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

  • Author Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Bin Jiang
    Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Author Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Yang-Yang Qian
    Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Author Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Jun Pan
    Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Xi Jiang
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Yuan-Chen Wang
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Jia-Hui Zhu
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Wen-Bin Zou
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Wei Zhou
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Zhao-Shen Li
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Zhuan Liao
    Correspondence
    Reprint requests: Zhuan Liao, National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, 168 Changhai Rd, Shanghai 200433, China.
    Affiliations
    National Clinical Research Center for Digestive Diseases, Department of Gastroenterology, Changhai Hospital, Naval Medical University, Shanghai, China
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  • Author Footnotes
    ∗ Drs Jiang, Qian, and Pan contributed equally to this article.
Published:January 22, 2020DOI:https://doi.org/10.1016/j.gie.2020.01.027

      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: NCT 03977935.)

      Abbreviations:

      CE (capsule endoscopy), fps (frames per second), GET (gastric examination time), MCCG (magnetically controlled capsule gastroscopy), UGI (upper GI)
      Magnetically controlled capsule gastroscopy (MCCG) provides good visualization of the stomach and is highly accepted because of the characteristics of painlessness, noninvasiveness, and equally favorable diagnostic accuracy as conventional endoscopy.
      • Liao Z.
      • Hou X.
      • Lin-Hu E.Q.
      • et al.
      Accuracy of magnetically controlled capsule endoscopy, compared with conventional gastroscopy, in detection of gastric diseases.
      ,
      • Liao Z.
      • Zou W.B.
      • Li Z.S.
      Clinical application of magnetically controlled capsule gastroscopy in gastric disease diagnosis: recent advances.
      However, the upper GI (UGI) tract under capsule endoscopy (CE) continues to present challenges, including rapid transit through the esophagus and duodenum
      • Hosoe N.
      • Naganuma M.
      • Ogata H.
      Current status of capsule endoscopy through a whole digestive tract.
      ,
      • Ching H.L.
      • Healy A.
      • Thurston V.
      • et al.
      Upper gastrointestinal tract capsule endoscopy using a nurse-led protocol: first reported experience.
      and longer gastric examination time (GET)
      • Zou W.B.
      • Hou X.H.
      • Xin L.
      • et al.
      Magnetic-controlled capsule endoscopy vs. gastroscopy for gastric diseases: a two-center self-controlled comparative trial.
      compared with conventional endoscopy. Technical improvements in frame rate, field of view, dual camera, image resolution, and battery life have been developed to optimize the clinical application of CE, and some turned out to be effective.
      • Tontini G.E.
      • Wiedbrauck F.
      • Cavallaro F.
      • et al.
      Small-bowel capsule endoscopy with panoramic view: results of the first multicenter, observational study (with videos).
      • Monteiro S.
      • de Castro F.D.
      • Carvalho P.B.
      • et al.
      PillCam® SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?.
      • Takamaru H.
      • Yamada M.
      • Sakamoto T.
      • et al.
      Dual camera colon capsule endoscopy increases detection of colorectal lesions.
      • Ou G.
      • Shahidi N.
      • Galorport C.
      • et al.
      Effect of longer battery life on small bowel capsule endoscopy.
      Therefore, a second-generation MCCG (MCCG-2) highlighted with a higher and adaptive frame rate of 8 frames per second (fps), better image resolution of 720 × 720 pixels, wider field of view of 150 degrees, extended battery life of more than 12 hours, and antijamming wireless data transmission has been developed. Hence, this pilot study was conducted to determine whether MCCG-2 can further optimize the visualization of the UGI tract, thus resulting in a better diagnosis of UGI diseases.

      Methods

      Study design

      This pilot study was a prospective, single-centered, blinded, randomized controlled study approved by the institutional review board of Shanghai Changhai Hospital and registered at clinicaltrials.gov (NCT03977935). Written informed consent was obtained from each enrolled subject.

