Clinicians have been taken aback by the rapid developments in magnetic resonance cholangiopancreatography (MRCP), including elegant computer reconstructions of the biliary and pancreatic ducts from images acquired by magnetic resonance scanning. Pioneer endoscopists of the late 1970s and 1980s struggled to produce diagnostic retrograde cholangiograms, at some risk to the patient, and now in the 1990s images of almost comparable quality can be produced without an endoscope, without contrast and even without radiation. The technical aspects are so complex that the non-radiologist is unlikely to understand the variations such as T2 spin weighting, half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences, and rapid acquisition with relaxation enhancement (RARE). For those wishing to try, they are clearly covered in a recent leading article in this journal.1 Yet the technique is so beguiling and the images so similar to those obtained with contrast injection that clinicians will have to be wary of serious errors of misinterpretation, particularly when viewing an image …