Late Gadolinium Enhancement Entropy as a Novel Imaging Biomarker of Myocardial Tissue Heterogeneity—A Comprehensive Review

Late gadolinium enhancement (LGE) cardiac magnetic resonance is the reference standard for non-invasive myocardial tissue characterization. Conventional LGE analysis focuses on the presence and extent of fibrosis, yet these measures incompletely describe the spatial complexity of myocardial scar that underpins arrhythmogenesis. Entropy, derived from radiomic analysis of LGE signal-intensity distributions, has emerged as a surrogate marker of myocardial tissue heterogeneity. Mechanistically, heterogeneous fibrosis promotes electrical conduction alterations, and entropy serves as a global descriptor of this complex substrate. A growing body of evidence suggests that higher LGE entropy is associated with increased arrhythmogenicity and major adverse cardiac events. Several studies have shown that this association remains significant after adjustment for conventional clinical and imaging predictors. A smaller number of studies have gone further, demonstrating that incorporation of LGE entropy improves the discriminatory or reclassification performance of established risk-prediction models. This narrative review critically synthesizes the current evidence on LGE-derived entropy, compares methodological approaches and clinical applications, and discusses its principal limitations. After standardization and prospective validation, entropy-based phenotyping may prove useful for individualized risk stratification beyond conventional LGE metrics and guide clinical decision-making.