      Patients

      From May 2019 to June 2019, 80 consecutive patients aged 18 to 80 years with or without abdominal complaints referring for MCCG examination were prospectively enrolled and randomly allocated into the MCCG-1 group or MCCG-2 group in a 1:1 ratio. Patients with any of the following contraindications for MCCG were excluded: pacemakers or electromedical devices implanted, which are incompatible with magnetic field; suspected or known GI stenosis, obstruction, or other known risk factors for capsule retention; scheduled magnetic resonance imaging examination before excretion of capsule; pregnancy or suspected pregnancy; and any other contraindications as determined by endoscopists.

      Study intervention

      The MCCG, a robotic magnetic capsule guidance system, was provided by Ankon Technologies Co Ltd (Shanghai, China). The MCCG system consisted of a guidance magnet robot, a CE, a data recorder, and a computer workstation with software for real-time view and 2 joysticks for capsule orientation control. The guidance magnet robot was of C-arm type with 5 degrees of freedom: 2 rotational (horizontal and vertical directions) and 3 translational (forward/backward, up/down, left/right).
      After a standardized GI preparation regimen for MCCG, patients were placed in the left lateral decubitus position. They swallowed the MCCG-1 or MCCG-2 with a small amount of water according to a random number table with the help of nurses at the digestive endoscopic center. When the capsule reached the stomach, it was lifted away from the posterior wall, rotated, and advanced to the fundus and cardiac regions, followed by the gastric body, angulus, antrum, and the pylorus. During this procedure, position changes such as supine, prone, left, and right lateral were also helpful in achieving clear observation and smooth transition. A standardized examination procedure of MCCG is available online at videogie.org.
      • Jiang X.
      • Pan J.
      • Li Z.S.
      • et al.
      Standardized examination procedure of magnetically controlled capsule endoscopy.
      Patients with suspected malignancy were rechecked under conventional endoscopy.
      The image capture rate in the esophagus and stomach were 2 fps or 6 fps in the MCCG-1 or MCCG-2 group, and standardized operations of MCCG were performed twice for complete gastric examination. After the capsule moved into the duodenum, patients left the hospital with the data recorder to continue with small-bowel examination. In the small bowel, MCCG-2 offered an adaptive frame rate technology that adjusted the image capture rate based on how fast the capsule was moving.

      Study outcomes and definition

      Basic characteristics of the enrolled patients were prospectively collected. The primary study outcome was efficacy analysis, including visualization of the esophagus and duodenum indicated by detection rate of the Z-line and duodenal papilla defined as obtaining at least 1 image of the Z-line or duodenal papilla, number of images captured for the esophagus and Z-line, circumferential visualization of the Z-line as the number of quadrants observed, and cleansing level of the Z-line as bubbles/saliva on Z-line.
      • Gralnek I.M.
      • Adler S.N.
      • Yassin K.
      • et al.
      Detecting esophageal disease with second-generation capsule endoscopy: initial evaluation of the PillCam ESO 2.
      Operation-related parameters included esophageal transit time, GET, gastric transit time, small-bowel transit time, and total running time. Image quality, maneuverability, and detection of lesions were also prospectively documented. All procedure-related adverse events were closely recorded.
      GET was defined as the time for examination of gastric primary anatomic landmarks twice. Image quality ranged from 1 to 10 denoting the worst to the best.
      • Chen Y.Z.
      • Pan J.
      • Luo Y.Y.
      • et al.
      Detachable string magnetically controlled capsule endoscopy for complete viewing of the esophagus and stomach.
      Maneuverability was classified as fluency (the response to operation and video effect), stability (the ability of holding the capsule at 1 position for at least 1 minute), and comfortableness (the operator’s fatigue degree during the examination), and each index was graded from 1 to 5, with 1 as the worst and 5 as the best.
      All examinations and maneuverability evaluation were performed by an endoscopist (W.Z.) with experience of more than 1000 cases of MCCG operation. Two other endoscopists blinded to the grouping independently evaluated the image quality with a mean value as the final score, and a third endoscopist made the final judgement when a discrepancy of more than 3 occurred. The randomization schedule was generated by the investigator using a random number table, so that patients and endoscopists were all blinded to the treatment protocol assigned.

