Hepatocyte-specific contrast agent-enhanced magnetic resonance cholangiography: perioperative evaluation of the biliary tree

Abstract

A large number of gadolinium chelates have recently been tested in clinical trials. Some of those have already been approved for clinical use in the United States and Europe. Thus, new diagnostic perspectives have been incorporated into magnetic resonance imaging studies. Among such gadolinium chelates are hepatobiliary-specific contrast agents (HSCAs), which, due to their property of being selectively taken up by hepatocytes and excreted by the biliary ducts, have been widely used for the detection and characterization of focal hepatic lesions. In comparison with conventional magnetic resonance cholangiography (MRC), HSCA-enhanced MRC provides additional information, with higher spatial resolution and better anatomic evaluation of a non-dilated biliary tree. A thorough anatomic assessment of the biliary tree is crucial in various hepatic surgical procedures, such as complex resection in patients with colorectal cancer and living-donor liver transplantation. However, the use of HSCA-enhanced MRC is still limited, because of a lack of data in the literature and the poor familiarity of radiologists regarding its main indications. This pictorial essay aims to demonstrate the use of HSCA-enhanced MRC, with particular emphasis on anatomical analysis of the biliary tree, clinical applications, and the most important imaging findings.

Non-neoplastic cholangiopathies: an algorithmic approach

“…Another important tool recently made available is MRI with hepatobiliary-specific contrast agents. This imaging technique gives functional information of the bile duct, providing greater accuracy in the identification of anatomical variations-especially in patients without biliary dilatation-and in the characterization of postoperative biliary stenosis and fistulas ( 10 , 37 ) . The most common anatomical variations seen in iatrogenic cholangiopathies are as follows ( 38 ) : common bile duct running parallel to an aberrant duct; long cystic duct with low medial insertion; right aberrant duct draining into the left bile duct; and triple confluence of the intrahepatic bile duct, as shown in Figure 9 .…”

Valoración anatómica de la vía biliar y de sus alteraciones por medio de resonancia magnética con el contraste hepatoespecífico ácido gadoxético

“…Existen dos tipos de contrastes que se derivan del gadolinio. Los extracelulares, que tienen un componente intravascular, y los intracelulares, que poseen propiedades extracelulares e intravasculares 4,5 . Estos últimos se conocen como específicos de órgano e incluyen el gadobento de dimeglumina y el ácido gadoxético 6 .…”

“…Es por este motivo que la disfunción hepática o la obstrucción pueden alterar su farmacocinética, al retardar o anular su excreción 5,7 . Una función hepática > 3 mg/dl altera la excreción del medio de contraste, dado que el ácido gadoxético actúa como antagonista competitivo 4,18 .…”

Percutaneous transhepatic cholangiobiopsy

“…The results of fine-needle aspiration biopsy (FNAB) of the biliary system are inferior to those of FNAB of other sites (2) . Therefore, other techniques for obtaining histological samples have been developed for use in the biliary tract (3)(4)(5)(6)(7)(8)(9)(10) .…”