Current and future role of magnetically assisted gastric capsule endoscopy in the upper gastrointestinal tract

Prospective, multicenter, self-controlled clinical trial on the effectiveness and safety of a cable-transmission magnetically controlled capsule endoscopy system for the examination of upper GI diseases

BACKGROUND AND AIMS

Many GI disorders and precancerous conditions often present asymptomatically, leading to delayed patient diagnoses and treatment interventions. In this study, we developed a novel cable-transmission magnetically controlled capsule endoscopy (CT-MCCE) system for detecting GI diseases and assessed its safety and feasibility through clinical trials.

METHODS

This prospective, multicenter trial compared CT-MCCE with conventional gastroscopy in patients aged 18 to 75 years with upper GI tract diseases between October 2022 and July 2023. The primary endpoints were the evaluation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in the detection of focal lesions within the esophagus, stomach, and duodenal bulb using CT-MCCE.

RESULTS

One hundred eighty individuals (mean age, 43.1 years; 52.22% women) were recruited from 3 hospitals in China. CT-MCCE detected lesions in the esophagus with a sensitivity of 97.22%, specificity of 100%, PPV of 100%, NPV of 98.18%, and accuracy of 98.89%; detected gastric focal lesions in the entire stomach with a sensitivity of 96.81%, specificity of 98.84%, PPV of 98.91%, NPV of 96.59%, and accuracy of 97.78%; and detected lesions in the duodenal bulb with a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. There were no significant differences between CT-MCCE and EGD regarding the cleanliness of the upper GI tract and visibility of the upper GI mucosa. However, CT-MCCE was associated with a lower incidence of discomfort than EGD (P < .001).

CONCLUSIONS

The diagnostic performance of CT-MCCE is comparable with that of EGD in the completion of upper GI tract examinations and lesion detection. Furthermore, the improved tolerance of CT-MCCE in detecting upper GI diseases was noted without any observed adverse events. (Clinical trial registration number: ChiCTR2200063630.).

Development of Precision Controllable Magnetic Field-Assisted Platform for Micro Electrical Machining

In order to introduce the magnetic field into micro electrical machining technology to explore the influence of magnetic field on micro electrical machining, the development of a precision controllable magnetic field-assisted platform is particularly important. This platform needs to precisely control the spatial magnetic field. This study first completes the hardware design and construction of the magnetic field generation device, using electromagnetic coils with soft iron cores as the sources of the magnetic field. Mathematical models of the magnetic field are established and calibrated. Since the magnetic dipole model cannot effectively describe the magnetic field generated by the electromagnetic coil, this study adopts a more precise description method: the spherical harmonic function expansion model and the magnetic multipole superposition model. The calibration of the magnetic field model is based on actual excitation magnetic field data, so a magnetic field sampling device is designed to obtain the excitation magnetic field of the workspace. The model is calibrated based on a combination of the theoretical model and magnetic field data, and the performance of the constructed setup is analyzed. Finally, a magnetic field-assisted platform has been developed which can generate magnetic fields in any direction within the workspace with intensities ranging from 0 to 0.2 T. Its magnetic field model arrives at an error percentage of 2.986%, a variance of 0.9977, and a root mean square error (RMSE) of 0.71 mT, achieving precise control of the magnetic field in the workspace.

Clinical guideline on magnetically controlled capsule gastroscopy (2021 edition)

With the development and generalization of endoscopic technology and screening, clinical application of magnetically controlled capsule gastroscopy (MCCG) has been increasing. In recent years, various types of MCCG are used globally. Therefore, establishing relevant guidelines on MCCG is of great significance. The current guidelines containing 23 statements were established based on clinical evidence and expert opinions, mainly focus on aspects including definition and diagnostic accuracy, application population, technical optimization, inspection process, and quality control of MCCG. The level of evidence and strength of recommendations were evaluated. The guidelines are expected to guide the standardized application and scientific innovation of MCCG for the reference of clinicians.

