Figure 1.

Overview of leptomeningeal collaterals and cerebral autoregulation. (A) When a perfusion pressure gradient develops after large vessel occlusion, leptomeningeal collaterals are instantaneously recruited to provide cerebral perfusion to the ischemic territory within the functional capacity of cerebral autoregulation. (B) Microscopically, leptomeningeal collateral channels utilize pre-existing arterial tubular structures between the pial arteries, arterioles, or proximal branches. (C) The recruitment of leptomeningeal channels depends primarily on the myogenic dilatation of the pial arteries responsive to decreased local perfusion pressure (i.e., cerebral autoregulation).