Capsule endoscopy compared with conventional colonoscopy for detection of colorectal neoplasms.

Colon capsule endoscopy (CCE) may be a means to overcome the low adherence to colorectal cancer screening. The device is an ingestible capsule with a video camera at both ends that can take photographs as it progresses through the gastrointestinal tract. PillCam colon (PCC1) may be used for structural evaluation of the large bowel following an adequate cleaning procedure. PCC1 measures 11 mm × 31 mm and has dual cameras that enable the device to acquire video images from both ends with a wide coverage area, automatic light control and a frame rate of four frames per second. The system includes a sensor array and data recorder connected to the patient during the procedure. The recorded data are downloaded to the Given Imaging Rapid workstation for review of the colon video. The second generation of PillCam Colon (PCC2) is similar to PCC1 and incorporates new developments. The angle of view has been increased to 172 degrees. It has an adaptive frame rate, alternating from 35 frames per second while in motion to 4 images when virtually stationary. The new RAPID(®) software now includes a simple graphic interface tool for polyp size estimation. The procedure of bowel cleansing until capsule ingestion is similar to that used for traditional colonoscopy. However it is more rigorous as the bowel cleanliness for capsule colonoscopy has to be excellent or at least good to result in an adequate sensitivity of the method. Briefly, it consists of 3.5-4 L of split dose polyethylene glycol. Oral NaP boosters are administered after 1-2 h if the capsule has entered the small bowel. Sodium phosphate (NaP) seems to be a necessary adjunct to the regimen because the total transit time is doubled without NaP. The cleansing level was considered to be good to excellent in 72%-88% in studies with PCC1. The sensitivity for significant polyps (> 6 mm or more than 3 polyps >3 mm) ranged from 63%-88% with specificities between 64%-94%. PCC2 showed an improved sensitivity of 89% and a specificity of 76%. CCE seems to be a safe and effective method of visualizing the colonic mucosa through colon fluids without the need for sedation or insufflation of air. The sensitivity of CCE to detect polyps, advanced adenomas and cancer is lower compared to optical colonoscopy but improvements will be made in the near future. With an increased recording duration, even a panenteric examination of the whole gastrointestinal tract may be possible.