Resistance model of an active capsule endoscope in a peristaltic intestine

In the past studies, the resistance of magnetically controlled capsules running through the small intestine has been modeled assuming that the small intestine was a circular tube with a constant diameter. Peristalsis is an important character of the human gastrointestinal system, and it would result in some changes in the diameter of the intestine, meaning that the existing resistance models would no longer be applicable. In this paper, based on the assumption that intestinal peristalsis is actually a sinusoidal wave, a resistance model of the capsule running in the peristaltic intestine is established, and then it is validated experimentally. The model provides a realistic foundation for the optimization and control of the magnetically controlled endoscopy.

Drug-induced entero-colitis due to interleukin-17 inhibitor use; capsule endoscopic findings and pathological characteristics: A case report

BACKGROUND

Interleukin-17 (IL-17) inhibitors are known to cause exacerbation or new onset of inflammatory bowel disease upon administration. However, few reports have described characteristic endoscopic and histopathologic findings, and no small intestinal lesions have been reported so far.

CASE SUMMARY

A woman in her 60s with psoriasis was administered ixekizumab (IXE), an anti-IL-17A antibody, for the treatment of psoriasis. Twenty months after commencing treatment, the patient visited our hospital because of persistent diarrhea. Blood tests performed at the time of the visit revealed severe inflammation, and colonoscopy revealed multiple round ulcers throughout the colon. A tissue biopsy of the ulcer revealed infiltration of inflammatory cells and granuloma-like findings in the submucosal layer. Capsule endoscopy revealed multiple jejunal erosions. After the withdrawal of IXE, the symptoms gradually improved, and ulcer reduction and scarring of the colon were endoscopically confirmed.

CONCLUSION

To the best of our knowledge, 17 reports have documented IL-17 inhibitor-induced entero-colitis with endoscopic images, endoscopic findings, and pathological characteristics, including the present case. Nine of these cases showed diffuse loss of vascular pattern, coarse mucosa/ulcer formation in the left colon, and endoscopic findings similar to those of ulcerative colitis. In the remaining eight cases, discontinuous erosions and ulcerations from the terminal ileum to the rectum were seen, with endoscopic findings similar to those of Crohn's disease. In this case, the findings were confirmed by capsule endoscopy, which has not been previously reported.

Evaluating clinical diversity and plausibility of synthetic capsule endoscopic images

Wireless Capsule Endoscopy (WCE) is being increasingly used as an alternative imaging modality for complete and non-invasive screening of the gastrointestinal tract. Although this is advantageous in reducing unnecessary hospital admissions, it also demands that a WCE diagnostic protocol be in place so larger populations can be effectively screened. This calls for training and education protocols attuned specifically to this modality. Like training in other modalities such as traditional endoscopy, CT, MRI, etc., a WCE training protocol would require an atlas comprising of a large corpora of images that show vivid descriptions of pathologies, ideally observed over a period of time. Since such comprehensive atlases are presently lacking in WCE, in this work, we propose a deep learning method for utilizing already available studies across different institutions for the creation of a realistic WCE atlas using StyleGAN. We identify clinically relevant attributes in WCE such that synthetic images can be generated with selected attributes on cue. Beyond this, we also simulate several disease progression scenarios. The generated images are evaluated for realism and plausibility through three subjective online experiments with the participation of eight gastroenterology experts from three geographical locations and a variety of years of experience. The results from the experiments indicate that the images are highly realistic and the disease scenarios plausible. The images comprising the atlas are available publicly for use in training applications as well as supplementing real datasets for deep learning.

Rotational Platform for Real-Time Localization for Active Implantable Medical Devices

This paper presents a sensor based localization system to localize active implantable medical devices i.e., Wireless Capsule Endoscopy (WCE). The importance of localizing the capsule arises once the images from the capsule detect the abnormalities in the Gastrointestinal tract (GI). A successful system can determine the location that associated with the abnormality for further medical investigation or treatment. The system proposed in this paper comprises a rotational platform that consists of magnetic sensors to detect the position of the embedded magnet in the capsule. The rotational platform provides advantageousness in terms of reducing the number of the sensors and increasing the monitoring accuracy during the real time movement.

A Wearable Capsule Endoscope Electromagnetic Localization System Based on a Novel WCL Algorithm

The wearable localization system for wireless capsule endoscopy (WCE) is a potential technology to realize rapid diagnosis and treatment of the gastrointestinal (GI). However, the electromagnetic localization accuracy of WCE still needs to be improved. In this paper, based on RSSI electromagnetic fading model, the accurate fitting parameter values are obtained by Kalman filter and the least square method. A novel weighted centroid localization (WCL) algorithm based on exponential weights is proposed, which can achieve high-accuracy localization by using only sparse reception matrix. The simulation results show that when the standard deviation of the localization data is 7.85, the localization root mean square error (RMSE) is 25.4 mm; when the standard deviation of the localization data is 5.475, the localization RMSE is 2.5 mm. These two localization RMSEs are 38% and 79% less than those of the conventional centroid localization algorithm, respectively. An experimental platform of wearable wireless communication and localization system using 24 array receiving antennas is developed in human phantom environment. The experimental results show that the wearable WCE electromagnetic localization system based on the proposed algorithm achieves a localization RMSE of 36.3 mm, which is 17% lower than that of the conventional centroid localization algorithm and meets the needs of clinical diagnosis.

A method for evaluating sensitivity of electromagnetic localization systems for wireless capsule endoscopes

This paper studies the use of electromagnetic induction in localization of wireless capsule endoscopes (WECs). There is still currently a need for an accurate localization system to enable localizing possible findings in the gastrointestinal tract, and to develop an active steering system for the capsule. Developing an optimal localization system requires the sensitivity of the system to be analyzed. In this paper, three different coil geometries are modelled with a computer simulation platform, and their sensitivities and target responses are compared. In order to do that, a formulation for the sensitivity based on the dipole model approximation is presented. The first coil array is based on literature and is used as a reference. The second array presents how having more transmit-receive channels in the array effects the sensitivity. The third coil array simulates the effect of increasing the field excitation intensity in different directions by using a three-axial Helmholtz array. In addition, both proposed coil arrays utilize larger coils than the reference. As a result, it seems that both increasing the coil size and the number of field projections interrogating the target increase the overall sensitivity in the region of interest and the target response. The findings suggest that an optimal coil array could utilize both large coils and multiple transmit-receive channels to increase the number of independent fields incident onto the target.

