Relation between myocardial edema and myocardial mass during the acute and convalescent phase of myocarditis – a CMR study

21 patients with acute myocarditis underwent CMR shortly after onset of symptoms and 1 year later. For visualization of edema, a T2-weighted breath-hold black-blood triple-inversion fast spin echo technique was applied and the ratio of signal intensity of myocardium/skeletal muscle was assessed. Left ventricular (LV) mass, volumes and function were quantified from biplane cine steady state free precession images.11 healthy volunteers served as a control group for interstudy reproducibility of LV mass.In patients with myocarditis, a significant decrease in LV mass was observed during follow-up compared to the acute phase (156.7 ± 30.6 g vs. 140.3 ± 28.3 g, p < 0.0001). The reduction of LV mass paralleled the normalization of initially increased myocardial signal intensity on T2-weighted images (2.4 ± 0.4 vs. 1.68 ± 0.3, p < 0.0001).In controls, the interstudy difference of LV mass was lower than in patients (5.1 ± 2.9 g vs. 16.3 ± 14.2 g, p = 0.02) resulting in a lower coefficient of variability (2.1 vs 8.9%, p = 0.04).Reversible abnormalities in T2-weighted CMR are paralleled by a transient increase in left ventricular mass during the course of myocarditis. Myocardial edema may be a common pathway explaining these findings.An array of reports demonstrated the linear correlation between myocardial water content and T2-weighted cardiovascular magnetic resonance (CMR) relaxation [1-7], justifying its use as an in-vivo marker of myocardial edema. Myocardial edema is a substantial feature of the inflammatory response in acute myocarditis[8,9]. Edema is associated with diastolic dysfunction[10], conduction disturbances[11], microvascular compression[12] and tissue swelling[9]. The relation between myocardial edema and myocardial mass over the course of myocarditis has only rarely been systematically investigated in a clinical setting [13,14]. This reflected the lack of a non-invasive imaging modality allowing the in vivo, accurate and simultaneous measurement of both para