      Statistical analysis

      As a pilot study to evaluate the clinical utility of MCCG-2, sample size was not calculated for this study. Quantitative data were summarized with parametric statistics, mean and standard deviation, or nonparametric statistics, median, and interquartile range (IQR), whereas categorical data were presented as frequency (percentage). Data with a normal distribution were compared using parametric analysis, and non-normally distributed data were compared using nonparametric statistical analyses. Categorical variables were analyzed with the χ2 exact test, and quantitative data were analyzed using the Mann-Whitney Wilcoxon test with a final 2-sided P < .05 indicating statistical difference. SPSS 13.0 software (IBM Corp, Armonk, NY, USA) was used.

      Results

      Patient characteristics and safety analysis

      Eighty subjects (40 in each group; mean age, 46 years [range, 24-78]) were enrolled. Characteristics of the study population are shown in Table 1. No statistical difference of baseline characteristics or indications for MCCG existed between the 2 groups. No capsule retention or adverse events were observed in all patients during the 2-week follow-up period.
      Table 1Demographics and indications for MCCG examination of enrolled patients in 2 groups
      MCCG-1 group (n = 40)MCCG-2 group (n = 40)P value
      Sex, M/F24/1623/17.820
      Age, y48.45 ± 13.5148.58 ± 14.24.968
      Body mass index, kg/m222.73 ± 3.6522.64 ± 3.53.925
      Diabetes32>.999
      Hp infection771.000
      History of abdominal surgery43>.999
      Smoking history75.531
      Drinking history42.671
      Indication.836
       Abdominal pain or distension2019.823
       Acid reflux or nausea/vomit551.000
       Chronic diarrhea64.499
       Physical examination912.446
      MCCG, Magnetically controlled capsule gastroscopy.

      Visualization of esophagus and duodenum

      As illustrated in Table 2 and Figure 1, MCCG-2 greatly improved the visualization of the esophagus as the frames captured for esophageal mucosa and Z-line were 171.00 (IQR, 81.25-409.25) and 2.00 (IQR, 0-13.00), a significant increase from those in the MCCG-1 group with 97.00 (IQR, 42.00-160.25) and .00 (IQR, 0-2.75; P = .002 and P = .028, respectively). Circumferential viewing of the Z-line was also greatly improved with complete observation of the Z-line in 5 patients (12.5%) under MCCG-2 compared with none under MCCG-1, and at least 2 quadrants of the Z-line were successfully viewed in 12 patients (30.0%) in the MCCG-2 group, greatly improved from only 5 patients (12.5%) in the MCCG-1 group (P = .043). Although there was no significant difference in the detection of the Z-line and duodenal papilla, an obvious upward trend still existed in MCCG-2 group.
      Table 2Efficacy analysis between first-generation and second-generation MCCG
      CharacteristicsMCCG-1 group (n = 40)MCCG-2 group (n = 40)P value
      Visualization of the esophagus
       Frames of esophagus97.00 (42.00-160.25)171.00 (81.25-409.25).002
       Frames of Z-line0 (0-2.75)2.00 (0-13.00).028
       Detection of Z-line17 (42.5)24 (60).117
      Circumferential viewing of the Z-line.043
       100%0 (.0)5 (12.5)
       ≥50%5 (12.5)7 (17.5)
       <50%12 (30.0)12 (30.0)
       0%23 (57.5)16 (40)
      Cleansing level of the Z-line area.950
       No bubbles13 (32.5)11 (27.5)
       A few bubbles18 (45.0)22 (55.0)
       Increased amount of bubbles7 (17.5)5 (12.5)
       Severe bubbles2 (5.0)2 (5.0)
       Detection of duodenal papilla3 (7.5)6 (15).479
      Examination-related parameters
       Esophageal transit time, s59.50 (24.75-82.75)44.50 (23.0-107.5).904
       Mean GET, min7.78 ± .975.27 ± .74<.001
       Gastric transit time, min53.09 (22.88-90.84)48.35 (19.09-78.83).364
       Small-bowel transit time, min327.60 (260.73-394.55)297.22 (239.68-369.27).349
       Total running time, min702.83 (648.47-856.10)1001.99 (774.42-1207.38)<.001
      Image quality score7.90 ± .618.63 ± .57<.001
      Maneuverability score
       Fluency3.04 ± .514.59 ± .42<.001
       Comfortableness3.16 ± .454.51 ± .43<.001
       Stability3.84 ± .554.17 ± .50.009
       Total score10.05 ± 1.0413.28 ± .90<.001
      Values are median (range), n (%), or mean ± standard deviation.
      MCCG, Magnetically controlled capsule gastroscopy; GET, gastric examination time.
      Figure thumbnail gr1ad
      Figure 1Comparison of representative images under magnetically controlled capsule gastroscopy (MCCG) and conventional endoscopy. Complete viewing of the Z-line under MCCG-1 (A, B) and MCCG-2 (C, D). Close-up image of midesophageal cancer and gastric greater curvature cancer under conventional endoscopy (E, F) and MCCG-2 (G, H).
      Figure thumbnail gr1eh
      Figure 1Comparison of representative images under magnetically controlled capsule gastroscopy (MCCG) and conventional endoscopy. Complete viewing of the Z-line under MCCG-1 (A, B) and MCCG-2 (C, D). Close-up image of midesophageal cancer and gastric greater curvature cancer under conventional endoscopy (E, F) and MCCG-2 (G, H).

