Monitoring of microsurgically and endovascularly treated aneurysms (META): protocol for an international multicentre retrospective cohort study

Introduction Following endovascular treatment (EVT) or microsurgical treatment (MT) of intracranial aneurysms (IA), radiological follow-up is performed to assess for recurrence and to determine the need for re-treatment. There is a paucity of evidence describing the long-term results of EVT and MT for IA and therefore data to inform the design of follow-up protocols are lacking. The overarching aim of the META study is to determine the clinically relevant long-term outcomes of EVT and MT for IA, and use this data to create evidence based radiological and clinical follow-up protocols for these aneurysms.