PET MRI Study in Patients With Cardiac Sarcoidosis

Myocarditis or inflammatory cardiomyopathy refers to inflammation of the myocardium. Sarcoidosis is a multisystem granulomatous disorder of unknown etiology, which can result in myocardial inflammation. Approximately 5% of patients with sarcoidosis have clinically apparent cardiac involvement, yet autopsy series indicate that cardiac involvement is present in up to 25% of cases. This discrepancy suggests that cardiac sarcoidosis may be under-diagnosed in clinical practice. Recent studies have demonstrated high diagnostic accuracy of both cardiac MRI and 18F-labelled fluoro-2-deoxyglucose (FDG) PET for detection of cardiac involvement. However, cardiac MRI may fail to identify areas of active inflammation even with fluid sensitive T2-weighted sequences.

Fasting 18F-FDG positron emission tomography (PET) has been shown to identify early cardiac sarcoidosis with relatively high sensitivity. To date, simultaneous PET/MRI evaluation of cardiac inflammation and sarcoidosis has only been described in limited case reports. The objective of the proposed research is to evaluate the utility of simultaneous PET/MRI imaging in patients with cardiac sarcoidosis and other inflammatory cardiomyopathies.

Inclusion criteria

• The primary criterion for enrolment will be patients ≥18 years of age with known or suspected sarcoidosis or other inflammatory cardiomyopathy who are referred for clinically indicated 18F-FDG PET/CT imaging

Exclusion criteria

• Standard cardiac MRI contraindications include arrhythmia, claustrophobia, history of allergic reaction or other contraindication to gadolinium-based contrast agent, impaired renal function with eGFR < 60 ml/min/1.73m2, pregnancy, breast-feeding, or any other general contraindication to MRI (pacemaker, cerebral aneurysm clips, shrapnel, etc).