Faculty Bibliography

PURPOSE OF REVIEW/OBJECTIVE:This review highlights the history, recent advances, and ongoing challenges of artificial intelligence (AI) technology in colonic polyp detection. RECENT FINDINGS/RESULTS:Hand-crafted AI algorithms have recently given way to convolutional neural networks with the ability to detect polyps in real-time. The first randomized controlled trial comparing an AI system to standard colonoscopy found a 9% increase in adenoma detection rate, but the improvement was restricted to polyps smaller than 10 mm and the results need validation. As this field rapidly evolves, important issues to consider include standardization of outcomes, dataset availability, real-world applications, and regulatory approval. AI has shown great potential for improving colonic polyp detection while requiring minimal training for endoscopists. The question of when AI will enter endoscopic practice depends on whether the technology can be integrated into existing hardware and an assessment of its added value for patient care.

PURPOSE OF REVIEW/OBJECTIVE:With the intent of maximizing adenoma detection rate (ADR), different devices and colonoscopic innovations have been introduced over the past few years. There are a variety of attachment devices available for use in colonoscopy, all intended to improve ADR. In this review, we evaluate the evidence surrounding the available attachment devices and their impact on ADR. RECENT FINDINGS/RESULTS:Endocuff, Endoring, Transparent cap, G-EYE balloon, and Third Eye Retroscope were all included in this review. Three of the devices, Endocuff, Endoring, and transparent hood or cap, have been shown to increase ADR without significantly altering the use of the colonoscope. Although balloon-assisted colonoscopy is not currently FDA-approved, it has the potential to increase ADR as well. Mechanical enhancement has been shown to complement the current forward-viewing colonoscope, and Endocuff appears to be the most beneficial attachment to improve ADR.

BACKGROUND & AIMS/OBJECTIVE:Mucosal exposure devices improve detection of lesions during colonoscopy and have reduced examination times in uncontrolled studies. We performed a randomized trial of Endocuff Vision vs standard colonoscopy to compare differences in withdrawal time (the primary end point). We proposed that Endocuff Vision would allow complete mucosal inspection in a shorter time without impairing lesion detection. METHODS:Adults older than 40 years undergoing screening or surveillance colonoscopies were randomly assigned to the Endocuff group (n=101, 43.6% women) or the standard colonoscopy group (n=99; 57.6% women). One of 2 experienced endoscopists performed the colonoscopies, aiming for a thorough evaluation of the proximal sides of all haustral folds, flexures, and valves in the shortest time possible. Inspection time was measured with a stopwatch and calculated by subtracting washing, suctioning, polypectomy and biopsy times from total withdrawal time. RESULTS:There were significantly fewer women in the Endocuff arm (P=.0475) but there were no other demographic differences between groups. Mean insertion time with Endocuff was 4.0 min vs 4.4 min for standard colonoscopy (P=.14). Mean inspection time with Endocuff was 6.5 min vs 8.4 min for standard colonoscopy (P<.0001). Numbers of adenomas detected per colonoscopy (1.43 vs 1.07; P=.07), adenoma detection rate (61.4% vs 52%; P=0.21), number of sessile serrated polyps per colonoscopy (0.27 vs 0.21; P=0.12), and sessile serrated polyp detection rate (19.8% vs 11.1%; P= 0.09) were all higher with Endocuff Vision. Results did not differ significantly when we controlled for age, sex, or race. CONCLUSION/CONCLUSIONS:In a randomized trial, we found inclusion of Endocuff in screening or surveillance colonoscopies to decrease examination time without reducing lesion detection. ClinicalTrials.gov no.: NCT03361917.

BACKGROUND AND AIMS/OBJECTIVE:Although screening for Barrett's esophagus (BE) is recommended in individuals with multiple risk factors, the type and number of risk factors necessary to trigger screening is unclear. In this systematic review and meta-analysis, we aimed to assess the relationship between number of risk factors and prevalence of BE. METHODS:Through October 17, 2018, we searched studies that described the prevalence of BE in the general population and based on presence of risk factors that included GERD, male gender, age >50 years, family history of BE and esophageal adenocarcinoma (EAC), and obesity (defined as body mass index >35). Risk of BE based on number of risk factors was assessed using meta-regression while controlling for potential confounders. RESULTS:Of 2,741 studies, 49 were included in the analysis (307,273 individuals, 1,948 with biopsy-proven BE). Indications varied by study. The prevalence of BE for various populations was as follows: low-risk general population: 0.8% (95% CI, 0.6% - 1.1%); GERD: 3% (95% CI, 2.3% - 4%); GERD plus presence of any other risk factor: 12.2% (95% CI,10.2% - 14.6%); family history: 23.4% (95% CI,13.7% -37.2%); age > 50: 6.1% (95% CI, 4.6% - 8.1%); obesity: 1.9% (95% CI, 1.2% - 3%); and male sex: 6.8% (95% CI, 5.3% - 8.6%). Prevalence of BE varied significantly between Western and non-Western populations. In a meta-regression, controlling for the region of the study, age, and gender, there was a positive linear relationship between the number of risk factors and the prevalence of BE. CONCLUSIONS:Results of this study provide estimates of BE prevalence based on the presence and the number of risk factors. These results add credence to current guidelines that suggest screening in the presence of multiple risk factors.

