Small bowel capsule endoscopy: Where are we after almost 15 years of use?

Endoscopic GI placement of capsule endoscopy to investigate the small bowel: a multicenter European retrospective series of 630 procedures in adult patients

BACKGROUND AND AIMS

Small-bowel (SB) capsule endoscopy (CE) is a first-line procedure for exploring the SB. Endoscopic GI PlacemenT (EGIPT) of SB CE is sometimes necessary. Although experience with EGIPT is considerable in pediatric populations, we aimed to describe the safety, efficacy, and outcomes of EGIPT of SB CE in adult patients.

METHODS

The international CApsule endoscopy REsearch (iCARE) group set up a retrospective multicenter study. Patients over age 18 years who underwent EGIPT of SB CE before May 2022 were included. Data were collected from medical records and capsule recordings. The primary endpoint was the technical success rate of the EGIPT procedures.

RESULTS

Of 39,565 patients from 29 centers, 630 (1.6%) were included (mean age, 62.5 years; 55.9% women). The technical success of EGIPT was achieved in 610 procedures (96.8%). Anesthesia (moderate to deep sedation or general anesthesia) and centers with intermediate or high procedure loads were independent factors of technical success. Severe adverse events occurred in 3 patients (.5%). When technically successful, EGIPT was associated with a high SB CE completion rate (84.4%) and with a substantial diagnostic yield (61.1%). The completion rate was significantly higher when the capsule was delivered in the SB compared with when it was delivered in the stomach.

CONCLUSIONS

EGIPT of SB CE is highly feasible and safe, with a high completion rate and diagnostic yield. When indicated, it should be performed with patients under anesthesia, and the capsule should be delivered in the duodenum rather than the stomach for better SB examination outcomes.

An ingestible near-infrared fluorescence capsule endoscopy for specific gastrointestinal diagnoses

Early diagnosis of gastrointestinal (GI) diseases is important to effectively prevent carcinogenesis. Capsule endoscopy (CE) can address the pain caused by wired endoscopy in GI diagnosis. However, existing CE approaches have difficulty effectively diagnosing lesions that do not exhibit obvious morphological changes. In addition, the current CE cannot achieve wireless energy supply and attitude control at the same time. Here, we successfully developed a novel near-infrared fluorescence capsule endoscopy (NIFCE) that can stimulate and capture near-infrared (NIR) fluorescence images to specifically identify subtle mucosal microlesions and submucosal lesions while capturing conventional white light (WL) images to detect lesions with significant morphological changes. Furthermore, we constructed the first synergetic system that simultaneously enables multi-attitude control in NIFCE and supplies long-term power, thus addressing the issue of excessive power consumption caused by the NIFCE emitting near-infrared light (NIRL). We performed in vivo experiments to verify that the NIFCE can specifically "light up" tumors while sparing normal tissues by synergizing with probes actively aggregated in tumors, thus realizing specific detection and penetration. The prototype NIFCE system represents a significant step forward in the field of CE and shows great potential in efficiently achieving early targeted diagnosis of various GI diseases.

Celiac disease diagnosis from endoscopic images based on multi-scale adaptive hybrid architecture model

Objective. Celiac disease (CD) has emerged as a significant global public health concern, exhibiting an estimated worldwide prevalence of approximately 1%. However, existing research pertaining to domestic occurrences of CD is confined mainly to case reports and limited case analyses. Furthermore, there is a substantial population of undiagnosed patients in the Xinjiang region. This study endeavors to create a novel, high-performance, lightweight deep learning model utilizing endoscopic images from CD patients in Xinjiang as a dataset, with the intention of enhancing the accuracy of CD diagnosis.Approach. In this study, we propose a novel CNN-Transformer hybrid architecture for deep learning, tailored to the diagnosis of CD using endoscopic images. Within this architecture, a multi-scale spatial adaptive selective kernel convolution feature attention module demonstrates remarkable efficacy in diagnosing CD. Within this module, we dynamically capture salient features within the local channel feature map that correspond to distinct manifestations of endoscopic image lesions in the CD-affected areas such as the duodenal bulb, duodenal descending segment, and terminal ileum. This process serves to extract and fortify the spatial information specific to different lesions. This strategic approach facilitates not only the extraction of diverse lesion characteristics but also the attentive consideration of their spatial distribution. Additionally, we integrate the global representation of the feature map obtained from the Transformer with the locally extracted information via convolutional layers. This integration achieves a harmonious synergy that optimizes the diagnostic prowess of the model.Main results. Overall, the accuracy, specificity, F1-Score, and precision in the experimental results were 98.38%, 99.04%, 98.66% and 99.38%, respectively.Significance. This study introduces a deep learning network equipped with both global feature response and local feature extraction capabilities. This innovative architecture holds significant promise for the accurate diagnosis of CD by leveraging endoscopic images captured from diverse anatomical sites.

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.

Preclinical study of a novel ingestible bleeding sensor for upper gastrointestinal bleeding

BACKGROUND/AIMS

Upper gastrointestinal bleeding (UGIB) is a life-threatening condition that necessitates early identification and intervention and is associated with substantial morbidity, mortality, and socioeconomic burden. However, several diagnostic challenges remain regarding risk stratification and the optimal timing of endoscopy. The PillSense System is a noninvasive device developed to detect blood in patients with UGIB in real time. This study aimed to assess the safety and performance characteristics of PillSense using a simulated bleeding model.

METHODS

A preclinical study was performed using an in vivo porcine model (14 animals). Fourteen PillSense capsules were endoscopically placed in the stomach and blood was injected into the stomach to simulate bleeding. The safety and sensitivity of blood detection and pill excretion were also investigated.

