system and pit patterns for all lesions were analyzed. For differential diagnosis of neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic) polyps, the sensitivity of the conventional colonoscope for detecting neoplastic polyps was 82.9%, specificity was 80.0% and diagnostic accuracy was 81.8%, significantly lower than those achieved with the NBI system (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%) and chromoendoscopy (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%). Therefore, no significant difference existed between the NBI system and chromoendoscopy during differential diagnosis of neoplastic and nonneoplastic polyps. CONCLUSION: The NBI system identified morphological details that correlate well with polyp histology by chromoendoscopy.     

Efficacy of magnifying endoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps of the large bowel

PURPOSE: We have introduced magnifying colonoscopy into clinical practice and analyzed its diagnostic efficacy, especially regarding the ability to distinguish neoplastic from non-neoplastic polyps. METHODS: The materials consisted of 923 polyps. After identifying the lesions during normal colonoscopy, a dye was sprayed, and then the zoom apparatus of the colonoscope was used to make a magnified observation at a maximum 100 times magnification. We classified the crypt orifices into six categories and labeled them A to F as follows: A, a medium round appearance; B, an asteroid appearance; C, an elliptic appearance; D, a small, round appearance; E, a cerebriform appearance; F, no apparent structural appearance. RESULTS: Forty-two of 923 polyps did not reveal any clear images of crypt patterns. The percentage of histologically neoplastic change in the lesions classified as A, B, C, D, E, and F were 10, 15.9, 93.7, 100, 94.8, and 87.5 percent, respectively. When we considered types A and B to represent a crypt pattern of non-neoplastic lesions, and types C, D, E, and F to represent neoplastic lesions, and when the lesions that did not show any clear images were classified as a misjudgment, the diagnostic accuracy of neoplastic lesions (sensitivity) was 92 percent and that of non-neoplastic lesions (specificity) was 73.3 percent. Overall, the diagnostic accuracy in differentiating neoplastic from non-neoplastic lesions was 88.4 percent. Twenty-three neoplastic lesions that were misjudged to be non-neoplastic were histologically adenoma with mild atypia in 22 and adenoma with moderate atypia in 1. CONCLUSION: Magnifying colonoscopy was considered to be useful in determining the indications for colonoscopic removal.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Philadelphia, Pennsylvania, June 22 to 26, 1997.     

窄带成像技术在大肠肿瘤性病变与非肿瘤性病变的鉴别诊断中的价值

目的探讨窄带成像技术(narrow band imaging,NBI)在大肠肿瘤性病变与非肿瘤性病变的鉴别诊断中的价值。方法收集2010年1月-2013年10月在梧州红十字会医院内镜室进行结肠镜检查的患者98例,通过普通肠镜、NBI检查结果与病理学检查结果进行对比分析,鉴别诊断大肠肿瘤性病变与非肿瘤性病变。结果 98例患者中共发现136个病变。普通内镜诊断肿瘤性病变的敏感性、特异性及准确性分别为75.5%、78.6%及76.5%;NBI诊断肿瘤性病变的敏感性、特异性及准确性分别为95.7%、95.2%及95.6%,后者明显高于前者,差异有统计学意义(P0.01)。病变轮廓、pit及CP显示清晰度比较,NBI明显优于普通内镜,差异均有统计学意义(P0.01)。结论相对于普通内镜,NBI内镜能更清晰地显示病变的轮廓、腺管开口的分型及微血管的形态,在大肠肿瘤性病变与非肿瘤性病变的鉴别诊断中有重要价值。     

Magnifying Endoscopy with Indigo Carmine Contrast for Differential Diagnosis of Neoplastic and Nonneoplastic Colonic Polyps

This study describes the feasibility of magnifying colonoscopy with indigo carmine dye contrast to distinguish neoplastic and nonneoplastic colonic polyps. This study sampled consecutive patients undergoing colonoscopy using an Olympus CF240ZI from January to October 2000 at Chang-Gung Memorial Hospital, Lin-Kou Medical Center. This study analyzed a total of 270 polyps. Indigo carmine (0.2%) was sprayed directly on the mucosa surface before observing the crypts using a magnifying colonoscope (1.5x-100x). The pit patterns were described using the classification proposed by Kudo. Finally, polypectomy or biopsy was performed for histological diagnosis. The study identified 155 adenomas, 99 hyperplastic polyps, 9 adenocarcinomas, and 7 other nonneoplastic lesions (harmatoma, inflammatory polyps, and mucosal tag). The pit pattern was analyzed for all lesions. Further classification into neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic and others) polyps revealed 156 neoplastic and 14 nonneoplastic polyps among the type III to type V pits and 92 nonneoplastic and 8 neoplastic polyps among the type I and II pits. The sensitivity of type III to type V pits in detecting neoplastic polyps was 95.1%, with a specificity of 86.8% and diagnostic accuracy of 91.9%. The positive likelihood ratio was 7.3, and the negative likelihood ratio was 0.06. Magnifying colonoscopy with indigo carmine dye contrast provides morphological detail that correlates well with polyp histology. Small flat lesions with typical type II pit pattern should have minimal neoplastic risk, thus endoscopic resection is not necessary.     