      Operation-related parameters

      For operation-related parameters, MCCG-2 dramatically shortened the GET from 7.78 ± .97 to 5.27 ± .74 minutes and extended the total running time from 702.83 (IQR, 648.47-856.10) to 1001.99 minutes (IQR, 774.42-1207.38; P < .001). Esophageal transit time, gastric transit time, and small-bowel transit time were similar between the 2 groups.

      Image quality and maneuverability analysis

      The mean score of the image quality was 8.63 ± .57 in the MCCG-2 group and 7.90 ± .61 in the MCCG-1 group; thus, the image quality was enhanced greatly using MCCG-2 (P < .001). As displayed in Video 1 (available online at www.giejournal.org) and Figure 2, anatomic landmarks of the stomach can be clearly observed using MCCG-2. Operators in MCCG-2 group definitely had a better experience elucidated by the improved maneuverability-related parameters: 4.59 ± .42 versus 3.04 ± .51 for fluency, 4.51 ± .43 versus 3.16 ± .45 for comfortableness, and 4.17 ± .50 versus 3.84 ± .55 for stability, respectively (all P < .01).
      Figure thumbnail gr2ad
      Figure 2Representative images of anatomic landmarks under second-generation magnetically controlled capsule gastroscopy. A, Middle esophagus. B, Cardiac and fundus. C and D, Gastric body. E, Angulus. F, Antrum. G, Pylorus. H, Duodenal papilla.
      Figure thumbnail gr2eh
      Figure 2Representative images of anatomic landmarks under second-generation magnetically controlled capsule gastroscopy. A, Middle esophagus. B, Cardiac and fundus. C and D, Gastric body. E, Angulus. F, Antrum. G, Pylorus. H, Duodenal papilla.

      Positive findings in UGI and small bowel

      Regarding positive findings, 25 (62.5%) and 24 (60.0%) patients were diagnosed with inflammation and 12 (30.0%) and 13 (32.5%) focal lesions were detected in the MCCG-1 and MCCG-2 groups, respectively. There was no significant difference in detection of inflammation and focal lesions (Table 3). Of note, 1 esophageal cancer and 1 gastric cancer were detected in the MCCG-2 group, and both were confirmed by subsequent conventional endoscopy within 24 hours (Fig. 1).
      Table 3Positive findings compared in 2 groups
      LesionsMCCG-1 group (n = 40)MCCG-2 group (n = 40)P value
      Inflammation25 (62.5)24 (60.0).818
      Detection of focal lesions12 (30.0)13 (32.5).809
       Polyps56
       Ulcer33
       Submucosal prominences21
       Arteriovenous malformation21
       Esophagus cancer01
      A patient in the MCCG-2 group with suspected tumor was confirmed as cancer by biopsy sampling.
       Gastric cancer01
      A patient in the MCCG-2 group with suspected tumor was confirmed as cancer by biopsy sampling.
      Values in parentheses are percents.
      MCCG, Magnetically controlled capsule gastroscopy.
      A patient in the MCCG-2 group with suspected tumor was confirmed as cancer by biopsy sampling.