RESULTS

All the sensors successfully detected the presence or absence of blood. The minimum threshold was 9% blood concentration, with additional detection of increasing concentrations of up to 22.5% blood. All the sensors passed naturally through the gastrointestinal tract.

CONCLUSION

This study demonstrated the ability of the PillSense System sensor to detect UGIB across a wide range of blood concentrations. This ingestible device detects UGIB in real time and has the potential to be an effective tool to supplement the current standard of care. These favorable results will be further investigated in future clinical studies.

Robotic Pills as Innovative Personalized Medicine Tools: A Mini Review

The most common route for drug administration is the oral route due to the various advantages offered by this route, such as ease of administration, controlled and sustained drug delivery, convenience, and non-invasiveness. In spite of this, oral drug absorption faces challenges due to various issues related to its stability, permeability and solubility in the GI tract. Biologic drugs generally face problems when administered by oral route as they are readily degradable and thus required to be injected. To overcome these issues in oral absorption, different approaches like novel drug delivery systems and newer pharmaceutical technologies have been adopted. With a combined knowledge of drug delivery and pharmaceutical technology, robotic pills can be designed and used successfully to enhance the adhesion and permeation of drugs through the mucus membrane of the GI tract to achieve drug delivery at the target site. The potential application of robotic pills in diagnosis and drug dispensing is also discussed. The review highlights recent developments in robotic pill drug-device technology and discusses its potential applications to solve the problems and challenges in oral drug delivery.

Small Bowel Capsule Endoscopy and Enteroscopy: A Shoulder-to-Shoulder Race

Traditional methods have their limitations when it comes to unraveling the mysteries of the small bowel, an area historically seen as the "black box" of the gastrointestinal tract. This is where capsule endoscopy and enteroscopy have stepped in, offering a remarkable synergy that transcends the sum of their individual capabilities. From their introduction, small bowel capsule endoscopy and device-assisted enteroscopy have consistently evolved and improved, both on their own and interdependently. Each technique's history may be told as a success story, and their interaction has revolutionized the approach to the small bowel. Both have advantages that could be ideally combined into a perfect technique: safe, non-invasive, and capable of examining the entire small bowel, taking biopsies, and applying therapeutical interventions. Until the realization of this perfect tool becomes a reality, the key for an optimal approach lies in the right selection of exploration method. In this article, we embark on a journey through the intertwined development of capsule endoscopy and enteroscopy, exploring the origins, technological advancements, clinical applications, and evolving inquiries that have continually reshaped the landscape of small bowel imaging.

Gastrointestinal Transit Times in Health as Determined Using Ingestible Capsule Systems: A Systematic Review

BACKGROUND

Ingestible capsule (IC) systems can assess gastrointestinal (GI) transit times as a surrogate for gut motility for extended periods of time within a minimally invasive, radiation-free and ambulatory setting.

METHODS

A literature review of IC systems and a systematic review of studies utilizing IC systems to measure GI transit times in healthy volunteers was performed. Screening for eligible studies, data extraction and bias assessments was performed by two reviewers. A narrative synthesis of the results was performed.

RESULTS

The literature review identified 23 different IC systems. The systematic review found 6892 records, of which 22 studies were eligible. GI transit time data were available from a total of 1885 healthy volunteers. Overall, seventeen included studies reported gastric emptying time (GET) and small intestinal transit time (SITT). Colonic transit time (CTT) was reported in nine studies and whole gut transit time (WGTT) was reported in eleven studies. GI transit times in the included studies ranged between 0.4 and 15.3 h for GET, 3.3-7 h for SITT, 15.9-28.9 h for CTT and 23.0-37.4 h for WGTT. GI transit times, notably GET, were influenced by the study protocol.

CONCLUSIONS

This review provides an up-to-date overview of IC systems and reference ranges for GI transit times. It also highlights the need to standardise protocols to differentiate between normal and pathological function.

Gastrointestinal angiodysplasias diagnosed using video capsule endoscopy in 15 dogs

BACKGROUND

Angiodysplasia (AGD) is rarely diagnosed in dogs with gastrointestinal bleeding (GIB) and is reported in case reports in dogs.

OBJECTIVE

Describe signalment, clinical and diagnostic features of dogs with gastrointestinal (GI) AGD diagnosed by video capsule endoscopy (VCE).

ANIMALS

Dogs with overt or suspected GIB which underwent VCE.

METHODS

Dogs for which a VCE was submitted for overt or suspected GIB from 2016 to 2021 were selected retrospectively. Medical records and full-length VCE recordings where AGDs were initially detected, were reviewed by 2 trained internists. AGD was considered definitive if 2 readers detected it. Signalment, clinical signs, blood work, medications, concurrent diseases, findings of previous conventional endoscopy, and surgical exploration (if applicable) of dogs with AGD were recorded.

RESULTS

Definitive AGD was diagnosed in 15 of 291 (5%) dogs (12 males, 3 females). Twelve (80%) had overt GIB, 11 (73%) had hematochezia, and 6 (40%) had microcytic and hypochromic anemia. AGD was missed by conventional endoscopy in 9/9 dogs and exploratory surgery in 3/3 dogs. Thirteen capsules were administered by mouth (1 incomplete study), and 2 via endoscopy directly into the duodenum. AGD was visualized in the stomach of 3 dogs, in the small intestine of 4, and in the colon of 13 dogs.

CONCLUSION AND CLINICAL IMPORTANCE

Although rare, AGD should be considered in dogs with suspected GIB after a negative conventional endoscopy or surgical exporation. Video capsuel endoscopy appears to be a sensitive test to identify AGD within the GI tract.

