3T MRI in the Evaluation of Brain Aneurysms Treated with Flow-Diverting Stents: Preliminary Experience

Deployment of stents across the neck of intracranial aneurysms to isolate the lesion from the circulation is a recently introduced endovascular treatment. These devices are known as flow-diverting stents because the stent mesh design drastically slows the blood flow within the aneurysm sac, thereby stimulating thrombus formation. Treated aneurysms require close follow-up monitoring using an effective minimally invasive method. We devised a dedicated follow-up protocol using a high field strength magnetic resonance system (MR) with gadolinium administration to monitor 11 patients treated by insertion of flow-diverting stents. Findings were compared with the results of a reference imaging procedure (CT angiography). MR accurately demonstrated patency of the stent lumen and monitored the evolution of the aneurysmal sac in all patients. Gadolinium administration proved essential in two patients to depict the complete exclusion of the flow within the aneurysmal sac.