In vivo animal study of the magnetic navigation system for capsule endoscope manipulation within the esophagus, stomach, and colorectum

BACKGROUND/PURPOSES

Magnetic navigation capsule endoscopy (MNCE) is considered to be an important means to realize the controllable and precise examination of capsule endoscopy (CE) in the unstructured gastrointestinal (GI) tract. For the current magnetic navigation system (MNS), due to the limitation of workspace, driving force, and control method of the CE, only clinical application in the stomach has been realized, whereas the examination of other parts of the GI tract is still in the experimental stage. More preclinical studies are needed to achieve the multisite examination of the GI tract.

METHODS

Based on the MNS (Supiee) developed in the laboratory, an X-ray imaging system with magnetic shielding and a commercial CE are integrated to form the MNCE system. Then, in vivo GI tract experiments with a porcine model are performed to verify the clinical feasibility and safety of this system. Moreover, the effects of different control modes on the efficiency and effect of GI tract examination are studied.

RESULTS

Animal experiments demonstrate that with the MNCE system, it is convenient to achieve steering control in any direction and multiple reciprocating movements of CE in the GI tract. Benefiting from the flexibility of the three basic control modes, the achieved swing movement pattern of CE can effectively reduce the inspection time. It is demonstrated that the esophageal examination time can be reduced from 13.2 to 9.2 min with a maximum movement speed of 5 mm/s.

CONCLUSION

In this paper, the feasibility, safety, and efficacy of the MNCE system for a one-stop examination of the in vivo GI tract (esophagus, stomach, and colorectum) is first demonstrated. In addition, complex movement patterns of CE such as the swinging are proved to effectively improve examination efficiency and disease detection rates. This study is crucial for the clinical application of the MNCE system.

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.

Magnetically controlled capsule endoscopy in one-time gastro-small intestinal joint examination: a two-centre experience

Background

The lesions of certain diseases are widely distributed in both stomach and small intestine, while the step-by-step strategy of gastroscopy followed by enteroscopy can be burdensome and costly. We aimed to determine if magnetically controlled capsule endoscopy (MCE) could be used in one-time gastro-small intestine (GSI) joint examination.

Methods

In this study, data of patients in Chinese PLA General Hospital and Changhai Hospital who underwent MCE GSI examination from January 2020 to August 2021 were retrospectively analysed. The primary outcome of this study was the success rate of one-time GSI joint examination, and secondary outcomes included visualization and cleanliness of gastrointestinal tract, gastrointestinal transit times, diagnostic yield and safety of MCE examination.

Results

A total of 768 patients were included. The success rate of one-time GSI joint examination was 92.58%. There were 94.92% MCEs observed > 90% gastric mucosa in the 6 anatomic landmarks. The rate of complete small bowel examination was 97.40%. The median gastric examination time, gastric transit time and small intestine transit time were 8.18 min, 63.89 min and 4.89 h, respectively. Magnetic steering of MCE significantly decreased gastric transit time (8.92 min vs. 79.68 min, P = 0.001) and increased duodenal lesion detection rate (13.47% vs. 6.26%, P = 0.001) when compared with non-magnetic steering group. Two capsules were retained and were removed by enteroscopy or spontaneously excreted.

Conclusions

MCE is feasible to complete GSI joint examination and the detection of both gastric and small intestinal diseases can be achieved simultaneously.

Trial registration Clinical Trial Registration ClinicalTrials.gov, ID: NCT05069233.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02302-0.

