18F-FSPG PET/MRI or PET/CT Imaging of Cardiac Sarcoidosis or Inflammation

Inclusion Criteria: * Patient is ≥ 18 years old at the time of the scan * Patient with known or suspected cardiac sarcoidosis. * Patient is capable of complying with study procedures * Patient can remain still for duration of imaging procedure Exclusion Criteria: * Patient is pregnant or nursing * Metallic implants (contraindicated for MRI) * History of renal insufficiency (only for MRI contrast administration)