Endoscopy 2009; 41(8): 731
DOI: 10.1055/s-0029-1214958
Letters to the editor

© Georg Thieme Verlag KG Stuttgart · New York

Swallowable capsule technology: current perspectives and future directions in image acquisition and processing

A.  Sanchez-Yague, T.  Nguyen-Tang
Further Information

Publication History

Publication Date:
10 August 2009 (online)

We read with interest the article by Twomey and Marchesi, “Swallowable capsule technology: current perspectives and future directions” [1]. They divide the current developments in capsule technology in four different areas: drug delivery, chemical sensing, controlled motion, and battery-less power. In our view capsule image acquisition and processing is an important topic not covered in the article.

In recent years there have been many exciting developments in capsule endoscopy. Since the first capsule endoscope was released in 2000 [2], up to seven different models have been presented by multiple companies. The M2A (mouth-to-anus) developed by Given Imaging (Yoqneam, Israel) featured a complementary metal-oxide sensor (CMOS) with a 140° vision field that acquired two frames per second, two batteries, four light-emitting diodes, and a radiofrequency transmitter. This capsule endoscope was renamed PillCam SB and then evolved to the PillCam SB2, featuring a wider field of vision (156°). Olympus (Tokyo, Japan) developed the EndoCapsule [3], which differs from the PillCam in the use of a charge-coupled device with a 145° vision field. Recently the MiRo capsule (IntroMedic Co. Ltd., Seoul, Korea) was added. This capsule uses a CMOS sensor with a vision field of 150°, but the main difference is the use of field propagation (instead of radiofrequency) to transmit three frames per second [4]. The OMOM capsule (Jianshan Science and Technology Group Co., Ltd., Chongqing, China) features a manually variable frame rate capture control [5]. Further developments have included the addition of a second viewing dome that was initially introduced with the PillCam Eso (designed for the study of the esophagus) and that has been also used in the PillCam Eso2 [6] and the PillCam Colon [7]. The esophageal capsules feature a higher image acquisition rate: seven and nine frames per second per viewing dome for the PillCam Eso and Eso2 respectively. On the other hand they have a shorter battery life.

Another development briefly mentioned by the authors is real-time viewing. Nowadays all the capsule endoscopes offer this possibility through different devices and the initial experiences have already been published [4] [5] [8] [9]. The authors point out correctly that these devices are still limited by the capsules’ low image acquisition rate. The possibility of advanced endoscopic imaging (high definition, digital chromoendoscopy) is a future perspective in capsule endoscopy that awaits development. Recently Zhang et al. [10] demonstrated the possibility of biochromoendoscopy using a capsule endoscope and molecular probes to differentiate adenomas from benign inflammatory polyps. Although this was an ex vivo study using external filters, the results are promising. Study of intestinal motor function through computerized analysis of capsule endoscopy images is in development and could be a useful noninvasive diagnostic test for intestinal motor disorders [11].

Competing interests: None

References

  • 1 Twomey K, Marchesi J R. Swallowable capsule technology: current perspectives and future directions.  Endoscopy. 2009;  41 357-362
  • 2 Iddan G, Meron G, Glukhovsky . et al . Wireless capsule endoscopy.  Nature. 2000;  405 417
  • 3 Cave D R, Fleischer D E, Leighton J A. et al . A multicenter randomized comparison of the Endocapsule and the PillCam SB.  Gastrointest Endosc. 2008;  68 487-494
  • 4 Bang S, Park J Y, Jeong S. et al . First clinical trial of the “MiRo” capsule endoscope by using a novel transmission technology: electric field propagation.  Gastrointest Endosc. 2009;  69 253-259
  • 5 Liao Z, Li Z S, Xu C. Reduction of capture rate in the stomach increases the complete examination rate of capsule endoscopy: a prospective randomized controlled trial.  Gastrointest Endosc. 2009;  69 418-425
  • 6 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.  Endoscopy. 2008;  40 275-279
  • 7 Eliakim R, Fireman Z, Gralnek I M. et al . Evaluation of the PillCam Colon capsule in the detection of colonic pathology: results of the first multicenter, prospective, comparative study.  Endoscopy. 2006;  38 963-970
  • 8 Sanchez Y ague, Allen M, Cabral P. et al . Clinical utility of the RAPID Access RT for real-time viewing of capsule endoscopy.  Gastrointest Endosc. 2007;  65 AB356
  • 9 Lai L H, Wong G L, Lau J Y. et al . Initial experience of real-time capsule endoscopy in monitoring progress of the videocapsule through the upper GI tract.  Gastrointest Endosc. 2007;  66 1211-1214
  • 10 Zhang H, Morgan D, Cecil G. et al . Biochromoendoscopy: molecular imaging with capsule endoscopy for detection of adenomas of the GI tract.  Gastrointest Endosc. 2008;  68 520-527
  • 11 Malagelada C, De Iorio F, Azpiroz F. et al . New insight into intestinal motor function via noninvasive endoluminal image analysis.  Gastroenterology. 2008;  135 1155-1162

Andres Sanchez-YagueMD, PhD 

Hospital Costa del Sol
Gastroenterology Department

Autovia A-7, Km. 187
29603 Marbella
Spain

Fax: +34-952771771

Email: asyague@gmail.com

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