Positron emission tomography in clinically suspected myocarditis – STREAM study design

Aim: Myocarditis is an inflammatory disease associated with increased glucose uptake. The hypothesis of this study assumes that 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) may improve specificity and sensitivity in the diagnosis of myocarditis and referral for endomyocardial biopsy (EMB), adding additional information for post-discharge risk stratification. The aim of the study is to assess the diagnostic and prognostic feasibility of FDG-PET/CT in comparison to cardiac magnetic resonance (CMR) (alone or in combination) in patients with clinically suspected myocarditis undergoing EMB. Methods: Fifty hospitalized patients with clinically suspected myocarditis who meet the inclusion/exclusion criteria will be enrolled in a prospective, observational, multicentre, cohort study (NCT04085718). The primary endpoint is the sensitivity and specificity of FDG-PET/CT imaging in the diagnosis of myocarditis. The main secondary endpoints include correlation of FDG-PET/CT imaging with CMR, echocardiography, and EMB results. The patients will undergo the following evaluations: clinical examination, blood tests (including biomarkers of fibrosis and anti-heart autoantibodies (AHA)), ECG, 24 h Holter ECG, echocardiography, CMR, as well as resting single photon emission computed tomography (SPECT) to assess possible myocardial perfusion defects, cardiac FDG-PET/CT and right ventricular EMB. After 6-months a follow-up visit will be performed (including 24 h Holter ECG, echocardiography and CMR). Investigators evaluating individual studies (CMR, SPECT, FDG-PET/CT and EMB) are to be blinded to the other tests' results. Conclusion: We believe that FDG-PET/CT alone or in combination with CMR may be a useful tool for improving diagnostic accuracy in patients with clinically suspected myocarditis.