Mohamed Abdelhafez

Predictors and characteristics of angioectasias in patients with obscure gastrointestinal bleeding identified by video capsule endoscopy

Background In obscure gastrointestinal bleeding, angioectasias are common findings in video capsule endoscopy (VCE). Objective The objective of this study was to identify predictors and characteristics of small bowel angioectasias. Methods Video capsule examinations between 1 July 2001 and 31 July 2011 were retrospectively reviewed. Patients with obscure gastrointestinal bleeding were identified, and those with small bowel angioectasia were compared with patients without a definite bleeding source. Univariate and multivariable statistical analyses for possible predictors of small bowel angioectasia were performed. Results From a total of 717 video capsule examinations, 512 patients with obscure gastrointestinal bleeding were identified. Positive findings were reported in 350 patients (68.4%) and angioectasias were documented in 153 of these patients (43.7%). These angioectasias were mostly located in the proximal small intestine (n = 86, 56.6%). Patients’ age >65 years (odds ratio (OR) 2.15, 95% confidence interval (CI) 1.36–3.38, p = .001) and overt bleeding type (OR 1.89, 95% CI 1.22–2.94, p = .004) were identified as significant independent predictors of small bowel angioectasia. Conclusion Angioectasias are the most common finding in VCE in patients with obscure gastrointestinal bleeding. They are mostly located in the proximal small bowel and are associated with higher age and an overt bleeding type.

Narrow-band imaging vs. high definition white light for optical diagnosis of small colorectal polyps: a randomized multicenter trial.

BACKGROUND AND STUDY AIM The aim of the study was to compare the latest narrow-band imaging (NBI) device with high-definition white light (HDWL) endoscopy for accuracy of real-time optical diagnosis of small colorectal polyps. PATIENTS AND METHODS We conducted a randomized, prospective, multicenter trial at three study sites in Germany. In the NBI arm, endoscopists used NBI for the prediction of polyp pathology on the basis of the NBI International Colorectal Endoscopic classification. In the HDWL arm, NBI was not used for optical classification of polyp histology. The primary outcome was accuracy of optical diagnoses (neoplastic vs. non-neoplastic) in small polyps measuring < 10 mm. Secondary end points included sensitivity and negative predictive value (NPV). RESULTS A total of 380 patients were randomized 1:1 to either the NBI or HDWL arm. A total of 421 polyps measuring < 10 mm were detected (55.8 % neoplastic, 44.2 % non-neoplastic). Accuracy, sensitivity, and NPV were 73.7 %, 82.4 %, and 75.5 %, respectively, in the NBI arm and 79.2 %, 79.8 %, and 73.4 %, respectively, in the HDWL arm (P = 0.225, P = 0.667, P = 0.765). More polyps were assessed with high confidence in the HDWL arm (82.6 %) than in the NBI arm (73.7 %; P = 0.038). The NPV of the prediction of neoplastic histology in diminutive polyps (≤ 5 mm) rated with high confidence was 90.3 % in the NBI arm. We detected significant differences between the participating study sites in the performance data of predictions. CONCLUSION The levels of accuracy for real-time prediction of polyp histology (< 10 mm) did not differ between NBI and HDWL for optical diagnosis. Variation in the performance of optical diagnosis was apparent between study centers. TRIAL REGISTRATION ClinicalTrials.gov (NCT02009774).

Longer observation time increases adenoma detection in the proximal colon – a prospective study

Background and study aims  Longer observation times are associated with increased adenoma detection rates (ADR) in the entire colon. However, adenomas in the proximal colon are at risk of being missed during colonoscopy. The aim of this study was to investigate the impact of observation time on detection of adenomatous polyps in the proximal colon. Patients and methods  This was a prospective study at a university hospital in Germany. Colonoscopies were conducted using magnetic endoscope imaging (MEI) in order to determine the exact position of the scope. Exact observation times spent for the detection of polyps in the proximal and distal colon segments were assessed. The primary outcome was adenoma detection in the proximal colon. ROC curves were generated in order to test the correlation between observation time and adenoma detection. Logistic regression analysis was used to check for interfering factors. Results  A total 480 procedures with 538 polyps were available for analysis. The overall adenoma detection rate was 38.5 %. ADR in the proximal colon was 28.0 %. There was a significant association between observation time in the proximal colon and the detection of proximal adenomas ( P  < 0.001). The impact of the time factor on ADR was stronger in the proximal compared to the distal colon ( P  = 0.030). A net period of 4 min 7 sec was found to be the minimum time span for sufficient adenoma detection in the proximal colon. Conclusion  Observation time is significant in terms of adenoma detection in the proximal colon. The impact of observation time on ADR is stronger in the proximal compared to the distal colon. In the proximal colon a minimum time span of 4 minutes should be spent in order to ensure adequate adenoma detection.

