With theadventof advancedMRandCT techniques and new endovascular procedures, diagnosis and management of acute stroke are a rapidly evolving field. It would be impossible to cover all the important aspects of acute stroke in a single edition of Neuroimaging Clinics of North America, and I have focused on selected topics. Since atheromatous disease is a major cause of acute ischemic stroke, one article includes a review of noninvasive imaging of the carotid artery with a focus on vulnerable plaque imaging. Five articles address advanced CT and MR techniques such as CTA, CT perfusion, diffusionweighted imaging,diffusion tensor imaging,dynamic susceptibility perfusion-weighted imaging, arterial spin labeling perfusion-weighted imaging, and permeability imaging for evaluating acute ischemic stroke. Three articles address intravenous and intraarterial therapies and the use of advanced imaging to guide patient selection. One reviews intraarterial recanalization strategies. One addresses the role of diffusion and perfusion MRI in selecting patients for IV therapy and reviews major trials to date. An additional article reviews ASPECTS and other neuroimaging scores that are used in the acute setting to guide patient selection for intravenous and intra-arterial therapies and to help predict outcome.