Cardiovascular magnetic resonance imaging for inflammatory heart diseases
Inflammatory myocardial diseases represent a diverse group of conditions in which abnormal inflammation within the myocardium is the primary driver of cardiac dysfunction. Broad causes of myocarditis include infection by cardiotropic viruses or other infectious agents, to systemic autoimmune disease, or to toxins. Myocarditis due to viral aetiologies is a relatively common cause of acute chest pain syndromes in younger and middle-aged patients and often has a benign prognosis, though this and other forms of myocarditis also cause serious sequelae, including heart failure, arrhythmia and death. Endomyocardial biopsy remains the gold standard tool for tissue diagnosis of myocarditis in living individuals, although new imaging technologies have a crucial and complementary role. This review outlines the current state-of-the-art and future experimental cardiovascular magnetic resonance (CMR) imaging approaches for the detection of inflammation and immune cell activity in the heart. Multiparametric CMR, particularly with novel quantitative T1- and T2-mapping, is a valuable and widely-available tool for the non- invasive assessment of inflammatory heart diseases. Novel CMR molecular contrast agents will enable a more targeted assessment of immune cell activity and may be useful in guiding the development of novel therapeutics for myocarditis.