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Wireless Small Bowel Capsule

Small Bowel CapsuleWireless capsule endoscopy is performed using a variety of capsules which contain video imaging, self-illumination, and image transmission modules, as well as a battery supply. These devices have been developed for small bowel imaging. The patient is first fitted with thoracic or abdominal sensors. Prior to being swallowed, the capsule is activated by removing it from a magnetic holder. Once swallowed, the indwelling camera takes images at a rate of two frames per second, as peristalsis carries the capsule through the gastrointestinal tract. The device uses wireless radio transmission to send the images to a receiving recorder device that the patient wears around the waist. This receiving device also contains some localizing antennae sensors that can roughly gauge where the image was taken. Images are then downloaded onto a workstation for viewing and processing.

Description/Scopecapsule

Wireless capsule endoscopy is performed using a variety of capsules which contain video imaging, self-illumination, and image transmission modules, as well as a battery supply. These devices have been developed for small bowel imaging. The patient is first fitted with thoracic or abdominal sensors. Prior to being swallowed, the capsule is activated by removing it from a magnetic holder. Once swallowed, the indwelling camera takes images at a rate of two frames per second, as peristalsis carries the capsule through the gastrointestinal tract. The device uses wireless radio transmission to send the images to a receiving recorder device that the patient wears around the waist. This receiving device also contains some localizing antennae sensors that can roughly gauge where the image was taken. Images are then downloaded onto a workstation for viewing and processing.

Wireless Capsule Endoscopy for Small Bowel Disease

Two comparative studies have been published that compare the results of both wireless capsule endoscopy (WCE) and push enteroscopy (PE) in patients with obscure gastrointestinal bleeding. Both report that capsule endoscopy reveals additional information not provided by push enteroscopy and rarely misses lesions detected by push enteroscopy. The results were consistent across these two studies reporting additional diagnostic yield from WCE in 25-50% of the cases. For example, in one study of 20 patients with obscure digestive tract bleeding, WCE found a bleeding site in 11 out of 20 patients (55%) studied and provided additional information not detected by push enteroscopy in 5 out of 20 cases (25%). All of the lesions detected by WCE were distal to the region examined during push enteroscopy.

The second comparative study was conducted on 32 subjects in Germany. Overall, this study found that WCE identified a definite source of bleeding in 21 out of 32 patients (66%) studied and provided additional information not detected by push enteroscopy in 16 of 32 cases (50%). No significant complications from WCE were reported in these studies.

More recently (2005) a meta-analysis compared WCE with other approaches (including small bowel barium radiography and push enteroscopy) in identifying small bowel pathology in patients with obscure gastrointestinal bleeding. The researchers extracted their findings from pooled data from studies which involved more than 500 patients. When WCE was compared with push enteroscopy for obscure gastrointestinal bleeding, WCE resulted in a yield of 63% and enteroscopy 28%. With regards to clinically significant findings, WCE accounted for 56% and push enteroscopy 26%. When WCE was compared with small bowel barium radiography, the yield for any findings was 67% and 8%, respectively. Clinically significant findings accounted for 42% and 6%, respectively.

Three published studies totaling 58 patients have prospectively examined the use of WCE for the initial diagnosis of suspected Crohn’s disease when all conventional diagnostic tests including small bowel follow through have failed to reveal bowel lesions suggestive of Crohn’s disease. An additional 41 patients were included in 2 abstract reports and case reports that provide supplemental evidence. These studies provide consistent evidence that WCE may demonstrate small bowel lesions suggestive of Crohn’s in from 43 to 71% of patients when other tests have been negative. Furthermore, patients diagnosed with Crohn’s disease were reported to improve after treatment for Crohn’s disease, representing an improvement in health outcomes.

There are inadequate data regarding other applications of WCE including, but not limited to evaluation of irritable bowel syndrome and small intestinal diverticula.