INTRODUCTION: Wide Area Transepithelial Sampling with 3-Dimensional Computer-Assisted Analysis (WATS) when used adjunctively to forceps biopsies (FB) has been demonstrated in multiple prospective studies to significantly increase detection of Barrett's esophagus (BE) and associated neoplasia in patients undergoing either BE screening or surveillance. The clinical impact ofWATS positive-FB negative diagnoses has never been evaluated. The aim of this IRB-approved clinical utility study was to determine changes in patient management when BE and/or dysplasia was detected by WATS but not by FB.
METHOD(S): Between 2013-2018, we identified 423 consecutive patients from WATS clinical registries who had a WATS positive diagnosis of BE or dysplasia and a negative FB result; 317 patients were diagnosed with BE, 90 with low grade dysplasia (LGD) and 16 with high grade dysplasia (HGD) by WATS only. Physicians subsequently completed an extensive survey to determine if the positive WATS diagnosis resulted in a change in patient management such as enrolment in a surveillance program, endoscopic ablation/antireflux surgery, initiating proton pump inhibitors (PPIs) or increasing the patient's dose of PPI.
RESULT(S): The clinical impact of WATS positive-FB negative diagnoses for patients with BE, LGD or HGD is summarized in Table 1. WATS had a direct impact on the clinical management of 97.8% of the 317 BE patients including enrolment in a surveillance program (96.2%), ablation/antireflux surgery (3.7%), or starting or increasing the dose of PPIs (60.2%). WATS impacted the management of 94.4% and 93.7% of LGD and HGD patients respectively. For instance, 30% and 50% respectively had ablation, 73.3% and 68.8% had increased frequency of or new enrollment in surveillance, and 56.7% and 62.5% had PPIs prescribed or the dose increased. Seven of 8 HGD patients not ablated were lost to follow up. One of 8 HGD patients not ablated developed invasive adenocarcinoma also identified with WATS upon follow-up endoscopy.
CONCLUSION(S): The results of this study demonstrate that physicians have a high degree of confidence in WATS diagnoses even when the concurrent FB is negative. This is evidenced by the fact that physicians changed their patient management in 96.9% of all cases, often significantly with invasive treatments such as ablation, EMR, and even antireflux surgery in a small %age of patients. As an adjunct to FB, WATS has high clinical utility and adds value to the management of patients with BE and associated dysplasia

Introduction: EUS-guided FNA and FNB have established their place for tissue acquisition. However, the procedure has been stagnating in recent years at a level of accuracy which falls short of patient and physician hopes. In recent years, needles have been redesigned to allow for core sampling, (FNB), to allow for immune-staining of specimens. However, false negative results for malignancy range from 4% (experts centers) to 30%. Multiple needle passes are often needed, but often slide along the same tract as the first pass, limiting diagnostic yield. An FNA approach usually requires 3-5 passes, with fewer passes for the FNB needles. Furthermore, rapid on-site cytology can lower number of passes, but the majority of centers find this to be logistically and/or financially prohibitive. Needles after repeated passes bend out of shape leading to use of a second needle, which has cost implications. Tumor composition can be a mosaic of desmoplasia, necrosis, cystic areas, and malignant cells. If the needle is in the wrong plane and the endoscopist is unable to do fanning an inconclusive diagnosis can occur. We introduce a new needle concept to improve diagnostic yield and lower false negatives, with use of a device which has five needles. Aims & Methods : A multi-pass needle has been designed which ensures five specimens will be from various sites, because the five needles are all penetrating at the same time in different planes of the lesion. This needle apparatus uses the same sheath as a standard 19 gauge needle, but within the sheath it houses a five-lumen plastic tube, which separates between the central 22g needle and the four peripheral 25g needles. The ergonomically- designed handle has a two-phase mechanism which allows the endoscopist to first place the 22g needle within the target lesion, which is the same as the process done today, and to then extrude the four 25g needles, which are pre-bent so as to spread out to a diameter of about one cm at a distance of about 3cm from the scope. These additional needles will each, without fanning, obtain specimens near to the central needle, and therefore a greater representation of tumor tissue will be obtained, while completing the procedure in one pass, with better accuracy due to less false negatives. The two channels for suction can be attached to either the single central needle and/or to all four peripheral needles with stopcocks facilitating the maintaining of suction when so desired. Each needle has its own stylet, these may be removed at any time desired.
Result(s): We present in the accompanying figure the InstaFan, a disruptive technological advance, for the delivery of better EUS biopsies. Ex vivo studies found that the 5 needles did not cause leakage from the gut or perforation of the gut wall, and that the 5 needles delivered resulted in five distinct specimens each of which was an adequate specimen for pathological diagnostic purposes using the cell block method and paraffin slices allowing immune-staining.
Conclusion(s): Future directions of the InstaFan will be animal in vivo animal safety study followed by first trials in humans. The goal of the InstaFan will be to reduce false negatives, thus increasing optimization of tumor diagnosis

