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.     

Colonic polyps diagnosis by conventional video colonoscopes and chromoscopy with indigo carmine dye solution

BACKGROUND: Magnification colonoscopy and contrast chromoscopy with indigo carmine dye solution have been used to differentiate neoplastic polyps (adenomas and adenocarcinomas) from non-neoplastic (hyperplastic, inflammatory, juvenile) in an attempt to obviate endoscopic polypectomy. On the other hand, little published information exists concerning conventional video colonoscopes and chromoscopy for polyp histology prediction. Aim - To assess usefullness of conventional video colonoscopes and contrast chromoscopy with indigo carmine solution for differential diagnosis of colon polyps. METHODS: In a routine colonoscopy series, we performed chromoscopy with conventional video colonoscopes before endoscopic excision of detected polyps. If a sulcus pattern was observed on the surface of the lesion, it was classified as neoplastic. Polyps were classified as non-neoplastic if no sulcus was detected on its surface. These observations were then compared with histology. RESULTS: In the study period (18 months), we detected 133 polyps in 53 patients. We were able to compare results of histology and chromoscopy in 126 lesions. The sensitivity, specificity, diagnostic accuracy, negative predictive value, and positive predictive value were 56,4%, 79,2%, 65,1%, 52,8%, and 81,5%, respectively. CONCLUSION: On the base of the presented data, we concluded that conventional video colonoscopes and contrast chromoscopy with indigo carmine solution is not a good technique for differential diagnosis of colon polyps.     

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.     

High-resolution chromoendoscopy for classifying colonic polyps: a multicenter study

BACKGROUND: Chromoendoscopy may reliably separate adenomatous from nonadenomatous polyps. The aim of this multicenter trial was to determine the accuracy of high-resolution chromoendoscopy for the determination of colonic polyp histology. METHODS: This multicenter trial included 4 academic centers and a primary care practice. In 299 patients referred for routine colonoscopy or sigmoidoscopy, 520 polyps 10 mm in size were sprayed with indigo carmine dye. Using a high-resolution endoscope, the endoscopist predicted the histology of each polyp based on its surface characteristics. Hyperplastic polyps had a "pitted" surface pattern of orderly arranged "dots" that resembled surrounding normal mucosa. Adenomatous polyps had at least one surface "groove" or "sulcus." Each polyp was subsequently resected for histopathologic evaluation. RESULTS: The resected polyps were comprised by 193 adenomas (37%), 225 hyperplastic polyps (43%), and 102 "other" types (20%). Forty polyps (7.7%) could not be classified by high resolution chromoendoscopy with indigo carmine dye. For the remaining polyps, the sensitivity, specificity, and negative predictive value of indigo carmine dye staining for adenomatous polyps were, respectively, 82%, 82%, and 88%. The results were consistent among the academic centers and the primary care practice. CONCLUSIONS: High-resolution chromoendoscopy with indigo carmine dye demonstrates morphologic detail of diminutive colorectal polyps that can reliably be used to separate adenomatous from nonadenomatous polyps.     

Accuracy of high-resolution chromoendoscopy in prediction of histologic findings in diminutive lesions of the rectosigmoid

BACKGROUND: The ability to differentiate adenomatous from nonadenomatous colonic polyps by using chromoendoscopy would obviate the need to remove hyperplastic lesions. The aim of this study was to define the accuracy of high-resolution chromoendoscopy for the determination of colonic polyp histology. METHODS: In 158 patients, 273 polyps (<5 mm) in the rectosigmoid were estimated for their histology. The endoscopists, in two steps, predicted the histopathology of each lesion on the basis of its surface characteristics by using high-resolution colonoscope without any staining and after indigo carmine dye according to the Kudo classification. RESULTS: The resected polyps included 48 adenomatous and 225 nonadenomatous polyps. When histologically confirmed hyperplastic polyps were compared with adenomatous polyps, the prediction of hyperplastic polyps based on endoscopic findings had a sensitivity of 93%, a specificity of 60%, and an overall accuracy of 81%. The corresponding sensitivity, specificity, and overall accuracy after indigo carmine dye were 94%, 64%, and 83%, respectively. CONCLUSIONS: The results suggest that the chromoendoscopy only marginally improves the determination between hyperplastic and adenomatous polyps when using high-resolution colonoscopes. The overall accuracy rate increased after dyeing, from 81% to 83%. The omission of histopathologic analysis cannot yet be achieved by chromoendoscopy.     