Wireless Capsule Endoscopy for Small Bowel Disease

Most recently the standard methods of detecting abnormalities in the intestines has been through endoscopic examinations such as colonoscopy, upper endoscopy, and radiological imaging procedures. Limitations of endoscopy include, incomplete visualization of the entire small intestine, patient discomfort, risk of perforation and the need to sedate the patient. Some of the advantages of endoscopy over the imaging system are the ability to wash, biopsy or re-examine lesions during the procedure.

The radiological examination of the small intestine is called an upper gastrointestinal series. The patient drinks barium to coat the lining of the small intestine before X-rays are taken. The barium shows up white on X-ray film, revealing inflammation or abnormalities in the intestine. It is typically used to diagnose Crohn’s disease, ulcerative colitis and peptic ulcers. While the single contrast study is simple, a more accurate method is the double contrast small bowel follow-through (SBFT) or enteroclysis. In this examination, a very dense preparation of barium is injected into the small intestine. The barium covers only the surface of the intestine, revealing a better view of the organ. Drawbacks to this procedure include exposure to X-rays, patient discomfort, limited capability to make a diagnosis (only gross abnormalities are observable), and diarrhea.

WCE of the small bowel is performed using a camera device that visualizes the inside of the small intestine to detect polyps, cancer, or causes of bleeding and anemia. The device comes in capsule form approximately the size of a large vitamin, and contains a camera, lights, transmitter and batteries. The capsule has a clear end that allows the camera to view the lining of the small intestine. Abdominal sensors are attached to the patient to track the progression of the device via the digestive tract. Prior to being swallowed, the capsule is activated by removing it from a magnetic holder. Once swallowed, the natural muscular waves of the digestive tract propel the capsule forward through the stomach, into the small intestine, through the large intestine, and then out in the stool. The indwelling camera takes images at a rate of 2 frames per second and uses wireless radio transmission to send the images to a recording device that the patient wears around the waist. The stored data is transferred to a computer for processing and analysis by a gastroenterologist. This software allows the physician to view both streaming video images and image-by-image, whichever the doctor prefers.

WCE does not require sedation and is usually well tolerated. It has been used most frequently as a technique to identify the source of obscure intestinal bleeding. Recently, there has been interest in exploring its use in patients with inflammatory bowel disease, small bowel neoplasms, small intestinal diverticula, and evaluation of malabsorptive syndromes such as celiac disease.

Potential harms associated with WCE include undergoing unnecessary or inappropriate treatment if the test falsely suggests a small-bowel lesion, incorrectly characterizes the extent of disease, or inaccurately represents the response to treatment. Children may require anesthesia in order to place the camera in the duodenum. In addition, entrapment of the capsule during transit within strictures or diverticuli that are not accessible by flexible endoscopy has occurred in as much as 1% of the cases studied, but could be potentially higher among patients with a tendency for stricture formation such as occurs in Crohn’s disease or nonsteroidal anti-inflammatory drug (NSAID) induced strictures. Failure of the capsule to advance through the intestinal tract has the potential to cause complications for patients that could result in the need for endoscopic or surgical retrieval of an entrapped capsule. Therefore, prior to initiation of the procedure, an X-ray exam of the small bowel should be performed in patients with the following conditions and WCE would be contraindicated in these and any clinical circumstance where there is concern that passage may be too narrow for the camera:

  • GI motility disorders such as severe gastroparesis
  • Pregnancy
  • Known or suspected strictures or fistulae
  • Large or numerous small-bowel diverticuli due to the risk of the capsule becoming lodged in transit
  • Zenker’s diverticulum
  • xtensive Crohn’s enteritis
  • Prior pelvic or abdominal surgery

Absolute contraindications exist in the following circumstances:

  • presence of a cardiac pacemaker or other implanted electromagnetic device,
  • presence of an intestinal blockage or a significantly narrowed small bowel, or
  • presence of an abnormal connection between the bowel and another organ

 

KMC Dermatology

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785-354-8518
2200 SW 6th Ave.
Topeka, KS 66606

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All information provided herein is for educational purposes only. If you have a medical condition, please consult a physician to get a proper diagnosis and treatment plan.

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