Classification of carotid plaque vessel wall changes in carotid stenosis accordingly to AHA classification (American Heart Association)- comparison between histology and CT. The CT is performed with a fast kVp-switching dual energy technique.

To compare the ability to detect iodine contrast enhancement in the carotid plaque compared with 3T MRI with gadolinium.

Patients planned for CEA (carotid endarterectomy) due to carotid stenosis will be examined with one extra CT and MRI before surgery. The CEA specimen is stored in the BiKE-registry (a biobank of operated carotid plaque at the Karolinska Institute). In that registry the patients will be given a personal code which is used to identify the CT, MRI and histology data further on.

Approved by regional ethical review board in Stockholm and local radiation comity at Karolinska University Hospital Solna (Dnr K2435-2014). Informed consent from the participating patients.

Inclusion Criteria:

• 50% stenosis (NASCET) or more based on CTA (CT-angiography),
• MRI or US,
• Scheduled for CEA
• 50 years or older,
• Normal kidney function (estimated GFR (glomerular filtration rate) 60 ml/min or more).

Exclusion Criteria:

• Contraindications to iodine contrast media,
• Contraindications to MRI or gadolinium contrast media.

Patients that are scheduled for CEA (carotid endarterectomy) and volunteer to participate in this study (fulfilling the incl and excl criteria).