A prospective comparative study of narrow-band imaging, chromoendoscopy, and conventional colonoscopy in the diagnosis of colorectal neoplasia

BACKGROUND: Discrimination between neoplastic and non-neoplastic lesions is crucial in colorectal cancer screening. Application of narrow-band imaging (NBI) in colonoscopy visualises mucosal vascular networks in neoplastic lesions and may improve diagnostic accuracy. AIM: To compare the diagnostic efficacy of NBI in differentiating neoplastic from non-neoplastic colorectal lesions with diagnostic efficacies of standard modalities, conventional colonoscopy, and chromoendoscopy. METHODS: In this prospective study, 180 colorectal lesions from 133 patients were observed with conventional colonoscopy, and under low-magnification and high-magnification NBI and chromoendoscopy. Lesions were resected for histopathological analysis. Endoscopic images were stored electronically and randomly allocated to two readers for evaluation. Sensitivity, specificity and diagnostic accuracy of each endoscopic modality were assessed by reference to histopathology. RESULTS: NBI and chromoendoscopy scored better under high magnification than under low magnification in comparison with conventional colonoscopy. The diagnostic accuracy of NBI with low or high magnification was significantly higher than that of conventional colonoscopy (low magnification: p = 0.0434 for reader 1 and p = 0.004 for reader 2; high magnification: p<0.001 for both readers) and was comparable to that of chromoendoscopy. CONCLUSION: Both low-magnification and high-magnification NBI were capable of distinguishing neoplastic from non-neoplastic colorectal lesions; the diagnostic accuracy of NBI was better than that of conventional colonoscopy and equivalent to that of chromoendoscopy. The role of NBI in screening colonoscopy needs further evaluation.     

Chromoendoscopic colonoscopy for detecting preneoplastic lesions in hereditary nonpolyposis colorectal cancer syndrome.

BACKGROUND & AIMS: In hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, flat and small adenomas are particularly prone to malignant transformation but might be missed by standard colonoscopy. We prospectively studied the diagnostic yield of high-resolution colonoscopy coupled with chromoendoscopy for preneoplastic and neoplastic colorectal lesions in patients with HNPCC syndrome. METHODS: Thirty-six consecutive asymptomatic patients (mean age, 42 years) belonging to HNPCC families and receiving genetic counseling were enrolled in this prospective study. Colonoscopy was performed in 2 steps. Conventional colonoscopy was performed first, followed by a second colonoscopy with chromoendoscopy with indigo carmine (.4%) dye sprayed onto the entire proximal colon. RESULTS: Conventional colonoscopy identified 25 lesions (mean size, 4 +/- 3 mm) in 13 patients. Seven lesions, detected in 5 patients, were adenomas, 3 of which were located in the proximal colon. Chromoendoscopy identified additional 45 lesions (mean size, 3 +/- 1 mm) in 20 patients; most of these lesions were flat and hyperplastic. Eleven additional adenomas were detected in the proximal colon of 8 patients, and 8 of these 11 lesions were flat. The use of chromoendoscopy significantly increased the detection rate of adenomas in the proximal colon, from 3 of 33 patients to 10 of 33 patients (P = .045). CONCLUSION: Relative to conventional colonoscopy, high-resolution colonoscopy with chromoendoscopy markedly improves the detection of adenomas in patients with HNPCC syndrome and might help to prevent colorectal carcinoma in these patients with a very high risk of colorectal cancer.     

