Scoring systems in clinical small-bowel capsule endoscopy: all you need to know!

Pan-Enteric Capsule Endoscopy: Current Applications and Future Perspectives

Background

The role of capsule endoscopy in the evaluation of the small bowel is well established, and current guidelines position it as a first-line test in a variety of clinical scenarios. The advent of double-headed capsules further enabled the endoscopic assessment of colonic mucosa and the opportunity for a one-step noninvasive examination of the entire bowel (pan-enteric capsule endoscopy [PCE]).

Summary

We reviewed the technical procedure and preparation of patients for PCE, as well as its current clinical applications and future perspectives. In non-stricturing and non-penetrating Crohn's disease affecting the small bowel and colon, PCE monitors disease activity by assessing mucosal healing, a major treatment outcome, with a higher diagnostic yield than cross-sectional imaging or conventional colonoscopy. Also in ulcerative colitis, double-headed capsules have been used to monitor disease activity noninvasively. Currently, validated scoring systems have been specifically devised for these double-headed capsules and permit a standardized assessment of the inflammatory burden. In suspected mid-lower digestive bleeding, some exploratory studies have demonstrated the feasibility and high diagnostic yield of PCE, which may work as a filter indicating which patients may benefit of further invasive procedures, namely, for planned hemostatic procedures. The possibility of using PCE is also discussed in the context of polyposis syndromes with simultaneous involvement of the small intestine and colon.

Key Messages

PCE is a feasible, effective, and safe diagnostic procedure to evaluate the small bowel and colon. It has been increasingly explored in the setting of inflammatory bowel diseases and, more recently, in suspected mid-lower digestive bleeding. PCE is expected to reduce the demand for invasive procedures and expand the scope of noninvasive intestinal evaluation in the coming future.

From Data to Insights: How Is AI Revolutionizing Small-Bowel Endoscopy?

The role of capsule endoscopy and enteroscopy in managing various small-bowel pathologies is well-established. However, their broader application has been hampered mainly by their lengthy reading times. As a result, there is a growing interest in employing artificial intelligence (AI) in these diagnostic and therapeutic procedures, driven by the prospect of overcoming some major limitations and enhancing healthcare efficiency, while maintaining high accuracy levels. In the past two decades, the applicability of AI to gastroenterology has been increasing, mainly because of the strong imaging component. Nowadays, there are a multitude of studies using AI, specifically using convolutional neural networks, that prove the potential applications of AI to these endoscopic techniques, achieving remarkable results. These findings suggest that there is ample opportunity for AI to expand its presence in the management of gastroenterology diseases and, in the future, catalyze a game-changing transformation in clinical activities. This review provides an overview of the current state-of-the-art of AI in the scope of small-bowel study, with a particular focus on capsule endoscopy and enteroscopy.

Diagnostic Yield of Small Bowel Videocapsule Endoscopy in Patients with Iron Deficiency Anemia. A Systematic Review and meta-analysis

BACKGROUND AND AIM

Gastrointestinal (GI) bleeding or malabsorption represents the most frequent aetiologies of iron deficiency anemia (IDA). The cause of IDA remains undetermined in ~10% to 20% of patients undergoing upper and lower GI endoscopies. In this scenario, a small bowel examination with videocapsule endoscopy (VCE) is recommended. We performed a systematic review with meta-analysis to evaluate the diagnostic yield of VCE in patients with IDA without overt bleeding, assessing the prevalence of either any lesion or lesions at high potential of bleeding.

MATERIALS AND METHODS

A computerized literature search was performed using relevant keywords to identify all the pertinent articles published until March 2023.

RESULTS

Twelve studies with a total of 1703 IDA patients (Males: 47%; age range: 19-92 y) were included in this systematic review. The diagnostic yield of VCE for overall lesions in the small bowel was 61% (95% CI=44-77; 95 CI=97.2-98.1; I2=97.7%). When analyzing only small bowel lesions likely responsible of IDA, the diagnostic yield was 40% (95% CI=27-53; 95% CI=95.3-97; I2=96.3%).

