Gastrointestinal Transit Time Assessed Using a CT-Based Radiopaque Marker Method in Patients With Acute Pancreatitis During Methylnaltrexone Treatment

Introduction: Dysmotility is common in acute pancreatitis (AP) and may be evaluated using radiopaque markers and imaging. We present a simple CT-based approach, which was employed in hospitalized patients with AP. Methods: This was a secondary analysis of a randomized, controlled trial conducted at four Danish centers. Patients admitted with AP and systemic inflammatory response syndrome were randomized to receive 5 days of intravenous methylnaltrexone or placebo (lactated ringer) added to standard management. Self-reported stool frequency was documented daily. Patients ingested a capsule containing 10 radiopaque markers on Day 3. A subsequent CT scan on Day 5 was used to identify the location of retained markers for the calculation of gastrointestinal transit, and colonic dimensions (diameters and cross-sectional areas) were measured. Results: In total, 47 patients were included. Patients receiving methylnaltrexone less often had laxative treatment (57% vs. 88%, p = 0.01) compared with placebo. Transit times were similar between the methylnaltrexone and the placebo groups (difference, −4 h (95% CI, −16 to 8), p = 0.53). Marker retention scores, colon diameters, and colon cross-sectional areas did not differ between treatment groups (all p > 0.05). Transit times (ρ = −0.53; p < 0.001), marker retention scores (ρ = −0.42; p = 0.004), diameter (ρ = −0.43; p = 0.003), and cross-sectional areas (ρ = −0.36; p = 0.01) of the descending colon were negatively correlated with self-reported stool frequency. Conclusion: Our CT-based method was feasible in hospitalized patients with AP. Methylnaltrexone did not change gastrointestinal transit compared with placebo. However, laxative therapy was more frequent with the placebo.