Imaging of the ischaemic penumbra with a particular diffusion-weighted imaging (DWI)/ perfusion-weighted imaging (PWI) mismatch is a promising approach to the selection of patients with acute ischaemic stroke for trials of intervention. The investigators want to apply multimodal resonance imaging methods such as functional magnetic resonance imaging ( fMRI), diffusion tensor imaging (DTI), arterial spin labeling (ASL) to guide treatment and predict the prognosis of stroke.

Inclusion Criteria:

Time from the onset of stroke till hospital within 24 hours. With clinical characteristics such as hemiplegia, headache. Willing and able to comply with the study procedures and provide written informed consent to participate in the study.

Patients must understand the nature of the study and give informed consent.

Exclusion Criteria:

The onset of stroke out of 24 hours. Pregnant women. Patients with intracranial metallic bodies from prior neurosurgical procedure, implanted pacemaker, medication pump, vagal stimulator, deep brain stimulator, TENS unit or ventriculoperitoneal shunt.

Past history of seizures within one year or unexplained loss of consciousness. Family history of epilepsy.

Hospitalized patients with stroke and the some healthy volunteers recruited from community