Wireless capsule endoscopy: Perspectives beyond gastrointestinal bleeding

Obscure Gastrointestinal Bleeding and Capsule Endoscopy: A Win-Win Situation or Not?

Obscure gastrointestinal bleeding (OGIB) refers to bleeding of uncertain origin that persists or recurs after negative workup using any of the radiologic evaluation modalities. It can be divided into two types based on whether clinically evident bleeding is present, namely, obscure overt and obscure occult bleeding. As the visualization of the bowel mucosa is challenging, capsule endoscopy (CE) is the ideal go-to procedure as the process is wireless, ingestible, small, disposable, and, most importantly, non-invasive. This review article has compiled various studies to shed light on the guidelines for using CE, its structure and procedure, patient preferences, diagnostic yield, cost-effectiveness, and the future. The goal of this review is to show the influence of CE on OGIB on the aspects mentioned earlier.

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.

Capsule Endoscopy in Crohn's Disease-From a Relative Contraindication to Habitual Monitoring Tool

Crohn’s disease (CD) is a chronic inflammatory disorder that may involve the gastrointestinal tract from the mouth to the anus. Habitual disease monitoring is highly important during disease management, aiming to identify and treat disease exacerbations, in order to avoid immediate and future complications. Currently, ilio-clonoscopy is the gold standard for mucosal assessment. However, the procedure is invasive, involves sedation and allows for visualization of the colon and only a small part of the terminal ileum, while most of the small bowel is not visualized. Since CD may involve the whole length of the small bowel, the disease extent might be underestimated. Capsule endoscopy (CE) provides a technology that can screen the entire bowel in a non-invasive procedure, with minimal side effects. In recent years, this technique has gained in popularity for CD evaluation and monitoring. When CE was first introduced, two decades ago, the fear of possible capsule retention in the narrowed inflamed bowel lumen limited its use in CD patients, and a known CD located at the small bowel was even regarded as a relative contraindication for capsule examination. However, at present, as experience using CE in CD patients has accumulated, this procedure has become one of the accepted tools for disease diagnosis and monitoring. In our current review, we summarize the historic change in the indications and contraindications for the usage of capsule endoscopy for the evaluation of CD, and discuss international recommendations regarding CE’s role in CD diagnosis and monitoring.

EndoSLAM dataset and an unsupervised monocular visual odometry and depth estimation approach for endoscopic videos

Deep learning techniques hold promise to develop dense topography reconstruction and pose estimation methods for endoscopic videos. However, currently available datasets do not support effective quantitative benchmarking. In this paper, we introduce a comprehensive endoscopic SLAM dataset consisting of 3D point cloud data for six porcine organs, capsule and standard endoscopy recordings, synthetically generated data as well as clinically in use conventional endoscope recording of the phantom colon with computed tomography(CT) scan ground truth. A Panda robotic arm, two commercially available capsule endoscopes, three conventional endoscopes with different camera properties, two high precision 3D scanners, and a CT scanner were employed to collect data from eight ex-vivo porcine gastrointestinal (GI)-tract organs and a silicone colon phantom model. In total, 35 sub-datasets are provided with 6D pose ground truth for the ex-vivo part: 18 sub-datasets for colon, 12 sub-datasets for stomach, and 5 sub-datasets for small intestine, while four of these contain polyp-mimicking elevations carried out by an expert gastroenterologist. To verify the applicability of this data for use with real clinical systems, we recorded a video sequence with a state-of-the-art colonoscope from a full representation silicon colon phantom. Synthetic capsule endoscopy frames from stomach, colon, and small intestine with both depth and pose annotations are included to facilitate the study of simulation-to-real transfer learning algorithms. Additionally, we propound Endo-SfMLearner, an unsupervised monocular depth and pose estimation method that combines residual networks with a spatial attention module in order to dictate the network to focus on distinguishable and highly textured tissue regions. The proposed approach makes use of a brightness-aware photometric loss to improve the robustness under fast frame-to-frame illumination changes that are commonly seen in endoscopic videos. To exemplify the use-case of the EndoSLAM dataset, the performance of Endo-SfMLearner is extensively compared with the state-of-the-art: SC-SfMLearner, Monodepth2, and SfMLearner. The codes and the link for the dataset are publicly available at https://github.com/CapsuleEndoscope/EndoSLAM. A video demonstrating the experimental setup and procedure is accessible as Supplementary Video 1.