      Discussion

      GI cancer constitutes an enormous burden worldwide that is expected to increase, and early detection can help seize control of the growing burden.
      • Torre L.A.
      • Bray F.
      • Siegel R.L.
      • et al.
      Global cancer statistics, 2012.
      MCCG is now attracting more attention and especially has a potential role in the GI disease screening modality because of its noninvasiveness and satisfactory diagnostic accuracy. However, there is still a long way to go before replacing conventional gastroscopy as a diagnostic modality, which remains the criterion standard diagnostic tool in the foregut.
      • Ching H.L.
      • Hale M.F.
      • McAlindon M.E.
      Current and future role of magnetically assisted gastric capsule endoscopy in the upper gastrointestinal tract.
      Thus, many methods, including increased frame rate,
      • Tontini G.E.
      • Wiedbrauck F.
      • Cavallaro F.
      • et al.
      Small-bowel capsule endoscopy with panoramic view: results of the first multicenter, observational study (with videos).
      ,
      • Monteiro S.
      • de Castro F.D.
      • Carvalho P.B.
      • et al.
      PillCam® SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?.
      widened view angle,
      • Tontini G.E.
      • Wiedbrauck F.
      • Cavallaro F.
      • et al.
      Small-bowel capsule endoscopy with panoramic view: results of the first multicenter, observational study (with videos).
      enhanced image resolution,
      • Monteiro S.
      • de Castro F.D.
      • Carvalho P.B.
      • et al.
      PillCam® SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?.
      and extended battery life
      • Tontini G.E.
      • Wiedbrauck F.
      • Cavallaro F.
      • et al.
      Small-bowel capsule endoscopy with panoramic view: results of the first multicenter, observational study (with videos).
      ,
      • Monteiro S.
      • de Castro F.D.
      • Carvalho P.B.
      • et al.
      PillCam® SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?.
      ,
      • Ou G.
      • Shahidi N.
      • Galorport C.
      • et al.
      Effect of longer battery life on small bowel capsule endoscopy.
      have been tried to further optimize the mucosal visualization of UGI and improve the complete examination of the small bowel.
      As shown in Table 4, MCCG-2 has been updated regarding multiple parameters. Compared with currently available wireless magnetically assisted CE,
      • Swain P.
      • Toor A.
      • Volke F.
      • et al.
      Remote magnetic manipulation of a wireless capsule endoscope in the esophagus and stomach of humans (with videos).
      • Rahman I.
      • Pioche M.
      • Shim C.S.
      • et al.
      Magnetic-assisted capsule endoscopy in the upper GI tract by using a novel navigation system (with video).
      • Rey J.F.
      • Ogata H.
      • Hosoe N.
      • et al.
      Blinded nonrandomized comparative study of gastric examination with a magnetically guided capsule endoscope and standard video endoscope.
      MCCG-2 also shows superiority especially in control method, image resolution, frame rate, battery life, and stable and powerful magnetic force. In addition, antijamming technology promises effective, steady, and smooth wireless data transmission, given the capability of spatial signal processing and error correction. The EndoCapsule system (Olympus Medical Systems Corporation, Tokyo, Japan, and Siemens Healthcare AG, Erlangen, Germany) under magnetic resonance imaging guidance has a dual-camera capsule to ensure complete visualization of gastric mucosa.
      • Rey J.F.
      • Ogata H.
      • Hosoe N.
      • et al.
      Blinded nonrandomized comparative study of gastric examination with a magnetically guided capsule endoscope and standard video endoscope.
      MCCG provides complete visualization of the stomach, and the dual camera may require extra consumption of battery. In addition, a novel magnetic-assisted CE system consisting of a cable CE and hand-held magnetic field navigator was reported. Despite satisfactory maneuverability and visualization completeness in the esophagus, stomach, and duodenum, it may increase patient discomfort during the procedure compared with wireless CE.
      • Lien G.S.
      • Wu M.S.
      • Chen C.N.
      • et al.
      Feasibility and safety of a novel magnetic-assisted capsule endoscope system in a preliminary examination for upper gastrointestinal tract.
      Table 4Comparison of 5 available wireless magnetically controlled capsule endoscopy systems
      ParametersGiven Imaging Pillcam
      Given Imaging,Yokneam, Israel.
      Intromedic