Noncontact magnetically controlled capsule endoscopy for infection-free gastric examination during the COVID-19 pandemic: a pilot, open-label, randomized trial

Background and study aims  Endoscopists have been at increased risk because of their direct contact with patients during the COVID-19 pandemic. For patients, being diagnosed with and monitored for gastrointestinal cancer and digestive diseases in timely fashion has been challenging, given pandemic-related adjustments in endoscopy departments. We developed a novel noncontact magnetically controlled capsule endoscopy (ncMCE) system in our medical center. In the current study, we aimed to evaluate the feasibility and safety of ncMCE for gastric examination. Patients and methods  Patients were randomly assigned to groups that received ncMCE or MCE in a 1:1 ratio from March 26, 2020 to April 26, 2020. Primary endpoints were feasibility assessed by completion rate (CR) and safety based on the occurrence of adverse events (AEs) including infection. Secondary endpoints included maneuverability of endoscopists, pre-procedure perception and post-procedure satisfaction of patients, gastric examination time (GET), and diagnostic yield (DY). Results  Forty patients were enrolled with 100 % CR in both groups without any AEs. Neither the endoscopist nor the patients were infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within 14 days after gastric examination. There were no significant differences in maneuverability (19.3 vs. 20.0, P  = 0.179), pre-procedure perception (9 vs. 9, P  = 0.626) and post-procedure satisfaction (45 vs. 44, P =  0.999), ord DY (20 % vs. 30 %, P  = 0.465). Conclusions  ncMCE is a feasible and safe method of gastric examination, which has the potential to protect both medical staff and patients from COVID-19 infection while providing serving as an essential endoscopy service.

Gastric examination using a novel three-dimensional magnetically assisted capsule endoscope and a hand-held magnetic controller: A porcine model study

Magnetically assisted capsule endoscopy (MACE) is a noninvasive procedure and can overcome passive capsule movement that limits gastric examination. MACE has been studied in many trials as an alternative to upper endoscopy. However, to increase diagnostic accuracy of various gastric lesions, MACE should be able to provide stereoscopic, clear images and to measure the size of a lesion. So, we conducted the animal experiment using a novel three-dimensional (3D) MACE and a new hand-held magnetic controller for gastric examination. The purpose of this study is to assess the performance and safety of 3D MACE and hand-held magnetic controller through the animal experiment. Subsequently, via the dedicated viewer, we evaluate whether 3D reconstruction images and clear images can be obtained and accurate lesion size can be measured. During real-time gastric examination, the maneuverability and visualization of 3D MACE were adequate. A polypoid mass lesion was incidentally observed at the lesser curvature side of the prepyloric antrum. The mass lesion was estimated to be 10.9 x 11.5 mm in the dedicated viewer, nearly the same size and shape as confirmed by upper endoscopy and postmortem examination. Also, 3D and clear images of the lesion were successfully reconstructed. This animal experiment demonstrates the accuracy and safety of 3D MACE. Further clinical studies are warranted to confirm the feasibility of 3D MACE for human gastric examination.

Advances in optical gastrointestinal endoscopy: a technical review

Optical endoscopy is the primary diagnostic and therapeutic tool for management of gastrointestinal (GI) malignancies. Most GI neoplasms arise from precancerous lesions; thus, technical innovations to improve detection and diagnosis of precancerous lesions and early cancers play a pivotal role in improving outcomes. Over the last few decades, the field of GI endoscopy has witnessed enormous and focused efforts to develop and translate accurate, user-friendly, and minimally invasive optical imaging modalities. From a technical point of view, a wide range of novel optical techniques is now available to probe different aspects of light-tissue interaction at macroscopic and microscopic scales, complementing white light endoscopy. Most of these new modalities have been successfully validated and translated to routine clinical practice. Herein, we provide a technical review of the current status of existing and promising new optical endoscopic imaging technologies for GI cancer screening and surveillance. We summarize the underlying principles of light-tissue interaction, the imaging performance at different scales, and highlight what is known about clinical applicability and effectiveness. Furthermore, we discuss recent discovery and translation of novel molecular probes that have shown promise to augment endoscopists' ability to diagnose GI lesions with high specificity. We also review and discuss the role and potential clinical integration of artificial intelligence-based algorithms to provide decision support in real time. Finally, we provide perspectives on future technology development and its potential to transform endoscopic GI cancer detection and diagnosis.

