Diagnosis and staging of cardiac masses: additional value of CMR with 18F-FDG-PET compared to CMR with CECT.

Purpose: Characterization of malignant cardiac masses is usually performed with cardiac magnetic resonance (CMR) and staging with whole-body contrast-enhanced computed tomography (CECT). In this study, our objective was to evaluate the role of 18Fluor-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) with CMR for both characterization and staging of cardiac masses.

Methods: Patients with cardiac masses who underwent CMR, CECT, and 18F-FDG-PET were retrospectively identified. For the characterization of cardiac masses, we calculated the respective performances of CMR alone, 18F-FDG-PET alone, and the combination of 18F-FDG-PET and CMR. For staging, we compared head-to-head the respective performances of 18F-FDG-PET and CECT. Histology served as gold standard for malignancy, and response to anticoagulation for thrombus.

Results: In a total of 28 patients (median age 60.5 years, 60.7% women), CMR accurately distinguished malignant from benign masses with sensitivity (Se) of 86.7%, specificity (Sp) of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 86.7%, and accuracy of 92.9%. 18F-FDG-PET demonstrated 93.3% Se, 84.6% Sp, 87.5% PPV, 91.7% NPV, and 89.3% accuracy. Combining CMR with 18F-FDG-PET allowed to benefit from the high sensitivity of 18F-FDG-PET (92.9%) and the excellent specificity of CMR (100%) for malignant diseases. For staging, 18F-FDG-PET outperformed CECT on per-patient (66.7% vs 55.6% correct diagnosis, respectively), per-organ (10 vs 7 organs, respectively), and per-lesion basis (> 29 vs > 25 lesions, respectively).

Conclusion: Combining 18F-FDG-PET with CMR improved the characterization of cardiac masses compared to each modality alone. Additionally, the diagnostic performance of 18F-FDG-PET was better than CECT for staging. This study suggests that the combination of CMR and 18F-FDG-PET is the most effective for the characterization of cardiac masses and the staging of these lesions.