      Mirocam-Navi
      Intromedic, Seoul, Korea.
      Olympus EndoCapsule
      Olympus, Tokyo, Japan.
      Ankon MCCG-1
      Ankon Technologies, Wuhan, China.
      Ankon MCCG-2
      Size, mm31 × 1124 × 1131 × 1126.8 × 11.626.8 × 11.6
      Weight, g74.2NA55
      Control methodHandheld magnetHandheld magnetMRI guidanceRobotic controlRobotic control
      CameraSingleSingleDualSingleSingle
      Field of view, degrees156170>145140150
      Depth of view, mm0-300-30>200-300-30
      Resolution256 × 256320 × 320512 × 512480 × 480720 × 720
      Frame rate, /s43428 adaptive technology in the small bowel
      Battery life, h108NA812
      Maximum continuous magnetic force at 25 cm distance, mN4NA121.721.7
      Error correctionNANANANoAntijamming wireless data transmission
      Food and Drug Administration approvalNoNoNoChina Food and Drug AdministrationChina Food and Drug Administration
      MCCG, Magnetically controlled capsule gastroscopy; MRI, magnetic resonance imaging; NA, not available.
      Given Imaging,Yokneam, Israel.
      Intromedic, Seoul, Korea.
      Olympus, Tokyo, Japan.
      § Ankon Technologies, Wuhan, China.
      In our study, the new upgraded MCCG-2 greatly improved the visualization of the esophagus and promoted the visualization of the duodenal papilla. Previous studies have shown the Pillcam ESO achieved satisfactory visualization in the esophagus, elucidated by a whole circumference of the Z-line of 92.5% for Pillcam UGI (Medtronic Ltd, Dublin, Ireland) with 35 fps,
      • Ching H.L.
      • Healy A.
      • Thurston V.
      • et al.
      Upper gastrointestinal tract capsule endoscopy using a nurse-led protocol: first reported experience.
      50% for Pillcam ESO 2 (Given Imaging Ltd, Yoqneam, Israel) with 18 fps,
      • Gralnek I.M.
      • Adler S.N.
      • Yassin K.
      • et al.
      Detecting esophageal disease with second-generation capsule endoscopy: initial evaluation of the PillCam ESO 2.
      and 30% for Pillcam ESO 1 (Given Imaging Ltd) with 14 fps, which can be greatly improved to 80% under string esophageal CE.
      • Chen W.S.
      • Zhu L.H.
      • Li D.Z.
      • et al.
      String esophageal capsule endoscopy with real-time viewing improves visualization of the distal esophageal Z-line: a prospective, comparative study.
      However, Pillcam ESO 1 and 2 were specialized for esophageal examination, and the Pillcam UGI with a higher frame rate and dual camera can be power-consuming. The detachable string MCCG has been used and proved to be feasible, safe, and well tolerated for viewing the esophagus.
      • Chen Y.Z.
      • Pan J.
      • Luo Y.Y.
      • et al.
      Detachable string magnetically controlled capsule endoscopy for complete viewing of the esophagus and stomach.
      Thus, the detachable string MCCG-2 can undoubtedly balance excellent visualization of the UGI tract with complete examination of the small bowel, which is our next investigation target.
      Another breakthrough was the dramatically shortened mean GET from 7.78 to 5.27 minutes using the MCCG-2, which was comparable with conventional endoscopy with an examination of about 5.00 minutes.
      • Zou W.B.
      • Hou X.H.
      • Xin L.
      • et al.
      Magnetic-controlled capsule endoscopy vs. gastroscopy for gastric diseases: a two-center self-controlled comparative trial.
      Previous reports showed that the mean GET of MCCG would decrease with operation experience and improved gastric preparation,
      • Zou W.B.
      • Hou X.H.
      • Xin L.
      • et al.
      Magnetic-controlled capsule endoscopy vs. gastroscopy for gastric diseases: a two-center self-controlled comparative trial.
