MiroCam capsule for obscure gastrointestinal bleeding: a prospective, single centre experience

Endoscope Capsules: The Present Situation and Future Outlooks

This paper presents new perspectives on photonic technologies for capsule endoscopy. It first presents a review of conventional endoscopy (upper endoscopy and colonoscopy), followed by capsule endoscopy (CE), as well as their techniques, advantages, and drawbacks. The technologies for CEs presented in this paper include integration with the existing endoscopic systems that are commercially available. Such technologies include narrow-band imaging (NBI), photodynamic therapy (PDT), confocal laser endomicroscopy (CLE), optical coherence tomography (OCT), and spectroscopy in order to improve the performance of the gastrointestinal (GI) tract examination. In the context of NBI, two optical filters were designed and fabricated for integration into endoscopic capsules, allowing for the visualization of light centered at the 415 nm and 540 nm wavelengths. These optical filters are based on the principle of Fabry-Perot and were made of thin films of titanium dioxide (TiO2) and silicon dioxide (SiO2). Moreover, strategies and solutions for the adaptation of ECs for PDT are also discussed.

Prediction models for recurrence in patients with small bowel bleeding

Obscure gastrointestinal bleeding (OGIB) has traditionally been defined as gastrointestinal bleeding whose source remains unidentified after bidirectional endoscopy. OGIB can present as overt bleeding or occult bleeding, and small bowel lesions are the most common causes. The small bowel can be evaluated using capsule endoscopy, device-assisted enteroscopy, computed tomography enterography, or magnetic resonance enterography. Once the cause of small-bowel bleeding is identified and targeted therapeutic intervention is completed, the patient can be managed with routine visits. However, diagnostic tests may produce negative results, and some patients with small bowel bleeding, regardless of diagnostic findings, may experience rebleeding. Predicting those at risk of rebleeding can help clinicians form individualized surveillance plans. Several studies have identified different factors associated with rebleeding, and a limited number of studies have attempted to create prediction models for recurrence. This article describes prediction models developed so far for identifying patients with OGIB who are at greater risk of rebleeding. These models may aid clinicians in forming tailored patient management and surveillance.

Computer vision-based solutions to overcome the limitations of wireless capsule endoscopy

Endoscopic investigation plays a critical role in the diagnosis of gastrointestinal (GI) diseases. Since 2001, Wireless Capsule Endoscopy (WCE) has been available for small bowel exploration and is in continuous development. Over the last decade, WCE has achieved impressive improvements in areas such as miniaturisation, image quality and battery life. As a result, WCE is currently a very useful alternative to wired enteroscopy in the investigation of various small bowel abnormalities and has the potential to become the leading screening technique for the entire gastrointestinal tract. However, commercial solutions still have several limitations, namely incomplete examination and limited diagnostic capacity. These deficiencies are related to technical issues, such as image quality, motion estimation and power consumption management. Computational methods, based on image processing and analysis, can help to overcome these challenges and reduce both the time required by reviewers and human interpretation errors. Research groups have proposed a series of methods including algorithms for locating the capsule or lesion, assessing intestinal motility and improving image quality.In this work, we provide a critical review of computational vision-based methods for WCE image analysis aimed at overcoming the technological challenges of capsules. This article also reviews several representative public datasets used to evaluate the performance of WCE techniques and methods. Finally, some promising solutions of computational methods based on the analysis of multiple-camera endoscopic images are presented.

Actuators for Implantable Devices: A Broad View

The choice of actuators dictates how an implantable biomedical device moves. Specifically, the concept of implantable robots consists of the three pillars: actuators, sensors, and powering. Robotic devices that require active motion are driven by a biocompatible actuator. Depending on the actuating mechanism, different types of actuators vary remarkably in strain/stress output, frequency, power consumption, and durability. Most reviews to date focus on specific type of actuating mechanism (electric, photonic, electrothermal, etc.) for biomedical applications. With a rapidly expanding library of novel actuators, however, the granular boundaries between subcategories turns the selection of actuators a laborious task, which can be particularly time-consuming to those unfamiliar with actuation. To offer a broad view, this study (1) showcases the recent advances in various types of actuating technologies that can be potentially implemented in vivo, (2) outlines technical advantages and the limitations of each type, and (3) provides use-specific suggestions on actuator choice for applications such as drug delivery, cardiovascular, and endoscopy implants.

