WCN 2021 | Imaging guide for thrombectomy in acute ischemic stroke

Marc Fisher, MD, Beth Israel Deaconess Medical Center, Boston, MA, discusses the use of various imaging modalities for identifying acute ischemic stroke patients who are candidates for thrombectomy. Computed tomography (CT) angiography or magnetic resonance angiography are very valuable modalities since they allow the identification of patients who have a clog in a vessel that is reachable and can potentially be retrieved. A controversial topic in the field is how much time should be spent identifying the extent of the ischemic core and penumbra. Dr Fisher explains that within the first several hours after stroke, the extensive identification of those areas is probably not needed in most situations. However, if the CT perfusion imaging can be done and processed quickly, not much additional time is spent, and further information is provided. Yet, some consider it not necessary up to 6 hours after onset. Beyond 6 hours after stroke onset, the clinical trials DEFUSE 3 (NCT02586415) and DAWN (NCT02142283) used advanced imaging to identify the extent of core and penumbra to select patients. Nevertheless, it is known that the timing for the evolution of the ischemic core growth is variable among patients, and it’s challenging to predict its evolution rate from clinical parameters. The Alberta Stroke Program Early CT Score (ASPECTS) evaluation is a qualitative method to evaluate focal hypoattenuation at brain CT in early acute stroke. However, the interobserver reliability is not good, and an ASPECTS score can be associated with different core volumes, which will have different implications regarding response to treatment. This interview took place during the XXV World Congress of Neurology.