First prospective European study for the feasibility and safety of magnetically controlled capsule endoscopy in gastric mucosal abnormalities

BACKGROUND

While capsule endoscopy (CE) is the gold standard diagnostic method of detecting small bowel (SB) diseases and disorders, a novel magnetically controlled capsule endoscopy (MCCE) system provides non-invasive evaluation of the gastric mucosal surface, which can be performed without sedation or discomfort. During standard SBCE, passive movement of the CE may cause areas of the complex anatomy of the gastric mucosa to remain unexplored, whereas the precision of MCCE capsule movements inside the stomach promises better visualization of the entire mucosa.

AIM

To evaluate the Ankon MCCE system’s feasibility, safety, and diagnostic yield in patients with gastric or SB disorders.

METHODS

Of outpatients who were referred for SBCE, 284 (male/female: 149/135) were prospectively enrolled and evaluated by MCCE. The stomach was examined in the supine, left, and right lateral decubitus positions without sedation. Next, all patients underwent a complete SBCE study protocol. The gastric mucosa was explored with the Ankon MCCE system with active magnetic control of the capsule endoscope in the stomach, applying three standardized pre-programmed computerized algorithms in combination with manual control of the magnetic movements.

RESULTS

The urea breath test revealed Helicobacter pylori positivity in 32.7% of patients. The mean gastric and SB transit times with MCCE were 0 h 47 min 40 s and 3 h 46 min 22 s, respectively. The average total time of upper gastrointestinal MCCE examination was 5 h 48 min 35 s. Active magnetic movement of the Ankon capsule through the pylorus was successful in 41.9% of patients. Overall diagnostic yield for detecting abnormalities in the stomach and SB was 81.9% (68.6% minor; 13.3% major pathologies); 25.8% of abnormalities were in the SB; 74.2% were in the stomach. The diagnostic yield for stomach/SB was 55.9%/12.7% for minor and 4.9%/8.4% for major pathologies.

CONCLUSION

MCCE is a feasible, safe diagnostic method for evaluating gastric mucosal lesions and is a promising non-invasive screening tool to decrease morbidity and mortality in upper gastro-intestinal diseases.

Image Aided Recognition of Wireless Capsule Endoscope Based on the Neural Network

Wireless capsule endoscopy is an important method for diagnosing small bowel diseases, but it will collect thousands of endoscopy images that need to be diagnosed. The analysis of these images requires a huge workload and may cause manual reading errors. This article attempts to use neural networks instead of artificial endoscopic image analysis to assist doctors in diagnosing and treating endoscopic images. First, in image preprocessing, the image is converted from RGB color mode to lab color mode, texture features are extracted for network training, and finally, the accuracy of the algorithm is verified. After inputting the retained endoscopic image verification set into the neural network algorithm, the conclusion is that the accuracy of the neural network model constructed in this study is 97.69%, which can effectively distinguish normal, benign lesions, and malignant tumors. Experimental studies have proved that the neural network algorithm can effectively assist the endoscopist's diagnosis and improve the diagnosis efficiency. This research hopes to provide a reference for the application of neural network algorithms in the field of endoscopic images.

Small bowel to closest human body surface distance calculation through a custom-made software using CT-based datasets

Screening of the gastrointestinal tract is imperative for the detection and treatment of physiological and pathological disorders in humans. Ingestible devices (e.g., magnetic capsule endoscopes) represent an alternative to conventional flexible endoscopy for reducing the invasiveness of the procedure and the related patient's discomforts. However, to properly design localization and navigation strategies for capsule endoscopes, the knowledge of anatomical features is paramount. Therefore, authors developed a semi-automatic software for measuring the distance between the small bowel and the closest human external body surface, using CT colonography images. In this study, volumetric datasets of 30 patients were processed by gastrointestinal endoscopists with the dedicated custom-made software and results showed an average distance of 79.29 ± 23.85 mm.

Endoluminal Motion Recognition of a Magnetically-Guided Capsule Endoscope Based on Capsule-Tissue Interaction Force

A magnetically-guided capsule endoscope, embedding flexible force sensors, is designed to measure the capsule-tissue interaction force. The flexible force sensor is composed of eight force-sensitive elements surrounding the internal permanent magnet (IPM). The control of interaction force acting on the intestinal wall can reduce patient's discomfort and maintain the magnetic coupling between the external permanent magnet (EPM) and the IPM during capsule navigation. A flexible force sensor can achieve this control. In particular, by analyzing the signals of the force sensitive elements, we propose a method to recognize the status of the motion of the magnetic capsule, and provide corresponding formulas to evaluate whether the magnetic capsule follows the motion of the external driving magnet. Accuracy of the motion recognition in Ex Vivo tests reached 94% when the EPM was translated along the longitudinal axis. In addition, a method is proposed to realign the EPM and the IPM before the loss of their magnetic coupling. Its translational error, rotational error, and runtime are 7.04 ± 0.71 mm, 3.13 ± 0.47∘, and 11.4 ± 0.39 s, respectively. Finally, a control strategy is proposed to prevent the magnetic capsule endoscope from losing control during the magnetically-guided capsule colonoscopy.

