A research roadmap of future endovascular stroke trials.

PATIENT SELECTION Imaging There is currently no consensus regarding the optimal imaging strategy for the selection of patients for intervention. The modality must be efficient, accurate, available and repeatable. Non-contrast CT using Alberta Stroke Program Early CT Score (ASPECTS) scoring, CT perfusion and MRI are all in widespread clinical usage at interventional stroke centers. A trial comparing different modes of imaging based patient selection would be valuable and currently does not exist. There are advantages and disadvantages to each technique with strong beliefs that each modality has its advantages. The question is whether the widespread availability, ease of access and time savings justify using non-contrast CT (supplemented by ASPECTS) as ‘good enough’ to select patients when compared to advanced imaging modalities that may be more specific to detecting ischemia. Developing an educational pathway with ASPECTS scoring to reduce inter-rater variability along with a standardized CT perfusion algorithm that can be replicated across institutions can allow for a trial examining this question to occur. The current landscape would potentially also allow for an MRI comparative trial. One starting point might be a core-lab adjudicated, prospective registry comparing preand post-treatment ASPECTS, computed tomography perfusion (CTP) and/or MRI data from a series of patients being screened for intervention. Such a study would allow for a systematic assessment of each modality with respect to its ability to detect both tissue at risk as well as completed infarct volume at presentation