CONCLUSION

VCE plays a relevant role in the diagnostic work-up of patients with IDA without overt bleeding with a satisfactory diagnostic yield.

The Role of Capsule Endoscopy in the Diagnosis and Management of Small Bowel Tumors: A Narrative Review

Small bowel tumors (SBT) are relatively rare, but have had a steadily increasing incidence in the last few decades. Small bowel capsule endoscopy (SBCE) and device-assisted enteroscopy are the main endoscopic techniques for the study of the small bowel, the latter additionally providing sampling and therapeutic options, and hence acting complementary to SBCE in the diagnostic work-up. Although a single diagnostic modality is often insufficient in the setting of SBTs, SBCE is a fundamental tool to drive further management towards a definitive diagnosis. The aim of this paper is to provide a concise narrative review of the role of SBCE in the diagnosis and management of SBTs.

The Future of Minimally Invasive Capsule Panendoscopy: Robotic Precision, Wireless Imaging and AI-Driven Insights

In the early 2000s, the introduction of single-camera wireless capsule endoscopy (CE) redefined small bowel study. Progress continued with the development of double-camera devices, first for the colon and rectum, and then, for panenteric assessment. Advancements continued with magnetic capsule endoscopy (MCE), particularly when assisted by a robotic arm, designed to enhance gastric evaluation. Indeed, as CE provides full visualization of the entire gastrointestinal (GI) tract, a minimally invasive capsule panendoscopy (CPE) could be a feasible alternative, despite its time-consuming nature and learning curve, assuming appropriate bowel cleansing has been carried out. Recent progress in artificial intelligence (AI), particularly in the development of convolutional neural networks (CNN) for CE auxiliary reading (detecting and diagnosing), may provide the missing link in fulfilling the goal of establishing the use of panendoscopy, although prospective studies are still needed to validate these models in actual clinical scenarios. Recent CE advancements will be discussed, focusing on the current evidence on CNN developments, and their real-life implementation potential and associated ethical challenges.

Deep Learning and Minimally Invasive Endoscopy: Automatic Classification of Pleomorphic Gastric Lesions in Capsule Endoscopy

INTRODUCTION

Capsule endoscopy (CE) is a minimally invasive examination for evaluating the gastrointestinal tract. However, its diagnostic yield for detecting gastric lesions is suboptimal. Convolutional neural networks (CNNs) are artificial intelligence models with great performance for image analysis. Nonetheless, their role in gastric evaluation by wireless CE (WCE) has not been explored.

METHODS

Our group developed a CNN-based algorithm for the automatic classification of pleomorphic gastric lesions, including vascular lesions (angiectasia, varices, and red spots), protruding lesions, ulcers, and erosions. A total of 12,918 gastric images from 3 different CE devices (PillCam Crohn's; PillCam SB3; OMOM HD CE system) were used from the construction of the CNN: 1,407 from protruding lesions; 994 from ulcers and erosions; 822 from vascular lesions; and 2,851 from hematic residues and the remaining images from normal mucosa. The images were divided into a training (split for three-fold cross-validation) and validation data set. The model's output was compared with a consensus classification by 2 WCE-experienced gastroenterologists. The network's performance was evaluated by its sensitivity, specificity, accuracy, positive predictive value and negative predictive value, and area under the precision-recall curve.

RESULTS

The trained CNN had a 97.4% sensitivity; 95.9% specificity; and positive predictive value and negative predictive value of 95.0% and 97.8%, respectively, for gastric lesions, with 96.6% overall accuracy. The CNN had an image processing time of 115 images per second.

DISCUSSION

Our group developed, for the first time, a CNN capable of automatically detecting pleomorphic gastric lesions in both small bowel and colon CE devices.

Middle small-bowel segment Lewis score may predict long-term outcomes among patients with quiescent Crohn's disease

Background

Video capsule endoscopy (VCE) has been proven to accurately diagnose small-bowel inflammation and predict flares among patients with quiescent Crohn's disease (CD). However, data regarding its predictive role in this population over an extended follow-up are scarce.

Objectives

To predict clinical exacerbation and to assess the yield of Lewis score in identifying CD patients with future clinical exacerbation during an extended follow-up (>24 months).

