  Cerebral microbleeds are small, dark, round lesions that can be visualised on
T2*-weighted MRI or other sequences sensitive to susceptibility effects. In
this work, we propose a multi-stage approach to both microbleed detection and
segmentation. First, possible microbleed locations are detected with a Mask
R-CNN technique. Second, at each possible microbleed location, a simple U-Net
performs the final segmentation. This work used the 72 subjects as training
data provided by the "Where is VALDO?" challenge of MICCAI 2021.
