Pigment GB Stones: MR Cholangiopancreatographic Evaluation with Emphasis on the Pitfalls

Introduction MR cholangiopancreatography reveals the biliary system and the pancreatic duct noninvasively. Many reports on MR cholangiopancreatography have described usefulness of assessing benign or malignant biliary diseases, pancreatic diseases, or both biliary and pancreatic diseases using various imaging techniques including gradient-echo (i.e., steady-state free-precession sequence) [l] or rapid acquisition with relaxation enhancement (RARE) or fast (or turbo) spin-echo sequences [2-31. Although MR cholangiopancreatography showed excellent results in the diagnosis of choledocholithiasis, precise determination of among various gallbladder lesions (stone, adenoma, or adenocarcinoma) is not so reliable, especially from our previous results [2]. The sensitivity, specificity, accuracy, and specific diagnosis with a single-shot RARE and a multislice HASTE technique, were 75% I 83% I 80% I 30%, and 75% I 33% I 50% / 20%, respectively. We aimed to define common pitfalls in evaluating pigment GB stones and to describe differentiating features from cancer or adenoma on MR cholangiopancreatography.