Conventional colonoscopy and magnified chromoendoscopy for the endoscopic histological prediction of diminutive colorectal polyps： A single operator study

AIM: To accurately differentiate the adenomatous from the non-adenomatous polyps by colonoscopy. METHODS: All lesions detected by colonoscopy were first diagnosed using the conventional view followed by chromoendoscopy with magnification. The diagnosis at each step was recorded consecutively. All polyps were completely removed endoscopically for histological evaluation. The accuracy rate of each type of endoscopic diagnosis was evaluated, using histological findings as gold standard. RESULTS: A total of 240 lesions were identified, of which 158 (65.8%) were non-neoplastic and 82 (34.2%) were adenomatous. The overall diagnostic accuracy of conventional view, and chromoendoscopy with magnification was 76.3% (183/240) and 95.4% (229/240), respectively (P< 0.001) CONCLUSION: The combination of colonoscopy and magnified chromoendoscopy is the most reliable non-biopsy method for distinguishing the non-neoplastic from the neoplastic lesions.     

Improved detection of colorectal neoplasms with selective use of chromoendoscopy in 2005 consecutive patients

Background Colorectal cancer mortality is decreased by endoscopic polypectomy, but conventional colonoscopy may be inadequate for detecting subtle colonic lesions. Methods We selectively performed chromoendoscopy in all patients undergoing colonoscopy between January 1999 and December 2005 at the International Health Union of Rome. Patients with a history of colorectal polyps, inflammatory bowel disease, colorectal surgery or coagulopathy and those with poor bowel preparation were excluded from this analysis. Whenever colonoscopy revealed suspicious mucosal areas, dye-spraying with 0.2% indigo carmine solution was also performed. Findings from conventional and dyespraying views were classified morphologically, and specimens were analyzed histologically. Non-adenomatous lesions were classified as negative findings. Results A total of 2005 patients underwent conventional colonoscopy and in 305 cases (15%) chromoendoscopy was also performed. Conventional colonoscopy identified 508 neoplasms in 381 patients (19%). Selective chromoendoscopy found an additional 244 neoplasms in 212 patients (11%). Thus, chromoendoscopy was positive in 212 (70%) of 305 patients in whom the examination was performed. Overall, 56 large, ulcerated, advanced cancers and 696 non-advanced neoplasms were found. Of the 696 nonadvanced neoplasms, 448 (65%) were polypoid and 248 (35%) were non-polypoid. All but 4 non-polypoid lesions were only detected with chromoendoscopy. Of the 248 non-polypoid lesions, 12 (5%) were depressed and 236 (95%) were flat. Advanced histology was present in 39 non-polypoid lesions (15%) and was more common in depressed lesions than in flat ones (58% vs. 13%; p<0.001). Conclusions Our study confirms the existence of flat and depressed neoplasms in an Italian population. The vast majority of non-polypoid lesions were only detected by chromoendoscopy, and many lesions with advanced histology were missed by conventional colonoscopy. We therefore recommend selectively performing chromoendoscopy when conventional colonoscopy provides clues for non-polypoid lesions. Therefore, endoscopists should be trained in the detection of these subtle mucosal clues, as well as in the use of chromoendoscopy to enhance their detection. An erratum to this article is available at .     

Validation of Fujinon intelligent chromoendoscopy with high definition endoscopes in colonoscopy

AIM: To validate high definition endoscopes with Fujinon intelligent chromoendoscopy (FICE) in colonoscopy.METHODS: The image quality of normal white light endoscopy (WLE), that of the 10 available FICE filters and that of a gold standard (0.2% indigo carmine dye) were compared.RESULTS: FICE-filter 4 [red, green, and blue (RGB) wavelengths of 520, 500, and 405 nm, respectively] provided the best images for evaluating the vascular pattern compared to white light. The mucosal surface was best assessed using filter 4. However, the views obtained were not rated significantly better than those observed with white light. The “gold standard”, indigo carmine (IC) dye, was found to be superior to both white light and filter 4. Filter 6 (RGB wavelengths of 580, 520, and 460 nm, respectively) allowed for exploration of the IC-stained mucosa. When assessing mucosal polyps, both FICE with magnification, and magnification following dye spraying were superior to the same techniques without magnification and to white light imaging. In the presence of suboptimal bowel preparation, observation with the FICE mode was possible, and endoscopists considered it to be superior to observation with white light.CONCLUSION: FICE-filter 4 with magnification improves the image quality of the colonic vascular patterns obtained with WLE.     

