Inclusion Criteria:  Atherosclerotic carotid stenosis, North American Symptomatic Trial Collaborators (NASCET) method 30-99% Ability to undergo a neck MR for carotid plaque imaging Ability to undergo a follow-up of at least 1-year For the prospective, longitudinal part: Hemispheric ischemic stroke or retinal ischemia ipsilateral to the carotid stenosis, with symptom onset within 24 hours (these patients will be followed-up for recurrent ischemic stroke)  Exclusion Criteria:  Carotid stenosis due to causes other than atherosclerosis (e.g. carotid dissection or post-actinic) Contraindication to MRI Lack of informed consent