A Robotic Biopsy Endoscope with Magnetic 5-DOF Locomotion and a Retractable Biopsy Punch

Capsule endoscopes (CEs) have emerged as an advanced diagnostic technology for gastrointestinal diseases in recent decades. However, with regard to robotic motions, they require active movability and multi-functionalities for extensive, untethered, and precise clinical utilization. Herein, we present a novel wireless biopsy CE employing active five degree-of-freedom locomotion and a biopsy needle punching mechanism for the histological analysis of the intestinal tract. A medical biopsy punch is attached to a screw mechanism, which can be magnetically actuated to extrude and retract the biopsy tool, for tissue extraction. The external magnetic field from an electromagnetic actuation (EMA) system is utilized to actuate the screw mechanism and harvest biopsy tissue; therefore, the proposed system consumes no onboard energy of the CE. This design enables observation of the biopsy process through the capsule's camera. A prototype with a diameter of 12 mm and length of 30 mm was fabricated with a medical biopsy punch having a diameter of 1.5 mm. Its performance was verified through numerical analysis, as well as in-vitro and ex-vivo experiments on porcine intestine. The CE could be moved to target lesions and obtain sufficient tissue samples for histological examination. The proposed biopsy CE mechanism utilizing punch biopsy and its wireless extraction-retraction technique can advance untethered intestinal endoscopic capsule technology at clinical sites.

Clinical and endoscopic manifestations of gastrointestinal amyloidosis: a case series

Gastrointestinal (GI) amyloidosis is rare and has varying clinical and endoscopic presentations. In this case series, we present three patients with primary systemic amyloid-light chain (AL) amyloidosis with GI involvement and complications of GI bleeding. We also provide a brief review of the literature, including clinical presentation, endoscopic findings, pathology, and management of GI amyloidosis. The endoscopic findings of GI amyloidosis can vary, including friable mucosa with erosions, ulcers, and submucosal hematomas or mucosal thickening with polypoid protrusions. The endoscopic findings may correlate with the pathologic deposition of amyloid fibrils. Treatment of GI amyloidosis is generally focused on management of the underlying condition and supportive care. Gastroenterologists should be familiar with the endoscopic findings as they may be the first suggestion of disease and allow for definitive diagnosis.

Is there an application for wireless capsule endoscopy in horses?

This pilot study assessed wireless capsule endoscopy in horses. Image transmission was achieved with good image quality. Time to exit the stomach was variable and identified as one limitation, together with gaps in image transmission, capsule tumbling, and inability to accurately locate the capsule. Findings demonstrate usefulness and current limitations.

Multiple gastric erosions diagnosed by means of capsule endoscopy in a dog

CASE DESCRIPTION A 6-year-old spayed female Golden Retriever was evaluated for a 2-week history of progressive hyporexia, signs of abdominal pain, and weight loss. CLINICAL FINDINGS Physical examination findings included mild signs of pain on palpation of the cranial part of the abdomen and a body condition score of 4 (scale, 1 to 9). A CBC revealed mild microcytosis and hypochromasia; results of serum biochemical analysis were within the respective reference ranges, and abdominal ultrasonography revealed no abnormalities. Capsule endoscopy was performed, and numerous gastric erosions and hemorrhages were detected, with rare dilated lacteals in the proximal aspect of the small intestine. TREATMENT AND OUTCOME Treatment was initiated with omeprazole and sucralfate for 6 weeks, and the dog was transitioned to a novel protein diet. Capsule endoscopy was repeated at the end of the initial treatment course and revealed overall improvement, with a few small erosions remaining; medical treatment was continued for an additional 2 weeks. At last follow-up 9 months after treatment ended, the dog was clinically normal. CLINICAL RELEVANCE Capsule endoscopy was useful for initial detection and subsequent reevaluation of gastrointestinal lesions in this patient without a need for sedation or anesthesia. Information obtained in the follow-up evaluation was valuable in identifying a need to extend the duration of medical treatment.