Which model of small bowel capsule endoscopy has a better diagnostic yield? A systematic review and meta-analysis

Background and study aims: Small-bowel capsule endoscopy (SBCE) is a safe and efficient method for diagnosis of small-bowel diseases. Since its development, different models have appeared. The aim of this study was to analyze which of the different models of SBCE has the best diagnostic yield. Patients and methods: Extensive medical literature research was reviewed, using MESH terms, searching studies comparing different SBCE types. We analyzed the diagnostic yield of all the comparisons and when there were 2 or more studies that compared the same model of SBCEs, a meta-analysis was performed. Results: Ten eligible studies including 1065 SBCEs procedures were identified. The main indication was occult gastrointestinal bleeding in 9/10 studies. Two of them included anemia, chronic diarrhea and/or chronic abdominal pain. The indication in one article was celiac disease. In 9 studies, different types of SBCEs (MiroCam, Endocapsule, OMOM and CapsoCam) were compared with PillCam (SB, SB2 and SB3). Three studies compared MiroCam vs PillCam and CapsoCam vs PillCam, while two studies contrast Endocapsule vs PillCam. None of the SBCEs show superiority over PillCam [OR 0.78 (95%CI;0.60-1.01)]. One study compared SBCEs other than Pillcam (MiroCam vs Endocapsule). Nine studies did not find statistical differences between SBCEs, one showed better diagnostic yield of Mirocam compared with PillCam SB3 (p=0.02). The difference between these SBCE was not replayed in the metaanalysis [OR 0.77 (95%CI;0.49-1.21)]. Conclusions: Despite the appearance of new SBCE models, there are no differences in diagnostic yield; therefore, SBCE endoscopist’s performance should be based on experience and availability.

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.

Recent developments in small bowel endoscopy: the "black box" is now open!

Over the last few years, capsule endoscopy has been established as a fundamental device in the practicing gastroenterologist’s toolbox. Its utilization in diagnostic algorithms for suspected small bowel bleeding, Crohn’s disease, and small bowel tumors has been approved by several guidelines. The advent of double-balloon enteroscopy has significantly increased the therapeutic possibilities and release of multiple devices (single-balloon enteroscopy and spiral enteroscopy) aimed at improving the performance of small bowel enteroscopy. Recently, some important innovations have appeared in the small bowel endoscopy scene, providing further improvement to its evolution. Artificial intelligence in capsule endoscopy should increase diagnostic accuracy and reading efficiency, and the introduction of motorized spiral enteroscopy into clinical practice could also improve the therapeutic yield. This review focuses on the most recent studies on artificial-intelligence-assisted capsule endoscopy and motorized spiral enteroscopy.

3D reconstruction of small bowel lesions using stereo camera-based capsule endoscopy

Three-dimensional (3D) reconstruction of capsule endoscopic images has been attempted for a long time to obtain more information on small bowel structures. Due to the limited hardware resources of capsule size and battery capacity, software approaches have been studied but have mainly exhibited inherent limitations. Recently, stereo camera-based capsule endoscopy, which can perform hardware-enabled 3D reconstruction, has been developed. We aimed to evaluate the feasibility of newly developed 3D capsule endoscopy in clinical practice. This study was a prospective, single-arm, feasibility study conducted at two university-affiliated hospitals in South Korea. Small bowel evaluation was performed using a newly developed 3D capsule endoscope for patients with obscure gastrointestinal bleeding, suspected or established Crohn's disease, small bowel tumors, and abdominal pain of unknown origin. We assessed the technical limitations, performance, and safety of the new capsule endoscope. Thirty-one patients (20 men and 11 women; mean age: 44.5 years) were enrolled. There was no technical defect preventing adequate visualization of the small bowel. The overall completion rate was 77.4%, the detection rate was 64.5%, and there was no capsule retention. All capsule endoscopic procedures were completed uneventfully. In conclusion, newly developed 3D capsule endoscopy was safe and feasible, showing similar performance as conventional capsule endoscopy. Newly added features of 3D reconstruction and size measurement are expected to be useful in the characterization of subepithelial tumours.