High resolution chromoendoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps

BACKGROUND: Magnifying colonoscopy brought the possibility of precise histologic diagnosis of colorectal lesions through their surface appearance. Despite the high accuracy of magnifying colonoscopy it is a specialized and expensive equipment not available in most medical centers. Due to these reasons the use of conventional colonoscopy with chromoscopy has been raised because this produce can reproduce most of the information previously obtained by magnifying colonoscopy. AIM: To determine the role of high resolution colonoscopy and indigo carmine chromoscopy for differential diagnosis between neoplastic and non-neoplastic colorectal lesions through measurements of accuracy, sensitivity, specificity, positive and negative predictive values. PATIENTS / METHODS: It was performed a prospective study. Seventy-four colorectal polyps were evaluated in 54 patients. A high resolution Olympus Exera CFQ 160L colonoscope was used. After the identification of the lesions, they were dyed with indigo carmine 0,2% and classified according to Kudo's classification by a single observer. After resection, the polyps were submitted to histopathological examination. RESULTS: The endoscopic findings were compared to histopathologic results. The accuracy of the method was 79,7%, sensibility of 88,8%, specificity of 55%, positive predictive value of 84,2% and a negative predictive value of 64,7%. CONCLUSION: We can conclude that we must be careful to apply high resolution colonoscopy and chromoscopy because adenomatous lesions can be misdiagnosed as non-neoplastic.     

Advanced diagnostic tools: virtual colonoscopy and magnifying chromoendoscopy

Early endoscopic diagnosis of colorectal cancers (CRCs) represents the best tool for the reduction of CRC mortality, but the conventional colonoscopic view seems unable to clarify faint changes of colorectal mucosa. For these reasons, during the last few decades, two new techniques have been developed in order to better define, diagnose and treat colorectal lesions: chromoendoscopy (CE) and magnifying chromoendoscopy (MC). The authors herein highlight the benefits of both and compare the results of conventional endoscopy and CE with 0.2% indigo carmine solution, evaluating 995 consecutive selected patients referred for colonoscopy between January 1999 and March 2003 at the International Health Union of Rome. CE showed new neoplastic patterns not detectable with conventional endoscopy in 102 patients (10.2%). The incidence of high-grade dysplasia and early carcinomas was 9.9% for protruded, 13.1% for flat and 60% for depressed lesions. Our comparative study on 995 consecutive selected patients confirmed the existence of flat and depressed neoplasms in Italy and shows the high accuracy rate of CE over conventional endoscopy for the detection of non-polypoid lesions. CE should be used routinely in order to enhance the early diagnosis of CRCs, while MC in experienced hands represents a significant advance in colonoscopic practice improving the diagnosis of every single lesion, enhancing therapeutic efficacy of colorectal tumours.     

Evaluation of autofluorescence colonoscopy for diagnosis of superficial colorectal neoplastic lesions

Background and aim

Autofluorescence (AF) imaging, which can potentially differentiate tissue types based on differences in fluorescence emission, may be useful in the diagnosis and treatment of colorectal malignancies. This study was designed to assess the potential usefulness of AF colonoscopy for evaluating superficial colorectal neoplastic lesions.

Methods

A total of 49 colorectal lesions in 43 patients were investigated. All superficial colorectal neoplastic lesions were identified with white light (WL) colonoscopy. Each detected lesion was investigated by WL colonoscopy, AF colonoscopy, and chromoendoscopy using 0.2% indigo carmine dye. Three endoscopists, blinded to each patient's history, evaluated the still images (as obtained with these three methods) in random order and evaluated their influence on the assessment of lesion visualization. All the lesions were biopsied or resected endoscopically, with the pathological results used as the gold standard.

