Metabolic Activity of the Spleen and Bone Marrow in Patients With Acute Myocardial Infarction Evaluated by F-18-Fluorodeoxyglucose Positron Emission Tomograpic Imaging

Abstract

Background-Atherosclerosis is considered to be an inflammatory disease associated with the activation of hematopoietic and immune-related organs such as the bone marrow (BM) and spleen. We evaluated the metabolic activity of those organs and of the carotid artery with F-18-fluorodeoxyglucose positron emission tomography in patients with coronary artery disease, including acute myocardial infarction. Methods and Results-Whole-body combined F-18-fluorodeoxyglucose positron emission tomography/computed tomography was performed in 32 patients with acute myocardial infarction, 33 patients with chronic stable angina, and 25 control subjects. The mean standard uptake value was calculated in the regions of interest in the spleen and the BM of lumbar vertebrae. The target-to-background ratio of the standard uptake values of the carotid artery and jugular vein was also calculated. In patients with acute myocardial infarction, the standard uptake values of the BM (1.67 +/- 0.16) and spleen (2.57 +/- 0.39), as well as the target-to-background ratio of the carotid artery (2.13 +/- 0.42), were significantly higher than the corresponding values of patients with angina (1.22 +/- 0.62; 2.03 +/- 0.35; 1.36 +/- 0.37; all P<0.001) and controls (0.80 +/- 0.44; 1.54 +/- 0.26; 1.22 +/- 0.22; all P<0.001), independent of traditional cardiovascular risk factors and high-sensitivity C-reactive protein. In all groups combined, the target-to-background ratio of the carotid artery was significantly associated with the standard uptake values of the BM (r=0.535; P<0.001), spleen (r=0.663; P<0.001), and high-sensitivity C-reactive protein (r=0.465; P<0.001). Conclusions-The metabolic activity of the BM and spleen, as well as of the carotid artery, was highest in patients with acute myocardial infarction, intermediate in patients with angina, and lowest in control subjects. The activation of the BM and spleen was significantly associated with inflammatory activity of the carotid artery.