Capsule endoscopy: a comprehensive review

The development of wireless capsule endoscopy (CE) has been a significant technologic advancement for the non-invasive visual evaluation of the entire small bowel and esophagus. The capsule endoscope is disposable and measures 11 x 26 mm. There are two capsule endoscopes currently available: PillCam ESO and PillCam SB for the evaluation of the esophagus and the small bowel, respectively. The PillCam ESO has two cameras on each end and captures images 7 frames per second per each camera, while the PillCam SB has one camera and captures images at a rate of 2 frames per second. Both capsule endoscopes transmit the image data using a radiofrequency signal to a recording device worn on the patient's waist. Once image acquisition is completed, the data from the recording device is downloaded to a computer workstation and analyzed by a gastroenterologist. Common indications for the small bowel CE include obscure gastrointestinal bleeding (OGIB), suspected Crohn disease (CD), as well as other suspected small bowel pathologies, while indications for the esophageal CE include screening of Barrett esophagus and esophageal varices. Small bowel CE appears to be more sensitive in the evaluation of OGIB and small bowel CD compared with other conventional radiological and endoscopic modalities. Preliminary results for the esophageal CE reveal good accuracy for screening of both Barrett and esophageal varices. CE is well tolerated by most patients, requires no sedation, and carries few side effects. One of the complications of CE is capsule retention; however, a patency capsule system has been developed, which can indicate whether an obstructing lesion is present before CE is performed. Finally, there are preliminary data suggesting that a new capsule endoscope for the colon may be useful in the evaluation of patients for colon polyps and possibly, screening for colon cancer.