Optimizing the MRI protocol in acute ischemic stroke remains a challenging issue. In this field, susceptibility-weighted sequences have proved their superiority over T2. Besides the strengthened susceptibility effect, enhanced susceptibility-weighted angiography (eSWAN) sequence provides also a time-of-flight (TOF) effect, allowing the exploration of the intracranial arterial circulation. The objective of this study is to compare eSWAN and 3D TOF, considered as the reference, in the detection of arterial occlusion in acute stroke.

Patients who undergo MRI for suspected acute stroke with an acute ischemic lesion on diffusion-weighted imaging (DWI) will be prospectively included in this study.eSWAN and TOF images will be analyzed under double-blind conditions by a junior radiologist and a senior neuroradiologist for the detection of arterial occlusion. eSWAN images will be assessed in order to estimate the inter-observer agreement. After a consensus, eSWAN and TOF data will be compared to calculate inter-modality agreement.

Inclusion Criteria:

• clinical symptoms compatible with acute stroke;
• time range between symptoms and magnetic resonance imaging less than 4 h 30
• presence of at least one acute ischemic lesion on the diffusion-weighted images (DWI).

Exclusion Criteria:

• MR contraindications;
• negative DWI;
• differential diagnosis;
• incomplete acquisition of the full magnetic resonance imaging protocol or technical issues leading to uninterpretable eSWAN and/or TOF sequences (e.g.motion artifacts).

Patients included in this prospective study will be recruited at Saint-Philibert Hospital -Lomme, France, when presenting symptoms of an acute stroke