Normal and Pathologic Features of the Postoperative Biliary Tract at 3D MR Cholangiopancreatography and MR Imaging

Abstract

Magnetic resonance (MR) imaging with cholangiopancreatographic sequences plays a critical role in evaluating alterations in the biliary tract after surgical procedures such as cholecystectomy, liver transplantation, hepatic resection, and the creation of a biliary-enteric anastomosis. MR cholangiopancreatography, a rapid, noninvasive, and accurate imaging technique for the assessment of early and late complications of hepatobiliary surgery, usually enables the identification of normal and abnormal postoperative changes. In cases of complete obstruction of the bile duct, MR cholangiopancreatography allows analysis of the biliary tract above and below the level of the obstruction, a capability essential for treatment planning and one that is not provided by either endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. MR cholangiopancreatography is particularly useful for the evaluation of biliary-enteric anastomoses, for which an endoscopic approach is generally precluded. It also can help detect and localize bile duct strictures and stones and can help accurately classify bile duct injuries. It is useful for detecting bile leaks, although it generally does not directly depict the extravasation of bile. In addition to MR cholangiopancreatography, T1- and T2-weighted MR imaging may be performed to depict extrabiliary soft-tissue structures and abnormalities such as an abscess, tumor recurrence or metastasis, hematoma, or hemobilia. Mangafodipir trisodium-enhanced MR cholangiopancreatography, a recently developed technique that provides a combination of anatomic and functional information, is particularly helpful for documenting bile leaks because it allows a functional evaluation of biliary excretion and may directly depict bile leakage from injured ducts.

Improvement of MR cholangiopancreatography (MRCP) images after black tea consumption

“…MRCP is a useful noninvasive imaging technique introduced in 1991 for morphological evaluation of the biliary tract and pancreatic duct [1][2][3][4]. This technique is based on heavily T2-Weighted sequences to enhance signal from fluid.…”

“…Magnetic resonance cholangiopancreaticography (MRCP) is a non-invasive imaging investigation for the evaluation of the pancreaticobiliary system [1][2][3][4]. The magnetic resonance techniques applied for the pancreaticobiliary tract are mainly based on heavily T2-weighed sequences [5].…”

Secretin-enhanced MR Imaging of the Pancreas

“…Both breath-hold (using half-Fourier pulse sequences) and non-breath-hold techniques (with respiratory triggering or navigator techniques) have been used, with images obtained either as two-dimensional or three-dimensional acquisitions (7). A three-dimensional technique provides a higher signal-tonoise ratio, which can be exploited for thinner contiguous sections.…”

“…Acquiring images with near isotropic voxels allows improved postprocessing of the images for multiplanar reconstruction, maximum intensity projection, and volume rendering. The introduction of faster gradients and a parallel acquisition technique has resulted in even greater spatial resolution and faster acquisition times (6,7).…”

Magnetic resonance pancreatography: comparison of two- and three-dimensional sequences for assessment of intraductal papillary mucinous neoplasm of the pancreas

“…Current MR cholangiopancreatography (MRCP) techniques typically utilize two-dimensional (2D) thick-section single-shot rapid acquisition with relaxation enhancement (RARE) and thinsection multislice half-Fourier RARE techniques to produce images of the pancreaticobiliary system. Recently developed three-dimensional (3D) MRP techniques have an advantage over 2D imaging as they enable operatorindependent imaging and provide thinner sections without interslice gaps and a higher signal-to-noise ratio (SNR) [12][13][14]. Furthermore, with recent technological advances in MR imaging, including high-performance gradients and parallel acquisition techniques (PATs), spatial resolution has improved remarkably within a shorter acquisition time [12,15].…”