Fully automated magnetically controlled capsule endoscopy for examination of the stomach and small bowel: a prospective, feasibility, two-centre study

BACKGROUND

The use of magnetically controlled capsules for gastroscopy is in the early stages of clinical adoption. We aimed to evaluate the safety and efficacy of a fully automated magnetically controlled capsule endoscopy (FAMCE) system in clinical practice for gastroscopy and small bowel examination.

METHODS

We did a prospective, comparative study to evaluate the safety and efficacy of FAMCE. Patients from two hospitals in Chongqing, China were consecutively enrolled. Eligible participants were aged 18-80 years with suspected gastric pathology and no previous surgery. Participants underwent FAMCE for screening of gastric lesions, then conventional transoral gastroscopy 2 h later, and stomach examination results were compared. The primary outcome was the rate of complete detection of gastric anatomy landmarks (cardia, fundus, body, angulus, antrum, and pylorus) by FAMCE. Secondary outcomes were the time required for gastric completion by FAMCE, the rate of detection of gastric lesions by FAMCE compared with conventional transoral gastroscopy, and the rate of complete small bowel examination. Adverse events were also evaluated. The study was registered in the Chinese Clinical Trial Registry, ChiCTR2000040507.

FINDINGS

Between May 12 and Aug 17, 2020, 114 patients (mean age 44·0 years [IQR 34·0-55·0]; 63 [55%] female) were enrolled. The rate of complete detection of gastric anatomical structures by FAMCE was 100% (95% CI 99·3-100·0). The concordance between FAMCE and conventional transoral gastroscopy was 99·61% (99·45-99·78). The mean completion time of a gastroscopy with FAMCE was 19·17 min (SD 1·43; median 19·00, IQR 19·00-20·00), compared with 5·21 min (2·00; 5·18, 3·68-6·45) for conventional transoral gastroscopy. In 114 enrolled patients, 214 lesions were detected by FAMCE and conventional transoral gastroscopy. Of those, 193 were detected by both modalities. FAMCE missed five pathologies (four cases of gastritis and one polyp), whereas conventional transoral gastroscopy missed 16 pathologies (12 cases of gastritis, one polyp, one fundal xanthoma, and two antral erosions). FAMCE was able to provide a complete small bowel examination for all 114 patients and detected intestinal lesions in 50 (44%) patients. During the study, two (2%) patients experienced adverse events. No serious adverse events were recorded, and there was no evidence of capsule retention.

INTERPRETATION

The performance of FAMCE is similar to conventional transoral gastroscopy in completion of gastric examination and lesion detection. Furthermore, it can provide a complete small bowel examination. Therefore, FAMCE could be effective method for examination of the gastrointestinal tract.

FUNDING

Chinese National Key Research and Development Program.

Second-generation magnetically controlled capsule gastroscopy with improved image resolution and frame rate: a randomized controlled clinical trial (with video)

BACKGROUND AND AIMS

Compared with conventional endoscopy, magnetically controlled capsule gastroscopy (MCCG) can be further optimized in gastric examination time and complete visualization of upper GI (UGI) mucosa. The second-generation MCCG (MCCG-2) was developed with higher image resolution and adaptive frame rate, and we aimed to evaluate its clinical availability for UGI examination in this study.

METHODS

Consecutive patients undergoing MCCG examination between May to June 2019 were prospectively enrolled and randomized to swallow the first-generation MCCG (MCCG-1) or MCCG-2 in a 1:1 ratio. The main outcomes included visualization of the esophagus and duodenum, operation-related parameters, image quality, maneuverability, detection of lesions, and safety evaluation.

