Rapid development of a de novo intracranial aneurysm following carotid occlusion

Carotid occlusion is a therapeutic intervention for specific intracranial vascular conditions, including giant, traumatic and intracavernous aneurysms. The long-term complications include de novo aneurysm formation at a distant site due to hemodynamic changes in the circle of Willis. The time frame for de novo aneurysm formation has been described in years with a mean of 9.6 years. There is no formalised radiological surveillance program following carotid occlusion. We describe the rapid development of a de novo posterior communicating artery aneurysm following contralateral carotid occlusion for a traumatic intracavernous aneurysm and suggest the need for a formalised radiological follow-up program following carotid occlusion.