Results

For visualization of the surface appearance and differences in color of the lesions compared with the surrounding mucosa, AF colonoscopy was superior to WL colonoscopy (p?<?0.01) and comparable to chromoendoscopy (Mann–Whitney U test). For visualization of the circumferential margin, AF colonoscopy was superior to WL colonoscopy (p?<?0.05) but inferior to chromoendoscopy (p?<?0.01).

Conclusions

AF colonoscopy may be a valuable tool for detection and diagnosis of superficial colorectal neoplastic lesions.     

Quest for the best endoscopic imaging modality for computer-assisted colonic polyp staging

BACKGROUND It was shown in previous studies that high definition endoscopy, high magnification endoscopy and image enhancement technologies, such as chromoendoscopy and digital chromoendoscopy [narrow-band imaging(NBI), iScan] facilitate the detection and classification of colonic polyps during endoscopic sessions. However, there are no comprehensive studies so far that analyze which endoscopic imaging modalities facilitate the automated classification of colonic polyps. In this work, we investigate the impact of endoscopic imaging modalities on the results of computer-assisted diagnosis systems for colonic polyp staging.AIM To assess which endoscopic imaging modalities are best suited for the computerassisted staging of colonic polyps.METHODS In our experiments, we apply twelve state-of-the-art feature extraction methods for the classification of colonic polyps to five endoscopic image databases of colonic lesions. For this purpose, we employ a specifically designed experimental setup to avoid biases in the outcomes caused by differing numbers of images per image database. The image databases were obtained using different imaging modalities. Two databases were obtained by high-definition endoscopy in combination with i-Scan technology(one with chromoendoscopy and one without chromoendoscopy). Three databases were obtained by highmagnification endoscopy(two databases using narrow band imaging and one using chromoendoscopy). The lesions are categorized into non-neoplastic and neoplastic according to the histological diagnosis.RESULTS Generally, it is feature-dependent which imaging modalities achieve high results and which do not. For the high-definition image databases, we achieved overall classification rates of up to 79.2% with chromoendoscopy and 88.9% without chromoendoscopy. In the case of the database obtained by high-magnification chromoendoscopy, the classification rates were up to 81.4%. For the combination of high-magnification endoscopy with NBI, results of up to 97.4% for one database and up to 84% for the other were achieved. Non-neoplastic lesions were classified more accurately in general than non-neoplastic lesions. It was shown that the image recording conditions highly affect the performance of automated diagnosis systems and partly contribute to a stronger effect on the staging results than the used imaging modality.CONCLUSION Chromoendoscopy has a negative impact on the results of the methods. NBI is better suited than chromoendoscopy. High-definition and high-magnification endoscopy are equally suited.     

Endoscopic submucosal dissection of multiple flat adenomas in the radiated rectum

We report a case of multiple flat adenomas and cancer of the rectum that occurred 15 years after pelvic irradiation following surgery for uterine cancer. Adenoma borders were diagnosed accurately by magnifying chromoendoscopy, leading to their adequate excision using endoscopic submucosal dissection. This enabled minimal dissection of the irradiated pelvis that would have otherwise been difficult. Furthermore, our approach probably helped minimize loss of bowel function, thereby preserving the patient’s quality of life as much as possible. Pathology of the resected specimens revealed thickened walls of the submucosal layer vessels, indicating chronic radiation proctitis. Pelvic irradiation of the bowel carries a high risk of causing flat adenomas and cancer. Close and long-term surveillance may be useful in such cases, using not only conventional colonoscopy but also chromoendoscopy with indigo carmine dye spray and magnifying endoscopy.     

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.     

