Ampulla of Vater: comprehensive anatomy, MR imaging of pathologic conditions, and correlation with endoscopy.

Endoscopic retrograde cholangiopancreaticography with or without an endoscopic biopsy is the method for making a definitive diagnosis of disease in or around the ampulla of Vater. However, the endoscopic findings of neoplastic and non-neoplastic conditions involving the perimapullary area may be similar and an endoscopic assessment is not entirely reliable for diagnosis. Recent MR and MRCP can allow the detection of lesions in a small complex structure such as the ampulla of Vater, and distinguish between an ampullary from periampullary lesion. This article reviews the normal anatomy of the ampulla of Vater, describes the role of MR in the detection and characterization of the lesion in or around the ampulla of Vater, and attempts to correlate them with ERCP.