Colocalization of T2 hypointense areas and iron deposits. (A) MRI reveals an abnormal T2 hypointensity in the ipsilateral subcortical white matter (WM) (beneath the star) relative to the injection. Additional hypointense structures perpendicular to the pial surface (arrows) were present in the contralateral hemisphere. (B) Iron histochemical staining reveals iron deposits that colocalize with T2 hypointensities observed in A. The region beneath the star indicates an area of subcortical WM with labeling in inflammatory cells, around vessels, within microglia and generally throughout the region. The arrows indicate labeling around descending vessels that extend towards the subcortical WM. (C) A more posterior slice from A. T2 hypointense areas are seen in the contralateral subcortical WM (e.g., arrowhead) and in a perpendicular structure that follows the pattern of a descending cortical vessel (arrow). (D) Iron histochemical staining reveals a colocalization of iron deposits and T2 hypointense areas observed in C. (E, F) Higher magnifications of stained areas observed in D (note, arrows and arrowheads label equivalent structures in C-F). Staining around vessels occurred in endothelial cells, macrophages/microglia and/or neuropil. Bar = 1 mm for A-D. Bar in F = ~175 μm for E; ~50 μm for F.