MRI with histological correlation of group 1 rat. Prussian blue staining of the coronal section of brain and MRI shows the distribution of ferumoxides labeled cells in the brain at day 1 post IC infusion of 3 × 106 cells. The T2*w image shows many hypointense spot due to metastatic tumor cells in the cerebral cortex and hippocampus. Inset in the MRI indicates the area photographed in Prussian blue staining (center). Although the differences in the slice thickness of the histological section (6 μm) and MRI (500 μm) precluded direct spatial co-localization of iron positive lesions, the distribution pattern of metastasis can be appreciated.