Liver cell-specific MRI with Primovist®
Primovist® is an innovative liver-specific contrast agent for MRI that significantly improves both detection and characterization of focal liver lesion compared to CT and unenhanced MRI. It is injected as a bolus (with an injection speed of 1-2 mL/second), offers a favorable tolerability and is rapidly distributed through the bloodstream. Primovist® is highly liver-specific with an uptake of about 50% into hepatocytes of injected dose. Due to its accumulation in the hepatocytes, a pronounced enhancement and a signal increase of normal liver tissue is seen
Primovist® in lesion detection
Since few if any functioning hepatocytes are present in malignant tumors, there is a little or no uptake of Primovist®, which results in improved contrast between the malignant tumor (dark=hypointense) and the surrounding normal liver tissue (bright=hyperintense). Benign liver lesions (e.g. focal nodular hyperplasia=FNH) can show even a greater enhancement compared to the surrounding normal liver tissue (bright=enhancement).
MRI with Primovist®: Very high specificity and sensitivity
Primovist®-enhanced MRI helps to detect intrahepatic lesions even of very small size (<1cm) with a very high sensitivity and specificity, because of the combined evaluation of dynamic vascular phase1 images and hepatobiliary phase images. Furthermore, Primovist® allows for the differentiation and characterization of benign and malignant liver lesions with a very high accuracy.
- Typical liver MR image: T2-weighted, fat-saturated sequence
- Typical T1-weighted MR liver image
1Different phases of contrast-enhanced (CE) liver imaging
The liver has a different blood supply as compared to all other organs. The arterial blood is supplied by the hepatic artery (approximately 20% of total blood supply), a branch of the celiac axis (Truncus coeliacus) and venous blood from the mesenteric and splenic veins is supplied by the portal vein (approximately 80%). Blood drains into the hepatic veins. Contemplation of this dual blood supply is mandatory for the understanding of the different phases of CE dynamic liver imaging.
Arterial phase: When a contrast agent is injected intravenously, the hepatic arterial system is enhanced during the first pass, whereas only minimal enhancement is registered in the parenchyma. These arterial or presinusoidal phase images (acquired approximately 15-25 sec after injection) are especially important for the detection of hypervascular malignancies of the liver, i.e. lesions which are predominantly supplied by the hepatic artery (e.g. HCC, FNH), and provide important information on the character of the lesion.
Portal-venous phase: Images of this phase of CE liver imaging are acquired approximately 40-70 seconds after administration of the contrast agent, when the portal vein system and the hepatic veins are enhanced. These images show maximal parenchymal enhancement and maximal contrast differentiation between liver and hypovascular lesions.
Equilibrium phase: Images of this phase are acquired 80-120 seconds after injection of contrast agent, when it has already diffused into the interstitium. Contrast enhancement in the equilibrium phase is particularly prominent in edematous tissues, such as neoplasms and areas of inflammation.