Repetitive Position Change After Dimethicone Premedication Improves Gastric Cleanliness for Magnetically Controlled Capsule Endoscopy: a Single-blind, Randomized Controlled Trial
Phase: NA
Conditions: Stomach Diseases
Sponsor: Changhai Hospital

Repetitive position change improves gastric cleanliness for magnetically controlled 
capsule gastroscopy 
 
Document Date: May 1, 2018 
Trial registration: ClinicalTrials.gov, ID: NCT03514966 
 
Yuan-Chen Wang1,2, M.D., Jun Pan1,2, M.D., Xi Jiang1,2, M.D., Xiao-Ju Su1, M.D., Wei Zhou1, 
M.D., Wen-Bin Zou1, M.D., Yang-Yang Qian1, M.D., Yi-Zhi Chen1, M.D., Xiao Liu1, M.D., Jin 
Yu1, M.D., Xiao-Nan Yan1, M.D., An-Jing Zhao1, M.D., Zhao-Shen Li1, M.D., Zhuan Liao1,*, 
M.D. 
 
1National Clinical Research Center for Digestive Diseases; Department of Gastroenterology, 
Changhai Hospital, Second Military Medical University, Shanghai, China 
2These authors contributed equally to this work 
 
*Correspondence 
Zhuan Liao 
National Clinical Research Center for Digestive Diseases; Department of Gastroenterology, 
Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 
200433, China 
Tel: 86-21-31161004; Fax: 86-21-65492727 
E-mail: liaozhuan@smmu.edu.cn 
 
Funding: This study is supported by grants from the National Natural Science Foundation of 
China (to Z. Liao, No.81422010); Foundation for the Author of National Excellent Doctoral 
Dissertation of China (to Z. Liao, No.201271); the Shuguang Program of Shanghai Education 
Development Foundation and Shanghai Municipal Education Commission (to Z. Liao, 
No.15SG33); the Chang Jiang Scholars Program of Ministry of Education (to Z. Liao, No. 
Q2015190); and Shanghai Sailing Program (to J. Pan, No. 18YF1422800), China. 
 

Author contributions: Study concept and design (ZL); registration of the study (YCW, JP); 
conduct of the study (YCW, JP); acquisition of data (YCW, XJS, XJ, WBZ, YYQ, WZ, XL, JY, 
XNY, AJZ); analysis and interpretation of data (YCW, JP); drafting of the manuscript (JP); 
statistical analysis (YCW); critical revision of the manuscript for important intellectual content 
(ZL, ZSL); obtained funding (ZL, JP). All authors had access to the study data and reviewed 
and approved the final manuscript. 
 
Competing Interests: None. 
Acknowledgement: None. 
 
 

 
Study Design and Patients  
We conducted a single-blind, randomized controlled trial approved by the institutional 
review board of Shanghai Changhai Hospital (ClinicalTrials.gov. ID: NCT03514966). From 
May 7 to May 31 2018, consecutive patients (aged ≥ 18 years) with upper abdominal 
complaints requiring MCCG in Changhai Hospital were included after providing informed 
consent. Patients with the following [7] were excluded: (1) dysphagia or symptoms of gastric 
outlet obstruction, suspected or known intestinal stenosis, overt gastrointestinal bleeding, 
history of upper gastrointestinal surgery or abdominal surgery altering gastrointestinal 
anatomy, or post abdominal radiation; (2) congestive heart failure, renal insufﬁciency, under 
therapeutic anticoagulation, in poor general condition (American Society of Anesthesiologists 
class III/IV), claustrophobia, metallic parts, a pacemaker or other implanted electromedical 
devices, or artiﬁcial heart valves; (3) pregnancy or suspected pregnancy; (4) exclusion criteria 
for standard magnetic resonance imaging examination such as the presence of surgical 
metallic devices, even though its low magnetic ﬁeld technically would not interfere with such 
devices; or (5) currently participating in another clinical study [6]. 
Examination were performed by one qualified capsule endoscopist with an experience 
of more than 500 cases of MCCG operation. Other two endoscopists (J.P., X.J.S.) was 
blinded to the type of gastric preparation, independently graded the quality by reviewing the 
images captured by MCCG. When discrepancies arise over the grading results, this will be 
resolved by consensus discussion between the two endoscopists, with arbitration by a third 
endoscopist (Z.L.) and made the final decision. 
 