Chromoendoscopy and other novel imaging techniques

The newly developed high-resolution and magnification endoscopes offer features that allow more and new mucosal details to be seen. They are commonly used in conjunction with chromoendoscopy. The analysis of mucosal surface details is beginning to resemble histologic examination. More accurate recognition of small flat and depressed neoplastic lesions is possible. Endoscopic prediction of neoplastic and nonneoplastic tissue is possible by analysis of surface architecture of the mucosa, which influences the endoscopic management. For the diagnosis of flat adenomas, chromoendoscopy should be a part of the endoscopist's armamentarium. In inflammatory bowel disease, chromoendoscopy can be used for patients with long-standing UC to unmask flat intraepithelial neoplasia and is likely to become the new standard method for surveillance colonoscopy in the near future. The new detailed images seen with magnifying chromoendoscopy are the beginning of a new era in which advances in optical development, such as confocal endomicroscopy, allow a unique look at detailed cellular structures.     

DIAGNOSTIC ACCURACY OF PIT PATTERN AND VASCULAR PATTERN ANALYSES IN COLORECTAL LESIONS

Background: The aim of this prospective study is to compare the usefulness of magnifying narrow band imaging (NBI) and magnifying chromoendoscopy in the diagnosis of colorectal lesions. Methods: The subjects were 1185 patients who underwent a complete colonoscopic examination and endoscopic or surgical treatment, from January 2006 to February 2008. A total of 1473 lesions were evaluated (53 hyperplastic polyps, 1317 adenomas, 103 submucosally invasive cancers). The digital images with NBI or chromoendoscopy were recorded and diagnosed independently from each other by two endoscopists who were blinded to the final pathological diagnosis. Results: We could differentiate between neoplastic and non‐neoplastic lesions with sensitivity of 88.9%, specificity of 98.5% and accuracy of 98.2% according to the vascular pattern. By recognizing an irregular or sparse pattern with NBI, massively invasive submucosal cancer could be diagnosed with the sensitivity and specificity of 94.9% and 76.0%. Using chromoendoscopy, we could differentiate between neoplastic and non‐neoplastic lesions with sensitivity of 86.8% and specificity of 99.2%. We were able to differentiate between massively invasive cancers and slightly invasive cancers using the pit patterns with sensitivity of 89.7% and specificity of 88.0%. The specificity was superior to that of NBI colonoscopy. Conclusion: Both NBI and chromoendoscopy can be useful for distinguishing between neoplastic and non‐neoplastic lesions. In the diagnosis of submucosal cancer, pit pattern diagnosis was slightly superior to vascular pattern diagnosis. It is desirable to perform chromoendoscopy in addition to NBI for distinguishing between slightly and massively invasive submucosal cancer lesions and determining the treatment.     

Two-Year Incidence of Colon Adenomas Developing after Tandem Colonoscopy

Objective: We attempted to determine an accurate frequency of new polyp growth in a cohort of veteran male patients who were initially cleared of polyps by tandem colonoscopy. Methods: Followup colonoscopy was performed 2 yr after tandem colonoscopy. A polyp was categorized as "new" if it was not located in a segment of the colon or rectum that had harbored a neoplastic polyp of the same histology at tandem colonoscopy, in contradistinction to lesions designated as "same-segment" polyps. Results: Fifty-eight of 90 patients who had tandem colonoscopy as a part of a previous study were available for follow-up colonoscopy for 2 yr. Ninety-one percent had a history of benign neoplastic polyps or cancer. Neoplastic polyps were documented in 52% (95% CI, 45–74%) of patients at followup, and 38% (95% CI, 26–52%) were found to have a total of 31 "new" lesions. All new lesions were tubular adenomas. The largest number of new polyps in an individual patient was four, and the largest new lesion was 20 mm in size with a flat, linear configuration. Most (25/31) new polyps were <5 mm, and the number of neoplastic polyps per patient at follow-up was less than at tandem colonoscopy. Conclusions: Approximately one-half of older, male patients with a history of neoplastic polyps will demonstrate neoplastic polyps at 2 yr. In at least one-third of patients, these appear to be new lesions. In some patients, de novo neoplastic polyps can grow to ≥1 cm within 2 yr.