Robotic Localization Based on Planar Cable Robot and Hall Sensor Array Applied to Magnetic Capsule Endoscope

Recently an active locomotive capsule endoscope (CE) for diagnosis and treatment in the digestive system has been widely studied. However, real-time localization to achieve precise feedback control and record suspicious positioning in the intestine is still challenging owing to the limitation of capsule size, relatively large diagnostic volume, and compatibility of other devices in clinical site. To address this issue, we present a novel robotic localization sensing methodology based on the kinematics of a planar cable driven parallel robot (CDPR) and measurements of the quasistatic magnetic field of a Hall effect sensor (HES) array. The arrangement of HES and the Levenberg-Marquardt (LM) algorithm are applied to estimate the position of the permanent magnet (PM) in the CE, and the planar CDPR is incorporated to follow the PM in the CE. By tracking control of the planar CDPR, the position of PM in any arbitrary position can be obtained through robot forward kinematics with respect to the global coordinates at the bedside. The experimental results show that the root mean square error (RMSE) for the estimated position value of PM was less than 1.13 mm in the X, Y, and Z directions and less than 1.14° in the θ and φ orientation, where the sensing space could be extended to ±70 mm for the given 34 × 34 mm² HES array and the average moving distance in the Z-direction is 40 ± 2.42 mm. The proposed method of the robotic sensing with HES and CDPR may advance the sensing space expansion technology by utilizing the provided single sensor module of limited sensible volume.

USB capsule endoscope for retrograde imaging of the esophagus

SIGNIFICANCE

Endoscopes represent electro-optical devices that are used to visualize internal body cavities. The specialized endoscopic procedure of the upper gastrointestinal tract from the esophagus down to the duodenum is called an esophagogastroduodenoscopy.

AIM

We bring our newly developed capsule endoscopy device as a promising alternative diagnostic method for visualization of the upper gastrointestinal tract.

APPROACH

Capsule endoscopy has become an attractive method that uses a tiny wireless camera to take pictures of the digestive tract. Existing esophageal capsule endoscopy does not allow a retrograde view of the esophagus while retrograde scanning can provide information on the esophageal pathology.

RESULTS

In comparison to the existing esophageal capsule endoscopy, our system is much simpler and cheaper due to the need for fewer electronic devices. Moreover, its use is not limited by the capacity of the batteries used by existing capsule endoscopes. The new esophageal endoscopic system was created by combining the universal serial bus (USB) endoscope module with the thin power wires that are routed through the USB port to the computer.

CONCLUSIONS

The endoscope was tested on a volunteer without any side effects such as nausea, belching, and general discomfort. The examination of the patient is performed in a sitting position and the patient discomfort during the examination is minimal so it can be performed without anesthesia.

Standing-type magnetically guided capsule endoscopy versus gastroscopy for gastric examination: multicenter blinded comparative trial

AIM

To compare feasibility and safety after gastrointestinal checkup by standing-type magnetically controlled capsule endoscopy (SMCE) and conventional gastroscopy.

METHODS

This was a prospective multicenter, blinded study that compared SMCE with gastroscopy in patients from April 2018 to July 2018. All patients first underwent SMCE and then subsequently had gastroscopy with i.v. anesthesia. We calculated the compliance rates of gastric lesion detection by SMCE using gastroscopy as the standard. Capsule retention rate, incidence of adverse events, and patient satisfaction were documented throughout the study.

RESULTS

One hundred and sixty-one patients who completed SMCE and gastroscopy were included in the analysis. Positive compliance rate among SMCE and gastroscopy was 92.0% (95% CI: 80.77%-97.78%). Negative compliance rate was 95.5% (89.80%, 98.52%). Moreover, overall compliance rate was 94.41% (89.65%, 97.41%). Sixty-four pathological outcomes were identified. Of these 64 outcomes, 50 were detected by both procedures. The gastroscopy method neglected seven findings (such as five erosions, one polyp, and one ulcer). Furthermore, SMCE also overlooked seven lesions (i.e. one erosion, two polyps, one atrophy, and three submucosal tumors). Capsule retention or related adverse events were not reported.

CONCLUSION

Standing-type magnetically controlled capsule endoscopy provides equivalent agreement with gastroscopy and may be useful for screening of gastric illnesses without any anesthesia.

Usefulness of panoramic 344°-viewing in Crohn's disease capsule endoscopy: a proof of concept pilot study with the novel PillCam™ Crohn's system

BACKGROUND

A new capsule endoscopy (CE) system featuring two advanced optics for 344°-viewing and a prolonged operative time has been recently developed for Crohn's disease (CD) patients. Hence, we evaluated, for the first time, the performance of this novel CE and the add-on value of the 344°-viewing in a multi-center real-life setting.

METHODS

Consecutive patients with suspected or established CD received the PillCam™ Crohn's System as supplementary diagnostic work-up focused on the small-bowel between June 2017 and June 2018. Technical and clinical data, including the panenteric CE diagnostic yield, the Lewis score and the impact of small-bowel findings on clinical management during a 6-months follow-up (new diagnosis, staging or treatment upgrade) were collected, thereby evaluating the added value of the 344° panoramic-view (lesions detected by camera A and B) over the standard 172°-view (lesions detected by one camera only).

RESULTS

Among 41 patients (aged 43 ± 20 years), 73% underwent CE for suspected CD and 27% for established CD. The rate of complete enteroscopy was 90%. No technical failure or retention occurred. Compared to the standard 172° view, the panoramic 344°-view revealed a greater number of patients with a relevant lesion (56.1% vs. 39.0%; P = 0.023), resulting in higher Lewis score (222,8 vs. 185.7; P = 0.031), and improved clinical management (48.8% vs. 31.7%, P = 0.023).

CONCLUSIONS

The panoramic 344°-view increases small-bowel CE accuracy, thereby improving the clinical management of CD patients with mild small-bowel active disease. This system should be regarded as a new standard for both small-bowel diagnosis and monitoring in inflammatory bowel diseases.

Predictive Tilt Compensation for Robot Assisted Magnetic Capsule Endoscope

Wireless capsule endoscopes provide a painless and non-invasive alternative to the flexible endoscope in various applications of the gastrointestinal tract diagnosis. Operating a wireless capsule endoscope in the colon may benefit from an active position control as the large colon diameter can lead to uncontrollable and unpredictable capsule trajectory. Robot assisted magnetic steering is an attractive technique that is being explored by researchers worldwide. This paper presents the implications of a novel capsule geometry to markedly improve capsule stabilization and locomotion compared to the cylinder-based capsule geometry that is commonly used.

