Detection of acute myocarditis using T1 and T2 mapping cardiovascular magnetic resonance: A systematic review and meta‐analysis

OBJECTIVES: This study was aimed to systematically review the existing literature and explore more the diagnostic value of T1 and T2 mapping in acute myocarditis. METHODS: Studies were searched from five electronic databases. Sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic curves (SROC) were calculated to present diagnostic performance. A meta‐regression and subgroup analysis was performed based on validation (endomyocardial biopsy [EMB] vs. clinical criteria). RESULTS: A total of 10 studies were included, with 400 myocarditis patients and 266 controls. Native T1, T2, and extracellular volume (ECV) values were significantly increased in the myocarditis group. Pooled sensitivities for T1, T2 mapping, and ECV were 0.84 (0.78–0.88), 0.77 (0.69–0.83), and 0.69 (0.50–0.83), respectively. Pooled specificities were 0.86 (0.69–0.95), 0.83 (0.73–0.89), and 0.77 (0.63–0.87), respectively. The DORs were 32 (12–87), 16 (8–30), and 7 (4–14), respectively. The areas under the curve (AUC) of SROC were 0.87 (0.84–0.90), 0.86 (0.82–0.89), and 0.80 (0.76–0.83), respectively. In the meta‐regression and subgroup analysis, significantly lower specificities of T1 and T2 mapping were observed in EMB studies (p < 0.01). CONCLUSION: The currently available evidence shows that T1 and T2 mapping including ECV alone offer comparably good diagnostic performance for the detection of acute myocarditis. The reason for the observed mismatch with EMB findings should be further investigated.