<qa>  What is the MRI of a brain?3. Subjects with baseline brain MRI showing more than four 4 cerebral microhemorrhages regardless of their anatomical location or diagnostic characterization as possible or definite, andor one 1 or more areas of superficial siderosis, andor evidence of a prior macrohemorrhage. MRI must include fluid-attenuation inversion recovery FLAIR and T2-weighted gradient-recalled-echo GRE sequences. 