Middle Cerebral Artery Bifurcation Aneurysm: Saccular Aneurysm of the Middle Cerebral Artery Bifurcation Treated with a Flow Diverter Stent

Abstract

A 66-year-old female patient with a history of multiple vascular risk factors, including ischemic heart disease, experienced repeated episodes of left-sided headaches associated with blurred monocular vision of her left eye and diplopia. Neuroradiological examination including CT and CT-angiography (CTA) demonstrated the presence of a round, medium-sized supraclinoid left internal carotid artery (ICA) aneurysm. Angiography confirmed the presence of a paraophthalmic ICA aneurysm, but also depicted a small, irregularly shaped saccular aneurysm at the middle cerebral artery (MCA) bifurcation with the fronto-orbital branch. The MCA aneurysm was missed at admission CTA but was clearly visible retrospectively. Before proceeding to treat the carotid aneurysm, we first approached the more distally located MCA aneurysm. The patient was started on dual antiplatelet and a flow diverter was implanted in the M1/M2 segment, from the largest MCA branch to the MCA stem. The procedure was uneventful and the patient was discharged after 48 h. Follow-up MRI 2 months later did not demonstrate any area of lenticulostriate infarction. Follow-up angiography 6 months after stent placement confirmed occlusion of the MCA aneurysm and preservation of the parent MCA arteries. Remodeling was observed in the jailed branch. The patient remained asymptomatic for a full year and treatment of the ICA aneurysm has been scheduled. This case supports previous observations regarding the safety and effectiveness of flow-diverter stent implantation for the management of wide-necked MCA aneurysms in which one of the bifurcating or distal branches arises directly from the sac, when other endovascular techniques are thought to be either infeasible or carry significant risks. Treatment of MCA aneurysms is the main topic of this chapter.