Management of obscure gastrointestinal bleeding: Comparison of guidelines between Japan and other countries

Small-bowel bleeding accounts for the majority of obscure gastrointestinal bleeding, but it is caused by various types of small bowel disease, upper gastrointestinal disease, and colorectal disease. For the diagnosis, history taking and physical examination are required, leading to a determination of what diseases are involved. Next, cross-sectional imaging, such as computed tomography, should be carried out, followed by the latest enteroscopy such as small bowel capsule endoscopy and deep enteroscopy according to the severity of hemorrhage and patient condition. After a comprehensive diagnosis, medical, enteroscopic, or surgical treatment should be selected. This article reviews recent advances in the endoscopic diagnosis of obscure gastrointestinal bleeding and compares perspectives of the management of obscure gastrointestinal bleeding in Japan with that in other countries.

Performance measures for small-bowel endoscopy: A European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative

The European Society of Gastrointestinal Endoscopy (ESGE) together with the United European Gastroenterology (UEG) recently developed a short list of performance measures for small-bowel endoscopy (i.e. small-bowel capsule endoscopy and device-assisted enteroscopy) with the final goal of providing endoscopy services across Europe with a tool for quality improvement. Six key performance measures both for small-bowel capsule endoscopy and for device-assisted enteroscopy were selected for inclusion, with the intention being that practice at both a service and endoscopist level should be evaluated against them. Other performance measures were considered to be less relevant, based on an assessment of their overall importance, scientific acceptability, and feasibility. Unlike lower and upper gastrointestinal endoscopy, for which performance measures had already been identified, this is the first time small-bowel endoscopy quality measures have been proposed.

Meta-analysis shows similar re-bleeding rates among Western and Eastern populations after index video capsule endoscopy

BACKGROUND & AIMS

Video capsule endoscopy (VCE) is the first-line diagnostic procedure for investigating obscure gastrointestinal bleeding (OGIB). Different re-bleeding rates following index VCE have been reported among Western and Eastern studies.

METHODS

We conducted a comprehensive literature search to identify studies examining re-bleeding rates after VCE for OGIB. Meta-analysis assessed the pooled proportion of re-bleeding events after VCE for OGIB according to study's origin (Western vs. Eastern) and according to the length of follow-up (≥24 months vs. <24 months). We also calculated the re-bleeding odds ratios (OR; 95% CI) after positive vs. negative index VCE, overt vs. occult initial presentation of bleeding and after interventional treatment for positive index cases, according to the study's origin.

RESULTS

We included 46 (30 Western and 16 Eastern) studies with 5796 patients. Significant heterogeneity was detected among meta-analyzed studies. Overall, the pooled re-bleeding rate was similar between Western (29%; 95% CI: 23-34) and Eastern (21%; 95% CI: 15-27) populations, irrespective of the length of follow-up. The odds of re-bleeding was significantly higher after positive as compared to negative index VCE in Eastern studies (OR: 1.77; 95% CI: 1.07-2.94). Application of specific treatment after positive index VCE was associated with lower re-bleeding odds in both Western (OR: 0.37; 95% CI: 0.16-0.87) and Eastern (OR: 0.39; 95% CI: 0.21-0.72) populations.

CONCLUSIONS

Patients undergoing VCE for OGIB have similar re-bleeding rates in the East and the West, regardless of the length of follow-up. However, increased re-bleeding odds after positive index VCE is observed in Eastern studies.

Retention associated with video capsule endoscopy: systematic review and meta-analysis

BACKGROUND AND AIMS

Video capsule endoscopy (VCE) has become a major diagnostic tool for small-bowel evaluation. However, retention of the video capsule endoscope remains a major concern.

METHODS

We performed a systematic review of VCE retention rates by using Pubmed and SCOPUS (1995-2015). We included studies that enrolled at least 10 patients, included VCE retention rates, and separated retention rates by indication. We used Comprehensive Meta-Analysis (Version 3.0) to calculate pooled prevalence rates with 95% confidence intervals (CIs) and assessed heterogeneity by using the Cochran Q statistic.

