Non-invasive Evaluation of Myocardial Fibrosis Using T1 and T2 Mapping by Cardiac Magnetic Resonance Imaging

Myocardial fibrosis is a common pathological substrate across a broad spectrum of cardiovascular diseases and represents a key determinant of adverse clinical outcomes, including heart failure progression, arrhythmias, and sudden cardiac death. It may present as focal replacement fibrosis, typically following myocardial infarction, or as diffuse interstitial fibrosis, more frequently observed in non-ischemic cardiomyopathies and pressure-overload conditions. At the cellular level, fibrosis is driven by fibroblast activation and differentiation into myofibroblasts, mediated by profibrotic signaling pathways and sustained extracellular matrix deposition. Inflammation and myocardial edema also play a critical role in initiating and amplifying fibrotic remodeling, linking acute injury to chronic structural changes. Cardiac magnetic resonance imaging has emerged as a reference non-invasive modality for myocardial tissue characterization. Parametric mapping techniques, including T1, T2, and extracellular volume fraction mapping, provide a quantitative and highly reproducible assessment of myocardial composition. Native T1 mapping and extracellular volume fraction allow sensitive detection and quantification of diffuse myocardial fibrosis and have demonstrated significant prognostic value across several cardiovascular conditions, while T2 mapping is particularly sensitive to myocardial edema and active inflammation, enabling differentiation between acute and chronic myocardial injury. When integrated, these techniques enable a comprehensive evaluation of the inflammation-fibrosis continuum. Clinically, T1 and T2 mapping have demonstrated substantial value across ischemic and non-ischemic heart diseases, valvular disorders, and infiltrative cardiomyopathies. These techniques contribute to improved risk stratification, prediction of adverse ventricular remodeling, guidance of therapeutic decision-making, and monitoring of treatment response. Compared with late gadolinium enhancement imaging, echocardiographic strain analysis, and circulating biomarkers, parametric mapping offers greater tissue specificity and quantitative characterization of myocardial remodeling, although its implementation requires specialized equipment and technical expertise.