Dynamic tracking effect of a magnetic navigated dual hemisphere capsule robot

For diagnostic and therapeutic applications in spacious spots of the gastrointestinal (GI) tract, the single rigid body capsule clinically applied is difficult to realize the fix-point posture adjustment function manipulated by the external permanent magnet system using the static balance control because the posture alignment and the locomotion interfere with each other. To realize this function easily, the dual hemisphere capsule robot (DHCR) is proposed, based on tracking effect—the axis of DHCR keeps tracking the normal orientation of the spatial universal rotating magnetic vector (SURMV). Since tracking effect employs dynamic balance control, dynamic stability of the DHCR system affects posture alignment performance. This paper focuses on posture alignment dynamic modeling and the influence of the magnetic flux density and the angular velocity of the SURMV, along with the damping coefficient of the GI tract surface on stability, obtaining the stability domains of parameters. Furthermore, to reduce error due to the uncertainties in complex GI tract environment, the sliding mode controller based on nominal model is proposed to achieve more accurate dynamic tracking, and Lyapunov theorem is employed to assess stability of controller. Finally, the tracking effect is verified through simulations and experiments, indicating that the fix-point posture adjustment can be realized with higher accuracy and efficiency.

Source multiplexing enhances the number of channels of a multispectral sensor

This paper presents preliminary work on a method to increase the number of detection channels of a commercial 6-channel spectrometric sensor, by employing a set of multiplexed spectrally colored illumination sources. A demonstrator has been built and tested on a set of independent dyes. The results suggest successful enhancement of the number of detection channels. More tests are needed to provide quantitative performance evaluation, and to demonstrate viability in a clinical setting. Clinical Relevance- The technique presented in this paper shows promise to provide a viable method for multispectral sensing in highly-miniaturized systems such as in-vivo sensing capsules.

Soft hybrid intrinsically motile robot for wireless small bowel enteroscopy

BACKGROUND

Difficulties in establishing diagnosis of small bowel (SB) disorders, prevented their effective treatment. This problem was largely resolved by wireless capsule endoscopy (WCE), which has since become the first line investigation for suspected SB disorders. Several types of WCE pills are now used in clinical practice, despite their limitations and complications. WCE pills are large, rigid and immotile capsules. When swallowed, they provide SB enteroscopy downloaded to a data logger carried by the patient. Most of the complications of WCEs result from lack of intrinsic locomotion: incomplete examination, capsule retention and impaction within strictures. In addition, the rigid nature and size of current generation of WCE pills is accompanied by 0.1% inability to swallow the pill by patients with normal esophageal motility.

METHODS

The aim of this communication is to describe the initial prototype, P1, which is thinner and slightly longer than the current generation of WCEs. In addition, it exhibits intrinsic active locomotion, produced by vibrating silicon legs. These generate a controlled-skid locomotion on the small bowel mucosal surface, rendered slippery by surface mucus and intraluminal surfactant bile salts. We demonstrate the mechanism responsible for the active locomotion of P1, which we consider translatable into a working prototype, suitable for further R&D for eventual clinical translation.

RESULTS

The shape and attachment of the rubber vibrating legs to vibrating actuators, have been designed specifically to produce a tight clockwise circular motion. When inserted inside a circular tube in vitro of equivalent diameter to human small intestine, the intrinsic circular clockwise motion of P1 translates into a linear locomotion by the constraints imposed by the surrounding circular walls of SB and rest of the gastrointestinal tract. This design ensures device stability during transit, essential for imaging and targeting lesions encountered during the enteroscopy. We preformed two experiments: (i) transit of P1 through a phantom consisting of a segment of PVC tube placed on a horizontal surface and (ii) transit through a transparent slippery nylon sleeve insufflated with air. In the PVC tube, its transit rate averages 15.6 mm/s, which is too fast for endoscopy: whereas inside the very slippery nylon sleeve insufflated with air, the average transit rate of P1 is reduced to 5.9 mm/s, i.e., ideal for inspection endoscopy.

CONCLUSIONS

These in-vitro experiments indicate that the P1 hybrid soft robot prototype has the potential specifically for clinical translation for SB enteroscopy.

Clinical impact of wireless capsule endoscopy for small bowel investigation (Review)

Wireless capsule endoscopy is currently considered the gold standard in the investigation of the small bowel. It is both practical for physicians and easily accepted by patients. Prior to its development, two types of imaging investigations of the small bowel were available: radiologic and endoscopic. The first category is less invasive and comfortable for patients; it presents the ensemble of the small bowel, but it may imply radiation exposure. Images are constructed based on signals emitted by various equipment and require special interpretation. Endoscopic techniques provide real-time colored images acquired by miniature cameras from inside the small bowel, require interpretation only from a medical point of view, may allow the possibility to perform biopsies, but the investigation only covers a part of the small bowel and are more difficult to accept by patients. Wireless capsule endoscopy is the current solution that overcomes a part of the previous drawbacks: it covers the entire small bowel, it provides real-time images acquired by cameras, it is painless for patients, and it represents an abundant source of information for physicians. Yet, it lacks motion control and the possibility to perform biopsies or administer drugs. However, significant effort has been oriented in these directions by technical and medical teams, and more advanced capsules will surely be available in the following years.

In vivo models to evaluate ingestible devices: Present status and current trends

Evaluation of orally ingestible devices is critical to optimize their performance early in development. Using animals as a pre-clinical tool can provide useful information on functionality, yet it is important to recognize that animal gastrointestinal physiology, pathophysiology and anatomy can differ to that in humans and that the most suitable species needs to be selected to inform the evaluation. There has been a move towards in vitro and in silico models rather than animal models in line with the 3Rs (Replacement, Reduction and Refinement) as well as the better control and reproducibility associated with these systems. However, there are still instances where animal models provide the greatest understanding. This paper provides an overview of key aspects of human gastrointestinal anatomy and physiology and compares parameters to those reported in animal species. The value of each species can be determined based upon the parameter of interest from the ingested device when considering the use of pre-clinical animal testing.

