Comparison between Gd-DTPA, Gd-EOB-DTPA, and Mn-DPDP in induced HCC in rats: a correlation study of MR imaging, microangiography, and histology.

The behaviour of two liver-specific contrast MR agents, Gd-EOB-DTPA and Mn-DPDP and one nonspecific contrast agent, Gd-DTPA, was compared in a rat model of chemically induced hepatocellular carcinoma (HCC). The study included contrast enhanced MR imaging and the corresponding microangiography and histology. Analysis of the MR images showed similar degrees of maximum relative liver enhancement: 47.5 +/- 8.2% for Gd-EOB-DTPA (0.03 mmol/kg) at 5 min postinjection and 52.5 +/- 14.4% for Mn-DPDP (0.025 mmol/kg) at 15 min; both exceeded the value obtained with Gd-DTPA (34.8 +/- 13.6%, at 5 min), even at 0.3 mmol/kg. Gd-EOB-DTPA caused a similar "negative" enhancement of all types of HCC, independent of their differentiation and vascularization, i.e., lesion-to-liver contrast-to-noise ratio (CNR) of differentiated and undifferentiated HCC increased negatively from, respectively, 1.9 +/- 1.1 and -5.1 +/- 3.1 before contrast to -5.2 +/- 2.4 and -11.8 +/- 4.8 at 5 min after contrast. On Mn-DPDP enhanced images, the undifferentiated HCCs showed up negatively (CNR -5.5 +/- 4.7 before contrast to -13.7 +/- 10 at 15 min after contrast), whereas the more differentiated tumors showed up positively (CNR from 2.3 +/- 2.0 before contrast to 12.5 +/- 3.5 at 24 hr postcontrast) due to active uptake and delayed elimination of Mn-DPDP.