Altered myocardial texture associated with inflammatory infiltration or fibrosis of the myocardium has already been described using qualitative and subjective analysis of two-dimensional echocardiograms. The aim of this work is to test whether quantitative analysis of regional image texture in two-dimensional echocardiograms would be an accurate method to identify myocarditis and myocardial fibrosis. A set of 20 two-dimensional studies with endomyocardial biopsy evaluation was examined in 13 patients. Biopsy-proven myocarditis was present in 8 studies; myocarditis and fibrosis in 4; fibrosis in 3; healing/healed myocarditis in 5. A control group of 8 normal subjects was also studied by echocardiography. After quantitative texture analysis of the first order, entropy appeared to consistently differentiate myocarditis from controls. Among second-order parameters, patients affected by myocarditis or fibrosis showed a decreased entropy and higher angular second moment versus controls. We conclude that myocarditis and fibrosis induce similar image texture alterations in ultrasonic images, with increased spatial heterogeneity of the gray level distribution, which can be differentiated from normal structures with digital image analysis techniques. Indexing Words: Ultrasound -Cardiomyopathy * Texture analysis Altered myocardial texture was described by qualitative analysis of two-dimensional echocardiograms in several myocardial diseases, generally associated with infiltration or fibrosis of the myocardium.
Also in myocarditis-which is a disease process that can alter the myocardial structure by provoking inflammatory infiltrates, edema, fibrosis, necrosis, and degeneration of m y ~c i t e s ~-~hyperrefractile areas were subjectively observed within the left ventricular myocardium (septum or papillar muscles or both). However, due to From the 'CNR Institute of Clinical Physiology, Pisa, 'Divisione di Cardiologia, Ospedale Maggiore, Trieste, 31stituto di Anatomia Patologica, University of Trieste, 4Centro "E. Piaggio", Faculty of Engineering, University of Pisa, and 51sti-