PURPOSE: To determine if MR cholangiography with Gd-EOB-DTPA can be used to assess cystic duct patency and to establish normal time range for reflux of contrast material into the cystic duct/gallbladder. MATERIALS AND METHODS: This retrospective study is HIPAA-compliant and IRB-approved with waiver for informed consent granted. From September 2008 to June 2009, 300 patients who underwent Gd-EOB-DTPA-enhanced MR imaging for various clinical indications, not specifically limited to evaluation for acute cholecystitis, were identified. 112 patients were excluded: prior cholecystectomy (n = 93), severe technical limitations (n = 9), or absence of appropriate clinical follow-up (n = 10). 188 total patients (82 male, 106 female, mean age 51.0 years) were included in the final dataset. Time between contrast administration and contrast reflux into the cystic duct/gallbladder on delayed phase imaging was measured. RESULTS: Reflux of contrast into the gallbladder was identified in 130/188 patients (69.1%) on delayed phase imaging. Average time to gallbladder reflux was 15:24 ± 5:51 minutes (range: 6:01-41:05 min). 58/188 patients (30.9%) demonstrated no reflux of contrast into the gallbladder at time of final delayed phase images. Of 58 patients who demonstrated no reflux into cystic duct/gallbladder, 15 patients demonstrated no extrahepatic biliary excretion, limiting evaluation of cystic duct patency. A total of 173 patients demonstrated biliary excretion of contrast with 76% overall sensitivity of detection of cystic duct patency. CONCLUSION: MR cholangiography with hepatobiliary MR contrast agents such as Gd-EOB-DTPA can demonstrate cystic duct patency with high sensitivity. MR protocols can be designed within a clinically feasible timeframe to optimize diagnosis of acute cholecystitis.