Cardiac Sarcoidosis: The Challenge of Radiologic-Pathologic Correlation

Cardiac sarcoidosis is a rare but potentially fatal disorder with a nonspecific spectrum of clinical manifestations, including conduction disorders, congestive heart failure, ventricular arrhythmias, and sudden cardiac death. Although early treatment to improve morbidity and mortality is desirable, sensitive and accurate detection of cardiac sarcoidosis remains a challenge. Except for the histopathologic finding of noncaseating granulomas in an endomyocardial biopsy specimen, most diagnostic tests are limited and nonspecific at best. Therefore, the decision to initiate treatment is based largely on the patient's clinical symptoms and the course of the disease, rather than histologic confirmation. Successful recognition of cardiac sarcoidosis ultimately requires rigorous collaboration among a clinician, radiologist, and pathologist. Advanced imaging modalities, such as cardiac magnetic resonance imaging and positron emission tomography with fluorodeoxyglucose, have become increasingly useful in facilitating diagnosis and therapeutic monitoring, although limited prospective studies exist. This article describes the clinical parameters and pathologic findings of cardiac sarcoidosis and the advanced imaging features and differential diagnostic challenges that must be considered for a successful diagnostic approach. In addition, to improve the understanding of abnormalities detected with different imaging modalities, we suggest a unified terminology in describing radiologic findings related to cardiac sarcoidosis. (C) RSNA, 2015 . radiographics.rsna.org