Design

A post hoc analysis study.

Methods

Adult patients with quiescent small-bowel CD who were followed with VCE, inflammatory biomarkers and magnetic resonance enterography in a prospective study (between 2013 and 2018). We extracted extended clinical data (up to April 2022). The primary composite outcome (i.e. clinical exacerbation) was defined as intestinal surgery, endoscopic dilation, CD-related admission, corticosteroid administration, or biological/immunomodulator treatment change during follow-up.

Results

Of the 61 patients in the study [median age 29 (24-37) years, male 57.4%, biologic treatment 46.7%], 18 patients met the primary outcome during an extended follow-up [median 58.0 (34.5-93.0) months]. On univariable analysis, complicated [hazard ratio (HR) 7.348, p = 0.002] and stricturing disease phenotype (HR 5.305, p = 0.001) were associated with higher risk for clinical exacerbation during follow-up. A baseline VCE middle small-bowel segment Lewis score (midLS) ⩾ 135 identified patients with future exacerbation [AUC (area under the curve) 0.767, 95% confidence interval (CI) 0.633-0.902, p = 0.001, HR 6.317, 93% negative predictive value], whereas the AUC of the conventional Lewis score was 0.734 (95% CI: 0.589-0.879, p = 0.004). Sensitivity analysis restricted to patients with either complicated (n = 34) or stricturing (n = 26) disease phenotype revealed that midLS still predicted clinical exacerbation during follow-up (AUC 0.747/0.753, respectively), in these patients.

Conclusion

MidLS predicts treatment failure in quiescent CD patients (median follow-up of 5 years) independently of disease phenotype.

Small Bowel CLEansing Assessment and Report (SB-CLEAR): Standardizing bowel preparation report in capsule endoscopy

BACKGROUND AND AIM

Small-bowel (SB) cleansing is crucial to assess the reliability of capsule endoscopy (CE) findings. However, the presence of multiple grading systems is hampering their use in clinical practice. In 2020, Colon CLeansing Assessment and Report (CC-CLEAR) was created and validated. We sought to develop and validate a new score for the evaluation of the SB cleansing, adapted from CC-CLEAR, aiming to standardize CE reporting regarding the quality of preparation.

METHODS

The new grading score, SB CLeansing Assessment and Report (SB-CLEAR), divided the SB into three tertiles, each being scored depending on the percentage of visualized mucosa (0, < 50%; 1, 50%-75%; 2, > 75%; 3, > 90%). The overall classification was a sum of each segment score, graded between excellent, good, and inadequate (0-5). Any segment scoring ≤1 resulted in inadequate overall classification. CE videos were prospectively evaluated by two experienced CE readers blinded to each other.

RESULTS

We included 52 CEs, 41(78.8%) female, with a mean age of 57.9 ± 17.9 years. Inter-observer agreement was very strong for each tertile (first: r = 0.863; second: r = 0.865; third: r = 0.861; P < 0.001), which resulted in overall excellent correlation when considering the quality of preparation in all tertiles (r = 0.940; P < 0.001). By applying final classifications of "inadequate," "good," and "excellent," correlation between observers was also very strong (r = 0.875; P < 0.001).

CONCLUSIONS

SB-CLEAR is an innovative and reproducible grading score for evaluation of SB preparation quality in CE, with overall excellent inter-observer agreement. Along with CC-CLEAR, this may become a valuable tool to uniformize reporting of bowel preparation quality in CE.

