Direct Comparison of Histology of Microbleeds with Postmortem MR Images

BACKGROUND: Although the clinical significance of so-called microbleeds (MBs) in gradient-echo MR images (GRE-MRI) has been extensively researched, the histopathological evaluation is notably insufficient. METHODS: Postmortem GRE-MRI was obtained of water-immersed formalin-fixed tissue blocks from a 97-year-old hypertensive woman with 9 antemortem MBs. Histologic slides were compared with those of MRI. RESULTS: Microscopic examination revealed clusters of hemosiderin-laden macrophages in 8 MBs and arteriolar pseudocalcification in 1 MB in the left pallidum. Hypertensive microangiopathies were found in 5 lesions. The sizes of the lesions with hemosiderin deposits were roughly comparable with the MBs of GRE-MRI. CONCLUSIONS: All of the MBs but for 1 exception were proved to be hemosiderin deposits and frequently associated with hypertensive microangiopathy.