A Miniaturized Capsule Endoscope Equipped a Marking Module for Intestinal Tumor Localization

This study introduces a miniaturized capsule endoscope equipped with a marking module for intestinal tumor or lesion localization. The design concept is based on an active wireless capsule endoscope platform that is manipulated by an external electromagnetic actuation (EMA) system. The magnetic response of a permanent magnet inside the capsule is designed to have flexible movement in viscous environment of bowel. This magnet is also utilized to activate tattooing process by triggering a gas-generated chemical reaction. Once approaching to a target region, gradient magnetic field from EMA system is induced to push magnet down, releasing water to dry chemical powder mixture. Then the gas pressure increases and pushes the piston move to inject ink into target point. During traveling in digestive organs, injection needle is stowed inside the capsule to avoid damage to the organs. The whole procedure is manipulated by EMA system, the injection consumes no internal battery and is observable through capsule's camera which provides clinician vision. Basic tests were conducted to evaluate the performance of proposed robotic capsule. The success of creating a black visible bled from serosa of intestine proves the feasibility and potential of the design. This study could be an alternative for traditional tattooing endoscopy and motivate other research groups for further development of functional wireless capsule endoscope.

Camera-Integrable Wide-Bandwidth Antenna for Capsule Endoscope

This paper presents a new antenna design for a capsule endoscope. The proposed antenna comprises a camera hole and meandered line. These features enable the antenna to be integrated on the same side as the camera, within the capsule endoscope. Moreover, light-emitting diodes can be mounted on the surface of the antenna for illumination. The antenna achieves a wide bandwidth, despite the small size owing to its meandered line structure.

Efficacy and safety of magnetic guided capsule gastroscopy in gastric diseases

The current mainstay of screening and diagnosis for gastric diseases is conventional standard gastroscopy. However, it is invasive and uncomfortable procedure for the patients especially in case of non-sedative procedures and other adverse effects related to conscious sedation anesthesia. Recently, a magnetic guided capsule gastroscopy (MGCG) was introduced to overcome these challenges. It is a safe and pleasant procedure with no involvement of sedation and no risks of cross-infection between patients. In addition, this method is anticipated to be an alternative tool for screening and diagnosis of gastric diseases with similar gastric visualization as one achieved through standard gastroscopy. In this narrative review, we focused on the recent advances in MGCG including technical issues, ideal gastric preparation, indications and contraindications, available evidences regarding the use of magnetic guided capsule gastroscopy in clinical practice and highlighted further technical advancements which are needed to make MGCG as a potential diagnostic tool. After reviewing the literature, we concluded that the magnetic guided capsule gastroscopy is a safe tool and would be a promising alternative examination equipment for gastric diseases.

An Automatic Navigation and Pressure Monitoring for Guided Insertion Procedure

Navigation is an important feature needed for medical insertion procedures. It is required to guide the medical device in the right direction at the right time. Navigation techniques used in the Wireless Capsule Endoscopy and conventional endoscopy fields are based on image-guided systems that require a large amount of data to be transferred and processed computationally. These issues increase system complexity as well as the overall system and procedure costs. Moreover, these systems cannot provide the required information in dark or liquid areas. To improve the medical internal inspections capabilities, we present a pressure direction measurement system that can be implemented for a capsule endoscope; ordinary endoscopy; and any other insertion procedure where navigation and safety are required. The system can operate in dark and liquid areas because no visualization is required. The system consists of a pressure sensor placed on a semi-hemisphere on top of the steering device to detect azimuth and polar angle variation according to the direction at any differentiable path.

Investigation of Current Control for a New Bi-directional Linear Capsule Robot

In this paper, a bi-directional linear capsule robot (capsulbot) for potential applications in Gastrointestinal (GI) tract inside human body is studied. Compared with the conventional endoscope limited by its poor locomotion and steering capabilities, active locomotion actuator will play an important role in the diagnosis of narrow organ tract of the human body in the future. This paper studies a new simple-structured actuator that can realize bi-directional linear motion by properly controlling the supplied current profile. It is demonstrated that the linear motion of the new capsulbot is affected by three main factors: current waveform, current duty ratio, and current amplitude. The optimized current profile that can maximize the capsulbot displacement is verified experimentally on a prototype capsulbot.

PillCamColon2 after incomplete colonoscopy - A prospective multicenter study

AIM

To evaluate the ability of PillCamColon2 to visualize colonic segments missed by incomplete optical colonoscopy (OC) and to assess the diagnostic yield.

METHODS

This prospective multicentre study included 81 patients from nine centres who underwent second-generation colon capsule endoscopy (CCE) following incomplete OC performed by an experienced gastroenterologist (> 1000 colonoscopies). Patients with stenosis were excluded. According to patient preferences, CCE was performed the following day (protocol A) after staying on clear liquids and 0.75 L Moviprep in the morning or within 30 d after new split-dose Moviprep (protocol B). Boosts consisted of 0.75 L and 0.25 L Moviprep, and phospho-soda was given as a rescue if the capsule was not excreted after seven hours.

RESULTS

Seventy-four patients were analysed (51% of them in group A; 49% in group B). Bowel cleansing was adequate in 67% of cases, and CCE could visualize colonic segments missed by incomplete colonoscopy in 90% of patients under protocol A and 97% of patients under protocol B (P = 0.35, n.s.). Significant polyps including adenocarcinoma were detected in 24% of cases. Detection rates for all polyps and significant polyps per patient were similar in both protocols. Polyps were found predominantly in the right colon (86%) in segments that were not reached by OC. Extracolonic findings - such as reflux esophagitis, suspected Barrett esophagus, upper GI-bleeding, gastric polyps, gastric erosions and angiectasia - were detected in eight patients. PillCamColon2 capsule was retained in the ileum of one patient (1.4%) without symptoms and removed during an uneventful resection for unknown Crohn’s disease that was diagnosed as the cause of anemia, which was the indication for colonoscopy. CCE was well tolerated. One patient suffered from self-limiting vomiting after consuming the phospho-soda.

