Dynamic MR imaging of liver metastases with Gd-EOB-DTPA

To assess liver and lesion enhancements by dynamic MR imaging after bolus injection of the hepatobiliary contrast agent gadolinium ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) in patients with liver metastases and to compare the effect of different doses.

A randomized double-blinded trial with doses of 12.5, 25 and 50 micromol/kg Gd-EOB-DTPA was performed in 35 patients with liver metastases. Liver enhancement, tumor enhancement and liver lesion contrast-to-noise (C/N) ratios were calculated from breath-hold gradient echo images (100/5/80 degrees) recorded precontrast and at different times up to 10 min postcontrast.

Normal liver showed a characteristic enhancement pattern, with a rapid enhancement in the first 45 s postcontrast and a slight but significant further increase up to 600 s. The initial enhancement in the lesions was also pronounced, but the enhancement was slightly decreased after 240 s postcontrast. At dose levels of 12.5 and 25 micromol/kg Gd-EOB-DTPA, C/N ratios significantly increased compared to baseline from 90 to 600 s. Postcontrast C/N-values obtained using 50 micromol/kg Gd-EOB-DTPA were not significantly increased, except for the examinations 480 s postcontrast.

In liver metastases, C/N ratios obtained with doses of 12.5 and 25 micromol/kg Gd-EOB-DTPA were slightly superior to 50 micromol/kg Gd-EOB-DTPA. This finding is probably due to a more pronounced extracellular effect of the contrast medium at higher doses.