![]() ![]() This property results in the increase in signal intensity of normal hepatic parenchyma. Mangafodipir trisodium (Mn-DPDP) is specifically taken up by hepatocytes due to its chemical similarity to vitamin B 6. It goes by the trade name Primovist (Eovist/Bayer). The delayed imaging time is also more convenient (10-20 minutes). Compared to gadobenate, it has more intense liver parenchymal enhancement. It has almost equal biliary and renal excretion (~50% each). G adoxetate disodium (Gd-EOB-DTPA): has protein binding of <10%. Its delayed imaging time is between 90 to 120 minutes.ī. It goes by the trade name MultiHance (Bracco). G adobenate dimeglumine (Gd-BOPTA): weak and transient protein bonding (<5%) and only 2-4% of it is taken up by the liver cells. Additionally, the biliary excretion enables biliary ductal mapping (post-contrast MRCP/ functional MRCP) using 3D T1 weighted fat-saturated GRE images.Ī. Thus, the enhancement of lesions in the hepatobiliary phase depends on the expression and activity of these transporters, depending on the presence or absence of functioning hepatocytes.ĭuring the hepatobiliary phase, they selectively increase the liver signal intensity and aid the in the detection of small tumors. The absorption by hepatocytes is via the OATP1 transporter (polypeptide adenosine triphosphate-dependent organic anion transporter), the same as the bilirubin transporter. However, in the delayed (hepatobiliary) phase, they are taken up by the liver as their excretion is not only through the renal but the hepatic route as well. These agents initially act like non-specific extracellular gadolinium chelates post bolus injection and show three primary phases of vascular and tissue enhancement (arterial, blood pool and extracellular phases). Hepatobiliary specific gadolinium agents include two of the high relaxivity agents: gadobenate dimeglumine (Gd-BOPTA) and gadoxetate disodium (Gd-EOB-DTPA).īiochemically, these agents are linear ionic molecules and show higher T1 relaxivity (>6.5 L/mmol/s at 1.5 T) as compared to the other Gd chelates (<4.8 L/mmol/s at 1.5 T). ![]() high relaxivity agents (bind to serum proteins).non-specific extracellular gadolinium chelates (do not bind to serum proteins).In this perspective article, we will discuss the various intravenous contrast agents used for liver MRI and their ideal utilization.īiliary tree Extracellular contrast agents Gadobenate dimeglumine Gadolinium-based contrast agents Gadoxetate disodium Hepatobiliary contrast agents.Gadolinium (Gd) based contrast agents are classified into: Gadoxetate, however, provides less satisfactory dynamic phase images compared to ECAs, particularly during the arterial phase. In the last decade, HBAs, particularly Gadoxetate, have been found useful for characterizing lesions with functioning hepatocytes and more importantly in evaluating the biliary tree. ECAs have been used for decades since their introduction into clinical practice and provide excellent dynamic phase information that is useful in characterizing focal liver lesions. The use of appropriate contrast agents for liver MRI requires knowledge of the clinical situation and question to be answered. ![]() Currently, two classes of MRI contrast agents are available for clinical use, namely the extracellular contrast agent (ECA) and the hepatobiliary agent (HBA). ![]() Contrast enhanced MRI of the liver provides valuable information in the evaluation of both chronic liver disease and focal liver lesions. ![]()
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