Magnetic resonance cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging method for examining the biliary and pancreatic ducts. The technique uses heavily T2-weighted imaging, which produces high signal from bile and other static fluids by virtue of their long T2 time, while suppressing background signal. Fast scanning techniques, particularly half-Fourier fast spin-echo techniques, are continuing to improve image resolution and allow scans within short breath-holds, reducing the effects of respiratory movement. The MRCP method has reached a level of resolution and reliability where it may well largely replace diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the near future. A review of MRCP techniques and imaging findings is presented with emphasis on half-Fourier imaging, with reference to potential clinical indications and limitations. Use of MRCP shows a high sensitivity and specificity for detection of biliary dilatation, calculi, strictures and anatomical variants. Experience with MR imaging of the pancreatic duct is less extensively described in the literature, but pancreatic duct dilatation, calculi and anatomy can now be reliably detected. However, as experience with MRCP increases, some sources of errors and limitations are becoming apparent, with image artefacts, and gas, blood or sludge within ducts potentially mimicking stones or strictures.