Differentiation of malignant and benign cardiac tumors using 18F-FDG PET/CT

摘要

In the diagnostic algorithm of cardiac tumors, the noninvasive determination of malignancy and metastatic spread is of major interest to stratify patients and to select and monitor therapies. In the diagnostic work-up, morphologic imaging modalities such as echocardiography or magnetic resonance tomography offer information on, for example, size, invasiveness, and vascularization. However, preoperative assessment of malignancy may be unsatisfactory. The aim of this study was to evaluate the diagnostic value of 18F-FDG PET and the incremental diagnostic value of an optimized CT score in this clinical scenario. Methods: 18F-FDG PET/CT scans (whole-body imaging with low-dose CT) of 24 consecutive patients with newly diagnosed cardiac tumors were analyzed (11 men, 13 women; mean age ± SD, 59 ± 13 y). The maximum standardized uptake values (SUV max) of the tumors were measured. Patients were divided into 2 groups: benign cardiac tumors (n = 7) and malignant cardiac tumors (n = 17) (cardiac primaries [n = 8] and metastases [n = 9]). SUV max was compared between the 2 groups. Results were compared with contrast-enhanced CT, using standardized criteria of malignancy. Histology served as ground truth. Results: Mean SUV max was 2.8 ± 0.6 in benign cardiac tumors and significantly higher both in malignant primary and in secondary cardiac tumors (8.0 ± 2.1 and 10.8 ± 4.9, P 0.01). Malignancy was determined with a sensitivity of 100% and specificity of 86% (accuracy, 96%), after a cutoff with high sensitivity (SUV max of 3.5) was chosen to avoid false-negatives. Morphologic imaging reached a sensitivity of 82% and a specificity of 86% (accuracy, 83%). Both false-positive and false-negative decisions in morphology could be corrected in all but 1 case using a metabolic threshold with an SUV max of 3.5. In addition, extracardiac tumor manifestations were detected in 4 patients by whole-body 18F-FDG PET/CT. Conclusion: 18F-FDG PET/CT can aid the noninvasive preoperative determination of malignancy and may be helpful in detecting metastases of malignant cardiac tumors.