RESULTS

We included 25 studies (N = 5876) for patients undergoing VCE for evaluation of potential small-bowel bleeding, 9 studies (N = 968) for patients with suspected inflammatory bowel disease (IBD), 11 studies (N = 558) for patients with established IBD, and 8 studies for patients (N = 111) undergoing VCE for evaluation of abdominal pain and/or diarrhea. We used a random effects model and found that the pooled retention rate was 2.1% for patients with suspected small-bowel bleeding (95% CI, 1.5%-2.8%). Retention rates were 3.6% (95% CI, 1.7%-8.6%) for suspected IBD, 8.2% (95% CI, 6.0%-11.0%) for established IBD, and 2.2% (95% CI, 0.9%-5.0%) for abdominal pain and/or diarrhea. Based on subgroup analysis, subsequent VCE completion rates after performance of a patency capsule or CT enterography in patients with IBD to exclude retentions due to strictures was 2.7% (95% CI, 1.1%-6.4%). Reasons for retention were provided in 60 (77%) studies. The most common reasons for retention were small-bowel strictures, although etiology was not provided in all studies.

CONCLUSION

VCE retention occurs in approximately 2% of patients undergoing evaluation for small-bowel bleeding and is most likely due to small-bowel strictures. Retention rates in patients with suspected or known IBD were approximately 4% and 8%, based on our meta-analysis. These rates decreased by half in those studies that used either a patency capsule or CT enterography to assess patency before performing VCE.

Capsule retention: prevention, diagnosis and management

Capsule retention (CR) has been defined as capsule remaining in the digestive tract for a minimum of two weeks. CR occurs approximately in 2% of all patients undergoing small bowel capsule endoscopy (CE). Prompt diagnosis of CR is important, as it has relevant clinical implications. CR should be suspected in (I) all asymptomatic patients who do not report capsule excretion within 15 days from capsule ingestion; and (II) patients with obstructive or perforation-related symptoms in which the capsule has not been excreted, regardless of the time between the onset of symptoms and capsule ingestion. Abdominal plain X-ray is the preferred test to confirm CR. An abdominal CT scan should be performed, on individual basis, if knowledge of the precise location of the retained capsule is necessary or whenever clinically indicated. Since CR is usually asymptomatic, an initial watchful monitoring is suggested. In inflammatory bowel disease (IBD) patients, a short course of medical therapy may allow capsule excretion. Nevertheless, in long-term CR, some cases of capsule fragmentation, acute obstruction and perforation have been described. Therefore, retrieval of the retained capsule is recommended if asymptomatic CR lasts for long time. A safe capsule retrieval is usually performed by endoscopy, whereas surgery remains a viable alternative if the first is unsuccessful or when clinically indicated. Either Patency Capsule^® (PC) or dedicated small bowel cross-sectional imaging techniques have been proposed to prevent CR. Both have pros and cons, but head-to-head comparative studies are lacking.

Long-term effects of video capsule endoscopy in the management of obscure gastrointestinal bleeding

Obscure gastrointestinal bleeding (OGIB) accounts for approximately 5% of all gastrointestinal (GI) hemorrhages. It usually arises from a small bowel lesion beyond the reach of conventional endoscopy including esophagogastroduodenoscopy and colonoscopy. Video capsule endoscopy (VCE) revolutionized the evaluation of OGIB patients since it allows reliable and noninvasive visualization of the small bowel mucosal surface. Since 2001, VCE has evolved into an efficient technology integrated in clinical practice. It is the cornerstone in the algorithm of OGIB investigation given its high diagnostic yield, which compares favorably to that of double-balloon enteroscopy (DBE). In terms of outcomes, a positive index VCE examination usually correlates to a high re-bleeding rate, while a negative one provides adequate evidence of low re-bleeding risk, suggesting a wait and watch approach in this subset of patients. Additionally, a variety of factors has been acknowledged as significant predictors of re-bleeding episodes. While research data regarding immediate endoscopic findings have matured, data concerning the clinical utility of VCE in patients with OGIB on the long-term remain sparse. This manuscript reviews the current literature, aiming to highlight the role of VCE in the long-term management of OGIB.

Clinical outcomes of negative small-bowel capsule endoscopy for small-bowel bleeding: a systematic review and meta-analysis

BACKGROUND AND AIMS

Small-bowel bleeding is the primary indication for capsule endoscopy (CE). Many experts advocate a "watch-and-wait" policy in negative CE. This meta-analysis examines the odds of rebleeding after negative index CE and the impact on long-term follow-up.