Feasibility of full-spectrum endoscopy:Korea’s first full-spectrum endoscopy colonoscopic trial

AIM: To evaluate the full-spectrum endoscopy(FUSE) colonoscopy system as the first report on the utility thereof in a Korean population.METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects(age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate(PDR), the adenoma detection rate(ADR), and the diverticulum detection rate(DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation.RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon.No colonoscopy was aborted because of colonoscope malfunction.CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.     

A prospective trial of variable stiffness pediatric vs. standard instrument colonoscopy

BACKGROUND: The pediatric variable stiffness colonoscope is believed to have theoretical advantages over the standard colonoscope, however a systematic evaluation of this instrument in routine clinical practice involving adult patients is lacking. METHODS: Consecutive patients (blinded) undergoing colonoscopy in an outpatient endoscopy center by one of 4 experienced colonoscopists had the procedure performed with a standard colonoscope (n=384) or pediatric variable stiffness colonoscope (n=413). Failure to negotiate the sigmoid colon within 10 minutes was regarded as a failure and, if suitable, the patient was crossed over to colonoscopy with the alternative instrument. RESULTS: Median (95% CI) time to the cecum was significantly faster in the pediatric variable stiffness colonoscope group (odds ratio 5.0: 95% CI[4.7,5.3] minutes) compared with the standard colonoscope group (odds ratio 5.5: 95% CI[5.2,5.8] minutes, p=0.01). There were 22 failures overall (2.8%), 14 in the standard colonoscope group (3.6%) and 8 in the pediatric variable stiffness colonoscope group (1.9%; p=0.1). With regard to the 14 failures in the standard colonoscope group, colonoscopy was attempted with the pediatric variable stiffness colonoscope in 13 and completed successfully in 12 (92%). The pediatric variable stiffness colonoscope was superior in cases of severe stenosing diverticular disease; two of 27 examinations with the pediatric variable stiffness colonoscope were rated as failed vs. 12 of 18 with the standard colonoscope (p<0.001). CONCLUSIONS: Intubation time was faster with the pediatric variable stiffness colonoscope, but use of this instrument was not associated with a superior cecal intubation rate compared with the standard colonoscope. However, in patients with severe stenosing diverticular disease, the intubation rate with the pediatric variable stiffness colonoscope was superior.     

Usefulness of pediatric colonoscopes in adult colonoscopy

Use of small diameter, extraflexible pediatric colonoscopes has proved to be valuable in adult endoscopy practice, not only for passing strictures and stomas but also where either fixation due to diverticular disease or postoperative adhesions, or unavoidably painful looping made passage of adult colonoscopes impossible. In 70 of 78 (92%) of the cases where the adult colonoscope could not be passed through the sigmoid colon by an expert endoscopist, the pediatric colonoscope passed through, often very easily. Fifteen of these patients were considered to have been saved surgery by successful passage. The "failure" rate for all colonoscopy examinations was only 2%; this low failure rate was attributable to the use of pediatric instruments whenever passage through the sigmoid colon proved to be impossible with standard colonoscopes. In our opinion every unit performing frequent colonoscopies should have a pediatric colonoscope available for selected adult patients as well as for use in children.     

Indications and techniques for lower intestinal endoscopy

The search for inflammatory and neoplastic lesions are the main indications for colonoscopy. A high rate of detection of polyps has become a quality criterion that depends on skilled handling of the colonoscope, on expertise and concentration during the examination, on excellent bowel preparation, and on a high standard of technical equipment. The diagnostic benefits outweigh the risk of bleeding, perforation and infection in almost all situations. Contraindications are signs of perforated intestine or imminent perforation due to deep ulcerations, necroses, or fulminant colitis. The patient's comorbidity must be considered to assess the physical stress of bowel preparation, colonoscopy and sedation. Informed consent is necessary and must be documented in all cases. It is advisable to explain planned therapeutic manoeuvres before the examination, since all non-invasive polyps must be removed completely. Total colonoscopy is possible in 95-99% of cases, but technical efforts are under way to solve the problem of looping and fixed colon angulations. Optimising optical imaging is another main focus of industrial development. The combination of narrow-band imaging, zoom magnification, and high-definition processor technology is currently the most promising tool for identifying small and flat lesions in the colon.     

