When to consider cardiac MRI in the evaluation of the competitive athlete after SARS-CoV-2 infection

CMR is a powerful diagnostic tool for the evaluation of myocarditis when clinically indicated. CMR is the only non-invasive imaging modality that can accurately measure myocardial function and provide tissue characterisation capable of detecting manifestations of myocarditis including necrosis/fibrosis/scar (using late gadolinium enhancement) and oedema/hyperaemia/capillary leak (using parametric mapping-derived T1 and T2 relaxation times).7 The European Society of Cardiology and the American Heart Association recommend a diagnostic algorithm for myocarditis predicated on both a clinical presentation suggestive of disease and concomitant abnormal diagnostic testing including data derived from CMR.8 9 Symptoms suggestive of myocarditis include acute/new-onset chest pain, dyspnoea, palpitations and syncope. Diagnostic criteria include ECG or rhythm abnormalities, elevated troponin, structural or functional abnormalities on cardiac imaging and abnormal tissue characterisation on CMR. Clinically suspected myocarditis is defined by the presence of ≥1 clinical symptom and ≥1 diagnostic criterion, or, in the absence of symptoms, ≥2 diagnostic criteria.8 Importantly, CMR-derived tissue characterisation abnormalities, in the absence of symptoms or other diagnostic abnormalities, do not fulfil the contemporary definition of clinical myocarditis.