CONCLUSION

Second-generation CCE using a low-volume preparation is useful after incomplete OC, and it allows for the detection of additional relevant findings, but cleansing efficiency could be improved.

In-Vivo Evaluation of Microultrasound and Thermometric Capsule Endoscopes

Clinical endoscopy and colonoscopy are commonly used to investigate and diagnose disorders in the upper gastrointestinal tract and colon, respectively. However, examination of the anatomically remote small bowel with conventional endoscopy is challenging. This and advances in miniaturization led to the development of video capsule endoscopy (VCE) to allow small bowel examination in a noninvasive manner. Available since 2001, current capsule endoscopes are limited to viewing the mucosal surface only due to their reliance on optical imaging. To overcome this limitation with submucosal imaging, work is under way to implement microultrasound (μUS) imaging in the same form as VCE devices. This paper describes two prototype capsules, termed Sonocap and Thermocap, which were developed respectively to assess the quality of μUS imaging and the maximum power consumption that can be tolerated for such a system. The capsules were tested in vivo in the oesophagus and small bowel of porcine models. Results are presented in the form of μUS B-scans as well as safe temperature readings observed up to 100 mW in both biological regions. These results demonstrate that acoustic coupling and μUS imaging can be achieved in vivo in the lumen of the bowel and the maximum power consumption that is possible for miniature μUS systems.

Real time visualization may be advisable to exclude aspiration in patients undergoing capsule endoscopy examination

Capsule endoscopy (CE) is currently considered as a first line diagnostic tool for small bowel examination. Some patients find swallowing the capsule difficult. However, capsule aspiration is relatively uncommon and is only reported in isolated cases. The majority of these cases are male (39/41; 95.1%) with an age ranging from 56-93 years and only 4 (9.8%) patients had a recorded history of dysphagia. Twenty-four out of 41 (58.5%) patients experienced symptoms of capsule aspiration. The aspiration self-resolved in 11/41 patients and the CE was retrieved during bronchoscopy in the other cases. We present the case of a 75 year old man with a history of chronic anemia who was referred for CE.

Different effects of anti-TNF-alpha biologic drugs on the small bowel macroscopic inflammation in patients with ankylosing spondylitis

BACKGROUND & AIMS

Considering the ability of anti-TNF alpha drugs to lower the burden intestinal inflammation in patients with inflammatory bowel disease (IBD), and the similarity between IBD and ankylosing spondylitis (AS) regarding inflammatory intestinal involvement, we aimed to investigate the impact of anti-TNF alpha biologic therapy on subclinical intestinal inflammation in AS patients.

METHODS

Between January 2008 and December 2013, 38 AS patients and 23 controls were enrolled in the study and investigated with small bowel videocapsule endoscopy examination and ileocolonoscopy. Each tertile of the small bowel (proximal, mid and distal) was assessed by calculating the Lewis score based on the image stream.

RESULTS

The Lewis scores were significantly higher in the AS group compared to controls (580.9 ± 818 vs. 81 ± 121, p<0.001). 16 patients (42.1%) were on anti-TNF alpha therapy (Adalimumab (n = 5), Infliximab (n = 5) or Etanercept (n = 6)).31.3% of them used NSAIDs simultaneously, compared with 77.3% of the other patients (p<0.01). Their Lewis scores were lower compared to the other patients for the entire small bowel (306 ± 164 vs. 790 ± 1038, p = 0.015), its proximal and distal tertiles (238 ± 154 vs. 560 ± 543, p = 0.021, and 140 ± 189 vs. 300 ± 220, p = 0.027, respectively). The Lewis score was also lower in patients receiving Adalimumab/Infliximab compared to those on Etanercept for the entire bowel and its distal tertile (262 ± 165 vs. 380 ± 148, p = 0.069 and 62 ± 101 vs. 273 ± 236, p = 0.060, respectively).

CONCLUSION

Anti-TNF alpha therapy in patients with AS reduces the subclinical intestinal inflammation, but the magnitude seems to depend upon the class anti-TNF alpha agent used (Clinical Trials. gov NCT00768950).

A wireless capsule endoscopy steering mechanism using magnetic field platform

In this paper, a new steering mechanism for wireless capsule devices is presented. The proposed system consists of a platform generating a magnetic field to direct and control the motion of a capsule. The platform contains an upper and a lower set of electromagnets. A permanent magnet is implanted inside the capsule to initiate the movement, which is set by the magnetic field delivered by the electromagnets. The total magnetic field at the capsule's location is the sum of the contributions of each electromagnet. An experimental setup has been designed for testing and comparing between the performance of the capsule mobility in practice and simulations.

Modeling and Optimization of Class-E Amplifier at Subnominal Condition in a Wireless Power Transfer System for Biomedical Implants

For the class-E amplifier in a wireless power transfer (WPT) system, the design parameters are always determined by the nominal model. However, this model neglects the conduction loss and voltage stress of MOSFET and cannot guarantee the highest efficiency in the WPT system for biomedical implants. To solve this problem, this paper proposes a novel circuit model of the subnominal class-E amplifier. On a WPT platform for capsule endoscope, the proposed model was validated to be effective and the relationship between the amplifier's design parameters and its characteristics was analyzed. At a given duty ratio, the design parameters with the highest efficiency and safe voltage stress are derived and the condition is called 'optimal subnominal condition.' The amplifier's efficiency can reach the highest of 99.3% at the 0.097 duty ratio. Furthermore, at the 0.5 duty ratio, the measured efficiency of the optimal subnominal condition can reach 90.8%, which is 15.2% higher than that of the nominal condition. Then, a WPT experiment with a receiving unit was carried out to validate the feasibility of the optimized amplifier. In general, the design parameters of class-E amplifier in a WPT system for biomedical implants can be determined with the proposed optimization method in this paper.

