20 patients will be recruited. The aim of the study is to determine the natural progression of atherosclerotic disease.

Inclusion Criteria:

• stable carotid artery disease not requiring revascularization
• asymptomatic carotid artery stenosis < 80% or symptomatic patients with stenosis < 60 %
• prophylactic therapy with aspirin (> 100mg/day, statin, blood pressure therapy if indicated (goal < 130/80 mmHg))
• informed consent

Exclusion Criteria:

• non atherosclerotic occlusive disease (Bürgers disease)
• uncontrolled BP (DBP > 110 mmHg and/or SBP > 200 mmHg)
• hemorrhagic disease or platelet count < 100'000 mm^3
• Known active liver disease (elevations of GPT GOT or increased ammonia)
• impaired renal function (crea > 180 mmol/l)
• pregnancy
• severe claustrophobic reactions
• short - term life - threatening pathology
• physically unable to participate in the study
• compliance not guaranteed

Patients of the districthospital Bellinzona