Cardiac and Pericardial 18F-FDG Uptake on Oncologic PET/CT: Comparison with Echocardiographic Findings

BACKGROUND: Interpretation of cardiac uptake on 18-fluorodeoxyglucose positron emission tomography/computed tomography ($^{18}F-FDG$ PET/CT) is often confounded by intense physiological FDG uptake and numerous benign conditions. The aim of the study was to describe the echocardiographic features in concordance with cardiac and pericardial $^{18}F-FDG$ uptake on whole-body oncology PET/CT. METHODS: We enrolled 43 consecutive patients (34 solid tumors, 8 lymphomas and 1 leukemia) who were newly diagnosed with non-cardiac malignancy showing incidental cardiac or pericardial $^{18}F-FDG$ uptake on PET/CT and underwent transthoracic Doppler echocardiography (TTE) within 1 month of PET/CT. The maximum standardized uptake ($SUV_{max}$) of all lesions was measured. RESULTS: Fifty-six $^{18}F-FDG$ uptake lesions (32 pericardium, 7 myocardium, 9 cardiac chambers and 8 great vessels) were found, and pericardial effusion was the most common echocardiographic finding (22/43, 51.2%) among study population. Pericardial FDG uptake was shown as pericardial effusion (68.8%), intrapericardial echogenic materials (31.3%), pericardial thickening (28.1%), hyperechogenicity of myopericardium (18.8%), and restricted sliding movement or constrictive pericarditis (15.6%) on TTE. Lesions with regional wall motion abnormality (p = 0.004) or constrictive pericarditis (p = 0.021) had significantly higher mean $SUV_{max}$ than those without. Myocardial FDG uptake demonstrated pericardial effusion (57.1%), regional wall motion abnormality (57.1%), and increased myocardial wall thickness (42.9%). All cardiac chamber FDG uptakes showed intracardiac mass on TTE. CONCLUSIONS: Cardiac or pericardial $^{18}F-FDG$ uptake on oncology PET/CT shows characteristic echocardiographic features according to which heart sites are involved.