MAGNETIC-RESONANCE MICROSCOPY AND HISTOPATHOLOGY - COMPARATIVE APPROACH OF BROMOBENZENE-INDUCED HEPATOTOXICITY IN THE RAT

The development of magnetic resonance (MR) microscopy has provided new approaches to histology and histopathology. Recent work has shown the promise of increased sensitivity in animal models of chemically induc ed hepatotoxicity, However, the field is so new that there is little e xperience to relate changes seen in MR micrographs to the more traditi onal optical images stained with hematoxylin and eosin. This work comp ares the sensitivity and reproducibility of MR microscopy with convent ional histopathology in detecting bromobenzene-induced hepatotoxicity in the rat. A time-course study was undertaken to provide a range of h istopathologies. Specimens were studied at 24, 48, 72, and 96 hours af ter exposure to 10% of the median lethal dose of bromobenzene. Using 4 animals per group (a total of 32 rats) added statistical significance to the study and defined a range of interanimal variability over 96 h ours. This work shows that MR microscopy, besides being nondestructive and three-dimensional, is at least as sensitive as conventional hemat oxylin-eosin staining in detecting bromobenzene-induced centrilobular lesions and recovery of the hepatocellular architecture in the rat. Th is study further suggests that, as we begin to understand the underlyi ng mechanisms of contrast in MR histology, MR may, in fact, supply eve n higher specificity than more traditional studies: variations were ob served in MR images of treated livers at a given time point that could be not be differentiated based on the grading of necrosis and inflamm ation on hematoxylin-eosin-stained sections.