Magnetic resonance microscopy--a new tool for the toxicologic pathologist.

Parallel to its many applications in medical imaging, magnetic resonance (MR) microscopy is a potentially powerful tool in toxicologic pathology. Because of the intrinsic qualities of MR microscopy (noninvasiveness, 3-dimensionality, and slicing in any chosen plane), the scientist has a new means by which to investigate different types of lesions based on differential contrast. By choosing appropriate proton stains to probe the state of the water in tissues, organ structure and vasculature can be seen and progressive lesion development can be followed in a given animal. This paper discusses toxicologic pathology applications for MR microscopy and compares MR microscopy with conventional histopathology using a time-course study of bromobenzene-induced hepatotoxicity in rats. Hematoxylin and eosin (H&E)-stained histological sections are compared with MR microscopy images from fixed tissue blocks to demonstrate one of the applications of MR microscopy to toxicologic pathology. The results indicate that MR microscopy is as sensitive as conventional H&E staining in detecting bromobenzene-induced hepatic lesions.