Clinical value of echocardiographic tissue characterization in the diagnosis of myocarditis

Inflammatory changes in the myocardium have been visually observed as alterations on echocardiograms. The goal of this study was to determine how these myocardial changes affect the texture of echocardiographic images, and how these could be described through quantitative texture analysis. The results of 142 endomyocardial biopsies were compared with those of texture analysis in echocardiograms of 106 patients suspected of having myocarditis. There were 52 cases of biopsy-proven acute myocarditis, 12 of persistent myocarditis, nine of healed myocarditis without fibrosis, 17 of healed myocarditis with fibrosis, and 35 cases of cardiomyopathy. Eight myocardial biopsies exhibited no pathological changes and nine patients had other cardiac problems. The echocardiograms of a control group of 24 healthy subjects were also evaluated by texture analysis. Three texture parameters were able to differentiate between normal and abnormal myocardium. The mean grey value, i.e. average brightness, was appreciably higher in cases of myocarditis than in control subjects, whereas one co-occurrence and one run length feature had markedly decreased. We conclude that myocarditis and fibrosis induce changes in echocardiographic image texture, i.e. increases in brightness, heterogeneity, and contrast. Performing digital image texture analysis of echocardiograms makes it possible to distinguish between myocarditis and normal myocardium.