How to Differentiate Benign versus Malignant Cardiac and Paracardiac¹⁸F FDG Uptake at Oncologic PET/CT

Abstract

Patients undergoing 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) whole-body oncologic positron emission tomography (PET)/computed tomography (CT) are studied while fasting. Cardiac FDG uptake in fasted patients has been widely reported as variable. It is important to understand the normal patterns of cardiac FDG activity that can be seen in oncologic FDG PET/CT studies. These include focal and regional patterns of increased FDG myocardial activity. Focal activity can be observed in papillary muscles, the atria, the base, and the distal anteroapical region of the left ventricle. Regional increased cardiac FDG activity may be diffuse or localized in the posterolateral wall or the base of the left ventricle. Abnormal patterns of cardiac FDG activity not related to malignancy include those associated with lipomatous hypertrophy of the interatrial septum, epicardial and pericardial fat, increased atrial activity associated with atrial fibrillation or a prominent crista terminalis, cardiac sarcoidosis, endocarditis, myocarditis, and pericarditis. Knowledge of these patterns of cardiac FDG activity is important to be able to recognize malignant disease involving the paracardiac spaces, myocardium, and pericardium. With a better understanding of the range of normal and abnormal patterns of cardiac FDG activity, important benign and malignant diseases involving the heart and pericardium can be recognized and diagnosed.

Additional Heparin Preadministration Improves Cardiac Glucose Metabolism Suppression over Low-Carbohydrate Diet Alone in 18F-FDG PET Imaging

“…Our findings on analyzing the patterns of 18 F-FDG distribution in physiologically nondiffuse cardiac uptake (score of 3) are in keeping with earlier publications (22)(23)(24). Knowledge of these variable patterns of nonpathologic uptake is important in the interpretation of 18 F-FDG PET scans for cardiac inflammatory or infectious disease when cardiac suppression may not be adequate.…”

Challenges of cardiac inflammation imaging with F-18 FDG positron emission tomography

“…6 Nonspecific findings that may indicate failed suppression, and/or physiologic uptake and make image interpretation challenging included diffuse myocardial activity exceeding liver uptake or uptake in the lateral wall and/or ring shaped/circumferential basal uptake (Nensa et al doi: 10.1007/s12350-016-0443-1) 7 or papillary muscle uptake. 8,9 Diffuse FDG uptake in the entire left ventricular wall without focal uptake generally does not indicate disease as cardiac sarcoidosis is histopathologically known to be localized and not diffuse. 10 Absence of contrast enhancement, edema, or wall motion abnormalities on cardiac MRI associated with these nonspecific FDG uptake patterns is useful in avoiding false positive interpretations (Nensa et al doi:10.1007/s12350-016-0443-1).…”

Features of non-malignant thoracic lesions on F-18 FDG PET/CT scan

“…During oncologic imaging, the required patient's fasting forces the heart to use free fatty acid as substrate and should result in low and uniformed cardiac uptake features [7] . In real practice, the cardiac uptake patterns are variable even in serial PET exams of the same patient.…”

“…Furthermore, new perfusion defects may appear 3 to 6 years post-treatment in patients who had initially normal cardiac SPECT scans after treatment [23,24] . It has been suggested that a radiation dose greater than 35 Gy is required to result in increased FDG activity [7] (see Figure 14). Talc pleurodesis is a procedure to treat persistent pneumothorax or recurrent pleural effusion.…”