A novel mechanical simulator for cannulation and sphincterotomy after Billroth II or Roux-en-Y reconstruction.

Introduction: In patients with Billroth II (B II) or Roux-en-Y anatomy, endoscopic retrograde cholangiopancreatography (ERCP) is demanding. Here, we describe a novel simulator with simulated fluoroscopy for cannulation and sphincterotomy training in such situations. Methods: A custom-made simulation system was built based upon a common chassis of a series of previously described ERCP simulators. The papilla is made out of organic material and can be cut by high frequency current. The advancement of guidewires and other instruments within transparent mock bile ducts can be viewed in the window of the simulator without the need for fluoroscopy. The ERCP B II/Roux-en-Y simulation system was first evaluated during an ERCP course. Results: There were no technical problems related to the novel simulator during the course. After sphincterotomy, the organic papillae could easily be exchanged within a few seconds. Overall, the novel B II/Roux-en-Y simulator achieved favorable results by trainees and expert endoscopists in all categories assessed. Conclusions: The new B II/Roux-en-Y mechanical simulator is simple and practicable. A first evaluation during an ERCP course showed promising results.

Optical classification of neoplastic colorectal polyps – a computer-assisted approach (the COACH study)

Abstract Background and aims: Clinical data suggest that the quality of optical diagnoses of colorectal polyps differs markedly among endoscopists. The aim of this study was to develop a computer program that was able to differentiate neoplastic from non-neoplastic polyps using unmagnified endoscopic pictures. Methods: During colonoscopy procedures polyp photographies were performed using the unmagnified high-definition white light and narrow band image mode. All detected polyps (n = 275) were resected and sent to pathology. Histopathological diagnoses served as the ground truth. Machine learning was used in order to generate a computer-assisted optical biopsy (CAOB) approach. In the test phase pictures were presented to CAOB in order to obtain optical diagnoses. Altogether 788 pictures were available (602 for training the machine learning algorithm and 186 for CAOB testing). All test pictures were also presented to two experts in optical polyp characterization. The primary endpoint of the study was the accuracy of CAOB diagnoses in the test phase. Results: A total of 100 polyps (of these 52% neoplastic) were used in the CAOB test phase. The mean size of test polyps was 4 mm. Accuracy of the CAOB approach was 78.0%. Sensitivity and negative predictive value were 92.3% and 88.2%, respectively. Accuracy obtained by two expert endoscopists was 84.0% and 77.0%. Regarding accuracy of optical diagnoses CAOB predictions did not differ significantly compared to experts (p = .307 and p = 1.000, respectively). Conclusions: CAOB showed good accuracy on the basis of unmagnified endoscopic pictures. Performance of CAOB predictions did not differ significantly from experts’ decisions. The concept of computer assistance for colorectal polyp characterization needs to evolve towards a real-time application prior of being used in a broader set-up.

Comparison of cap-assisted endoscopy vs. side-viewing endoscopy for examination of the major duodenal papilla: a randomized, controlled, noninferiority crossover study

BACKGROUND : Use of a side-viewing endoscope is currently mandatory to examine the major duodenal papilla; however, previous studies have used cap-assisted endoscopy for complete examination of the papilla. The aim of this study was to compare cap-assisted endoscopy with side-viewing endoscopy for examination of the major duodenal papilla. METHODS : This was a prospective, randomized, blinded, controlled, noninferiority crossover study. Patients were randomized to undergo either side-viewing endoscopy followed by cap-assisted endoscopy or cap-assisted endoscopy followed by side-viewing endoscope. Photographs of the major duodenal papilla were digitally edited to mask the cap area before they were evaluated by three blinded external examiners. Our primary end point was complete visualization of the major duodenal papilla. Secondary end points were the ability to examine the mucosal pattern, the overview of the periampullary region, overall satisfaction, and time to locate the papilla. RESULTS : 62 patients completed the study. Complete visualization of the major duodenal papilla was achieved in 60 examinations by side-viewing endoscopy and in 59 by cap-assisted endoscopy (97 % vs. 95 %). The difference between the two examinations was 1.6 % with a two-sided 95 % confidence interval of -4.0 % to 7.3 %, which did not exceed the noninferiority margin of 8 %. Cap-assisted endoscopy achieved better scores regarding the examination of mucosal pattern and overall satisfaction, whereas side-viewing endoscopy had a better overview score (P < 0.001, P = 0.004, and P < 0.001, respectively). There was no relevant difference in the median times to locate the major duodenal papilla. CONCLUSION : Cap-assisted endoscopy and side-viewing endoscopy had similar success rates for complete visualization of the major duodenal papilla. Cap-assisted endoscopy is superior to side-viewing endoscopy regarding the mucosal pattern and overall satisfaction. Side-viewing endoscopy gives a better overview of the periampullary region.