Breath-holding 3D MRCP: the time is now?

Excerpt

For more than 25 years, magnetic resonance cholangiopancreatography (MRCP) has been part of the standard protocol of abdominal MR imaging when a pancreatic or a biliary disease was suspected [1]. Different and complementary approaches, all using two-dimensional (2D) sequences, were initially developed for the assessment of the pancreatic duct and biliary tract with MRCP [1]: a thick slab single-shot fast spin-echo (SSFSE) T2-weighted sequence and a multi-section thin-slab, single-shot TSE T2-weighted sequence [1]. Both sequences have many advantages since they provide an excellent selective display of the whole extrahepatic biliary tract and pancreatic duct with few respiratory artefacts, few susceptibility effects and good in-plane resolution and are still in use in many reference centres [1]. However, these sequences have also some drawbacks: motion artefacts, including respiratory, may produce misregistration of thin-slice MRCP images, which may result in areas of missed anatomy. Thick-slab MR imaging is operator-dependent and even when examinations are technically relevant, inherent in-plane volume averaging effect may obscure small stones or anatomic variants [2]. For these reasons, many authors have advocated the use of three-dimensional (3D) MRCP sequences [2]. The theoretical main advantages of 3D MRCP compared to 2D MRCP sequences include: (1) acquisition of contiguous sections that may be used to reconstruct images in any projection, yielding the anatomical overview normally provided with thick-slab 2D images, (2) better spatial resolution with thinner imaging section and better signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) and (3) acquisition of all slices with a single coronal volume placed over the biliary tree and pancreatic ducts without need to obtain rotating oblique 2D SSFSE thick-slab planes [2, 3]. …