Celiac Disease Detection From Videocapsule Endoscopy Images Using Strip Principal Component Analysis

The purpose of this study was to implement principal component analysis (PCA) on videocapsule endoscopy (VE) images to develop a new computerized tool for celiac disease recognition. Three PCA algorithms were implemented for feature extraction and sparse representation. A novel strip PCA (SPCA) with nongreedy L1-norm maximization is proposed for VE image analysis. The extracted principal components were interpreted by a non-parametric k-nearest neighbor (k-NN) method for automated celiac disease classification. A benchmark dataset of 460 images (240 from celiac disease patients with small intestinal villous atrophy versus 220 control patients lacking villous atrophy) was constructed from the clinical VE series. It was found that the newly developed SPCA with nongreedy L1-norm maximization was most efficient for computerized celiac disease recognition, having a robust performance with an average recognition accuracy of 93.9 percent. Furthermore, SPCA also has a reduced computation time as compared with other methods. Therefore, it is likely that SPCA will be a helpful adjunct for the diagnosis of celiac disease.

A Descriptive Analysis of Capsule Endoscopy Events in the FDA Manufacturer and User Facility Device Experience (MAUDE) Database

Introduction

The malfunction of capsule endoscopy (CE) devices is a significant reason for the failure of CE procedures, which could hinder and prevent diagnosis. Unfortunately, malfunction-related adverse events (AEs) caused by CE devices are rarely reported in publications. Although most malfunction-related AEs could not lead to physical harm, they could reduce the efficiency of medical care and increase medical costs. The manufacturer and user facility device experience (MAUDE) database, a publicly accessible resource for patient safety, contains not only the common complications of CE but also valuable malfunction-related AEs, which have been underutilized. Therefore, the study aims to discover and analyze the possible AEs associated with CE and demonstrate the utility of the MAUDE reports to promote patient safety.

Materials and Methods

We acquired MAUDE reports of CE systems from January 01, 2008, to July 31, 2020, through a systematic search strategy. We utilized the manufacturers, brand names, and product codes as search terms from which medical device reports including structured data and narrative texts were extracted, followed by a manual review of the narrative texts, reporter occupation, device involved, event type and the phase of the event; finally, patient outcomes were recorded and analyzed as per CE categories and characteristics.

Results

A total of 377 CEs medical device reports were retrieved, and 342 reports were included after reviewing. There were 327 mandatory reports (96%) and 15 voluntary reports (4%). These reports referred to capsule endoscope (n = 213), sensing system (n = 66), patency capsule (n = 38), and capsule delivery device (n = 26). A total of 349 CE-related AEs were identified, including complications (n = 228), malfunction-related AEs (n = 109), and other events (n = 12). The composition of AEs was not the same for the CE devices. Complications were major AEs of capsule endoscope and patency capsule, but malfunction-related AEs were the most common in AEs of sensing systems and capsule delivery devices.

Conclusion

MAUDE serves as an invaluable data source for investigating malfunction-related AEs. In addition to common complications, malfunction of CE devices could threaten patient safety in CE procedures. Improving awareness of the malfunction of CE devices and raising adequate training for staff working in gastrointestinal (GI) endoscopic units could be critical and beneficial in preventing malfunction-related AEs.

Feature Point Tracking-Based Localization of Colon Capsule Endoscope

In large bowel investigations using endoscopic capsules and upon detection of significant findings, physicians require the location of those findings for a follow-up therapeutic colonoscopy. To cater to this need, we propose a model based on tracking feature points in consecutive frames of videos retrieved from colon capsule endoscopy investigations. By locally approximating the colon as a cylinder, we obtained both the displacement and the orientation of the capsule using geometrical assumptions and by setting priors on both physical properties of the intestine and the image sample frequency of the endoscopic capsule. Our proposed model tracks a colon capsule endoscope through the large intestine for different prior selections. A discussion on validating the findings in terms of intra and inter capsule and expert panel validation is provided. The performance of the model is evaluated based on the average difference in multiple reconstructed capsule’s paths through the large intestine. The path difference averaged over all videos was as low as 4±0.7 cm, with min and max error corresponding to 1.2 and 6.0 cm, respectively. The inter comparison addresses frame classification for the rectum, descending and sigmoid, splenic flexure, transverse, hepatic, and ascending, with an average accuracy of 86%.

Artificial Intelligence in Small Bowel Endoscopy: Current Perspectives and Future Directions

Artificial intelligence (AI) is a computer system that is able to perform tasks which normally require human intelligence. The role of AI in the field of gastroenterology has been gradually evolving since its inception in the 1950s. Discovery of wireless capsule endoscopy (WCE) and balloon enteroscopy (BE) has revolutionized small gut imaging. While WCE is a relatively patient-friendly and noninvasive mode to examine the nonobstructed small gut, it is limited by a lengthy examination time and the need for expertise in reading images acquired by the capsule. Similarly, BE, despite having the advantage of therapeutic intervention, is costly, invasive, and requires general sedation. Incorporation of concepts like machine learning and deep learning has been used to handle large amounts of data and images in gastroenterology. Interestingly, in small gut imaging, the application of AI has been limited to WCE only. This review was planned to examine and summarize available published data on various AI-based approaches applied to small bowel disease.

We conducted an extensive literature search using Google search engine, Google Scholar, and PubMed database for published literature in English on the application of different AI techniques in small bowel endoscopy, and have summarized the outcome and benefits of these applications of AI in small bowel endoscopy. Incorporation of AI in WCE has resulted in significant advancements in the detection of various lesions starting from dysplastic mucosa, inflammatory and nonmalignant lesions to the detection of bleeding with increasing accuracy and has shortened the lengthy review time in image analysis. As most of the studies to evaluate AI are retrospective, the presence of inherent selection bias cannot be excluded. Besides, the interpretability (black-box nature) of AI models remains a cause for concern. Finally, issues related to medical ethics and AI need to be judiciously addressed to enable its seamless use in future.

