1Universitätsklinikum Tübingen Innere Medizin III, Kardiologie und Angiologie Tübingen, Deutschland; 2Universitätsklinikum Tübingen Diagnostische und Interventionelle Radiologie Tübingen, Deutschland; 3Universitätsklinikum Tübingen Kardiopathologie Tübingen, Deutschland
Background: The detection of ongoing inflammation in myocarditis patients has prognostic relevance and may have significant impact on the further patient treatment and monitoring regimen. To date, there are scarce cardiac magnetic resonance (CMR) data on the detection of chronic lymphocytic myocarditis and its separation from healed myocarditis in a biopsy-proven setting.
Objectives: To assess the performance of a comprehensive CMR protocol for 1) the detection of ongoing inflammation and 2) the discrimination of chronic lymphocytic myocarditis from healed myocarditis.
Methods: Consecutive patients with persistent symptoms (>30 days) suggestive of myocarditis were prospectively enrolled from a single tertiary center. All patients underwent a multiparametric 1.5-T CMR protocol including cine, biventricular strain, T1/T2 mapping, and late gadolinium enhancement (LGE). Endomyocardial biopsy was chosen for reference standard diagnosis.
Results: Of 452 consecutive patients, 103 patients (median age 50 years; 66 men) had evaluable CMR data and a cardiopathological reference standard diagnosis of either chronic lymphocytic myocarditis or healed myocarditis. Specifically, 53 patients (51%) demonstrated chronic lymphocytic myocarditis, and 50 patients (49%) demonstrated healed myocarditis on endomyocardial biopsy. T2 mapping as a single CMR parameter 1)showed the best accuracy in detecting chronic myocarditis if abnormal increased in ≥3 myocardial segments (92%; 95% confidence interval [CI]: 85-97) and 2) provided the best discrimination from healed myocarditis as defined by the area under the ROC curve (AUC: 0.87; 95% CI: 0.79-0.93; P< 0.001), followed by radial peak systolic strain rate of the left ventricle (0.86) and the right ventricle (0.84); T1 mapping (0.64), ECV (extracellular volume fraction, 0.62), and LGE (0.57).
Conclusions: A multiparametric CMR protocol allows reliable 1) detection of ongoing myocardial inflammation and 2) discrimination of chronic lymphocytic myocarditis from healed myocarditis, with segmental T2 mapping and biventricular strain analysis showing superior diagnostic accuracy compared to other CMR parameters such as T1 mapping, ECV and LGE.