Liver. III: Gadolinium-based hepatobiliary contrast agents (Gd-EOB-DTPA and Gd-BOPTA/Dimeg)

Gd-EOB-DTPA and Gd-BOPTA/Dimeg are two paramagnetic contrast agents that are unlikely ECF contrast agents but that are selectively taken up by hepatocytes and yield a selective enhancement of the liver parenchyma on T1-weighted images. Gd-EOB-DTPA yields hepatocellular specific uptake within the biliary excretion rate of 50% of the injected dose. Gd-BOPTA/Dimeg is taken up by hepatocytes in a small portion (2%-4%); however, its high relaxivity provides a significant and sustained increase of signal intensity of the normal liver. Both compounds have demonstrated a safe pharmacologic and toxicologic profile on preclinical evaluation and phase I clinical trials. Preliminary results demonstrate that these contrast agents may improve the MR imaging capability to detect focal liver lesions, with a dramatic and selective increase of liver signal-to-noise ratio and lesion-liver contrast-to-noise ratio. The wide imaging window, allowed by the sustained enhancement achieved after injection also provides flexibility in selecting an imaging sequence.