Adverse events of video capsule endoscopy over the past two decades: a systematic review and proportion meta-analysis

BACKGROUND

A full spectrum of video capsule endoscopy (VCE) adverse events over the past two decades has not been evaluated. We aimed to determine pooled rates, predictors and temporal-trend of VCE adverse events over the past two decades.

METHODS

Systematic search of PubMed and EMBASE for English-language publications reporting VCE adverse events (January 1, 2000 to March 31, 2019). Data were extracted independently by two investigators. Pooled VCE adverse event rates were calculated using the random or fixed model as appropriate. Predictors and temporal-trend of each adverse event were performed by meta-regression analyses.

RESULTS

In total, 402 studies were identified, including 108,079 VCE procedures. Rate of retention, swallow disorder, aspiration, technical failure, and procedural adverse events were 0.73% (95% confidence interval [CI] 0.59-0.89%), 0.75% (95% CI 0.43-1.13%), 0.00% (95% CI 0.00-0.00%), 0.94% (95% CI 0.65-1.28%), 0.67% (95% CI 0.32-1.10%), respectively; incomplete examination rate of esophagus, stomach, small bowel, and colon were 9.05%, 7.69%, 12.08%, 19.19%, respectively. Patency capsule reduced retention rate by 5.04%, whereas known inflammatory bowel disease increased retention rate by 4.29%. Elder was the risk and protective factor for small bowel incomplete examination (0.30%) and swallow disorder (- 0.72%), respectively. Rates of retention and small bowel incomplete examination significantly declined over time (P = .0006 and P < .0001)..

CONCLUSIONS

VCE adverse event rates were generally low, and retention and small bowel incomplete examination rates declined over the past two decades. Patients with known inflammatory bowel disease or elder should be alerted to high risk of retention or small bowel incomplete examination (PROSPERO: CRD42019139595).

Ingestible Sensors and Sensing Systems for Minimally Invasive Diagnosis and Monitoring: The Next Frontier in Minimally Invasive Screening

Ingestible electronic systems that are capable of embedded sensing, particularly within the gastrointestinal (GI) tract and its accessory organs, have the potential to screen for diseases that are difficult if not impossible to detect at an early stage using other means. Furthermore, these devices have the potential to (1) reduce labor and facility costs for a variety of procedures, (2) promote research for discovering new biomarker targets for associated pathologies, (3) promote the development of autonomous or semiautonomous diagnostic aids for consumers, and (4) provide a foundation for epithelially targeted therapeutic interventions. These technological advances have the potential to make disease surveillance and treatment far more effective for a variety of conditions, allowing patients to lead longer and more productive lives. This review will examine the conventional techniques, as well as ingestible sensors and sensing systems that are currently under development for use in disease screening and diagnosis for GI disorders. Design considerations, fabrication, and applications will be discussed.

An Ingenious Design of a High Performance-Low Complexity Image Compressor for Wireless Capsule Endoscopy

Wireless Capsule Endoscopy is a state-of-the-art technology for medical diagnoses of gastrointestinal diseases. The amount of data produced by an endoscopic capsule camera is huge. These vast amounts of data are not practical to be saved internally due to power consumption and the available size. So, this data must be transmitted wirelessly outside the human body for further processing. The data should be compressed and transmitted efficiently in the domain of power consumption. In this paper, a new approach in the design and implementation of a low complexity, multiplier-less compression algorithm is proposed. Statistical analysis of capsule endoscopy images improved the performance of traditional lossless techniques, like Huffman coding and DPCM coding. Furthermore the Huffman implementation based on simple logic gates and without the use of memory tables increases more the speed and reduce the power consumption of the proposed system. Further analysis and comparison with existing state-of-the-art methods proved that the proposed method has better performance.

Clinical characteristics of small bowel tumors diagnosed by double-balloon endoscopy: Experience from a Chinese tertiary hospital

BACKGROUND/AIMS

To determine the characteristics of small bowel tumors (SBTs) in patients underwent double balloon endoscopy (DBE) and to compare the clinical value of DBE with other diagnostic tools.

MATERIALS AND METHODS

A retrospective study was conducted in patients underwent DBE procedures from March 2008 to April 2017.The demographic, clinical and pathological characteristics of patients with SBTs were recorded, while the diagnosis of SBTs was achieved either by DBE biopsy or surgical specimens.

RESULTS

One thousand one hundred and two patients (761 males, range 3-85 years) were enrolled in this study, with 1140 procedures completed in total. 99/1102 patients (9.0%) had SBTs, including benign polyps (20, 20.2%), gastrointestinal stromal tumors (GISTs) (24, 24.2%), lymphomas (13, 13.1%), adenocarcinoma (39, 39.4%), and neuroendocrine tumors (3, 3.0%). The most common clinical symptom for benign polyps was obscure gastrointestinal bleeding (OGIB) (75.0%). But among patients with malignant SBTs, the main indication for DBE was chronic abdominal pain (43.8%), followed by OGIB (36.3%), vomit (10.0%), abnormal images (6.3%) and diarrhea (3.8%) (P<0.001). Moreover, SBTs were primarily located in the jejunum alone (40/99, 40.4%). DBE had better sensitivity (89.2%), specificity (95.2%), positive predictive value (PPV) (90.0%), and negative predictive value (NPV) (94.8%) than other tools for suspected SBTs.

CONCLUSION

Small bowel tumor is mainly located in jejunum and with OGIB and abdominal pain as major complaints. DBE is a reliable method for the diagnosis of SBTs compared with other diagnostic tools.

