Abstract
ObjectiveThis article reviews the different technical aspects and pitfalls of gadolinium (Gd)-ethoxibenzyl (EOB)-diethylenetriamine pentaacetic acid (DTPA) and the advantages of the hepatocellular phase (HCP) and defines its specific imaging features of liver lesions.BackgroundGd-EOB-DTPA is a contrast agent with combined properties of a conventional non-specific extracellular and a hepatocyte-specific contrast agent. Benign cirrhosis-associated nodules are characterised by isointensity in dynamic imaging and the HCP. Hepatocellular carcinomas (HCCs) usually show hyperenhancement in the arterial phase, with washout in the portal vein pressure (PVP) and hypointensity in the HCP. Among other characteristic findings, we have the mosaic pattern, a capsule, the “nodule-in-nodule” appearance and the satellite nodules. The fibrolamellar HCC is a large enhancing heterogeneous lesion, on a non-cirrhotic liver, with a hypointense scar in every sequence. THIDs (transient hepatic intensity differences) are perfusional alterations, characterised by hyperintensity in the arterial phase, with no alterations in the rest of the sequences including the HCP. Adenoma and focal nodular hyperplasia (FNH) are lesions, occurring more frequently in young women, with brisk arterial enhancement, differentiated by the scar and the uptake of Gd-EOB-DTPA in the HCP. Focal eosinophilic infiltration is a difficult diagnosis, with characteristics such as a non-spherical shape and irregular borders suggesting it. Besides these lesions, in which Gd-EOB-DTPA has a clear advantage, there are a few where the specificities of this agent can be troublesome: haemangiomas, focal fat/sparing, foreign body reaction, cholangiocarcinoma and metastases.ConclusionGd-EOB-DTPA is comparable to extracellular agents, and uptake by functioning hepatocytes in the delayed phase provides additional information that further improves detection and characterisation of many hepatic lesions.Main Messages Gd-EOB-DTPA offers advantages for the imaging of many liver lesions including HCC, fibrolamellar HCC, FNH and adenoma. The properties of Gd-EOB-DTPA can pose problems when dealing with haemangiomas, cholangiocarcinoma and metastases among others. The uptake of Gd-EOB-DTPA by functioning hepatocytes in the delayed phase provides additional information that further improves detection and characterisation of many hepatic lesions.
Highlights
Hepatocyte-specific magnetic resonance (MR) imaging contrast agents were developed for detection and characterisation of focal liver lesions
Gd-EOB-diethylenetriamine pentaacetic acid (DTPA)—known generically as gadoxetic acid and commercially as Eovist (United States) or Primovist (Bayer Healthcare)—is a highly water-soluble contrast agent in which a lipophilic EOB group is attached to gadolinium (Gd)-DTPA (Fig. 1)
Due to the presence of the lipophilic EOB group, Gd-EOB-DTPA is actively transported from the sinusoidal space into hepatocytes via organic anion transporting polypeptides (OATPs)
Summary
Hepatocyte-specific magnetic resonance (MR) imaging contrast agents were developed for detection and characterisation of focal liver lesions. The resulting compound has properties of a conventional nonspecific extracellular contrast agent in the vascular phases after administration, permitting assessment of tissue vascularity, and those of a hepatocyte-specific agent in the more delayed phases, allowing assessment of hepatocellular uptake and biliary excretion [1, 2]. Excretion into the bile ducts causes biliary luminal enhancement, as early as 5-10 min after injection in normal individuals. It is eliminated in approximately equal proportions by the liver, via hepatocellular uptake with subsequent biliary excretion (43.1–53.2%), and by the kidneys (41.6–51.2%) [5, 6]. Gd-EOB-DTPA has been shown to be comparable to non-specific extracellular agents for lesion detection and characterisation in the vascular imaging phases. The lesions are divided into those for which Gd-EOB-DTPA demonstrates advantages, those in which have pitfalls and those in which the lesion behaviour is equivalent to that of the use of an extracellular fluid (ECF) contrast agent
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