Teaco Kuiper

Endoscopic trimodal imaging detects colonic neoplasia as well as standard video endoscopy.

BACKGROUND & AIMS Endoscopic trimodal imaging (ETMI) is a novel endoscopic technique that combines high-resolution endoscopy (HRE), autofluorescence imaging (AFI), and narrow-band imaging (NBI) that has only been studied in academic settings. We performed a randomized, controlled trial in a nonacademic setting to compare ETMI with standard video endoscopy (SVE) in the detection and differentiation of colorectal lesions. METHODS The study included 234 patients scheduled to receive colonoscopy who were randomly assigned to undergo a colonoscopy in tandem with either ETMI or SVE. In the ETMI group (n=118), first examination was performed using HRE, followed by AFI. In the other group, both examinations were performed using SVE (n=116). In the ETMI group, detected lesions were differentiated using AFI and NBI. RESULTS In the ETMI group, 87 adenomas were detected in the first examination (with HRE), and then 34 adenomas were detected during second inspection (with AFI). In the SVE group, 79 adenomas were detected during the first inspection, and then 33 adenomas were detected during the second inspection. Adenoma detection rates did not differ significantly between the 2 groups (ETMI: 1.03 vs SVE: 0.97, P=.360). The adenoma miss-rate was 29% for HRE and 28% for SVE. The sensitivity, specificity, and accuracy of NBI in differentiating adenomas from nonadenomatous lesions were 87%, 63%, and 75%, respectively; corresponding values for AFI were 90%, 37%, and 62%, respectively. CONCLUSIONS In a nonacademic setting, ETMI did not improve the detection rate for adenomas compared with SVE. NBI and AFI each differentiated colonic lesions with high levels of sensitivity but low levels of specificity.

Accuracy for Optical Diagnosis of Small Colorectal Polyps in Nonacademic Settings

BACKGROUND & AIMS When small colorectal lesions are accurately characterized, adenomas can be removed and discarded without formal histopathology analysis. Previous studies in an academic setting showed that many lesions can be managed accurately on the basis of their endoscopic image (optical diagnosis). We performed a prospective study to assess the accuracy of optical diagnosis of small colorectal polyps in a nonacademic setting (the DISCOUNT trial) by using high-resolution endoscopy (HRE) and narrow-band imaging (NBI). METHODS During colonoscopy, 1 of 3 nonacademic endoscopists characterized small lesions and declared whether this was done with low or high confidence. In cases of high confidence, the endoscopists decided whether lesions should be removed and discarded or whether they could be left in situ. A surveillance interval was then recommended on-site. RESULTS Of 215 patients in the study, 108 were found to have 281 small lesions. Of these lesions, 231 were characterized with high confidence by using HRE or NBI; the level of corresponding sensitivity was 77.0% (95% confidence interval, 68.4-83.8), and specificity was 78.8% (95% confidence interval, 70.6-85.2). Of these lesions, 164 were assigned for removal, and 67 were assigned to remain in situ, including 9 adenomas. In 54 patients, a surveillance interval could be recommended on-site that was in line with Dutch guidelines for 44 patients. CONCLUSIONS Even though many lesions were characterized by HRE or NBI with high confidence, optical diagnosis in a nonacademic setting proved to be disappointing, with a sensitivity of 77.0% and a specificity of 78.8%. Many lesions were accurately assigned to be removed or remain in situ, although few adenomas were assigned to remain in situ. Also, 19% of on-site recommendations for a surveillance interval proved to be inaccurate.

Feasibility and Accuracy of Confocal Endomicroscopy in Comparison With Narrow-Band Imaging and Chromoendoscopy for the Differentiation of Colorectal Lesions

