Spontaneous regression of an intracranial aneurysm after carotid endarterectomy

BACKGROUND: Recent studies have hypothesized that hemodynamic changes in parent vessels are responsible for the formation and regression of cerebral aneurysms. One author has described regression of a “flow-related” 4-mm posterior communicating artery (PCoA) aneurysm following ipsilateral carotid endarterectomy (CEA), resulting in reversal of blood flow in the PCoA. CASE DESCRIPTION: We report a 68-year-old woman with a coincidental intracranial aneurysm (ICA) and contralateral internal carotid artery stenosis. The aneurysm spontaneously regressed subsequent to contralateral ICA endarterectomy as documented by repeat computed tomographic angiography. This report also demonstrates the first known case of an ICA in the anterior cerebral artery territory to undergo spontaneous regression. CONCLUSIONS: We conclude that the regression and potentially the formation of this aneurysm correlated with hemodynamic factors associated with stenosis of the contralateral ICA.