INTRODUCTION: Missed lesions are considered a major cause of interval cancer of the colon. The new Automatic Polyp Detection System (APDS) from Magentiq Eye was developed to enhance the ability of endoscopists to detect polyps. It is designed for offline use with future real-time applications. The system uses recorded colonoscopy videos to assess endoscopist performance against the APDS. The APDS reviews the videos to generate a computerized automatic signature of polyps; a separate screen then shows the corresponding ?heat map' contour of areas suspicious for presence of polyps (see Figure 1).
METHOD(S): In this proof-of-concept study, the performance of the trained system was compared with a known testing database of 35 videos (each sequence approximately 30 seconds and 1000 frames). Overall, the testing database included 35,290 frames, with polyps found in the right colon (cecum and ascending colon, 10), transverse colon (5), and left colon (sigmoid and rectum, 20). Of the 35, 33 polyps were sessile and 2 were pedunculated; sizes ranged from less than 3 mm (10), 3 to 6 mm (16), 6 to 10 mm (5), and over 10 mm (4). Our goal was to define the optimal system working point in terms of sensitivity and specificity to detect polyps present in at least 3 consecutive frames. Physicians reviewed videos for polyps that were missed by the APDS and compare it with those missed by the endoscopists.
RESULT(S): The best working point of the system showed 88% sensitivity with 98.4% specificity (0.016 false positive rate). This resulted in a system polyp detection rate (SPDR) of 85.8% with 5 missed polyps. Missed lesions were found in the ascending (2), transverse (2), and descending (1) colon. All were sessile with sizes of less than 3 mm (1), 3 to 6 mm (3), 6 to 10 mm (1). The physicians missed 4 polyps found in the transverse colon (3) and descending colon (1). All polyps missed by physicians were sessile with sizes of less than 3 mm (1), 3 to 6 mm (2), and 6 to 10 mm (1). Only one polyp was missed both by the APDS and the physician.
CONCLUSION(S): Given that only one polyp was missed both by the APDS and the endoscopists, the APDS demonstrated the potential to behave as a complementary tool during colonoscopy in order to alert the endoscopist to lesions that may otherwise be missed, aiming to decrease the incidence of interval colon cancers

INTRODUCTION: Colorectal cancer remains the second leading cause of cancer death in the world. Incidence has declined as rates of screening colonoscopy have increased, but colonoscopy is not perfect. Low adenoma detection rates (ADR's) have been associated with increased interval cancers. Both optical and mechanical devices for improving ADR have shown promising results. Here we demonstrate a novel colonoscope with a 360degree integrated view to improve visualization behind folds (Figure 1). The aim of this study is to compare polyp detection rates using the novel 360degree scope and a standard forward only view (FOV) scope in colon models.
METHOD(S): 324 endoscopists around the US were enrolled in the study. 20 anatomic colon models (Champerlain Group, Great Barrington, MA) containing simulated 6-15 mm polyps were used. Polyps varied in number, location, and shape. Models were examined in a tandem fashion with the 360degree scope and the FOV scope. Endoscopists were randomly assigned to perform the initial exam with either scope. The primary outcome was the number of polyps identified during withdrawal. Subgroup analysis was performed evaluating effects of order of examination, experience, and practice setting. Means were compared with a paired T-test and subgroups were compared with ANOVA.
RESULT(S): 153 endoscopists performed their initial exam with the 360degree scope, and 171 with the FOV scope. The 360degree view colonoscope identified significantly more polyps overall (13.2 vs 7.7, mean difference 5.5, P< 0.0001). Each individual endoscopist identified more polyps with the 360degree scope. The difference persisted regardless of which scope was used first. The difference also persisted between endoscopists of different experience and practice environments (Table 1). The only statistically significant difference was between endoscopists stratified by years of training, in which the <5 year group had a larger difference in polyp detection (P=0.0006).
CONCLUSION(S): This study shows that the 360degree integrated view colonoscope is more effective at polyp detection than a traditional colonoscope in simulated models. The increased polyp detection is not dependent on experience level or practice environment. The expanded field of view allows endoscopists to identify polyps that may be missed by a traditional scope such as behind folds. Further studies in humans will be needed to prove safety/efficacy for clinical use but these initial results show promise for increasing ADR using this novel colonoscope (Figure Presented)