The value of cardiovascular magnetic resonance in myocarditis with different clinical presentation

Objective: to assess the diagnostic meaning of cardiac magnetic resonance imaging (CMR) in various clinical forms of myocarditis. Materials and methods. 11 (8 men, mean age 32.8 +/- 11.1 years) patients (pts), hospitalized with suspected acute coronary syndrome, while an acute myocardial infarction was excluded during the examination (group I); 48 pts (31 men, 43.1 +/- 12.7 years), with clinical and instrumental signs of dilated cardiomyopathy (DCM) - group II; and 20 patients (12 men, 39.5 +/- 14 years), with episodes of ventricular tachycardia (group III) underwent cardiac magnetic resonance imaging (CMRI). In 38 patients endomyocardial biopsy (EMB) was performed. Results and discussion. According to EMB, signs of active myocarditis were revealed in 10 (34.5%) group II pts and in 3 (37.5%) group III pts; signs of resolved myocarditis - in 8 (27.6%) patients in group II and in 3 (37.5%); minimal morphological changes - in 11 (37.9%) patients of group II and in 2 (25%) patients of group III. In 9 (81.9%) patients of group I MRI data allowed to establish the diagnosis of acute myocarditis. Signs of active inflammation from MRI data were detected in myocardium 5 (10.4%) in group II pts and 7 (35%) in group III pts. In 22 (45.8%) pts in group II and 10 (50%), CMR data corresponded to the picture of resolved myocarditis. In 21 (43.8%) cases of group II and 3 (15%) of group III, MRI revealed minimal structural changes. In pts with clinical and instrumental signs of DCM and/or ventricular tachycardia MRI allows to identify signs of "active myocarditis" with a sensitivity of 37.5% with a specificity of 83.4%. At the same time, in cases of resolved myocarditis and minimal morphological changes MRI has high sensitivity (70 and 71.5%) and specificity (71.5 and 75%, respectively). Conclusion. CMR has high diagnostic significance in patients with infarct-like course of myocarditis. In patients with clinical syndrome of dilated cardiomyopathy or arrhythmias, the sensitivity of MRI in detecting active myocarditis is low (37.5%) with high specificity (83.4%). In cases of minimal structural changes in the myocardium and resolved inflammation, CMR is a good alternative to EMB.