Current Evidence on Computer-Aided Diagnosis of Celiac Disease: Systematic Review

Celiac disease (CD) is a chronic autoimmune disease that occurs in genetically predisposed individuals in whom the ingestion of gluten leads to damage of the small bowel. It is estimated to affect 1 in 100 people worldwide, but is severely underdiagnosed. Currently available guidelines require CD-specific serology and atrophic histology in duodenal biopsy samples for the diagnosis of adult CD. In pediatric CD, but in recent years in adults also, nonbioptic diagnostic strategies have become increasingly popular. In this setting, in order to increase the diagnostic rate of this pathology, endoscopy itself has been thought of as a case finding strategy by use of digital image processing techniques. Research focused on computer aided decision support used as database video capsule, endoscopy and even biopsy duodenal images. Early automated methods for diagnosis of celiac disease used feature extraction methods like spatial domain features, transform domain features, scale-invariant features and spatio-temporal features. Recent artificial intelligence (AI) techniques using deep learning (DL) methods such as convolutional neural network (CNN), support vector machines (SVM) or Bayesian inference have emerged as a breakthrough computer technology which can be used for computer aided diagnosis of celiac disease. In the current review we summarize methods used in clinical studies for classification of CD from feature extraction methods to AI techniques.

Wireless intravesical device for real-time bladder pressure measurement: Study of consecutive voiding in awake minipigs

Traditional urodynamics have poor correlation with urological symptoms. Ambulatory urodynamics may improve this correlation but the need for a transurethral catheter and the time-consuming nature of this examination limits its use. Therefore, the objective of this study was to develop a wireless real-time bladder pressure measurement device for repeated and prolonged-term measurement of bladder behavior in awake pigs. The Bladder Pill is an intravesical device with a pressure microsensor and a 3-dimensional inductive coupling coil for energy supply. A corresponding external coil provides wireless power transmission and real-time communication of bladder pressure data. To test the correlation between the pressure data measured by the device and by standard methods, we compared static water column pressures with this device and water-filled urodynamic catheter systems. In vivo assessment of awake voiding by the pill was done by introducing the bladder pill into the bladder of Göttingen minipigs. An air-charged urodynamic catheter was introduced transurethrally as control for pressure measurements. The optimal physical configuration of the pill was investigated to maximize the containment in the bladder. We used two versions of external signal receivers (one waistband and one rectangular frame) to test the optimal external signal capture. Next to that, we performed short-term and medium-term comparative pressure studies. The in vitro static pressure measurement demonstrated a mean difference of less than 1 cm H₂O between the methods. The optimal design of the pill for maximal retainment in the bladder proved to be a pigtail configuration. The bending of the device during bladder contractions caused offset of 2.7 +/- 1.4 cm H₂O (mean +/- SD) on the pressure measurements. The rectangular frame performed signal capture during 5 consecutive voids with a good correlation of the pressure measurements. The device can be inserted through the urethra and is retrieved using string or endoscopic extraction. In conclusion, wireless long-term measurement of bladder pressure is demonstrated and yields comparable results to current available catheter methods of measurement in a pig model.

Evaluation of Suitability of Current Industrial Standards in Designing Control Applications for Internet of Things Healthcare Sensor Networks

Internet of Things (IoT) holds great promises for industrial, commercial, and consumer applications. While wireless techniques have matured with time and have gained the users’ confidence in relaying data containing qualitative as well as quantitative information, cynicism still exists on trusting them for applications involving control. The wireless protocols and techniques used for industrial control have proved their robustness. In this work we have attempted to test some aspects of feasibility on the use of wireless control involving such protocols for IoT healthcare sensor networks (IoT-HSNs). We conceptualized and simulated a 24-channel IoT-HSN model that includes biosensors as well as bioactuators. Currently, no protocol supporting control in such networks has been standardized. We tried to fit in the widely used WirelessHART (Highway Addressable Remote Transducer) industrial protocol for sensing as well as control in the model to test if it would work for a healthcare sensor network. We probed the performance of the model with respect to network parameters such as channels, bandwidth, Quality of Service (QoS) requirements, payload, transmission delays, and allowable errors. For the parameters considered, the results obtained from the model were encouraging, suggesting that WirelessHART fits the IoT-HSN control requirements according to this initial probe. The findings could provide useful insights for researchers working in the field of control in IoT-HSNs and for designers and manufacturers of IoT-HSN equipment.

Automatic detection of small bowel tumors in wireless capsule endoscopy images using ensemble learning

PURPOSE

Wireless Capsule Endoscopy (WCE) is a minimally invasive diagnosis tool for lesion detection in the gastrointestinal tract, reaching places where conventional endoscopy is unable to. However, the significant amount of acquired data leads to difficulties in the diagnosis by the physicians; which can be eased with computer assistance. This paper addresses a method for the automatic detection of tumors in WCE by using a two-step based procedure: region of interest selection and classification.

METHODS

The first step aims to separate abnormal from normal tissue by using automatic segmentation based on a Gaussian Mixture Model (GMM). A modified version of the Anderson method for convergence acceleration of the expectation-maximization (EM) algorithm is proposed. The proposed features for both segmentation and classification are based on the CIELab color space, as a way of bypassing lightness variations, where the L component is discarded. Tissue variability among subjects, light inhomogeneities and even intensity differences among different devices can be overcome by using simultaneously features from both regions. In the second step, an ensemble system with partition of the training data with a new training scheme is proposed. At this stage, the gating network is trained after the experts have been trained decoupling the joint maximization of both modules. The partition module is also used at the test step, leading the incoming data to the most likely expert allowing incremental adaptation by preserving data diversity.

