  Imaging the brain vasculature can be critical for cerebral perfusion
monitoring in the context of neurocritical care. Although ultrasensitive
Doppler (UD) can provide good sensitivity to cerebral blood volume (CBV) in a
large field of view, it remains difficult to perform through the skull. In this
work, we investigate how a minimally invasive burr hole, performed for
intracranial pressure (ICP) monitoring, could be used to map the entire brain
vascular tree. We explored the use of a small motorized phased array probe with
a non-implantable preclinical prototype in pigs. The scan duration (18 min) and
coverage (62 $\pm$ 12 % of the brain) obtained allowed global CBV variations
detection (relative in brain Dopplerdecrease =-3[-4-+16]% \& Dopplerincrease. =
+1[-3-+15]%, n = 6 \& 5) and stroke detection (relative in core Dopplerstroke.
=-25%, n = 1). This technology could one day be miniaturized to be implanted
for brain perfusion monitoring in neurocritical care.
