A technique of MRI infusion -l'Arterial Spin Labeling-, non-invasive and non-irradiating, repeatable over time, appears promising in the field. This sequence allows for routine, generate perfusion maps relating to the entire brain volume

The subarachnoid hemorrhage (SAH) is a relatively severe disease whose prognosis is particularly related to the early onset of arterial vasospasm, maximum between the 5th and 14th day after SAH. Many obstacles make it difficult screening and monitoring of such complication. The challenge is to be able to demonstrate a reduction in regional cerebral blood flow before the onset of irreversible parenchymal sequelae, responsible for the majority of long-term morbidity among survivors. In clinical routine, screening vasospasm is achieved by Doppler intracranial arteries (DTC). However, its sensitivity is poor with regard to the middle and anterior cerebral arteries. The gold standard for diagnosis is cerebral arteriography. However, vasospasm in arteriography or trans-cranial Doppler does not prejudice the appearance of a delayed ischemic deficit.

A technique of MRI infusion -l'Arterial Spin Labeling-, non-invasive and non-irradiating, repeatable over time, appears promising in the field. This sequence allows for routine, generate perfusion maps relating to the entire brain volume

Inclusion Criteria:

• Adults.
• Who have given their written consent.
• Affiliated to a social security system.
• Any patient hospitalized at the University Hospital of Angers in neurosurgical intensive care unit for supervision by ASL and DTC a subarachnoid hemorrhage from all etiologies (excluding traumatic).

Exclusion Criteria:

• Contraindications to MRI
• patient hospitalized at the University Hospital of Angers in surgical intensive care for monitoring a subarachnoid hemorrhage.
• patient hospitalized at the University Hospital of Angers for monitoring a subarachnoid hemorrhage traumatic.