Effects of VitamIN K2 and D3 supplementaTion on PET/MRI in Carotid Artery Disease

Inclusion Criteria: * Asymptomatic carotid artery disease on at least one side with a degree of stenosis \> 25% (according to on the ECST criteria). If the patient has a symptomatic carotid artery disease on the contra-lateral side, he/she will still be included in the study, if intensified medical treatment for this symptomatic stenosis (e.g. statins, antiplatelet medication) was started ≥ 6 month before inclusion of the patient. This protocol was chosen in order to widely assure a stable situation on the plaque(s), which avoids an overspill from this medication on the assumed effects of the MK-7 and vitamin D3 supplementation. * Age older than 18 years * Signed informed consent provided Exclusion Criteria: * Antiplatelet or cholesterol lowering medication started within the past 6 months * Chronic or paroxysmal atrial fibrillation * Presence or scheduled coronary or carotid revascularisation procedure (e.g. stent implantation, coronary artery bypass graft, balloon-dilatation, endarterectomy, angioplasty) * History of myocardial infarction or stroke * Malignant disease (except for treated basal-cell or squamous cell carcinoma) * Use of vitamin K antagonists or any other anticoagulation treatment * A life-expectancy \< 1 year * Claustrophobia * Presence of a pacemaker, intra-cardiac defibrillator, or metallic implant (e.g. vascular clip, neuro-stimulator, cochlear implant) * Body weight \> 130kg or body habitus that does not fit into the gantry * Pregnancy or wish to become pregnant in the near future * Breast feeding * (History of) metabolic or gastrointestinal disease * Use of vitamin K or D containing supplements or vitamin K-rich foods (i.e. soya) * Chronic inflammatory disease * Systemic treatment or topical treatment likely to interfere with evaluation of the study parameters * Corticoid treatment * Participation in a clinical study more recently than one month before the current study