Very High Yield of Urgent Small-Bowel Capsule Endoscopy for Ongoing Overt Suspected Small-Bowel Bleeding Irrespective of the Usual Predictive Factors

Evidence for an urgent approach to ongoing overt suspected small-bowel bleeding (SSBB) is scarce. We aimed to analyze our series of urgent small-bowel capsule endoscopies (SBCEs) for ongoing overt SSBB and to identify factors associated with positive findings and outcomes. A retrospective study of all SBCEs performed in the first 48 h after admission for overt SSBB between January 2006 and February 2022 was performed. Descriptive and inferential analyses (univariate and multivariable) were performed. Eighty-three urgent SBCEs were performed for overt SSBB. Patients were mostly men (69.2%, median age 68) and were followed for a median of 58.2 months (range 5-176). The diagnostic yield was 80.7%; in 60.2%, blood was detected in the small bowel (SB), while in 50.6%, a bleeding lesion was identified, mostly angioectasia. Patients with diabetes mellitus or taking NSAIDs were more prone to present SB findings, yet the explanatory power was low. Endoscopic or surgical treatments were performed in 28.9% and 19.3%, respectively, with the "non-conservative" therapeutic yield being 56.6%. Rebleeding occurred in 20.5% and was associated in the multivariable analysis with the female gender and anticoagulants use. This cohort of urgent SBCE, the largest from a European center, reinforces the usefulness of SBCE for ongoing overt SSBB management. This prompt performance of this procedure is highly effective, regardless of patients' features.

An Overview of the Evolution of Capsule Endoscopy Research—Text-Mining Analysis and Publication Trends

There has been a steady increase (annual percentage growth rate of 19.2%, average of 18.3 citations per document) in capsule endoscopy (CE) publications from a global, interdisciplinary research community on a growing range of CE applications over the last 20+ years. We here present the status of CE as a field of research, tracing its evolution over time and providing insight into its potential for diagnostics, prevention and treatment of gastrointestinal (GI) tract diseases. To portray the development of the CE research landscape in the 2000–2021 time span, we analyzed 5764 scientific publications. Analyses were performed using the R language and environment for statistical computing and graphics and VOSviewer, a software developed for scientific literature analysis by scientometricians. The aim of this paper is to provide a wide comprehensive analysis of the trends in CE publications. We thus performed subgroup analysis on the selected papers, including indications, annual percentage growth rate, average citations per document, most publications from research areas/interdisciplinary field of the articles, geography, collaboration networks through institutions, specific clinical keywords and device type. The firm increase in CE publications over the last two decades highlights the overall strength of the technology in GI applications. Furthermore, the introduction to the field of artificial intelligence (AI) tools has been promoting a range of technological advances that keep on affecting the diagnostic potential of CE.

New Generation Express View: An Artificial Intelligence Software Effectively Reduces Capsule Endoscopy Reading Times

BACKGROUND: Reading capsule endoscopy (CE) is time-consuming. The Express View (EV) (IntroMedic, Seoul, Korea) software was designed to shorten CE video reading. Our primary aim was to evaluate the diagnostic accuracy of EV in detecting significant small-bowel (SB) lesions. We also compared the reading times with EV mode and standard reading (SR). METHODS: 126 patients with suspected SB bleeding and/or suspected neoplasia were prospectively enrolled and underwent SB CE (MiroCam®1200, IntroMedic, Seoul, Korea). CE evaluation was performed in standard and EV mode. In case of discrepancies between SR and EV readings, a consensus was reached after reviewing the video segments and the findings were re-classified. RESULTS: The completion rate of SB CE in our cohort was 86.5% and no retention occurred. The per-patient analysis of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of EV compared to SR were 86%, 86%, 90%, 81%, and 86%, respectively, before consensus. After consensus, they increased to 97%, 100%, 100%, 96%, and 98%, respectively. The median reading time with SR and EV was 71 min (range 26−340) and 13 min (range 3−85), respectively (p < 0.001). CONCLUSIONS: The new-generation EV shows high diagnostic accuracy and significantly reduces CE reading times.

RHEMITT score: Predicting the risk of mid gastrointestinal rebleeding after small bowel capsule endoscopy: A prospective validation

BACKGROUND AND AIM

The RHEMITT score (Renal disease; Heart failure; Endoscopic findings; Major bleeding; Incomplete SBCE; Tobacco; Treatment by enteroscopy) was the first score to accurately predict the individual risk of small bowel rebleeding after capsule endoscopy (SBCE). The aim of the study is on the prospective validation of the RHEMITT score.

