Cardiac magnetic resonance feature tracking myocardial strain analysis in suspected acute myocarditis: diagnostic value and association with severity of myocardial injury

Background Albeit that cardiac magnetic resonance feature tracking (CMR-FT) has enabled quantitative assessment of global myocardial strain in the diagnosis of suspected acute myocarditis, the cardiac segmental dysfunction remains understudied. The aim of the present study was using CMR-FT to assess the global and segmental dysfunction of the myocardium for diagnosis of suspected acute myocarditis. Methods Forty-seven patients with suspected acute myocarditis (divided into impaired and preserved left ventricular ejection fraction [LVEF] groups) and 39 healthy controls (HCs) were studied. A total of 752 segments were divided into three subgroups, including segments with non-involvement (S Ni ), segments with edema (S E ), and segments with both edema and late gadolinium enhancement (S E+LGE ). 272 healthy segments served as the control group (S HCs ). Results Compared with HCs, patients with preserved LVEF showed impaired global circumferential strain (GCS) and global longitudinal strain (GLS). Segmental strain analysis showed that the peak radial strain (PRS), peak circumferential strain (PCS), and peak longitudinal strain (PLS) values significantly reduced in S E+LGE compared with S HCs , S Ni , S E . PCS significantly reduced in S Ni (-15.3 ± 5.8% vs. -20.3 ± 6.4%, p < 0.001) and S E (-15.2 ± 5.6% vs. -20.3 ± 6.4%, p < 0.001), compared with S HCs . The area under the curve (AUC) values of GLS (0.723) and GCS (0.710) were higher than that of global peak radial strain (0.657) in the diagnosis of acute myocarditis, but the difference was not statistically significant. Adding the Lake Louise Criteria to the model resulted in a further increase in diagnostic performance. Conclusions Global and segmental myocardial strain were impaired in patients with suspected acute myocarditis, even in the edema or relatively non-involved regions. CMR-FT may serve as an incremental tool for assessment of cardiac dysfunction and provide important additional imaging-evidence for distinguishing the different severity of myocardial injury in myocarditis.