In the USA, every year 795,000 patients suffer a cerebral vascular accident (CVA), which represents a yearly cost of $73.7 billion. CVA is the third main cause of death and the main source of acquired handicap in adults, as a result it is now a key priority in public health and part of " The CVA National Action Plan 2013-2014".

Copeptin is a polypeptide, by- product of Vasopressin metabolism. The increase of Copeptin plasma level, as for Vasopressin, is connected to hydric balance disorders found in cardio-vascular, renal and endocrine diseases. This link has already shown its interest in the early diagnosis of myocardial infarction and, in a more indirect way, CVA.

Copeptin is associated with acute endogenous stress. It seems to have interesting potential in the diagnosis of CVA by its negative predictive value like D-dimeres in pulmonary embolism. Proadrenomedullin and Brain Natriuretic Peptide (BNP) are both associated with the prognosis of cardio-vascular diseases and could be interesting in evaluating CVA prognosis.

Inclusion Criteria:

• All patients, male or female, may be included if they meet the following criteria:

• patients with suspected ischemic CVA admitted in an acute stroke unit (thrombolysis unit).

• aged 18 and over.

• MRI Scan undertaken under the current protocol which includes the following sequences: distribution, T2* (gradient echo), ARM, TOF and FLAIR.

• after information given the consent form is signed:

  • by the patient .or for those unable to express their consent (in case of coma or severe neurological disorder) by a relative or next of kin.

.the patient will be informed as soon as he has recovered his faculties in order to be able to express, if he wishes, his opposition to the pursuit of the research (sample destruction before tested).

- the patient must be registered with the Social Security

Exclusion Criteria:

All patients with a contraindication to MRI Scan:

• Pacemaker,
• Implanted cardiac defibrillator,
• Implanted Neuro-stimulator,
• Cochlear Implants
• Implanted Insulin pump
• Other implanted electronic medical device
• Vascular intracerebral Clip
• Cardiac Valve
• Other metallic implant
• Metallic foreign body
• Ventricular diversion valve
• Eye or hearing prosthesis
• Current or suspected pregnancy
• Breast feeding

Those who are under protection of justice, under guardianship or curatorship will also be excluded.