Usefulness of iron colloid-enhanced MRI in differentiating experimental hepatocellular carcinoma from hyperplastic nodules in rats: analysis by microautoradiography.

Abstract

To demonstrate the usefulness of iron colloid-enhanced MR images in differentiating hepatocellular carcinoma (HCC) from hyperplastic nodules (HN), microautoradiographs of chemically induced rat liver tumours were prepared 4 h after intravenous injection of chondroitin sulphate iron colloid (CSIC) labelled with 59Fe by the dipping technique. 20 Wistar rats were allocated into three groups: (1) a normal group, 10; (2) an HN group, 5; and (3) a liver cancer (LC) group, 5. In the I.C group, a diet containing 0.06% 3'-methydiaminobenzine tetrahydro-chloride (DAB) was administered for 3 months. In the HN group, a diet containing 0.025% acetylaminofluorene (AAF) was administered for 4 months. Non-labelled CSIC was intravenously injected into five rats in the normal group, and pseudomicroautoradiographs were prepared using the same technique (normal cold group). 50 sites for examination were randomly selected for each of the normal liver tissue, HN, well-differentiated HCC (HCC-W), and moderately to poorly-differentiated HCC (HCC-MP). The number of Kupffer cell-like macrophages and the photosensitized area ratio (PAR) per field of view were calculated. There was no significant difference in either the number of Kupffer cell-like macrophages or the PAR between HN and normal liver tissue. Although there was no significant difference in the number of these cells between groups HN and HCC-W, the PAR in group HCC-W was significantly lower than that in group HN (p = 0.045). In HCC-MP, both their number (p = 0.003) and the PAR (p = 1.18 x 10(-9)) were significantly lower than in group HCC-W. However, the PAR in HCC-MP was significantly higher than those in the normal cold group (p = 0.019). Iron colloid-enhanced MRI is useful for differentiating HCC from HN, and for diagnosing the degree of HCC differentiation.