Design of an autofocus capsule endoscope system and the corresponding 3D reconstruction algorithm

A traditional capsule endoscope can only take 2D images, and most of the images are not clear enough to be used for diagnosing. A 3D capsule endoscope can help doctors make a quicker and more accurate diagnosis. However, blurred images negatively affect reconstruction accuracy. A compact, autofocus capsule endoscope system is designed in this study. Using a liquid lens, the system can be electronically controlled to autofocus, and without any moving elements. The depth of field of the system is in the 3-100 mm range and its field of view is about 110°. The images captured by this optical system are much clearer than those taken by a traditional capsule endoscope. A 3D reconstruction algorithm is presented to adapt to the zooming function of our proposed system. Simulations and experiments have shown that more feature points can be correctly matched and a higher reconstruction accuracy can be achieved by this strategy.

A more acceptable endoluminal implantation for remotely monitoring ingestible sensors anchored to the stomach wall

Several types of implant devices have been proposed and introduced into healthcare and telemedicine systems for monitoring physiological parameters, sometimes for very long periods of time. To our disappointment, most of the devices are implanted invasively and by surgery. We often have to surgically remove such devices after they have finished their mission or before the battery becomes worn out. Wearable devices have the possibility to become new modalities for monitoring vital parameters less-invasively. However, for round-the-clock monitoring of data from sensors over long periods of time, it would be better to put them inside the body to avoid causing inconvenience to patients in their daily lives. This study tested a less invasive endoluminal approach and innovative tools (developed during our research into therapeutic capsule endoscopy) for remotely anchoring ingestible sensors to the stomach wall. Preliminary investigations are also described about wireless communication (NFC, ZigBee, and Bluetooth) for low power consumption and inductive extracorporeal power feeding wirelessly to the circuits in a phantom lined with swine gastric mucosa. Electrocardiogram and pH were monitored and those parameters were successfully transmitted by wireless communication ICs to the Internet via a portable device.

A Therapeutic Wireless Capsule for Treatment of Gastrointestinal Haemorrhage by Balloon Tamponade Effect

OBJECTIVE

Wireless capsule endoscope (WCE) is a revolutionary approach to diagnose small bowel pathologies. Currently available WCEs are mostly passive devices with image capturing function only, while on-going efforts have been placed on robotizing WCEs or to enhance them with therapeutic functions. In this paper, the authors present a novel inflatable WCE for haemostasis in the gastrointestinal (GI) tracts by balloon tamponade effect.

METHODS

The proposed wireless capsule consists of a balloon that can be inflated using the endothermic reaction of acid and base. When the balloon reached a precalculated pressure level, it is able to stop at a bleeding site in the bowel, and achieve haemostasis by tamponade effect. The prototype is 14 mm in diameter, with three sections of 13, 35, and 12 mm in length, respectively. The three sections are linked together with flexible joints and enclosed in a silicone balloon. The prototypes were tested in ex vivo porcine intestine models.

RESULTS

In the ten ex vivo trials conducted, the inflatable wireless capsule achieved average balloon pressure of 46.0 mmHg and withstood average maximum longitudinal pulling force at 1.46 N. An in vivo study was carried out as a proof-of-concept for treating bleeding in a porcine model. The proposed inflatable WCE succeeded in the animal test by controlling haemostasis within 5 min. No rebleeding was observed in the next 20 min.

CONCLUSION

The results suggested that the inflatable capsule with a real-time bleeding detection algorithm can be implemented. Moreover, the proposed inflatable WCE prototype can achieve haemorrhage control in the lower GI.

SIGNIFICANCE

To our best knowledge, this is the first study that demonstrated the potential to treat GI haemorrhage by an inflatable WCE. The proposed capsule enables the development of a closed-loop system based on a body sensor network to provide early treatment of GI bleeding for p-medicine.

A Review of Locomotion Systems for Capsule Endoscopy

Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties.

Investigation of in-body path loss in different human subjects for localization of capsule endoscope

Recent developments in capsule endoscopy have highlighted the need for accurate techniques to estimate the location of a capsule endoscope. A highly accurate location estimation of a capsule endoscope in the gastrointestinal (GI) tract in the range of several millimeters is a challenging task. This is mainly because the radio-frequency signals encounter high loss and a highly dynamic channel propagation environment. Therefore, an accurate path-loss model is required for the development of accurate localization algorithms. This paper presents an in-body path-loss model for the human abdomen region at 2.4 GHz frequency. To develop the path-loss model, electromagnetic simulations using the Finite-Difference Time-Domain (FDTD) method were carried out on two different anatomical human models. A mathematical expression for the path-loss model was proposed based on analysis of the measured loss at different capsule locations inside the small intestine. The proposed path-loss model is a good approximation to model in-body RF propagation, since the real measurements are quite infeasible for the capsule endoscopy subject.

Capsule enteroscopy is useful for the therapeutic management of Crohn’s disease

AIM: To analyze therapeutic changes in Crohn’s disease (CD) patients following video capsule endoscopy (VCE) and to assess the usefulness of Lewis score and the Patency Capsule.

METHODS: Patency Capsule was performed in every patient that had indication for VCE, and those with negative patency did not undergo VCE. Patients with established CD that underwent VCE between January 2011 and February 2014 were selected for this study; those with suspected CD were excluded, independent of VCE results, since our purpose was to address differences in therapeutic regimen in CD patients before and after VCE. Patients with inconclusive VCE were also excluded. Patients had to be free of non-steroidal anti-inflammatories for at least 1 mo. Those patients who met these criteria were allocated into one of three groups: Staging group (asymptomatic CD patients that underwent VCE for staging of CD), Flare group (patients with active CD), or Post-op group (CD patients evaluated for post-operative recurrence). Lewis score was calculated for every VCE procedure. Statistical analysis was performed to address the impact of VCE findings on the therapeutic management of CD patients and to evaluate the utility of the Lewis score.

