The purpose of this study is to determine whether FDG-PET is capable of detecting atherosclerotic plaque inflammation and monitoring the effects of statins on plaque inflammation. The usefulness of FDG-PET in risk stratification is also investigated.

There is increasing evidence that inflammation plays a role in progression and destabilization of atherosclerotic plaque. However, currently, no non-invasive method is available for detecting plaque inflammation in clinical practice. FDG-PET can visualize activated metabolic levels of not only tumor cells but also inflammatory cells. Thus, it is possible that FDG-PET can detect atherosclerotic plaque inflammation and that, if so, FDG-PET can monitor the direct effect of statins on plaque inflammation. Additionally, monitoring the plaque inflammation by FDG-PET may be useful for determining the risk stratification of atherosclerotic patients.

Originally, we sought to compare patients with FDG-positive plaque with patients with plaque but not with FDG uptake, patients with FDG-positive plaque receiving statin therapy, and patients with FDG-positive plaque receiving diet management therapy. However, because patient number enrolled in the study was too small, the comparison was performed between FDG-positive patients with and without any statin therapy.

Inclusion Criteria:

• Protocol 1: patients who had carotid atherosclerosis detected by carotid ultrasound.
• Protocol 2: patients who underwent FDG-PET for cancer screening and had vascular FDG uptakes

Exclusion Criteria:

• Active inflammatory diseases
• Dyslipidemia under medications
• Uncontrolled diabetes mellitus, vasculitis, symptomatic coronary artery disease, symptomatic cerebrovascular diseases
• Known systemic disorders such as hepatic, renal, hematopoietic, and malignant diseases