How I do it - MRI with liver-specific contrast agent. When and how?

Liver lesions are a frequent indication for imaging. Small lesions in particular are now being detected more frequently, which is due on the one hand to technical developments and on the other hand to the increasing use of imaging techniques in general, above all sonography, CT and MRI. Due to the intrinsically high soft tissue contrast and the lack of radiation exposure, MRI is now the method of choice for the clarification or exclusion of focal liver lesions. The additional administration of an intravenous contrast agent in MRI facilitates both the detection of smaller lesions and often a somewhat more precise differential diagnostic classification. Most contrast agents currently available in MRI are based on gadolinium (Gd), a strongly paramagnetic element that has a particular effect on the relaxation time T1 in the tissue. The structure of the contrast agents influences their distribution mechanisms in the body and allows a fundamental distinction to be made between extracellular and liver-specific contrast agents: When extracellular contrast agents are used, a lesion behaves in a similar way to when iodinated contrast agents are used in CT. This behaviour is based on tumour vascularization and morphology. In contrast, liver-specific contrast agents are partially absorbed hepatocellularly. The portion remaining extracellularly is then competitively excreted via the kidneys, while the hepatocellular portion is eliminated biliary. There are currently 2 approved Gd-based liver-specific contrast agents in Germany, Gd-BOPTA (Multihance, Bracco) and Gd-EOB-DTPA (Primovist, Bayer Healthcare). In patients with normal liver and kidney function, around 50% of Gd-EOB-DTPA is absorbed hepatocellularly; for Gd-BOPTA this proportion is around 3 - 5%.