RESULTS: From a total of 542 VCEs, 135 were performed in patients with CD. Patency capsule excluded nearly 25% of the patients who were supposed to undergo VCE. No videocapsule retention during VCE was reported. From these 135 patients, 29 were excluded because CD diagnosis was not established at the time of VCE. Therefore, a total of 106 patients were included in the final analysis. From these, the majority were in the Staging group (n = 73, 69%), and the remaining were in the Flare (n = 23, 22%) or Post-op (n = 10, 9%) group. Median time between diagnosis and VCE was 5.5 years. Overall, VCE determined changes in the treatment of 40% of patients: only 21% remained free of immunosuppressors after VCE compared to 44% before VCE (P < 0.001). The differences in therapy before and after VCE achieved statistical significance in the Staging and Flare groups. In addition, patients were significantly different when stratified regarding time since diagnosis to the date of VCE. A higher Lewis score was associated with therapeutic modifications (P < 0.0001); where a score higher than 1354 was related to 90% probability of changing therapy [area under the receiver operative characteristic (AUROC) 0.80 (95%CI: 0.69-0.88)].

CONCLUSION: VCE significantly changed the therapeutic management of CD patients, even in those with long-term disease. Systematic use of Patency capsule allowed for no videocapsule retention.

Capsule endoscopy of the future: What's on the horizon?

Capsule endoscopes have evolved from passively moving diagnostic devices to actively moving systems with potential therapeutic capability. In this review, we will discuss the state of the art, define the current shortcomings of capsule endoscopy, and address research areas that aim to overcome said shortcomings. Developments in capsule mobility schemes are emphasized in this text, with magnetic actuation being the most promising endeavor. Research groups are working to integrate sensor data and fuse it with robotic control to outperform today's standard invasive procedures, but in a less intrusive manner. With recent advances in areas such as mobility, drug delivery, and therapeutics, we foresee a translation of interventional capsule technology from the bench-top to the clinical setting within the next 10 years.

Color multiplexing method to capture front and side images with a capsule endoscope

This paper proposes a capsule endoscope (CE), based on color multiplexing, to simultaneously record front and side images. Only one lens associated with an X-cube prism is employed to catch the front and side view profiles in the CE. Three color filters and polarizers are placed on three sides of an X-cube prism. When objects locate at one of the X-cube's three sides, front and side view profiles of different colors will be caught through the proposed lens and recorded at the color image sensor. The proposed color multiplexing CE (CMCE) is designed with a field of view of up to 210 deg and a 180 lp/mm resolution under f-number 2.8 and overall length 13.323 mm. A ray-tracing simulation in the CMCE with the color multiplexing mechanism verifies that the CMCE not only records the front and side view profiles at the same time, but also has great image quality at a small size.

Appendicitis following capsule endoscopy

A 19-year-old woman presented to the emergency department with abdominal pain 10 h after ingesting a capsule endoscope. The pain subsequently localised to the right iliac fossa with guarding and cough/percussion tenderness. Follow-up pelvic ultrasound showed a tender non-compressible appendix consistent with appendicitis. The patient underwent a laparoscopic appendectomy with good recovery. This report describes an unusual presentation of appendicitis following ingestion of a capsule endoscope.

Intraoperative bowel cleansing tool in active locomotion capsule endoscopy

Capsule endoscopy (CE) can be considered an example of "disruptive technology" since it represents a bright alternative to traditional diagnostic methodologies. If compared with traditional endoscopy, bowel cleansing procedure in CE becomes of greater importance, due to the impossibility to intraoperatively operate on unclean gastrointestinal tract areas. Considering the promising results and benefits obtained in the field of CE for gastrointestinal diagnosis and intervention, the authors approached the bowel cleansing issue with the final aim to propose an innovative and easy-to-use intraoperative cleansing system to be applied to an active locomotion softly-tethered capsule device, already developed by the authors. The system, that has to be intended as an additional tool for intraoperatively cleansing procedure of the colonic tract, is composed by a flexible tube with a metallic deflector attached to the distal end; it can be headed to the target area through the capsule operating channel. Performances of the colonoscopic capsule and intraoperative cleansing capabilities were successfully confirmed both in an in-vitro and ex-vivo experimental session. The innovative intraoperative cleansing system demonstrated promising results in terms of water injection, colonic wall cleansing procedure and subsequent water suction, thus guaranteeing to reduce the risk of inadequate visualization of the mucosa in endoscopic procedures.

Design of Endoscopic Capsule With Multiple Cameras

In order to reduce the miss rate of the wireless capsule endoscopy, in this paper, we propose a new system of the endoscopic capsule with multiple cameras. A master-slave architecture, including an efficient bus architecture and a four level clock management architecture, is applied for the Multiple Cameras Endoscopic Capsule (MCEC). For covering more area of the gastrointestinal tract wall with low power, multiple cameras with a smart image capture strategy, including movement sensitive control and camera selection, are used in the MCEC. To reduce the data transfer bandwidth and power consumption to prolong the MCEC's working life, a low complexity image compressor with PSNR 40.7 dB and compression rate 86% is implemented. A chipset is designed and implemented for the MCEC and a six cameras endoscopic capsule prototype is implemented by using the chipset. With the smart image capture strategy, the coverage rate of the MCEC prototype can achieve 98% and its power consumption is only about 7.1 mW.

