Utilization of cardiac imaging in sarcoidosis

Cardiac sarcoidosis (CS) is the cardiac, and occasionally the only manifestation, of a systemic disease of unknown etiology inherently challenging to definitively diagnose due to the lack of a reliable gold standard, the current being endomyocardial biopsy, the yield of which is low owing to the patchy nature of involvement. Societal guidelines employ specific criteria to make a probabilistic diagnosis, integrating clinical assessment with conventional and advanced cardiac imaging.

This review begins with an introduction to CS, followed by a discussion of diagnostic guidelines commonly used, then delves into an in-depth review of the imaging modalities currently available to assess for CS. Particular attention is made to discussing findings, strengths, limitations, and future directions for each modality.

The burden of CS may be significantly larger than previously thought. With the low yield of endomyocardial biopsy, advanced cardiac imaging is increasingly employed to determine CS likelihood. Cardiac magnetic resonance is adept at detecting myocardial scar and able to differentiate between CS and other cardiomyopathies. F-18 Fluorodeoxyglucose positron emission tomography is superior at detecting active disease (myocardial inflammation) which may be amenable to immunosuppressive treatment, as well as detecting extracardiac involvement and identifying potential biopsy sites.