Table 1 Inclusion and exclusion criteria

• Age > 49 years old

• Primary referral to an outside hospital

• Acute ischemic stroke or transient ischemic attack (TIA)

• DWI positive lesions outside the territory of a single internal carotid artery

• Neurological symptoms compatible with a stroke or TIA in the territory of the internal carotid artery

• Surgical procedure within 24 hours preceding the MRI

• Onset of symptoms within the last 7 days

• History of radiation to the neck area

• 1 or more acute ischemic lesion(s) visible on MR diffusion-weighted imaging (DWI) in the territory of a single internal carotid artery

• Carotid artery stenosis ≥70% (NASCET) ipsilateral to the stroke or TIA as defined by ultrasound (systolic peak flow velocity ≥ 300 cm/s)

• Presence of carotid artery plaques in the ipsi- or contra-lateral carotid artery as defined by ultrasound (plaque thickness at least 2 mm; located within 1 cm proximal or distal to the carotid bifurcation)

• Creatinine levels > 2 times the upper limit of the standard range of the respective laboratory within the last 30 days prior to MRI and Renal clearance < 30 ml/minute

• Written informed consent

• Standard contra-indications for MRI