METHODS

Cohort of consecutive patients with mid-gastrointestinal bleeding (MGIB) submitted to SBCE and followed prospectively, during at least 12 months, since 2017 until 2020. Rebleeding was defined as an overt bleeding event (melena or hematochezia) or a hemoglobin decrease of at least 2 g/dL. The RHEMITT score was calculated for each patient and the rebleeding rates compared. The performance of the score was tested by calculating the area under curve of the receiver operator characteristic curve. A rebleeding-free survival was assessed, corresponding to the period between the date of SBCE and the date of the first post-SBCE rebleeding event.

RESULTS

We included 162 patients, 102 (62.9%) were female, with a mean age of 64 years old. The sensitivities and specificities of the score grades for predicting rebleeding were as following: for low-risk patients, 0% (0-10%) and 28.8% (21.1-36.5%); for intermediate-risk patients, 23.3% (8.2-38.4%) and 72% (64.3-79.7%); for high-risk patients, 76.7% (61.6-91.8%) and 99.2% (97.7-100%), corresponding to an area under curve of the receiver operator characteristic of 0.988 (P < 0.001). Kaplan-Meyer plots were statistically different according to the attributed risk (log-rank P value <0.001; Breslow-Wilcoxon P value <0.001).

CONCLUSION

The RHEMITT score performed with excellent discriminative power in predicting rebleeding risk, and we herewith propose a surveillance of MGIB patients guided by the RHEMITT score.

Small-Bowel Capsule Endoscopy-Optimizing Capsule Endoscopy in Clinical Practice

The small bowel is the longest organ within the gastrointestinal tract. The emergence of small bowel capsule endoscopy (SBCE) over the last 20 years has revolutionized the investigation and diagnosis of small bowel pathology. Its utility as a non-invasive and well-tolerated procedure, which can be performed in an outpatient setting, has made it a valuable diagnostic tool. The indications for SBCE include obscure gastrointestinal bleeding, small bowel Crohn's disease, and, less frequently for screening in polyposis syndromes, celiac disease, or other small bowel pathology. Currently, there are several small bowel capsules on the market from different manufacturers; however, they share many technological features. The European Society of Gastrointestinal Endoscopy (ESGE) only recently developed a set of key quality indicators to guide quality standards in this area. Many of the technical aspects of capsule endoscopy still feature a degree of uncertainty in terms of optimal performance. Incomplete studies due to slow transit through the bowel, poor imaging secondary to poor preparation, and the risk of capsule retention remain frustrations in its clinical utility. Capsule review is a time-consuming process; however, artificial intelligence and machine learning offer opportunities to improve this. This narrative review examines our current standing in a number of these aspects and the potential to further the application of SBCE in order to maximize its diagnostic utility.

Lavage, Simethicone, and Prokinetics-What to Swallow with a Video Capsule

The development of new capsules now allows endoscopic diagnosis in all segments of the gastrointestinal tract and comes with new needs for differentiated preparation regimens. Although the literature is steadily increasing, the results of the conducted trials on preparation are sometimes conflicting. The ingestion of simethicone before gastric and small bowel capsule endoscopy for prevention of air bubbles is established. The value of a lavage before small bowel capsule endoscopy (SBCE) is recommended, although not supported by all studies. Ingestion in the morning before the procedure seems useful for the improvement of mucosa visualization. Lavage after swallowing of the capsule seems to improve image quality, and in some studies also diagnostic yield. Prokinetics has been used with first generation capsules to shorten gastric transit time and increase the rate of complete small bowel visualization. With the massively prolonged battery capacity of the new generation small bowel capsules, prokinetics are only necessary in significantly delayed gastric emptying as documented by a real-time viewer. Lavage is crucial for an effective colon capsule or pan-intestinal capsule endoscopy. Mainly high or low volume polyethylene glycol (PEG) is used. Apart from achieving optimal cleanliness, propulsion of the capsule by ingested boosts is required to obtain a complete passage through the colon within the battery lifetime. Boosts with low volume sodium picosulfate (NaP) or diatrizoate (gastrografin) seem most effective, but potentially have more side effects than PEG. Future research is needed for more patient friendly but effective preparations, especially for colon capsule and pan-intestinal capsule endoscopy.