Study intervention 
Magnetically controlled capsule gastroscopy system 
The MCCG system used in this study includes an endoscopic capsule, a portable 
external data recorder, a guidance magnet robot, and a computer workstation with software 
for real-time viewing and controlling, all provided by Ankon Technologies Co. Ltd (Shanghai, 
China). The endoscopic capsule has a size of 27 * 11.8 mm, with light-emitting diodes 
surrounding two metal oxide chip cameras placed at both ends. Images are captured and 

recorded at a rate of 2 frame/s, and information sent wirelessly to the data recorder. The view 
angle of capsule is 140, and view distance is 0 to 30 mm. It is powered by two silver oxide 
batteries for up to 10-12 hours. In addition, a permanent magnet was also contained within 
the dome of capsule, which is guided by the C-arm type guidance magnet robot with five 
degrees of freedom—two rotational degrees and three translational degrees. Through 
simulation on the basis of the magnetic field generated by the magnet guidance system, the 
magnetic field can be adjusted and reaches a maximum of 200 mT. Using two joysticks, the 
examiner can control capsule movement to varying the strength of magnetic field by altering 
the distance of the magnet from the patient and change the polarity of the magnet. The size 
of lesions could be measured by the ESNavi software [5, 6]. 
 
Gastric preparation regimen and MCCG examination protocol 
After overnight fasting (> 8h), subjects receiving magnetically controlled capsule 
gastroscopy at the institution who met the inclusion criteria will be randomly allocated into 1 
of 2 groups (1:1): position change or conventional groups. An independent research assistant 
generated the computerized random number sequence. The sequence was concealed in an 
opaque envelope until the intervention was obtained from eligible subjects, study nurses 
telephoned the independent research assistant, and then informed the patient’s intervention 
allocation. Right after ingesting 5 g dimethicone (Zigong Honghe Pharmaceutical Co.,Ltd; 
Sichuan, China) mixed with 100 ml of water, subjects in the conventional group were allowed 
to walk freely; while subjects in the position change group were instructed by the study nurses 
to repeatedly change the body position according to a pre-specified protocol for a period of 
15 min: in the order of supine position, left lateral position, three cycles of prone, left lateral, 
supine, and right lateral positions, and finally supine position, with a duration of 1 min for each 
position. Thirty and forty min after dimethicone administration, subjects in both groups would 
additionally take 200 ml and 800 ml water, respectively before undergoing MCCG 
examination (Supplementary Figure S1).  
After attaching the data recorder, patients were asked to lie down on the examination 
couch beneath the guidance magnet robot. Then the capsule was swallowed in a supine 
position with approximately 100 ml of water for investigating the esophagus. The patient 

remained sat upright to facilitate the esophageal passage if capsule stop in the esophagus 
more than one minute. The examination was conducted with the patient lying in left lateral, 
supine, and ﬁnally right lateral positions. If difﬁculties in navigation were encountered, further 
positional change (including the prone position) was tried. Additional water was needed if 
distension was insufﬁcient. When the capsule reached the stomach, the investigator lifted the 
capsule away from the posterior wall, rotated and advanced the capsule to the fundus and 
cardiac regions, and then to the gastric body, angulus, antrum, and pylorus. The gastric 
examination time of MCCG was recorded. If lesions were identified during MCCG 
examination, conventional EGD was performed according to standard practice to obtain 
biopsy or for therapeutic intervention. 
 
Outcome parameters 
Primary Outcome Measure 
The primary outcome was gastric cleanliness score (GCS). Six primary anatomical 
landmarks of the stomach (cardia, fundus, body, angulus, antrum, and pylorus) were 
recorded for evaluation. A 4-point grading scale was introduced to define the cleanliness as 
excellent (no adherent mucus and foam: score 4), good (mild mucus and foam but does not 
obscure vision: score 3), fair (considerable amount of mucus or foam present precluding a 
completely reliable examination: score 2) and poor (large amount of mucus or foam residue 
needing water to clear it: score 1) (Supplementary Figure S2) [6, 7]. GCS was the total scores 
of all six landmarks, ranging from 6 (completely unprepared) to 24 (perfect). GCS of ≥ 18 was 
regarded as acceptable. 
Secondary Outcome Measure 
Secondary outcomes included detection rate of positive findings, number of lesions per 
patient (NLPP), gastric examination time, and safety of MCCG. Positive findings defined as 
any pathology detected by MCCG, including polyp, ulcer, gastric fundus varices, submucosal 
tumor, and carditis. The diffuse lesions such as superficial, atrophic, and erosive gastritis 
were defined as negative findings [6]. NLPP was defined as the number of positive findings 
divided by the total number of patients, the location of NLPP were also recorded. Gastric 
examination time was determined using digital stopwatch in the ESNavi software. Safety of 

MCCG, or adverse events, defined as symptoms or signs such as abdominal distention, 
nausea, or vomiting, were monitored closely during the MCCG procedure. Capsule retention 
(i.e., a capsule endoscope remaining in the gastrointestinal tract for more than two weeks or 
a capsule endoscope that requires directed intervention or therapy to aid its expulsion) was 
monitored and followed up for up to two weeks.