[Basic principles and historical consideration of MR cholangiopancreatography]

Basic principle of MR cholangiopancreatography (MRCP) is heavily T2-weighted imaging (hydrography) to use bile and pancreatic juice as "natural contrast medium". Firstly developed sequence for MRCP was a CE-FAST sequence, which employed time-reversed FID signal. The current most popular sequences for MRCP are single-shot fast spin-echo sequences, which are divided into three types (2D single slice, 2D mutiple slice and 3D methods). The advantage of 2D single slice method is conveniently obtained projection imaging within a few seconds of examination time. Both 2D multiple slice and 3D methods consists of a MIP image and a series of source images. The MIP image creates global images of pancreatico-biliary system. The source images provide detailed evaluation of various anatomical structures and abnormalities. By using these sequences properly, MRCP can yield valuable informations of pancreatico-biliary diseases non-invasively.