Evaluation of the small bowel has always been difficult because of its length and multiple loops. Bleeding from the small bowel is often the diagnosis that is made after excluding other gastrointestinal sources through upper endoscopy and colonoscopy. Treatment of other small bowel pathologies, including Crohn's disease, tumors, and polyps, can be delayed by the inability to adequately visualize the area using standard endoscopy. The looping of the small bowel makes push endoscopy difficult. Enteroclysis may be more accurate than barium follow-through, but it requires examiner skill and involves patient sedation, increased radiation exposure, and patient discomfort. Video capsule systems are being developed to allow greater visualization of the entire gastrointestinal tract. Costa-magna and colleagues compared results of routine barium follow-through with results obtained using the Given M2A video capsule system.
Twenty patients with suspected small bowel disease were evaluated first with a barium follow-through test and then, four days later, with wireless video capsule endoscopy using a miniscule color video camera encased in a swallowable capsule. The capsule endoscopy procedure included attaching sensors to the skin, and use of a battery pack and a recorder placed around the patient's waist for eight hours after the encapsulated camera was swallowed. Examiners reviewing the video capsule movies were blinded to the results of the previous barium studies.
The barium follow-through examinations showed ileal stenosis in two patients who had to be excluded from the study because stricture and obstruction are contraindications for use of video capsule endoscopy. Barium studies were normal in 17 patients and showed distal ileal nodularity in three patients. Patients tolerated the video capsule endoscopy well, and multiple positive findings were noted, including angiodysplastic lesions in eight patients, active bleeding in one patient, multiple polyps in four patients, and ulcers compatible with Crohn's disease in three patients.
Capsule endoscopy was significantly more successful in identifying lesions considered to be diagnostic (likely to be causing the signs or symptoms for which the test was being performed) or suspicious (not likely to be the complete cause of the signs or symptoms for which the test was being performed). In the 13 patients with obscure gastrointestinal bleeding, capsule endoscopy was significantly more likely to have found a definitive diagnosis than barium follow-through.
The authors conclude that video endoscopy is superior to small bowel radiography for diagnosing small bowel diseases, especially obscure gastrointestinal bleeding. Preceding barium study remains useful to identify patients with subclinical ileal stenosis who may develop bowel obstruction with capsule endoscopy. Limitations of video endoscopy include the inability to obtain a biopsy, difficulty in identifying the exact location of findings within the small bowel, the identification of potentially insignificant findings, the need for scrupulous bowel cleansing before the study, and the lengthy viewing time required to analyze the video, which can be up to two hours.
In an editorial in the same journal, Faigel and Fennerty discuss capsule endoscopy in detail, noting some variations in preparation and technique. They support the use of capsule video endoscopy to identify lesions causing gastrointestinal blood loss or when there is objective evidence of small bowel disease, such as significant weight loss, and high suspicion of mucosal disease or tumor. The test should not be used in patients with abdominal pain or diarrhea because of the paucity of findings on small bowel evaluation in this patient group.