OBJECTIVES:Several advanced imaging techniques have been developed to improve differentiation of colorectal lesions. These techniques need to be assessed for both feasibility and accuracy in order to prove their value in daily clinical practice. The current study assessed the feasibility of probe-based confocal laser endomicroscopy (pCLE) in acquiring videos of sufficient quality. Furthermore, the accuracy of pCLE for the differentiation of colorectal lesions was assessed and compared with narrow-band imaging (NBI) and chromoendoscopy (CE).METHODS:Consecutive patients scheduled for surveillance colonoscopy at our centre were included. All procedures were performed by two expert colonoscopists, who previously participated in studies evaluating pCLE, NBI, and CE. All detected lesions during colonoscopy were differentiated real-time with NBI and CE for Kudo pit pattern. Lesions were also assessed real-time for vascular pattern intensity (VPI) during NBI. Subsequently, pCLE videos of each lesion were acquired and biopsies were taken for histopathology. All pCLE videos were assessed post-hoc for the percentage of time demonstrating sufficient image quality (i.e., depicting at least one crypt or vessel). Finally, pCLE videos were assessed post-hoc for diagnostic accuracy by two experts.RESULTS:A total of 154 lesions detected in 64 patients were included. Accuracy of Kudo pit pattern with NBI for predicting neoplasia (88.7%) was significantly better than accuracy of VPI (77.5%, P=0.05) but not significantly different from CE (89.3%, P=0.125). During pCLE, no histology was shown at all on the video in 19 lesions (12%). The mean time to acquire a pCLE video of the remaining 135 lesions was 50 seconds (s.d. 47) per lesion. The median percentage demonstrating sufficient quality per video was 40.5% (interquartile range 21.2–67.0). Accuracy of pCLE for both observers (66.7 and 71.9%) was significantly lower than accuracy of CE (P<0.001) and NBI (P<0.001).CONCLUSIONS:Video acquisition with pCLE could not be achieved in a small number of lesions. The majority of pCLE videos demonstrated insufficient quality in more than half of the time recorded. Moreover, post-hoc accuracy of pCLE was significantly lower in comparison with real-time accuracy of CE and NBI. Future research should assess whether further increase in experience could improve pCLE video acquisition and determine the real-time accuracy of pCLE for differentiating colorectal lesions.

The learning curve, accuracy, and interobserver agreement of endoscope-based confocal laser endomicroscopy for the differentiation of colorectal lesions

BACKGROUND The endoscope-based confocal laser endomicroscopy (eCLE) system allows in vivo imaging of colorectal epithelium. Little is known about the learning curve for accurate interpretation of confocal images acquired with eCLE. OBJECTIVE To determine the learning curve of eCLE, its diagnostic accuracy, and the intra- and interobserver agreement for the differentiation of colorectal lesions. DESIGN Post hoc assessment of selected eCLE images. SETTING Academic centers. PATIENTS This study involved colonoscopic images from 47 patients. MAIN OUTCOME MEASUREMENTS Learning curve of eCLE, accuracy, and intraobserver and interobserver agreement. METHODS Three endoscopists received a short introduction to eCLE before evaluating 90 images. Observers assessed all eCLE images by using the Mainz classification. After each set of 30 images, the accuracy of each observer was assessed. The same procedure was repeated 6 months later by using the same set of images. LIMITATIONS Post hoc assessment. RESULTS There were no significant changes between the first set of 30 images and the 2 consecutive sets (P = .08 and P = .180, respectively). The overall accuracy was 85.6%, 95.6%, and 92.2% for each observer. The κ values of the intraobserver agreement were 0.68, 0.84, and 0.77 for each observer. The κ value for interobserver agreement was 0.73 during the first and 0.72 during the second assessment. CONCLUSIONS Accurate post hoc interpretation of eCLE confocal images can be learned quickly. High diagnostic accuracy was achieved by all 3 observers during the initial stage of the assessment, which remained high thereafter. Intra- and interobserver agreement was substantial for all 3 observers. Future studies should focus on the real-time assessment of eCLE images.

Study designs to compare new colonoscopic techniques: clinical considerations, data analysis, and sample size calculations

BACKGROUND AND STUDY AIMS Novel imaging techniques need to be evaluated for their ability to improve the detection of polyps. Critical appraisal of reported studies reveals remarkable differences in study designs, despite their similar objectives. The aim of the current study was to compare frequently used study designs for their required sample size to detect relevant differences in polyp detection rates. PATIENTS AND METHODS Three commonly reported study designs were compared: design 1, the parallel randomized design; design 2, the randomized cross-over design with direct removal of polyps; and design 3, the randomized cross-over design without direct removal of polyps. A total of five different scenarios were analyzed per study design, representing a variety of clinical settings. Each scenario was repeated 1000 times for each study design and the sample size that produced a significant result per study design in each scenario was recorded. RESULTS In many scenarios, study design 1 required 10-15 times more patients to reach the same statistical power of 80% compared with study design 2. Further reductions in sample size could be achieved when study design 3 was used, although this design is limited by its impracticality. CONCLUSIONS The randomized parallel design requires a larger sample size to achieve equivalent power to the cross-over design. Researchers should carefully consider whether the latter design could be used instead, as it requires a lower number of subjects, although it may be more cumbersome for patients, endoscopists, and researchers.

