The Role of Cardiac MRI in the Diagnosis of Myocarditis: Diagnostic Value of Mapping Techniques and Prognostic Implications

M. Kural (Köln)¹, K. Kaya (Köln)², J. Janßen (Köln)³, J. Kottlors (Köln)⁴, R. J. Gertz (Köln)⁴, D. Maintz (Köln)⁵, S. Baldus (Köln)⁶, H. ten Freyhaus (Köln)⁷, L. Pennig (Köln)², K. Seuthe (Köln)^7
1Universitätsklinikum Köln Klinik III für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin Köln, Deutschland; ²Uniklinik Köln Institut für diagnostische und interventionelle Radiologie Köln, Deutschland; ³Universitätsklinikum Köln Institut und Poliklinik für Radiologische Diagnostik Köln, Deutschland; ⁴University of Cologne Institute for Diagnostic and Interventional Radiology Köln, Deutschland; ⁵Institut für Diagnostische und Interventionelle Radiologie/ Köln, Deutschland; ⁶Herzzentrum der Universität zu Köln Klinik für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin Köln, Deutschland; ⁷Herzzentrum der Universität zu Köln Klinik III für Innere Medizin Köln, Deutschland

Introduction: Myocarditis is an inflammatory cardiac disease with variable clinical presentation and potentially severe outcomes. Given the potential for rapid clinical deterioration and long-term sequelae, early risk stratification in myocarditis is essential. Cardiac MRI (CMR) has become crucial in non-invasive myocarditis diagnosis, particularly making use of mapping techniques. This study aimed to evaluate the relationship between CMR parameters including mapping parameters and clinical outcomes to detect their potential for risk stratification. 
Methods: In this retrospective single-centre study, patients with diagnosed myocarditis who were treated at our centre and underwent standardised CMR including native T1, T2 and extracellular volume (ECV) mapping, late gadolinium enhancement (LGE) and left ventricular ejection fraction (LVEF) assessment were included. Clinical (including clinical presentation, ECG, complications), laboratory and imaging data were analysed and Spearman's correlation analyses were performed.
Results: 69 patients (mean age 31.7 ± 13 years, 20.3% female) were enrolled. Native T1, T2 and ECV mapping values showed significant correlations with several clinical and laboratory parameters. Lower LVEF correlated with higher T1 and T2 values and LGE quantification (r=-0.28 to r=-0.39). Higher NT-proBNP levels correlated with higher T1, T2 and ECV mapping values (r up to 0.6). Cardiogenic shock showed significant positive correlation with all mapping modalities (r up to 0.4), but not with LGE quantification. Mapping parameters also correlated positively with the overall hospital stay. 
Conclusions: CMR mapping parameters are linked to clinical course in patients with myocarditis, with higher mapping values associated with higher NT-proBNP, lower LVEF and more frequent cardiogenic shock. These findings support the potential value of T1, T2 and ECV mapping for risk stratification beyond conventional CMR. Mapping parameters may thus serve as non-invasive markers for early risk assessment and treatment planning in myocarditis.