© Georg Thieme Verlag KG Stuttgart · New York
06 November 2009 (eFirst)
How good is capsule endoscopy for detection of periampullary lesions? Results of a tertiary-referral center (Clarke et al., Gastrointest Endosc 2008 )
There is no doubt that capsule endoscopy had been a major breakthrough in the field of small-bowel endoscopy. But capsule endoscopy is a pure diagnostic tool that does not give the option of obtaining histologic samples or carrying out endoscopic treatments. Nevertheless, it has proven its value within the past years, particularly in patients with suspected mid-gastrointestinal bleeding  . One of the reasons for this is that capsule endoscopy allows, in most cases, the endoscopic visualization of the entire small bowel. However, there are still some limitations that have to be faced: a unidirectional camera, the inability to insufflate air and to suck fluid, and the lack of control of the transit through the small bowel. The question of how much of the small bowel cannot be seen adequately remains unanswered.
One attempt to clarify this question involved systematic examinations and the detection rate of a landmark, such as the major papilla, during the capsule transit . Following the exclusion of 21 capsule studies for various reasons (e. g. capsule retention, prior surgery with altered anatomy in the duodenum), the images of 125 consecutive capsule videos were reviewed by two gastroenterologists using the slowest sequence of images (five per second). The results were disappointing because only 13 major duodenal papillas were seen. This corresponds to a detection rate of only 10.4 %. However, the detection rates cannot be transferred to the whole small bowel as transit time varies along its entire length. When the capsule is pushed through the pylorus by stomach movements, the first part of the duodenum in particular is passed through very rapidly, and visualization of lesions in this region is worse than in the remaining small bowel, depending on the quality of view and transit time. On the other hand, this study demonstrated very clearly that solitary lesions can be easily missed by the capsule, particularly if they are small or are located behind a fold. The authors concluded that a nondiagnostic capsule exam cannot be regarded as proof of no small-bowel lesion. This statement is underlined by a small retrospective trial of solitary small-bowel tumors, which had been diagnosed by double-balloon enteroscopy (DBE). Only one-third of the tumors (5 / 15) had been detected by prior capsule endoscopy . Therefore other flexible small-bowel endoscopy methods, such as DBE, should be considered in patients with ongoing symptoms, such as recurrent bleedings.