Cardiac magnetic resonance visualizes acute and chronic myocardial injuries in myocarditis

Abstract

Our objective was to evaluate the ability of CMR to visualize myocardial injuries over the course of myocarditis. We studied 42 patients (39 males, 3 females; age 37 ± 14 years) with myocarditis during the acute phase and after 12 ± 9 months. CMR included function analyses, T2-weighted imaging (T2 ratio), T1-weighted imaging before and after i.v. gadolinium injection (global relative enhancement; gRE), and late gadolinium enhancement (LGE). In the acute phase, the T2 ratio was elevated in 57%, gRE in 31%, and LGE was present in 64% of the patients. In 32 patients (76%) were any two (or more) out of three sequences abnormal. At follow-up, there was an increase in ejection fraction (57.4 ± 11.9% vs. 61.4 ± 7.6; P < 0.05) while both T2 ratio (2.04 ± 0.32 vs. 1.70 ± 0.28; P < 0.001) and gRE (4.07 ± 1.63 vs. 3.11 ± 1.22; P < 0.05) significantly decreased. The LGE persisted in 10 patients. Dilated cardiomyopathy was present in 3 patients and 4 patients received a defibrillator or a pacemaker. A comprehensive CMR approach is a useful tool to visualize myocardial tissue injuries over the course of myocarditis. CMR may help to differentiate acute from healed myocarditis, and add information for the differential diagnoses.

Fig. 1

Patient with myocarditis (a–l). CMR demonstrates T2-weighted (a, b, g, h), gRE (c, d, i, j), and LGE (e, f, k, l) during the acute phase (top) and follow-up (bottom). During the acute phase, lateral intramural signal elevation is seen in all images (white arrows). At follow-up, the T2 changes are not seen, but gRE and LGE lesions persisted (spotty appearance; white arrows/circles)

Fig. 2

Line graphs demonstrate the changes in ejection fraction (EF), gRE, and T2 ratios over the course of myocarditis. The increased EF (P < 0.05) is paralleled by a normalization of gRE (P < 0.05) and T2 ratio (P < 0.001)

Fig. 3

CMR demonstrates a patient with DCM (a–h). EF is 19% and EDV 348 ml (a; end-diastole, b; end-systole). The T2-weighted (c, d) and gRE (e, f) images are normal, but there is lateral epicardial LGE (g, h; white arrows). This patient had later an ICD implanted and no follow-up CMR was done