The role of F¹⁸-fluorodeoxyglucose positron emission tomography in guiding diagnosis and management in patients with known or suspected cardiac sarcoidosis

Cardiac sarcoidosis (CS) has gained significant interest in recent years with the emergence of advanced imaging modalities such as MRI and F¹⁸-fluorodeoxyglucose-positron emission tomography (FDG-PET) as modalities to aid in the diagnosis of this condition. CS remains a difficult condition to diagnose, particularly in cases of isolated cardiac involvement and it can present with a broad spectrum of clinical syndromes. Furthermore, the appropriate management of these patients remains controversial. FDG-PET has a potential role not only in diagnosis of CS but also in directing further therapies, facilitating the decision to start immunosuppression and monitoring the response to it. In this article, we discuss when to consider FDG-PET, outline the current optimal patient preparation and scanning protocols and then, using case examples, discuss the use of FDG-PET in follow-up of patients with known or suspected CS. We also outline how PET can influence management decisions in these patients.