Performance of the patency capsule compared with nonenteroclysis radiologic examinations in patients with known or suspected intestinal strictures

Background: The patency capsule (PC) is used before capsule endoscopy (CE) in patients with known or suspected small-bowel (SB) strictures or obstruction (SBO) to avoid CE retention. False-positive PC examination results can occur in patients with delayed transit without obstruction, precluding the use of CE. Radiological tests are another option to evaluate the presence of SBO before CE. Objectives: Comparison of the PC and radiological examinations to detect clinically significant SB strictures. Main Outcome Measurements: Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PC, and radiological tests for detecting significant strictures. Results: Forty-two patients underwent a PC study and radiological examinations. Both of the examinations showed similar sensitivity (57% vs 71%; P = 1.00) and specificity (86% vs 97%; P =.22). The receiver-operating characteristic curves evaluating combined sensitivity and specificity were also similar in both the PC and radiological examinations (0.71 vs 0.84, respectively; P =.46). Pooling results from both the PC and radiological tests had the highest sensitivity and NPV (100%, 100%). False-positive results occurred in 5 PC examinations and 1 radiological examination. The PC examination had 3 false-negative results (9%), whereas radiological tests had 2 (6%). Limitations: Retrospective study. Conclusions: The NPV for the PC and radiological tests were not significantly different, suggesting that if findings on either test are negative before CE, the patient will most likely pass the capsule without incident. Radiological tests can be used to minimize PC study false-positive results by confirming or excluding the presence of a significant stricture suspected by the PC and to localize the PC if passage is delayed.