Focal hepatic lesions in Gd-EOB-DTPA enhanced MRI: the atlas.
OBJECTIVE
This 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.


BACKGROUND
Gd-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.


CONCLUSIONS
Gd-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.


CONCLUSIONS
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.
Department of Radiology, FMUP, Hospital S. João, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal, jtraila@hotmail.com.
José Traila
JT
Campos
Claude B
CB
Sirlin
Jin-Young
JY
Choi