Quality Indicators for Small Bowel Capsule Endoscopy

Capsule endoscopy (CE) enables evaluation of the entire mucosal surface of the small bowel (SB), which is one of the most important steps for evaluating obscure gastrointestinal bleeding. Although the diagnostic yield of SB CE depends on many clinical factors, there are no reports on quality indicators. Thus, the Korean Gut Image Study Group (KGISG) publishes an article titled, “Quality Indicators for Small Bowel Capsule Endoscopy” under approval from the Korean Society of Gastrointestinal Endoscopy (KSGE). Herein, we initially identified process quality indicators, while the structural and outcome indicators are reserved until sufficient clinical data are accumulated. We believe that outcomes of SB CE can be improved by trying to meet our proposed quality indicators.

Diagnostic value of capsule endoscopy combined with computed tomography enterography for small intestinal diseases

AIM: To assess diagnostic value of capsule endoscopy (CE) combined with computed tomography enterography (CTE) for small bowel diseases.

METHODS: One hundred and fourteen patients with suspected small bowel diseases underwent CE and CTE examinations (interval time 2-7 d). The diagnostic accuracy for small bowel diseases was compared between CE and CTE, based on pathological or follow-up results. The diagnostic accuracy of combined CE and CTE was also estimated.

RESULTS: The symptoms of enrolled patients included obscure gastrointestinal bleeding (OGIB, 35 cases), unexplained abdominal pain (32 cases), suspected Crohn's disease (29 cases) and unexplained weight loss (18 cases). For OGIB, CE had a higher diagnostic accuracy than CTE (51.4% vs 40.0%, P < 0.05). The diagnostic accuracy reached 57.1% when the two methods were combined. For unexplained abdominal pain, diagnostic accuracy was comparable between CE and CTE (46.9% vs 40.6%, P > 0.05). The diagnostic accuracy reached 59.3% when the two methods were combined, which was higher than that of CE or CTE alone. For suspected Crohn's disease, CE had a higher diagnostic accuracy than CTE (86.2% vs 65.5%, P < 0.05). The diagnostic accuracy reached 93.1% when the two methods were combined, which was higher than that of CTE alone.

CONCLUSION: Both CE and CTE prove to be effective procedures for patients with suspected small bowel disease, but the diagnostic value of CE is higher than that of CTE for OGIB and suspected Crohn's disease. The combination of CE and CTE may be a better strategy.

Beneficial effects of combining computed tomography enteroclysis/enterography with capsule endoscopy for screening tumor lesions in the small intestine

Aim. To compare the efficacy of using computed tomography enteroclysis/enterography (CTE), capsule endoscopy (CE), and CTE with CE for diagnosing tumor lesions in the small intestine. Materials and Methods. We included 98 patients who underwent CE during the observation period and were subjected to CTE at our hospital from April 2008 to May 2014. Results. CTE had a significantly higher sensitivity than CE (84.6% versus 46.2%, P = 0.039), but there were no significant differences in specificity, positive or negative predictive values, or diagnostic accuracy rates. The sensitivity of CTE/CE was 100%, again significantly higher than that of CE (P = 0.002). The difference in specificity between CTE/CE and CE was not significant, but there were significant differences in positive predictive values (100% for CTE/CE versus 66.7% for CE, P = 0.012), negative predictive values (100% versus 92.1%, P = 0.008), and diagnostic accuracy rate (100% versus 89.8%, P = 0.001). The diagnostic accuracy rate was also significantly higher in CTE/CE versus CTE (100% versus 95.9%, P = 0.043). Conclusion. Our findings suggested that a combination of CTE and CE was useful for screening tumor lesions in the small intestine. This trial is registered with number UMIN000016154.