The meaning of FDG accumulation on blood vessel wall

1004 Learning Objectives Mild to moderate FDG accumulation on the artery walls is often observed in daily PET treatment, but it is believed that such findings are not unique to angiitis and they are related to smooth muscle cell proliferation caused by arteriosclerosis, the presence of macrophages inside atherosclerotic plaque, or both. We describe cases related to accumulation on the blood vessel wall to examine the usefulness and limitations of PET/CT and also discuss the role of PET/CT. In cases of aortitis syndrome, high levels of accumulation were observed on the artery walls of the thoracic ascending aorta, the aortic arch, the subclavian artery, the common carotid artery, the thoracic descending aorta, and the abdominal aorta. Contrast CT examinations revealed wall thickening accompanying contrast effects at locations corresponding to the accumulation areas. Cases in which high levels of accumulation were observed in the arterial plaque of the thoracic descending aorta were believed to involve active atherosclerotic changes. In contrast, there were also cases of arterial plaque with no findings of accumulation believed to indicate finished inactive arteriosclerotic changes. In cases in which high levels of localized accumulation were observed in part of the grafted areas of the great vessels and disappeared after antibiotic treatment, a diagnosis of graft infection was obtained. However, even in cases involving no infection or inflammation, diffuse increases in accumulation are sometimes observed along the graft due to granulation tissue, etc. of the grafted area, and although such cases are considered to indicate physiological accumulation, the identification of such accumulation is often difficult. After radiation therapy for head and neck tumors, accumulation to the neck arteries was enhanced compared to before therapy. In cases of retroperitoneal fibrosis, caution is required because some cases that appear to involve accumulation to the artery walls may actually be accumulation in areas demonstrating the outgrowth of soft parts surrounding the arteries