High-resolution magnetic resonance imaging of intracranial aneurysms treated by flow diversion

Object: Flow diverter treatment of intracerebral aneurysms is highly successful and has low rates of morbidity and mortality. Among the primary concerns after endovascular treatment are failure to achieve aneurysm obliteration and recurrence, and close imaging follow-up is required. High-resolution magnetic resonance imaging (HRMRI) is being employed in evaluation of an increasingly wide variety of pathological conditions, but investigations into its use after flow diversion for aneurysm treatment have been limited. We present a brief overview of the literature on the use of HRMRI as a follow-up tool after aneurysm treatment using flow diversion, along with a case series describing three patients in whom we used HRMRI to assess aneurysm treatment response. Case descriptions: Patient 1 presented with an ischemic stroke and was found to have an unruptured ophthalmic segment aneurysm. Patient 2 presented with subarachnoid hemorrhage from a ruptured vertebral artery pseudoaneurysm. Patient 3, on workup for possible metastatic melanoma, was found to have an unruptured posterior communicating aneurysm. All three were treated with flow diversion, and in all three cases HRMRI was used to evaluate aneurysm obliteration on outpatient follow-up. HRMRI offered excellent resolution of the parent vessel, aneurysm sac, and aneurysm wall, demonstrating decreased or loss of flow-related enhancement in the aneurysm lumen and development of aneurysm sac thrombosis. Conclusion: HRMRI is a useful tool to evaluate aneurysm treatment by flow diversion and may represent an alternative to repeat digital subtraction angiography. Keywords: High-resolution MRI, Flow diverter, Aneurys