The prevalence of dysplasia in the ileoanal pouch following restorative proctocolectomy for ulcerative colitis with associated dysplasia.

Aim  A recent systematic review indicated that dysplasia present before restorative proctocolectomy is a predictor of subsequent dysplasia in the pouch. This prospective study was carried out to assess the prevalence of dysplasia in the ileal pouch in patients having RPC for ulcerative colitis with co‐existing dysplasia in the operation specimen.

Automatic optical diagnosis of small colorectal lesions by laser-induced autofluorescence

BACKGROUND AND STUDY AIMS Endoscopic optical diagnosis can potentially replace histopathological evaluation of small colorectal lesions. The aim of this study was to evaluate diagnostic performance of WavSTAT, a novel system for automatic optical diagnosis based on laser-induced autofluorescence spectroscopy. PATIENTS AND METHODS Consecutive patients who were scheduled for colonoscopy were included in the study. Each detected lesion with a size of ≤ 9 mm was differentiated using high resolution endoscopy (HRE) by the endoscopist, who then reported this as a low or high confidence call. Thereafter, all lesions were analyzed using WavSTAT. Histopathology was used as the reference standard. The primary outcome measures were the accuracy of WavSTAT to differentiate between adenomatous and nonadenomatous lesions, and the accuracy of an algorithm combining HRE (lesions differentiated with high confidence) and WavSTAT (all remaining lesions). The secondary outcome measure was the accuracy of on-site recommended surveillance intervals. RESULTS At total of 87 patients with 207 small colorectal lesions were evaluated. Accuracy and negative predictive value of WavSTAT were 74.4 % and 73.5 %, respectively. The corresponding figures for the algorithm were 79.2 % and 73.9 %, respectively. Accuracy of on-site recommended surveillance interval was 73.7 % for WavSTAT alone and 77.2 % for the algorithm of HRE and WavSTAT. CONCLUSIONS Both accuracy of WavSTAT alone and the algorithm combining HRE with WavSTAT proved to be insufficient for the in vivo differentiation of small colorectal lesions, and do not fulfill American Society for Gastrointestinal Endoscopy performance thresholds for assessment of diminutive lesions. Future studies should assess whether combining WavSTAT with more advanced imaging techniques could result in a higher accuracy.Netherlands Trial Registry (NTR 3235).

Imaging: NBI—detection and differentiation of colonic lesions

Narrow-band imaging (NBI) is a new imaging modality that may improve the effectiveness of endoscopic surveillance and screening. Two recent studies have compared NBI with white light endoscopy; one study demonstrated no difference in adenoma detection rate between the two imaging modalities, the other study demonstrated improved differentiation of lesions with NBI compared with white light endoscopy.

Chromoendoscopy versus autofluorescence imaging for neoplasia detection in patients with longstanding ulcerative colitis (FIND-UC): an international, multicentre, randomised controlled trial

