Sonographic detection of a patency capsule prior to capsule endoscopy: case report.

To avoid retention of the capsule used in capsule endoscopy (CE), the patency capsule (PC), a self-disintegrating sham capsule, is administered prior to CE in patients suspected of small intestinal stenosis. If the PC is excreted intact within 30 hours of ingestion, the patient can undergo CE without retention. However, if the PC is not excreted within 30 hours, its location must be confirmed as in either the small intestine or the colon because of the potential for small intestinal stenosis in the former case. It is often difficult to confirm the location of the PC by abdominal radiograph. We report the case of one patient who did not excrete the PC within 30 hours and for whom it was difficult to distinguish whether the PC was in the small intestine or the colon on abdominal series. Abdominal sonography revealed the PC in the colon and subsequent CE was performed without complication.