Cardiac magnetic resonance imaging assessment of myocardial disease in children and adolescents.

Cardiac magnetic resonance (CMR) imaging has become a crucial diagnostic and prognostic tool for assessing myocardial health, especially in pediatric patients with congenital heart disease. This review focuses on the role of CMR in myocardial tissue characterization, particularly its ability to detect and quantify fibrosis using techniques such as late gadolinium enhancement (LGE), T1 and T2 mapping, and extra-cellular volume (ECV) measurements. CMR offers superior anatomical and functional information, complementing traditional imaging modalities by enabling detailed visualization of native myocardial edema, interstitial fibrosis, and other tissue changes. These advanced imaging techniques are particularly useful in diagnosing conditions such as myocarditis, cardiac allograft rejection, Kawasaki disease (KD), and other cardiomyopathic processes. In pediatric myocarditis, CMR has demonstrated strong diagnostic utility, with T1 and ECV values helping to differentiate between healthy controls and patients with acute myocarditis, while also predicting disease severity and outcomes. In the context of cardiac transplant, T1 mapping, shows promise in detecting early signs of rejection, providing a less invasive alternative to endomyocardial biopsy. Additionally, CMR has been employed to monitor myocardial damage in KD, where it detects increased ECV in both coronary-affected and remote myocardial areas. The review also discusses CMR's application in tracking myocardial fibrosis in pediatric cardiomyopathies, highlighting its potential as a prognostic marker for heart failure progression. Despite its advantages, challenges remain in standardizing imaging protocols across disease states and establishing comprehensive guidelines for routine use. The future of CMR in pediatric cardiology lies in its ability to improve early diagnosis, guide personalized treatment, and enhance long-term monitoring of heart conditions, ultimately improving patient outcomes.