Multi-parametric Cardiac MRI in Myocarditis: A Meta-Analytical Evaluation

Background: Myocarditis is an inflammatory disease of the myocardium with diverse clinical manifestations ranging from subclinical disease to acute heart failure and sudden cardiac death. Accurate diagnosis remains challenging due to nonspecific symptoms, variable biomarker profiles, and limited sensitivity of conventional tests. Multi-parametric cardiac magnetic resonance imaging (CMR), incorporating T1 and T2 mapping, late gadolinium enhancement (LGE), and extracellular volume (ECV) quantification, has emerged as a non-invasive gold standard for tissue characterization in suspected myocarditis. However, variability in image acquisition protocols and interpretation thresholds has limited its standardized clinical application. Methods and Results: This meta-analysis systematically reviewed and quantitatively synthesized data from 37 studies comprising 4,218 patients who underwent multi-parametric CMR for clinically suspected myocarditis. Pooled sensitivity and specificity were calculated for individual and combined CMR parameters using bivariate random-effects models. Native T1 and T2 mapping demonstrated pooled sensitivities of 81% and 75%, respectively, while LGE showed the highest specificity at 88% for identifying myocardial injury. Combinatorial approaches using updated Lake Louise Criteria significantly improved diagnostic accuracy, with area under the curve (AUC) reaching 0.91. Subgroup analyses revealed higher diagnostic yield in acute versus chronic presentations and among studies using standardized 1.5T imaging protocols. Heterogeneity in ECV quantification was noted across platforms, underscoring the need for calibration. Conclusion: Multi-parametric CMR provides robust diagnostic performance in myocarditis and enables comprehensive assessment of myocardial edema, fibrosis, and necrosis. When applied using harmonized protocols, CMR achieves high sensitivity and specificity and should be integrated into diagnostic workflows for myocarditis. This meta-analysis supports broader clinical adoption and standardization of advanced CMR techniques to guide diagnosis, risk stratification, and therapeutic decision-making in inflammatory cardiomyopathy.