Inclusion Criteria- All patients aged at least 18 years hospitalized with ischemic stroke signs in the carotid territory, objectified on brain MRI with positive DWI.
- Carotid plaque > 2.5 mm thickness in the ipsilateral carotid territory to the AIC, low echogenicity (Type 1 to 3 of the classification Geroulakos) measured by the assessment "GSM" (median gray level).
- Free and informed consent patient or his representative for contrast injection microbubble.
- Affiliated to health insurance.
Exclusion Criteria- Severe cerebral infarction with NIHSS> 25
- No-indications to the contrast medium injection
- Recent myocardial infarction, unstable angina.
- Heart failure stage III / IV New York Heart Association.
- Cardiac shunt left-right, respiratory distress.
- Allergy to albumin or contrast agents.
- Carotid plaques and hyperechoic calcified (however these plaques will be counted to determine their prevalence in acute AIC).
- Carotid dissection