BACKGROUND Patients with longstanding ulcerative colitis undergo regular dysplasia surveillance because they have an increased colorectal cancer risk. Autofluorescence imaging and chromoendoscopy improve dysplasia detection. The aim of this study was to determine whether autofluorescence imaging should be further studied as an alternative method for dysplasia surveillance in patients with longstanding ulcerative colitis. METHODS This prospective, international, randomised controlled trial included patients from an ulcerative colitis-dysplasia surveillance cohort from five centres in the Netherlands and the UK. Eligible patients were aged 18 years or older who were undergoing dysplasia surveillance after being diagnosed with extensive colitis (Montreal E3) at least 8 years before study start or with left-sided colitis (Montreal E2) at least 15 years before study start. Randomisation (1:1) was minimised for a previous personal history of histologically proven dysplasia and concomitant primary sclerosing cholangitis. The coprimary outcomes were the proportion of patients in whom at least one dysplastic lesion was detected and the mean number of dysplastic lesions per patient. The relative dysplasia detection rate, calculated as the ratio of the detection rates by autofluorescence imaging and chromoendoscopy, needed to be more than 0·67 (using an 80% CI) for both primary outcomes to support a subsequent large non-inferiority trial. Outcomes were analysed on a per-protocol basis. The trial is registered at the Netherlands Trial Register, number NTR4062. FINDINGS Between Aug 1, 2013, and March 10, 2017, 210 patients undergoing colonoscopy surveillance for longstanding ulcerative colitis were randomised for inspection with either autofluorescence imaging (n=105) or chromoendoscopy (n=105). Dysplasia was detected in 13 (12%) patients by autofluorescence imaging and in 20 patients (19%) by chromoendoscopy. The relative dysplasia detection rate of autofluorescence imaging versus chromoendoscopy for the proportion of patients with ulcerative colitis with at least one dysplastic lesion was 0·65 (80% CI 0·43-0·99). The mean number of detected dysplastic lesions per patient was 0·13 (SD 0·37) for autofluorescence imaging and 0·37 (1·02) for chromoendoscopy (relative dysplasia detection rate 0·36, 80% CI 0·21-0·61). Adverse events were reported for two patients in the autofluorescence imaging group (one patient had intraprocedural mild bleeding, and one patient had abdominal pain) and for three patients in the chromoendoscopy group (two patients had intraprocedural mild bleeding, and one patient had perforation). INTERPRETATION Autofluorescence imaging did not meet criteria for proceeding to a large non-inferiority trial. Therefore, existing autofluorescence imaging technology should not be further investigated as an alternative dysplasia surveillance method. FUNDING Olympus Europe and Olympus Keymed.

Sa1601 Differentiation of Small Colorectal Lesions; Laser-Induced Autofluorescence Using the Wavstat

However, limited data are available on the validity of endocytoscopy in the diagnosis of gastric disorders. The aim of this prospective study was to evaluate the feasibility of endocytoscopy in the diagnosis of early gastric cancer. Methods: Patients who planned to undergo magnifying endoscopic work-up before or after gastric ESD were eligible. Examination was done with a single CCD integrated endocytoscope. Patients who had gastric lesions that required histopathological diagnosis with biopsy specimen were enrolled and evaluated by endocytoscopy with a double staining of 0.05% crystal violet and 0.1% methylene blue. Endocytoscopic atypia of gland structure was assessed. Structural atypia was defined by the presence of three morphological abnormalities; absence or narrowing of inter-glandular space, glandular fusion and glandular destruction. Endocytoscopic atypia were graded as none, low and high. The primary endpoint was the accuracy of endocytoscopic diagnosis for gastric cancer using histopathological diagnosis of biopsy specimens as the gold standard. Results: 1) Eighty-two lesions in 54 patients were enrolled; 23 early gastric cancers (21 well differentiated type, 2 poorly differentiated type), 10 gastric adenomas, 10 gastric ulcers, 10 gastric erosions, 18 gastric protruded lesions. Eleven points of gastric mucosa surrounding gastric neoplasia were also examined to evaluate neoplasia extent for precise endoscopic resection. 2) Ten lesions could not be well observed by endocytoscopy because of poor staining due to viscous mucus or dense ulcer plaque. The assessable rates with endocytoscopy were 88% (72/ 82) in total and 91% (21/23) in gastric cancer, whereas it was 78% in gastric protruded lesions, especially was low at 50% in hyperplastic polyps.3) High grade of endocytoscopic atypia was observed in 86% of assessable gastric cancers (n 21), whereas high grade of endocytoscopic atypia was not observed in assessable lesions of gastric adenomas and other nonneoplastic lesions. Low grade of endocytoscopic atypia was observed in 78% of assessable gastric adenomas (n 9), 9% of gastric cancer, and 2.3% of nonneoplastic lesions. Using the criterion of high grade-endocytoscopic atypia, sensitivity, specificity, PPV and NPV of endocytoscopic diagnosis for gastric cancer were 86%, 100%, 100% and 94%, respectively. 4) No serious complication occurred during and after the examinations. Conclusion: Endocytoscopy is a clinically feasible modality to obtain in vivo histology with high diagnostic accuracy in gastric cancer.