Anterior communicating artery aneurysms are the most common intracranial aneurysm and have a high risk of rupture which can lead to morbidity and mortality. Traditionally, intracranial aneurysms were treated by clipping with neurosurgical access. However, certain patients may prefer less invasive approaches or not represent open surgical candidates. Flow diverters, including flow-redirection endoluminal devices (FRED), are new-generation stents that are placed endovascularly by transfemoral or transradial access. Recent studies have demonstrated that FRED is both safe and effective, with complete occlusion of aneurysms in over 90% of patients. This case highlights an interesting phenomenon of post-flow diversion circulatory remodeling, where flow diverter treatment can alter the circle of Willis anatomy and physiology.

Carotid webs are known to cause acute ischemic stroke in younger adults and have a high recurrence rate. Herein, we report a case of a symptomatic carotid web in a 51-year-old man who was transferred to our hospital after developing consciousness disturbance and left hemiparesis. He was diagnosed with right middle cerebral artery occlusion and underwent mechanical thrombectomy. Because his carotid web was the likely embolic source, we performed carotid artery stenting using a dual-layer stent to crimp the vessel wall and secure closure of the web pocket. Follow-up angiography was performed at 3 weeks after stenting, and endothelialization on the web pocket was confirmed. The high scaffolding effect of the dual layer stent may promote the endothelialization on the carotid web.

The authors report a rare autopsy case. A 59-year-old woman underwent flow diverter (FD) therapy using a pipeline embolization device (PED) for a large paraclinoid internal carotid artery aneurysm. Follow-up magnetic resonance (MR) examinations were performed 6 months after the treatment. Although the T2-weighted images showed progressive thrombosis of the aneurysm, the silent MR angiography (MRA) clearly showed the residual blood flow within the aneurysm. The patient committed suicide 2 months after the follow-up MR examinations. An autopsy specimen showed a small section of the defective membranes with the PED that matched the entry point of residual blood flow seen clearly in the silent MRA. Macroscopic photograph and hematoxylin and eosin stained sections showed defective endothelialization. In contrast, complete endothelialization was observed in membranes covering the PED. The autopsy findings after FD therapy showed defective endothelialization that perfectly matched and corroborated the silent MRA findings.