The mIPs over five slices served to further distinguish an isolated hypointensity
from a vein. Once a potential CMB was identified, the HP-filtered phase image was zoomed by a factor of 4 to allow for a better tracing of its boundary using our in-house software SPIN (signal processing in NMR). Each CMB’s boundary was selected to measure its volume content (from which the microbleed diameter was calculated) and average phase intensity; these boundaries were saved to prevent double counting.