G adoxetic acid-enhanced MRI is used to depict and help characterize focal liver nodules (1,2) in patients with chronic liver diseases (CLDs) (3,4), including nonalcoholic steatohepatitis (5) and chronic hepatitis C (5,6). Gadoxetic acid-enhanced MRI has been shown to help predict both liver failure after subtotal hepatectomy and graft survival after liver transplant (7-9).As laboratory and clinical estimators of liver disease severity, the albumin-bilirubin index, the Model for End-Stage Liver Disease, and the Child-Turcotte-Pugh score correlate well with gadoxetic acid uptake in the liver in the hepatobiliary phase (ie, 20 minutes after contrast agent administration of gadoxetic acid) (10,11). Previously described methods to assess hepatobiliary phase uptake include the relative liver enhancement, the hepatic uptake index, the contrast enhancement index, and T1 values (12). These methods all require complex computations and have vendor, field-strength, and sequence dependencies that complicate their clinical application.Recently, Bastati et al ( 13) introduced the functional liver imaging score (FLIS), derived from the three hepatobiliary phase features of gadoxetic acid-enhanced MRI and each scored on an ordinal 0-2 scale. The three features included in the FLIS semiquantitatively assess the enhancement

In liver transplant recipients, gadoxetic acid-enhanced MRI-derived QSs (ie, EnQS, ExQS, and PVsQS), as well as the FLIS and RLE, can predict graft survival probability.

The introduction of hepatobiliary contrast agents, most notably gadoxetic acid (GA), has expanded the role of MRI, allowing not only a morphologic but also a functional evaluation of the hepatobiliary system. The mechanism of uptake and excretion of gadoxetic acid via transporters, such as organic anion transporting polypeptides (OATP1,3), multidrug resistance-associated protein 2 (MRP2) and MRP3, has been elucidated in the literature. Furthermore, GA uptake can be estimated on either static images or on dynamic imaging, for example, the hepatic extraction fraction (HEF) and liver perfusion. GA-enhanced MRI has achieved an important role in evaluating morphology and function in chronic liver diseases (CLD), allowing to distinguish between the two subgroups of nonalcoholic fatty liver diseases (NAFLD), simple steatosis and nonalcoholic steatohepatitis (NASH), and help to stage fibrosis and cirrhosis, predict liver transplant graft survival, and preoperatively evaluate the risk of liver failure if major resection is planned. Finally, because of its noninvasive nature, GA-enhanced MRI can be used for long-term follow-up and post-treatment monitoring. This review article aims to describe the current role of GA-enhanced MRI in quantifying liver function in a variety of hepatobiliary disorders.

Secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) provides a non-invasive way, with which, to evaluate pancreatic duct (PD) anatomy and exocrine pancreatic function. S-MRCP can be added to the routine pancreas MR examination in equivocal cases. Moreover, it can detect subtle PD involvement, allowing diagnosis of early, rather than end-stage, pancreatic diseases. Although S-MRCP is a valuable non-invasive diagnostic method, it is only performed in a few centres due to relative high cost. Furthermore, less familiarity with its indications, the examination technique, and image interpretation also contribute to its limited use. Thus, the purpose of this article is to explain secretin's mechanism of action, the examination technique, the clinically relevant indications, the advantages, and limitations. Finally, we will focus on image analysis and its role in achieving an early and accurate diagnosis of specific pancreatic and PD diseases.