Diagnosis of Cardiac Sarcoidosis Clinical suspicion ECG, echocardiography, and sometimes cardiac MRI with late gadolinium enhancement and / or fluorodeoxyglucose (FDG) - positron emission tomography (PET) scan Biopsy of noncardiac tissue that appears affected by systemic sarcoidosis Rarely cardiac biopsy About half of the patients with clinical manifestations suggestive of cardiac sarcoidosis are already known to have systemic sarcoidosis.