RESULTS

This algorithm outperforms others based on texture features selected from Wavelets and Curvelets transforms, classified by a regular support vector machine (SVM) in more than 5%.

CONCLUSIONS

This work shows that simpler features can outperform more elaborate ones if appropriately designed. In the current case, luminance was discarded to cope with saturated tissue, facilitating the color perception. Ensemble systems remain an open research field. In the current case, changes in both topology and training strategy have led to significant performance improvements. A system with this level of performance can be used in current clinical practice.

Towards an ASIC-based Fluoroscopic Capsule for the Early Cancer Detection in the Small Intestine

Early micro-cancer detection in the small intestine can be realized using infrared fluorescence endoscopy (IRFE) in conjunction with an infrared fluorescence biomarker. In this paper, we present a third-generation capsule that detects weak fluorescence signals emitted by low concentrations of indocyanine green (ICG). An applicationspecific integrated circuit (ASIC) has been designed and fabricated that integrates many of the peripheral components of the capsule system. The ASIC enables the system to have greater sensitivity whilst reducing the capsule size and lowering the power consumption.

Evaluating a combined bowel preparation for small-bowel capsule endoscopy: a prospective randomized-controlled study

Background

Capsule endoscopy (CE) is frequently hindered by intra-luminal debris. Our aim was to determine whether a combination bowel preparation would improve small-bowel visualization, diagnostic yield, and the completion rate of CE.

Methods

Single-blind, prospective randomized–controlled study of outpatients scheduled for CE. Bowel-preparation subjects ingested 2 L of polyethylene glycol solution the night prior to CE, 5 mL simethicone and 5 mg metoclopramide 20 minutes prior to CE and laid in the right lateral position 30 minutes after swallowing CE. Controls had no solid food after 7 p.m. the night prior to CE and no liquids 4 hours prior to CE. Participants completed a satisfaction survey. Capsule readers completed a small-bowel-visualization assessment.

Results

Fifty patients were prospectively enrolled (56% female) with a median age of 54.4 years and 44 completed the study (23 patients in the control group and 21 in the preparation group). There was no significant difference between groups on quartile-based small-bowel visualization (all P > 0.05). There was no significant difference between groups in diagnostic yield (P = 0.69), mean gastric (P = 0.10) or small-bowel transit time (P = 0.89). The small-bowel completion rate was significantly higher in the preparation group (100% vs 78%; P = 0.02). Bowel-preparation subjects reported significantly more discomfort than controls (62% vs 17%; P = 0.01).

Conclusions

Combined bowel preparation did not improve small-bowel visualization but did significantly increase patient discomfort. The CE completion rate improved in the preparation group but the diagnostic yield was unaffected. Based on our findings, a bowel preparation prior to CE does not appear to improve CE performance and results in decreased patient satisfaction (ClinicalTrials.gov, No. NCT01243736).

Gastrointestinal diagnosis using non-white light imaging capsule endoscopy

Capsule endoscopy (CE) has proved to be a powerful tool in the diagnosis and management of small bowel disorders since its introduction in 2001. However, white light imaging (WLI) is the principal technology used in clinical CE at present, and therefore, CE is limited to mucosal inspection, with diagnosis remaining reliant on visible manifestations of disease. The introduction of WLI CE has motivated a wide range of research to improve its diagnostic capabilities through integration with other sensing modalities. These developments have the potential to overcome the limitations of WLI through enhanced detection of subtle mucosal microlesions and submucosal and/or transmural pathology, providing novel diagnostic avenues. Other research aims to utilize a range of sensors to measure physiological parameters or to discover new biomarkers to improve the sensitivity, specificity and thus the clinical utility of CE. This multidisciplinary Review summarizes research into non-WLI CE devices by organizing them into a taxonomic structure on the basis of their sensing modality. The potential of these capsules to realize clinically useful virtual biopsy and computer-aided diagnosis (CADx) is also reported.

Capsule Endoscopy and Enteroscopy in Celiac Disease

Celiac disease predominantly involves the proximal small bowel, but villus atrophy can be patchy, spare the duodenum, and be present more distally. Video capsule endoscopy is more sensitive than standard endoscopy to detect villus atrophy, and can define extent of disease, though it cannot obtain biopsies. Duodenal biopsy is the gold standard for diagnosis. Video capsule endoscopy assists in special circumstances when biopsy is not possible, and in equivocal diagnosis. Video capsule endoscopy and enteroscopy are recommended for evaluating complicated celiac disease, especially refractory celiac disease type II. Future developments include computer-assisted capsule programs and advanced capsule and enteroscope design.

Benefit of Capsule Endoscopy in the Setting of Iron Deficiency Anemia in Patients Above Age 65

Background

Iron deficiency anemia (IDA) is a common indication for a capsule endoscopy (CE), which is often offered after a negative bidirectional endoscopy. Since malignancy is a concern in the older population with IDA, upper and lower endoscopic exams are typically performed. If these tests are negative, CE may be offered to evaluate the small intestine. However, choosing the ideal candidates who are most likely to benefit from a CE study is challenging.

Aims

The goal of this study was to assess the outcomes for CE in patients with IDA over age 65 and assess which factors are more likely to contribute to a positive CE yield.

Methods

A retrospective review of all CE studies at St. Paul's Hospital from January 2010 to June 2016 was conducted after ethics approval. Inclusion criteria included the following: age >65, hemoglobin <120 g/L, serum ferritin <70 μg/L, and at least one high-quality complete EGD/colonoscopy performed before CE. Variables to assess factors that are more likely to contribute to a positive capsule yield included use of anticoagulation medications, NSAIDs, PPIs, transfusion burden and cardiac disease. A Chi-Square test was then used to determine clinical predictive factors of a positive and negative study.

