Effectiveness of using low-dose computed tomography to assess patency in gastrointestinal tracts with a patency capsule.

Background/aims: A patency capsule (PC) is used to safely perform capsule endoscopy. When the PC is not excreted within the defined time frame, radiography often cannot localize the PC. Computed tomography (CT) localizes a PC more definitively than radiography. We evaluated the localization of PCs using low-dose (LD)-CT.

Methodology: Forty-nine patients received a PC and 33 did not excrete the PC within the defined time frame and underwent radiography and LDCT with a 90% exposure reduction.

Results: LDCT localized the PC in 31 patients (93.9%), whereas radiography localized it in 7 (21.2%), indicating a significantly higher detection rate with LDCT (P<0.0001). PC retention in the small intestine was confirmed by LDCT in 4 patients. Retention was not observed during capsule endoscopy in the patients with confirmed patency of the gastrointestinal tract. In 21 patients who underwent LDCT with the conventional photographing area, the effective radiographic exposure dose associated with LDCT was 1.43±1.08 mSv. Conversely, in the 12 patients who underwent LDCT with a reduced photographing area, the effective dose was reduced to 0.62±0.27 mSv (P<0.05).

Conclusion: LDCT with a reduced exposure dose can definitively localize a PC. Therefore, this method may allow capsule endoscopy to be performed for more diseases.