Acute cholecystitis: comparison of MR cholangiography and US.

Abstract

PURPOSE: To evaluate the clinical usefulness of magnetic resonance (MR) cholangiography in the assessment of acute cholecystitis by comparing the diagnostic accuracy of MR cholangiography with that of ultrasonography (US). MATERIALS AND METHODS: Thirty-five patients with symptoms of acute cholecystitis underwent both US and MR cholangiography before cholecystectomy, which helped confirm acute cholecystitis. Two reviewers evaluated US and MR cholangiographic images for evidence of calculi and gallbladder wall thickening and compared these findings with surgical findings. RESULTS: MR cholangiography depicted all 21 (100%) calculi and one false-positive calculus in the cystic duct and gallbladder neck, but US depicted only one (14%) of seven cystic duct calculi and 12 (86%) of 14 gallbladder neck calculi. In the diagnosis of cystic duct obstruction, MR cholangiography had a sensitivity of 100%, a specificity of 93%, and an accuracy of 97%. US had a sensitivity of 62%, a specificity of 100%, and an accuracy of 77%. In the diagnosis of gallbladder wall thickening, MR cholangiography had a sensitivity of 69%, a specificity of 83%, and an accuracy of 71%. US had a sensitivity of 96%, a specificity of 83%, and an accuracy of 94%. CONCLUSION: In the assessment of acute cholecystitis, US is superior to MR cholangiography in the evaluation of gallbladder wall thickening. However, MR cholangiography is superior to US in the depiction of cystic duct and gallbladder neck calculi at the evaluation of cystic duct obstruction.