Comparison of Spectral Photon Counting CT (SPCCT) With Dual Energy CT (DECT) and Magnetic Resonance Imaging (MRI) for Plaque and Lumen Carotid Arteries Evaluation

Inclusion Criteria: * Male or female subjects of any ethnic background, aged \> 18 years * Any of the following known or suspected supra-aortic arterial disease based on : Prior stroke; Transient Ischemic Attack; Amaurosis Fugax; Referred for evaluation of any supra-aortic vessel; Follow-up for a stent in a supra-aortic vessel; Prior imaging ultrasounds study showing \> ou = 50 % stenosis of a supra-aortic vessel segment (within 60 days before consent) * Patient undergoing surgery within one month of carotid plaque evaluation * Willingness and ability to follow directions and complete all study procedures specified in the protocol * Pre-menopausal women only : Negative urinary pregnancy test on the day of imaging before the administration of study drug * Patient has accepted to participate to the study and has signed the written consent * Patient is affiliated to social security Exclusion Criteria: * Contraindication to MRI examinations (e.g. inability to hold breath, severe arrhythmias, very low cardiac output, severe claustrophobia, metallic devices not approved for MRI such as defibrillators, pacemaker, heart valve prostheses, cochlear implants, neuro-stimulators, implanted automated injection device, intraocular metallic foreign bodies, neurosurgical and vascular clips); * Contraindication to the use of iodine and gadolinium containing contrast media (including subjects with suspicion for/or known to have NSF);- History of severe allergic or anaphylactic reaction to an…