[Design of Adjustable Magnetic Field Generating Device in the Capsule Endoscope Tracking System]

The capsule endoscope swallowed from the mouth into the digestive system can capture the images of important gastrointestinal tract regions. It can compensate for the blind spot of traditional endoscopic techniques. It enables inspection of the digestive system without discomfort or need for sedation. However, currently available clinical capsule endoscope has some limitations such as the diagnostic information being not able to correspond to the orientation in the body, since the doctor is unable to control the capsule motion and orientation. To solve the problem, it is significant to track the position and orientation of the capsule in the human body. This study presents an AC excitation wireless tracking method in the capsule endoscope, and the sensor embedded in the capsule can measure the magnetic field generated by excitation coil. And then the position and orientation of the capsule can be obtained by solving a magnetic field inverse problem. Since the magnetic field decays with distance dramatically, the dynamic range of the received signal spans three orders of magnitude, we designed an adjustable alternating magnetic field generating device. The device can adjust the strength of the alternating magnetic field automatically through the feedback signal from the sensor. The prototype experiment showed that the adjustable magnetic field generating device was feasible. It could realize the automatic adjustment of the magnetic field strength successfully, and improve the tracking accuracy.

PillCam COLON 2© in Crohn’s disease: A new concept of pan-enteric mucosal healing assessment

AIM: To evaluate mucosal healing in patients with small bowel plus colonic Crohn’s disease (CD) with a single non-invasive examination, by using PillCam COLON 2^© (PCC2).

METHODS: Patients with non-stricturing nonpenetrating small bowel plus colonic CD in sustained corticosteroid-free remission were included. At diagnosis, patients had undergone ileocolonoscopy to identify active CD lesions, such as ulcers and erosions, and small bowel capsule endoscopy to assess the Lewis Score (LS). After ≥ 1 year of follow-up, patients underwent entire gastrointestinal tract evaluation with PCC2. The primary endpoint was assessment of CD mucosal healing, defined as no active colonic CD lesions and LS < 135.

RESULTS: Twelve patients were included (7 male; mean age: 32 years), and mean follow-up was 38 mo. The majority of patients (83.3%) received immunosuppressive therapy. Three patients (25%) achieved mucosal healing in both the small bowel and the colon, while disease activity was limited to either the small bowel or the colon in 5 patients (42%). It was possible to observe the entire gastrointestinal tract in 10 of the 12 patients (83%) who underwent PCC2.

CONCLUSION: Only three patients in sustained corticosteroid-free clinical remission achieved mucosal healing in both the small bowel and the colon, highlighting the limitations of clinical assessment when stratifying disease activity, and the need for pan-enteric endoscopy to guide therapeutic modification.

Quantitative evaluation of in vivo vital-dye fluorescence endoscopic imaging for the detection of Barrett's-associated neoplasia

Current imaging tools are associated with inconsistent sensitivity and specificity for detection of Barrett's-associated neoplasia. Optical imaging has shown promise in improving the classification of neoplasia in vivo. The goal of this pilot study was to evaluate whether in vivo vital dye fluorescence imaging (VFI) has the potential to improve the accuracy of early-detection of Barrett's-associated neoplasia. In vivo endoscopic VFI images were collected from 65 sites in 14 patients with confirmed Barrett's esophagus (BE), dysplasia, oresophageal adenocarcinoma using a modular video endoscope and a high-resolution microendoscope(HRME). Qualitative image features were compared to histology; VFI and HRME images show changes in glandular structure associated with neoplastic progression. Quantitative image features in VFI images were identified for objective image classification of metaplasia and neoplasia, and a diagnostic algorithm was developed using leave-one-out cross validation. Three image features extracted from VFI images were used to classify tissue as neoplastic or not with a sensitivity of 87.8% and a specificity of 77.6% (AUC = 0.878). A multimodal approach incorporating VFI and HRME imaging can delineate epithelial changes present in Barrett's-associated neoplasia. Quantitative analysis of VFI images may provide a means for objective interpretation of BE during surveillance.

[THE WAYS FOR IMPROVEMENT OF PERITONITIS TREATMENT OUTCOMES AT A MODERN TIME]

The results of treatment of 53 patients, suffering extended peritonitis, were analyzed. Application of differentiated surgical tactics, the least traumatic volume of operative intervention for the patient, determination of indications for relaparotomy and secondary videolaparoscopic sanation, taking into account data on ultrasonic monitoring of abdominal organs, optimization of the inserted draining tubes quantity, depending on source and severity of peritonitis on background of early enteral feeding accomplished, have permitted to improve the patients treatment results, to reduce a postoperative complications and lethality rate.

Effect of longer battery life on small bowel capsule endoscopy

AIM: To determine if longer battery life improves capsule endoscopy (CE) completion rates.

METHODS: A retrospective study was performed at a tertiary, university-affiliated hospital in Vancouver, Canada. Patients who underwent CE with either PillCam™ SB2 or SB2U between 01/2010 and 12/2013 were considered for inclusion. SB2 and SB2U share identical physical dimensions but differ in their battery lives (8 h vs 12 h). Exclusion criteria included history of gastric or small bowel surgery, endoscopic placement of CE, interrupted view of major landmarks due to technical difficulty or significant amount of debris, and repeat CE using same system. Basic demographics, comorbidities, medications, baseline bowel habits, and previous surgeries were reviewed. Timing of major landmarks in CE were recorded, and used to calculate gastric transit time, small bowel transit time, and total recording time. A complete CE study was defined as visualization of cecum. Transit times and completion rates were compared.

RESULTS: Four hundred and eight patients, including 208 (51.0%) males, were included for analysis. The mean age was 55.5 ± 19.3 years. The most common indication for CE was gastrointestinal bleeding (n = 254, 62.3%), followed by inflammatory bowel disease (n = 86, 21.1%). There was no difference in gastric transit times (group difference 0.90, 95%CI: 0.72-1.13, P = 0.352) and small bowel transit times (group difference 1.07, 95%CI: 0.95-1.19, P = 0.261) between SB2U and SB2, but total recording time was about 14% longer in the SB2U group (95%CI: 10%-18%, P < 0.001) and there was a corresponding trend toward higher completion rate (88.2% vs 93.2%, OR = 1.78, 95%CI 0.88-3.63, P = 0.111). There was no statistically significant difference in the rates of positive findings (OR = 0.98, 95%CI: 0.64-1.51, P = 0.918).

CONCLUSION: Extending the operating time of CE may be a simple method to improve completion rate although it does not affect the rate of positive findings.