Cardiac Magnetic Resonance Quantitative Tissue Markers in the Clinical Application Value for the Diagnosis of Acute Myocarditis

Objectives: To determine the value of cardiac magnetic resonance (CMR) quantitative tissue markers in the diagnosis of acute myocarditis, compared with the traditional Lake-Louise criteria (LLC). Methods: Totally 35 cases of patients diagnosed as acute myocarditis in Beijing Anzhen Hospital and 35 healthy volunteers were enrolled in our study, from May 2014 to August 2016. CMR protocol included quantitative assessment of T1 relaxation times using modified Look-Locker inversion recovery (MOLLI), extracellular volume fraction (ECV), T2 relaxation times. Established Lake-Louise criteria (LLC) consisting of T2-weighted signal intensity ratio (T2-ratio), early gadolinium enhancement ratio (EGEr), and late gadolinium enhancement (LGE) were assessed. Receiver operating characteristics analysis was performed to compare diagnostic performance. Results: T2-ratio (1.85±0.21 vs. 1.58±0.15; P = 0.002) and EGEr (3.87±1.62 vs. 2.15±1.36; P =0.024) were significantly higher in myocarditis subjects than in control subjects. Non-ischemic LGE was found in 27/35 (77.1%) of all myocarditis patients. Regional myocardial edema was found in 23/35 (65.7%) of all myocarditis patients. Myocardial T1 and T2 relaxation times and ECV were significantly prolonged in the myocarditis group compared with the control group (T1 native relaxation time: 1310±62 vs. 1247±27 ms, T2 native relaxation time: 65.46±8.49 vs. 55.17±3.59 ms; ECV: 34.47±8.52 vs. 27.68±5.82, P < 0.001, respectively). Areas under the curve of native T1 (0.94) and T2 relaxation times (0.91) were higher compared with those of the other CMR parameters (T2-ratio: 0.73, EGEr: 0.72, LGE: 0.88, LLC: 0.90, ECV: 0.79). Combined with LGE, each native mapping technique outperformed the diagnostic performance of LLC (P < 0.01, respectively). A combination of native parameters (T1, T2 relaxation times) significantly increased the diagnostic performance of CMR compared with LLC without need of contrast media application (0.99 vs. 0.90; P < 0.05). Conclusion: CMR quantitative tissue markers has good diagnostic efficiency for acute myocarditis, it may be potential to replace the Lake-Louise criteria in the future in patients with contraindications for the use of gadolinium-based contrast agents.