Multimodality imaging to distinguish between benign and malignant cardiac masses

Background. To compare the diagnostic accuracy of CMR and FDG-PET/CT and their complementary role to distinguish benign vs malignant cardiac masses. Methods. Retrospectively assessed patients with cardiac mass who underwent CMR and FDG-PET/CT within a month between 2003 and 2018. Results. 72 patients who had CMR and FDG-PET/CT were included. 25 patients (35%) were diagnosed with benign and 47 (65%) were diagnosed with malignant masses. 56 patients had histological correlation: 9 benign and 47 malignant masses. CMR and FDG-PET/CT had a high accuracy in differentiating benign vs malignant masses, with the presence of CMR features demonstrating a higher sensitivity (98%), while FDG uptake with SUVmax/blood pool >= 3.0 demonstrating a high specificity (88%). Combining multiple (> 4) CMR features and FDG uptake (SUVmax/blood pool ratio >= 3.0) yielded a sensitivity of 85% and specificity of 88% to diagnose malignant masses. Over a mean follow-up of 2.6 years (IQR 0.3-3.8 years), risk-adjusted mortality were highest among patients with an infiltrative border on CMR (adjusted HR 3.1; 95% CI 1.5-6.5; P = .002) or focal extracardiac FDG uptake (adjusted HR 3.8; 95% CI 1.9-7.7; P < .001). Conclusion. Although CMR and FDG-PET/CT can independently diagnose benign and malignant masses, the combination of these modalities provides complementary value in select cases.