Advanced MRI in acute stroke: Is the whole penumbra salvageable?

The recent Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention With Trevo (DAWN) and Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study III (DEFUSE III) trials have underscored the importance of advanced imaging in the selection of patients for endovascular treatment (EVT); patients presenting more than 6 hours after last known well showed substantial benefits if selected based on either a mismatch between the volume of the ischemic core on diffusion-weighted imaging (DWI) and the clinical deficit or between the volume of the ischemic core and the potentially reversible ischemia (penumbra).1,2 These studies showed the efficacy of treating patients well outside the 6-hour treatment window established by 5 randomized trials completed by 2015.3