Flow dynamics in a lethal anterior communicating artery aneurysm

We describe and analyze the how dynamics in replicas of a human anterior co mmunicating artery aneurysm. The replicas were placed in a circuit of pulsa ting non-Newtonian fluid, and hows were adjusted to replicate human physiol ogic parameters. Individual slipstreams were opacified with isobaric dyes, and images were recorded on film and by CT/MR angiography, When flow in the afferent (internal carotid) and efferent (anterior and middle cerebral) ar teries was bilaterally equal, slipstreams rarely entered the aneurysm, When how in either the afferent or efferent vessels was not symmetrical, howeve r, slipstreams entered the aneurysm neck, impinged upon the aneurysm dome, and swirled within the aneurysm. Unequal flow in carotid or cerebral system s may be necessary to direct pathologic, fluid slipstreams into an aneurysm .