Role of imaging in current acute ischemic stroke workflow for endovascular therapy

Ischemic stroke is caused by a thrombus that blocks an intracranial artery. Brain tissue beyond the blocked artery survives for a variable period of time because of blood and nutrients received through tiny vessels called collaterals. Imaging the brain and the vasculature that supplies it is therefore a vital first step in treating patients with acute ischemic stroke. In this review, we focus on current evidence for imaging selection of patients for endovascular therapy in the context of the recently positive clinical trials, such as Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing Computed Tomography to Recanalization Times (ESCAPE), Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME), and Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial (EXTEND-IA). We discuss evidence for and use of the various imaging paradigms available. We discuss how to set up quick and efficient imaging protocols for patient selection and address common concerns about the use of imaging, including time spent, contrast, radiation, and other advantages and disadvantages. Finally, we briefly comment on how imaging can integrate itself within various health systems of care in the future, thereby potentially improving patient outcomes further.