Assessment Characteristics of Acute Myocarditis by 3-Tesla Cardiac Magnetic Resonance Imaging

Abstract

Introduction: Acute myocarditis (AM) is a nonspecific clinical condition. Clinical and paraclinical diagnosis of AM includes many different criteria, of which cardiac magnetic resonance imaging (CMR) is a useful tool to diagnose AM.
Purpose: Systematically evaluate non-invasive CMR parameters in AM.
Methods: 45 patients with clinically suspected AM underwent CMR. Patient onset of symptoms ranges from 1 day to 6 weeks. CMR includes pulse sequences assessing morphology, function, late gadolinium enhancement (LGE) images, and mapping parameters (T2 mapping, native T1 mapping, and ECV).
Results: 45 patients with clinically suspected AM (mean age 31.4±11.4 (14-68); 26.7% female). Time to symptoms onset was 6.5±5.9 (1-18) days. Average T1 mapping time: 1305.0 ±127.2ms; T2 mapping: 54.07± 10.95ms, ECV: 41.18 ±18.40%, LGE: 75.55%. Sensitivity of pulse sequences: T1 mapping: 97.8%, T2 mapping: 97.8%, ECV: 95.6%, LGE: 75.55%, Lake Louise: 76.5%. LGE lesions are mainly linear (52.9%) and located in the subepicardial (76.4%) of the inferior lateral wall of the cardiac base (44.4%). There is a moderate positive correlation between T1 mapping and hs-Troponin T (k=0.452, p=0.006) and between T2 mapping and NT-proBNP (k=0.546, p=0.02). High agreement in assessing regional motion on ultrasound and CMR (k=0.789)
Conclusion: CMR is a comprehensive method that allows reliable diagnosis of suspected AM clinical. Among them, LGE alone or combined with T1 map, T2 map, and ECV are the most useful pulse sequences to diagnose myocarditis.