Preoperative colonoscopy after self-expandable metallic stent placement in patients with acute neoplastic colon obstruction

BACKGROUND: In patients with colorectal cancer, a preoperative colonoscopy is recommended to exclude synchronous lesions. Unfortunately, between 7% and 29% of patients with colorectal cancer present with acute colonic obstruction, making complete colonoscopy impossible. OBJECTIVE: The aim of our study was to evaluate the feasibility of a preoperative colonoscopy after effective stent placement in patients with acute neoplastic obstruction. DESIGN: Single-center prospective study. SETTING: All examinations were carried out at a tertiary referral center with 24-hour emergency endoscopy service. PATIENTS: Fifty-seven patients with acute neoplastic colon obstruction. INTERVENTIONS: Patients who recovered from an acute colon obstruction by an effective stent placement and who had a resectable cancer underwent a preoperative colonoscopy. MAIN OUTCOME MEASUREMENTS: Patients with a resectable cancer, complete preoperative colonoscopies, and synchronous lesions rates. RESULTS: Self-expandable metallic stents (SEMS) were placed in 50 of 57 patients (87.8%). Thirty-one of 50 patients had a resectable cancer (62%), and a complete preoperative colonoscopy was possible in 29 of 31 patients (93.4%). A synchronous cancer was detected in 3 patients (9.6%), changing the surgical plan. LIMITATIONS: Seven patients in whom the SEMS placement (12.2%) was unsuccessful underwent an urgent surgical intervention. Nineteen of 50 patients who had stent placement were not eligible for our study because of unresectable cancer. CONCLUSIONS: Our study indicates that it is feasible in a majority of patients to perform full preoperative colonoscopy after relief of acute colonic obstruction with SEMS before surgical resection.     

Methods of Reducing Discomfort During Colonoscopy

In the United States sedation for colonoscopy is usual practice. Unsedated colonoscopy is limited to a small proportion of unescorted patients and those with a personal preference for no sedation. Over 80% of patients who accept the option of as-needed sedation can complete colonoscopy without sedation. Colonoscopy in these unsedated patients is performed with techniques similar to those used in the sedated patients. Uncontrolled observations indicate willingness to repeat colonoscopy amongst these patients was correlated significantly with low discomfort score during the examination. Methods reported to minimize patient discomfort or enhance cecal intubation during sedated or unsedated colonoscopy included use of pediatric colonoscope, variable stiffness colonoscope, gastroscope, and inhalation of nitrous oxide or insufflation of carbon dioxide, hypnosis, music, audio distraction, or simply allowing the patients to participate in administration of the medication. Research focusing on confirming the efficacy of a simple inexpensive nonmedication dependent method for minimizing discomfort will likely improve the outcome of care and more importantly will ensure compliance with future surveillance in patients accepting the unsedated option.     

Clinical usefulness of single-balloon endoscopy in patients with previously incomplete colonoscopy

AIM: To evaluate the clinical usefulness of single-balloon endoscopy (SBE) in patients in whom a colonoscope was technically difficult to insert previously.METHODS: The study group comprised 15 patients (8 men and 7 women) who underwent SBE for colonoscopy (30 sessions). The number of SBE sessions was 1 in 7 patients, 2 in 5 patients, 3 in 1 patient, 4 in 1 patient, and 6 in 1 patient. In all patients, total colonoscopy was previously unsuccessful. The reasons for difficulty in scope passage were an elongated colon in 6 patients, severe intestinal adhesions after open surgery in 4, an elongated colon and severe intestinal adhesions in 2, a left inguinal hernia in 2, and multiple diverticulosis of the sigmoid colon in 1. Three endoscopists were responsible for SBE. The technique for inserting SBE in the colon was basically similar to that in the small intestine. The effectiveness of SBE was assessed on the basis of the success rate of total colonoscopy and the presence or absence of complications. We also evaluated the diagnostic and treatment outcomes of colonoscopic examinations with SBE.RESULTS: Total colonoscopy was successfully accomplished in all sessions. The mean insertion time to the cecum was 22.9 ± 8.9 min (range 9 to 40). Abnormalities were found during 21 sessions of SBE. The most common abnormality was colorectal polyps (20 sessions), followed by radiation colitis (3 sessions) and diverticular disease of the colon (3 sessions). Colorectal polyps were resected endoscopically in 15 sessions. A total of 42 polyps were resected endoscopically, using snare polypectomy in 32 lesions, hot biopsy in 7 lesions, and endoscopic mucosal resection in 3 lesions. Fifty-six colorectal polyps were newly diagnosed on colonoscopic examination with SBE. Histopathologically, these lesions included 2 intramucosal cancers, 42 tubular adenomas, and 2 tubulovillous adenomas. The mean examination time was 48.2 ± 20.0 min (range 25 to 90). Colonoscopic examination or endoscopic treatment with SBE was not associated with any serious complications.CONCLUSION: SBE is a useful and safe procedure in patients in whom a colonoscope is technically difficult to insert.