Wireless video endoscopy or video capsule endoscopy (VCE) is a noninvasive technology designed primarily to provide diagnostic imaging of the small intestine, an anatomic site that has proven peculiarly difficult to visualize. Images acquired are of excellent resolution and have a 1:8 magnification, which is higher than that of conventional endoscopes.

Indications
The indications for VCE of the small bowel are evolving and include:
* Diagnosis of the site of obscure gastrointestinal bleeding in adults including iron deficiency anemia
* Suspected Crohn’s disease
* Suspected Small bowel tumors and surveillance in patients with polyposis syndromes
* Suspected or refractory malabsorptive syndromes such as celiac disease
* In addition, VCE is being used to detect small bowel injury associated with the use of NSAIDs, and evaluate abdominal pain of unclear etiology.

Obscure Bleeding
VCE was able to identify causes of obscure bleeding more often than push enteroscopy in most report.

* The overall yield of VCE for obscure gastrointestinal bleeding is in the range of 50 to 70%
* A meta-analysis of 14 observational studies estimated that the overall yield of VCE (63%) was significantly higher than for push enteroscopy (26%), and barium studies (8%).
* Comparison of the published reports is somewhat limited since the definition of a bleeding site was variable.
* The diagnostic yield with capsule studies for bleeding is highest when they are performed as close as possible to the bleeding episodes.

Crohn’s Disease
VCE can be useful in diagnosing Crohn’s disease in patients with symptoms suggestive of Crohn’s disease or in patients with indeterminate colitis. It can also be used in patients with known Crohn’s disease to detect active disease and to evaluate responses to therapy.
VCE should not be used in patients with known or suspected strictures without very careful consideration and preprocedure evaluation. A small bowel follow-through that does not reveal strictures does not necessarily exclude strictures. Capsule retention has been described in up to 5% of patients who underwent a capsule study for Crohn’s disease, even after performing an initial small bowel study. Small bowel tumors, polyps, and other pathology A variety of small intestinal lesions have been detected with VCE, including small intestinal varices, tumors and polyps, and intestinal graft-versus-host disease. VCE is comparable to EGD for the diagnosis of celiac disease when there are overt villous changes.
It also detects small bowel injury associated with the use of NSAIDs such as ulcers. VCE may have a role in surveillance of patients with polyposis syndromes. VCE frequently fails to identify the ampulla of Vater and should not be used for ampullary surveillance in patients with familial adenomatous polyposis.

Risks
VCE is an extremely safe technology. No deaths have been attributed to the device, despite more than a million ingestions. One of the main risks associated with VCE, although not inherently serious, is retention of the capsule. Clinically important retention develops in less than 1% of patients. However, in up to 30%, the battery runs out before the capsule passes through the ileocecal valve, making it unclear if the capsule has been retained until it is passed with a bowel movement. However, not all patients will note passage of the capsule in their stool.

Contraindications
The procedure may be contraindicated in patients with the following conditions, albeit these contraindications may not be absolute:
* Dementia (in patients who cannot cooperate with swallowing of the capsule or who may inadvertently damage the equipment)

* Gastroparesis (the capsule can be placed in the duodenum by endoscopy to avoid this problem)
* An esophageal stricture, swallowing disorders that could prevent passage of the capsule (eg, Zenker’s diverticulum) (the capsule can be placed in the duodenum by endoscopy to avoid this problem)
* Partial or intermittent small bowel obstruction (unless a surgeon is involved, the patient understands the risks, and the patient has been cleared for surgery)
* Those who are inoperable or refuse surgery
* Patients who have defibrillators or pacemakers (this is a recommendation in the package insert, but does not appear to be a significant clinical problem)
* Pregnancy

Future
An esophageal PillCam (PillCam ESO) has been approved for detection of mucosal disease and varices in the esophagus and a colon capsule for colorectal cancer screening is in clinical trials in Europe.