      ,
      • Jiang X.
      • Qian Y.Y.
      • Liu X.
      • et al.
      Impact of magnetic steering on gastric transit time of a capsule endoscopy (with video).
      ,
      • Wang Y.C.
      • Pan J.
      • Jiang X.
      • et al.
      Repetitive position change improves gastric cleanliness for magnetically controlled capsule gastroscopy.
      and this study further proposed MCCG-2 as a more-suitable modality for gastric examination with favorable diagnostic accuracy and reduced examination time. This could potentially benefit countries with gastric cancer screening programs the most by reducing the burden of the gastroscopy requirement.
      The diagnostic yield of CE in the small bowel may be hampered by incomplete small-bowel examination. Studies revealed a pooled completion rate of 83.5%, with the possibility of missed diagnoses in the terminal ileum.
      • Liao Z.
      • Gao R.
      • Xu C.
      • et al.
      Indications and detection, completion, and retention rates of small-bowel capsule endoscopy: a systematic review.
      Magnetic steering of the capsule during transpyloric passage can lead to a completion rate of 100%,
      • Luo Y.Y.
      • Pan J.
      • Chen Y.Z.
      • et al.
      Magnetic steering of capsule endoscopy improves small bowel capsule endoscopy completion rate.
      thus significantly promoting gastric transit time. It was suggested that the adaptive frame rate technology of the Pillcam SB3 and Pillcam Colon 2 may enhance diagnostic yield.
      • Monteiro S.
      • de Castro F.D.
      • Carvalho P.B.
      • et al.
      PillCam® SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?.
      MCCG-1 can provide a traditional image capture rate of 2 fps, whereas MCCG-2 also introduced an adaptive technology to combat CE limitations during periods of rapid transit in the small bowel. Thus, an extended battery life and adaptive frame rate in the small bowel further guarantee complete examination and diagnostic accuracy of the small bowel and even more inspection of the colon.
      • Ou G.
      • Shahidi N.
      • Galorport C.
      • et al.
      Effect of longer battery life on small bowel capsule endoscopy.
      This trial has limitations. First, as a pilot study to access the efficacy and safety of the updated MCCG, lesion detection rate was not significantly different between the 2 groups mainly because of the small sample size, warranting further large-scale studies to test the diagnostic ability compared with conventional endoscopy. Second, the evaluation of maneuverability and image quality was somehow subjective, which may cause over-interpretation.
      In conclusion, this pilot study was the first trial for efficacy and safety evaluation of the updated MCCG, proposing an optimized visualization and diagnosis of UGI tract. Also, it established the foundation for more large-scale investigations validating MCCG as a promising examination modality for the entire GI tract, especially under the introduction of deep learning–based artificial intelligence models, a hotspot introduced both in conventional endoscopy
      • Luo H.Y.
      • Xu G.L.
      • Li C.F.
      • et al.
      Real-time artificial intelligence for detection of upper gastrointestinal cancer by endoscopy: a multicentre, case-control, diagnostic study.
      and CE.
      • Ding Z.
      • Shi H.
      • Zhang H.
      • et al.
      Gastroenterologist-level identification of small-bowel diseases and normal variants by capsule endoscopy using a deep-learning model.

      Supplementary data

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