RESULTS

Eighty patients were enrolled. In the MCCG-2 group, frames captured for esophageal mucosa and Z-line were 171.00 and 2.00, significantly increased from those in the MCCG-1 group (97.00 [P = .002] and .00 [P = .028], respectively). The gastric examination time was shortened from 7.78 ± .97 minutes to 5.27 ± .74 minutes (P < .001), with the total running time of the capsule extended from 702.83 minutes to 1001.99 minutes (P < .001). MCCG-2 also greatly improved the image quality (P < .001) and maneuverability (P < .01). No statistical difference existed in the detection of lesions between the 2 groups, and no adverse events occurred.

CONCLUSIONS

MCCG-2 showed better performance in mucosal visualization, examination duration, and maneuverability, making better diagnosis of UGI diseases a possibility. (Clinical trial registration number: NCT03977935.).

Magnetically Actuated Soft Capsule Endoscope for Fine-Needle Biopsy

Wireless capsule endoscopes have revolutionized diagnostic procedures in the gastrointestinal (GI) tract by minimizing discomfort and trauma. Biopsy procedures, which are often necessary for a confirmed diagnosis of an illness, have been incorporated recently into robotic capsule endoscopes to improve their diagnostic functionality beyond only imaging. However, capsule robots to date have only been able to acquire biopsy samples of superficial tissues of the GI tract, which could generate false-negative diagnostic results if the diseased tissue is under the surface of the GI tract. To improve their diagnostic accuracy for submucosal tumors/diseases, we propose a magnetically actuated soft robotic capsule robot, which takes biopsy samples in a deep tissue of a stomach using the fine-needle biopsy technique. We present the design, control, and human-machine interfacing methods for the fine-needle biopsy capsule robot. Ex vivo experiments in a porcine stomach show 85% yield for the biopsy of phantom tumors located underneath the first layers of the stomach wall.

Screening for gastric cancer with magnetically controlled capsule gastroscopy in asymptomatic individuals

BACKGROUND AND AIMS

Gastric cancer (GC) is the fourth most common cancer and the fourth leading cause of cancer death worldwide. In some Asian countries, screening EGD has greatly improved the survival rate. However, patients' discomfort and the need for sedation may limit adherence to screening programs. Previous studies have shown good tolerance and good agreement of magnetically controlled capsule gastroscopy (MCCG) with EGD. This study was designed to assess the application of MCCG in GC detection in an asymptomatic population.

METHODS

In this observational cohort study, 3182 asymptomatic individuals undergoing MCCG in 99 participating medical examination centers from April to December 2016 were enrolled. Patients with ulcers and suspected malignancies were referred for gastroscopy and biopsy. The detection rate of GC and focal lesions were used to explore the application of MCCG in asymptomatic individuals.

RESULTS

Seven patients (0.22%) were diagnosed with GC among the enrolled 3182 individuals, accounting for 0.74% (7/948) in patients over 50 years. No gender disparity was observed. EGD and biopsy confirmed adenocarcinoma in all cases of suspected malignancy. Benign polyps, gastric ulcers, and submucosal tumors were found in 10.4%, 4.9%, and 3.6% of patients, respectively. There was a trend for the prevalence of focal lesions to increase with age. MCCG examination proved to be safe.

CONCLUSIONS

MCCG can detect cancer and benign lesions and is safe and clinically feasible in a large population. Studies of its role in a screening program should be considered.

Evaluation of Gastric Disease with Capsule Endoscopy

The clinical indication for capsule endoscopy has expanded from small bowel evaluation to include esophagus or colon evaluation.Nevertheless, the role of capsule endoscopy in evaluation of the stomach is very limited because of the large volume and surface.However, efforts to develop an active locomotion system for capsule manipulation in detailed gastric evaluation are ongoing, becausethe technique is non-invasive, convenient, and safe, and requires no sedation. Studies have successfully reported gastric evaluation usinga magnetic-controlled capsule endoscopy system. Advances in technology suggest that capsule endoscopy will have a major role notonly in the evaluation of gastric disorders but also in the pathologic diagnosis, intervention, and treatment of any gastrointestinal tractdisorder.

