Magnetic Resonance Imaging of the Heart in Diagnostics of Various Types of Myocarditis

Aim. To study the radiation semiotics of various clinical and morphological types of myocarditis with magnetic resonance imaging (MRI). Material and methods. Totally, 70 patients included, with suspected by clinical and lab data myocarditis (28 females, 42 males; mean age 37,0±13,1 y.o). All patients underwent endomyocardial biopsy (EMB) and MRI with intravenous contrasting. Sensitivity of MRI method was evaluated with relation to EMB. Exclusion criteria had been the comorbid ischemic heart disease. Results. Among 70 patients with histologically verified myocarditis, only 47 had this diagnosis by MRI data, sensitivity was set as 67%. In acute active and acute borderline myocardities there is high sensitivity of MRI — 86%; in chronic active myocarditis — 74%, in patients with chronic borderline myocarditis — 55%. Three MRI-criteria of myocarditis were found in acute active myocarditis. Acute borderline myocarditis in most cases presented with 2 signs: edema and delayed contrast enhancement. Significant difference of active myocarditis from other clinical and morphological types is dominance of transmural pattern of delayed contrasting. Also, there is interdependence of inflammation activity by EMB and severity of myocardium edema (64,3% vs. 40,5%, p=0,005). The main differentiating factor of chronic myocarditis is collecting kind of the delayed contrasting areas, which spread more than the zone of myocardium edema. Conclusion. Magnetic resonance imaging shows the highest sensitivity in revealing of acute myocarditis, and in cases of chronic myocarditis the sensitivity depends on activity of inflammation. The overlap of the areas of delayed contrasting and myocardial edema make it to differentiate acute and chronic process in myocardium. Dignostics of chronic borderline myocarditis is impossible unless EMB is done.