Abstract
Introduction: Recently, PET/TC has been incorporated into the diagnostic algorithm and treatment monitoring of cardiac sarcoidosis (CS).
Objective: To evaluate the complementary value of cardiac PET/TC and whole-body PET/TC in patients with suspected myocardial inflammation due to sarcoidosis.
Materials and Methods: Between March and December 2024, 8 patients (6 men and 2 women) were referred to our center for evaluation of myocardial inflammation. A diet for cardiac suppression was indicated 36 hours before the study plus 12 hs of fasting. 13N-Ammonia was administered to assess myocardial perfusion, and 18F-Fluorodeoxyglucose (18F-FDG) was used to evaluate inflammation and obtain whole-body scan images. To quantify perfusion, the summed rest score (SRS) was used, and for inflammation assessment, quantitative parameters: SUVmax, cardiac metabolic activity (CMA), and cardiac metabolic volume (CMV) were used.
Results: The average age was 51±20 years, and the left ventricular ejection fraction was 49±16%. All patients showed late gadolinium enhancement consistent with CS on magnetic resonance imaging. In 50% of the patients, the indication for PET/TC was to evaluate the response to immunosuppressive treatment, half of whom had a history of systemic sarcoidosis. Two had myocardial inflammation (SUVmax: 13.63±0.3, CMV: 148.6±4.5 ml, CMA: 741±170 g). The other 2 had fibrosis (SRS: 10±9). Supra- and infradiaphragmatic lymph node involvement was observed in 3 patients (SUVmax: 10-13.6), leading to a change in their immunosuppressive regimen. In the remaining 50%, the study was performed due to suspected CS. Two patients showed perfusion defects (SRS: 12 ± 21), while only 1 had biventricular myocardial inflammation (SUVmax: 10.93, CMV: 113.8 ml, LV CMA: 593 g), associated with mediastinal and intrapulmonary adenopathy (SUVmax: 4.7), leading to the initiation of corticosteroids. The other 2 patients did not show pathological findings on the PET/TC study.
Conclusion: In our group of patients, the combination of cardiac PET/TC imaging with whole-body scan images was useful in therapeutic decision-making.
Keywords: Cardiac sarcoidosis, inflammation, PET/TC, 18F-Fluorodeoxyglucose, 13N-Ammonia, immunosuppression.