Association between patient characteristics and magnetically controlled capsule endoscopy findings

BACKGROUND/AIM

Magnetically-controlled capsule endoscopy (MCE) is a potential option for the evaluation of gastric diseases in cases that are unsuited for conventional endoscopy, avoiding discomfort, sedation, and related complications. This retrospective study investigated associations between MCE findings and patient gender, age, and inpatient/outpatient status.

PATIENTS AND METHODS

The data of 580 consecutive patients who underwent MCE from 2015 to 2016 were analyzed. Data included age, gender, indication for MCE, inpatient/outpatient status, overall coverage of gastric anatomical landmarks, and comorbid conditions.

RESULTS

Compared with outpatients, inpatients had a higher rate of overall significant MCE findings (P = 0.014), polyp (P = 0.03), and ulceration (P = 0.003). MCE findings of the inpatient men and women were similar. Considering all patients, the percentage with ulceration was significantly higher in men than in women (P = 0.004), and men were younger (P < 0.001). Compared with younger patients, those aged ≥60 years had significantly higher rates of overall significant findings, mainly polyp and angiodysplasia.

CONCLUSIONS

Compared with outpatients, the inpatients showed higher overall significant findings. Men undergoing MCE were younger than the women, and more likely to have ulcerations. Older patients, whether outpatient or inpatient, had higher rates of significant findings, mainly polyp and angiodysplasia.

Gastric preparation for magnetically controlled capsule endoscopy: A prospective, randomized single-blinded controlled trial

BACKGROUND AND AIMS

Magnetically controlled capsule endoscopy (MCE) is a novel technique for which there is no agreed gastric preparation. We aimed to determine an optimal standardized gastric preparation regimen.

METHODS

120 patients referred for MCE were randomly assigned to gastric preparation with either water alone (A), water with simethicone (B) or water, simethicone and pronase (C). Image quality was assessed using cleanliness and visualization scores, higher scores equating to better image quality.

RESULTS

The total cleanliness scores were (mean±SD) 15.83±2.41 (A), 21.35±1.23 (B), and 20.82±1.90 (C). The total visualization scores (mean±SD) were 10.75±2.02 (A), 15.20±1.32 (B), and 15.08±1.86 (C). While the image quality of the whole stomach in groups B and C were significantly better than group A (P<0.0001), there was no statistical difference between group B and C (P>0.05). MCE detected positive findings in 21 (52.5%), 27 (67.5%) and 21 (53.8%) patients in group A, B and C respectively, with no significant difference between groups (P>0.5).

CONCLUSIONS

Simethicone swallowed with water prior to MCE produced the optimal gastric mucosal image quality. The addition of pronase had no demonstrable additional benefit.

Magnetically guided capsule endoscopy

Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera-integrated capsule allows for visualization of the small intestine, a region which was previously inaccessible to classical flexible endoscopy. As a diagnostic tool, it allows to localize the sources of bleedings in the middle part of the gastrointestinal tract and to identify diseases, such as inflammatory bowel disease (Crohn's disease), polyposis syndrome, and tumors. The screening and diagnostic efficacy of the WCE, especially in the stomach region, is hampered by a variety of technical challenges like the lack of active capsular position and orientation control. Therapeutic functionality is absent in most commercial capsules, due to constraints in capsular volume and energy storage. The possibility of using body-exogenous magnetic fields to guide, orient, power, and operate the capsule and its mechanisms has led to increasing research in Magnetically Guided Capsule Endoscopy (MGCE). This work shortly reviews the history and state-of-art in WCE technology. It highlights the magnetic technologies for advancing diagnostic and therapeutic functionalities of WCE. Not restricting itself to the GI tract, the review further investigates the technological developments in magnetically guided microrobots that can navigate through the various air- and fluid-filled lumina and cavities in the body for minimally invasive medicine.