METHODS

A comprehensive literature search identified articles examining the rebleeding rate after negative CE. Demographic and clinical information with emphasis on outcomes was retrieved, pooled, and analyzed. Heterogeneity among studies was assessed using the I² statistic. A random effects model was used as the pooling method because of high heterogeneity. Risk of bias was assessed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool. The primary outcome evaluated was the pooled odds ratios (ORs) for rebleeding after a negative CE for obscure GI bleeding (OGIB).

RESULTS

Twenty-six studies with 3657 patients were included. The pooled rate of rebleeding after negative CE was .19 (95% CI, .14-.25; P < .0001). The pooled OR of rebleeding was .59 (95% CI, .37-.95; P < .001). The effect was more pronounced in studies with a short follow-up (OR, .47; 95% CI, .24-.94; P < .001). There was no statistically significant difference in rebleeding after CE for occult and overt OGIB. Prospective studies showed a lower OR of rebleeding of .24 (95% CI, .08-.73; P = .01). Most studies were high quality.

CONCLUSIONS

Our analysis shows that negative CE provides adequate evidence of a subsequently low risk of rebleeding. Such patients can therefore be safely managed with watchful waiting. However, patients who rebleed after 2 years may need to be investigated for a new source of blood loss.

Video Capsule Endoscopy: Technology, Reading, and Troubleshooting

Video capsule endoscopy (VCE) has completed the endoscopic visualization of the entire luminal gastrointestinal tract. VCE can be performed in inpatients and outpatients, requires appropriate bowel preparation before the study, and can be administered via oral swallowing or endoscopic device placement into the small bowel based on outlined patient-dependent factors. Current commercially available VCE systems were reviewed and compared for individual features and attributes. This article focuses on preparation for VCE, currently available VCE technology, how to read a VCE study, and risks and contraindications to VCE.

The role of capsule endoscopy in the diagnosis and treatment of obscure gastrointestinal bleeding in older individuals

BACKGROUND/AIM

Capsule endoscopy (CE) is currently recommended as the first-line diagnostic modality for the investigation of obscure gastrointestinal bleeding (OGIB). This study aimed to evaluate the diagnostic efficacy of CE and to determine the subsequent impacts on the treatment of the OGIB episode in older individuals.

METHODS

Eight hundred and fifty-three patients who underwent CE for the indication of OGIB were investigated in a single center between January 2004 and December 2015. Patients were divided into two groups: those 65 years of age and older and those younger than 65 years of age.

RESULTS

There were no significant differences between older patients and younger patients with respect to the CE completion rate. The diagnostic yield was significantly higher in older patients than in younger patients (55.1 vs. 46.6%, P=0.021). Vascular lesions were the main cause of bleeding in the elderly, whereas ulcerated/erosive lesions were found most frequently in younger patients. Furthermore, 56.0% of older patients with positive CE results had relevant changes in their management plans and received specific treatment on the basis of CE findings.

CONCLUSION

Our study confirmed the important role of CE in the diagnosis of OGIB and its huge impact on decision making in the management plan for older patients.

Obscure gastrointestinal bleeding: diagnosis and treatment

Small-bowel bleeding comprises a majority of obscure gastrointestinal bleeding, but is caused by various kinds of diseases. For its diagnosis, history-taking and physical examination is requisite, leading to a suspicion of what diseases are involved. Next, cross-sectional imaging such as computed tomography should be done, followed by the latest enteroscopy, videocapsule endoscopy and deep enteroscopy according to the severity of hemorrhage and patient conditions. After comprehensive diagnosis, medical, enteroscopic, or surgical treatment should be selected.

Clinical applications of small bowel capsule endoscopy

Video capsule endoscopy has revolutionized our ability to visualize the entire small bowel mucosa. This modality is established as a valuable tool for the diagnosis of obscure gastrointestinal bleeding, Crohn's disease, small bowel tumors, and other conditions involving the small bowel mucosa. This review includes an overview of the current and potential future clinical applications of small bowel video endoscopy.

Clinical applications of small bowel capsule endoscopy

Video capsule endoscopy has revolutionized our ability to visualize the entire small bowel mucosa. This modality is established as a valuable tool for the diagnosis of obscure gastrointestinal bleeding, Crohn’s disease, small bowel tumors, and other conditions involving the small bowel mucosa. This review includes an overview of the current and potential future clinical applications of small bowel video endoscopy.