Future Projections of Capsule Endoscopy
The inherent limitation of capsule endoscopy is that its movement is passively controlled by the gut peristalsis. Various approaches have been studied allowing steering or active locomotion of the capsule system. Recently, Rey et al. introduced a novel magnetically navigated capsule which is steered by a low-level magnetic field. The magnetically guided capsule endoscopy (MGCE) system was recently prospectively evaluated in patients with routine indications for gastroscopy. One hundred eighty-nine symptomatic patients underwent capsule and conventional gastroscopy. The gold standard was unblinded conventional gastroscopy with biopsy. Accuracy of capsule endoscopy was 91% with a specificity of 94% and a sensitivity of 62%, respectively. Therefore, it was shown that MGCE is feasible in clinical practice. MGCE was also clearly preferred by patients.
Capsule recordings are of extraordinary length, therefore, requiring significant time for analysis of the examiner. Proceedings of software algorithms now allow for more time-sparing approaches by automatically identifying gastric, duodenal and cecal landmarks and by automatically scanning images for bleeding-suspicious or lesion-suspicious images.
Another potential limitation of capsule endoscopy is that no tissue analysis can be performed once a suspicious lesion is found. Recent studies have shown the potential benefit of virtual chromoendoscopy techniques (i.e., flexible spectral imaging color enhancement; FICE, Fujifilm, Tokyo, Japan) for detection and diagnosis of small intestinal lesions found by capsule endoscopy.
In addition to software improvements and enhancements, novel capsule prototypes also allow obtainment of mucosal biopsies and placement of clips for hemostasis. The Nano-based capsule-Endoscopy with Molecular Imaging and Optical biopsy project by Given Imaging Ltd. and a global consortium [Zarlink Semiconductor (Sweden and United Kingdom), Fraunhofer Institute for Biomedical Engineering, Israelitic Hospital and Indivumed (Germany), Imperial College of Science, Technology and Medicine (London, England), ITC-irst Research Institute (Italy), The Hebrew University of Jerusalem, Novamed and Ernst & Young (Israel)] ultimately intends to develop a capsule system that will combine optical and nano technologies in order to further improve diagnostic and therapeutic possibilities.
At least, externally rechargeable batteries (using radio frequency, microwave, ultrasound or electric induction) or even 'battery-free' capsule endoscopy systems are under development to extend retention times and enable activities like capsule movements or clip placements.