PRLONGED POSITIVE CONTRAST ENHANCEMENT WITH GD-EOB-DTPA IN EXPERIMENTAL LIVER-TUMORS - POTENTIAL VALUE IN TISSUE CHARACTERIZATION

To evaluate the potential of the hepatobiliary magnetic resonance (MR) imaging contrast agent gadolinium EOB-DTPA (ethoxybenzyl diethylenetr iaminepentaacetic acid) for the characterization of hepatic tumors, 79 primary and six implanted hepatomas in 38 rats were studied. MR imagi ng findings after administration of Gd-DTPA (0.3 mmol/kg) and Gd-EOB-D TPA (30 mumol/kg) were correlated with microangiographic and histologi c findings. Gd-EOB-DTPA produced a strong liver enhancement, which cau sed prompt negative contrast enhancement (CE) in all implanted hepatom as and in 77 of 79 primary hepatomas. A positive CE that lasted up to 2 hours was found in two of 79 primary hepatomas, both of which were h ighly differentiated (grade 1) hepatocellular carcinomas (HCCs). The r est were moderately differentiated to undifferentiated HCCs (grades II -IV). Rim enhancement, which corresponded histologically to peritumora l malignant infiltration sequestering normal hepatocytes, was seen aro und all implanted and some primary hepatomas. Positive tumor CE after administration of Gd-EOB-DTPA in this study is much less frequent but much more specific in comparison with the results of previous studies with manganese-DPDP (N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5, 5'-bis[phosphate]). These findings may help further discriminate hepat ic tumors.