Results

There were 1149 CE studies that were reviewed, of which 130 CE studies met inclusion criteria. Fifty-one studies (40.6%) had positive findings, and from this group, 30 (58.8%) recommended active intervention (i.e., EGD, n = 8; colonoscopy, n = 12; push enteroscopy, n = 3; double-balloon [DB] enteroscopy, n = 2; small bowel resection, n = 3; escalation of Crohn's therapy, n = 2), while 21 (41.2%) were managed supportively, typically with iron supplementation. Most negative studies (73 of 79) recommended supportive therapy (other recommendations included hematological workup, n = 3; hiatal hernia repair, n = 1; proton-pump inhibitors [PPI] initiation, n = 1; stop donating blood, n = 1).A history of cardiac disease had a significant association with positive findings (0.54 versus 0.33, P = 0.001). Conversely, a known history of low ferritin levels (0.84 versus 0.68, P = 0.046) and a known history of hiatal hernia (0.25 versus 0.08, P = 0.012) were associated with a negative study.

Conclusions

These findings suggest that the clinical yield of CE in IDA in patients above age 65 is relatively low. The majority of all CE studies recommended supportive therapy or repeat endoscopic exams (EGD/colonoscopy) of areas previously assessed and lesions missed. Provided that initial endoscopic exams were thorough and Crohn's disease management was optimized, the overall rate of changing management significantly was low at five of 130 studies (two DB enteroscopies and three resections) or 3.8%. Clinical factors focusing on cardiac history, ferritin levels and the presence of a hiatal hernia may be of utility to predict benefit of CE. Emphasis on these data may help select more appropriate patients for capsule endoscopy.

2D reconstruction of small intestine's interior wall

Examining and interpreting of a large number of wireless endoscopic images from the gastrointestinal tract is a tiresome task for physicians. A practical solution is to automatically construct a two dimensional representation of the gastrointestinal tract for easy inspection. However, little has been done on wireless endoscopic image stitching, let alone systematic investigation. The proposed new wireless endoscopic image stitching method consists of two main steps to improve the accuracy and efficiency of image registration. First, the keypoints are extracted by Principle Component Analysis and Scale Invariant Feature Transform (PCA-SIFT) algorithm and refined with Maximum Likelihood Estimation SAmple Consensus (MLESAC) outlier removal to find the most reliable keypoints. Second, the optimal transformation parameters obtained from first step are fed to the Normalised Mutual Information (NMI) algorithm as an initial solution. With modified Marquardt-Levenberg search strategy in a multiscale framework, the NMI can find the optimal transformation parameters in the shortest time. The proposed methodology has been tested on two different datasets - one with real wireless endoscopic images and another with images obtained from Micro-Ball (a new wireless cubic endoscopy system with six image sensors). The results have demonstrated the accuracy and robustness of the proposed methodology both visually and quantitatively - registration residual error of 0.93±0.33 pixels on 2500 real endoscopy image pairs and residual error accumulation of 16.59 pixels and without affecting the visual registration quality on stitching 152 images of Micro-Ball.

Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn's Disease

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn's disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35–75 mSv), mostly patients with Crohn's disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn's disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the “ALARA” principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn's disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn's disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

Update on small bowel surveillance in hereditary colorectal cancer syndromes

Despite its rarity in the general population, small bowel adenocarcinoma risk is increased in individuals with hereditary colorectal cancer syndromes (HCCS). In the last decade, the advent of capsule endoscopy and device-assisted balloon enteroscopy procedures in patients with HCCS have allowed to investigate the whole small bowel, increasing the diagnostic yield of small bowel tumor. Nonetheless, there is a significant variability in the international guideline recommendations. The aim of this review is to provide an update on surveillance of small bowel in HCCS and to identify the key points for the clinical management of these patients.

Role of capsule endoscopy in alarm features and non-responsive celiac disease: A European multicenter study

BACKGROUND AND AIM

The role of capsule endoscopy (CE) in established celiac disease (CD) remains unclear. Our objective was to analyze the usefulness of CE in the suspicion of complicated CD.

METHODS

This was a retrospective multicenter study. One hundred and eighty-nine celiac patients (mean age: 46.6 ± 16.6, 30.2% males) who underwent CE for alarm symptoms (n = 86, 45.5%) or non-responsive CD (n = 103, 54.5%) were included. Diagnostic yield (DY), therapeutic impact and safety were analyzed.

RESULTS

Capsule endoscopy was completed in 95.2% of patients (small bowel transit time: 270.5 ± 100.2 min). Global DY was 67.2%, detecting atrophic mucosa (n = 92, 48.7%), ulcerative jejunoileitis (n = 21, 11.1%), intestinal lymphoma (n = 7, 3.7%) and other enteropathies (n = 7, 3.7%, six Crohn's disease cases and one neuroendocrine tumor). The DY of CE was significantly higher in patients presenting with non-responsive disease compared to patients with alarm symptoms (73.8% vs 59.3%, P = 0.035). The new findings of the CE modified management in 59.3% of the cases. There were no major complications.

CONCLUSION

Capsule endoscopy may be a moderately helpful and safe diagnostic tool in the suspicion of complicated CD, modifying the clinical course of these patients.

What defines quality in small bowel capsule endoscopy

Small bowel capsule endoscopy is considered a first-line diagnostic tool for the investigation of small bowel diseases. Gastroenterological and endoscopic societies have proposed and established measures known as quality indicators, quality measures or performance measures for the majority of endoscopic procedures, in order to ensure competence, healthcare quality and define areas requiring improvement. However, there is a paucity of publications describing small bowel capsule endoscopy quality indicators. Hereby, we attempt to identify and describe a number of pre-procedure, intra-procedure and post-procedure quality indicators, regarding process measures in small bowel capsule endoscopy, after a comprehensive review of the literature.

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.