Although there is no definite definition,the stroke that has no abnormalities before going to sleep and finds a neurological deficit after waking up are classified as wake-up strokes (WUS) in most of the literature.WUS account for 15％ ～30％ of all stroke cases,and little is known about its pathogenesis.Studies have shown that there is no significant difference in risk factors,clinical features,especially initial severity and outcome between WUS and non-WUS.The current research focuses on the benefits and risks of intravenous thrombolysis and endovascular treatment in WUS.

Endovascular therapy is another revascularization therapy after intravenous thrombolysis, but it is strictly limited by the time window as with the venous thrombolysis.For patients exceeding the time window, there is a tendency to use imaging means to assess their benefits and risks to guide decisions, which are particularly important for the assessment of collateral circulation. This article reviews collateral circulation assessment and its application in endovascular treatment of acute ischemic stroke.