Diagnostic and Prognostic Value of Cardiac Magnetic Resonance Strain in Suspected Myocarditis With Preserved LV-EF: A Comparison Between Patients With Negative and Positive Late Gadolinium Enhancement Findings

Background: Late gadolinium enhancement (LGE) is absent in many patients with suspected myocarditis and preserved left ventricular ejection fraction (LV-EF), which poses difficulties in diagnosis and risk stratification. Purpose: To investigate the diagnostic and prognostic value of ventricular myocardial strain in patients with suspected myocarditis, preserved LV-EF, and negative Lake Louis Criteria (LLC) by comparing the findings in LGE negative and LGE positive patients. Study Type: Retrospective. Population: A total of 108 patients with clinically suspected myocarditis who did not satisfy LLC were divided into LGE negative (N = 65) and LGE positive (N = 43) groups. A control group consisted of 50 healthy volunteers. Field Strength/Sequence: Steady-state free precession cine and phase-sensitive inversion recovery segmented gradient echo LGE sequences at 3.0 T. Assessment: Myocardial strain of the ventricles was evaluated by feature tracking, major adverse cardiovascular events (MACE) were assessed during follow-up since the date of magnetic resonance examination. Statistical Tests: Independent-samples t test, Mann–Whitney U test, receiver operating characteristic curve analysis, and Cox proportional hazard regression were performed. A P-value <0.05 was considered statistically significant. Results: Cardiac function and myocardial deformability were impaired in all patients relative to controls. Left ventricular-global radial (LV-GRS), circumferential (LV-GCS), and longitudinal (LV-GLS) strain had diagnostic value, even in LGE negative patients (sensitivity = 0.446, 0.523, and 0.662; specificity = 0.92, 0.80, and 0.64; AUC = 0.685, 0.675, and 0.648, respectively). After a median follow-up of 530.5 (interquartile range: 168.5–969.25) days, MACE occurred in 18 (16.67%) patients. Right ventricular GLS showed prognostic value in all patients and in LGE negative patients, both in univariable analysis (hazard ratio [HR] 1.049, 95% confidence interval [CI] 1.001–1.099 and HR 1.068, 95% CI 1.011–1.127, respectively) and in multivariable Cox survival analysis. LV-GLS was associated with MACE in LGE positive patients in multivariable Cox survival analysis. Data Conclusion: Myocardial strain provides diagnostic and prognostic value in suspected myocarditis with preserved LV-EF, even in the absence of LGE. Level of Evidence: 3. Technical Efficacy: 2.