MYOCARDIAL TISSUE CHARACTERIZATION AFTER ACUTE MYOCARDIAL-INFARCTION WITH WAVELET IMAGE DECOMPOSITION - A NOVEL-APPROACH FOR THE DETECTION OF MYOCARDIAL VIABILITY IN THE EARLY POSTINFARCTION PERIOD

Background-Only a few texture measures can be used for texture charact erization of infarcted myocardium and detection of reperfused myocardi um early after infarction. This study was conducted to establish the r elationship between texture properties of infarcted myocardium and inf arct-related artery patency by quantitative computer analysis of 2-dim ensional echocardiographic images with the wavelet-based method for te xture characterization, evaluate the relationship between texture prop erties and myocardial viability, and correlate histopathologic changes after experimental infarction with the texture measures. Methods and Results-We analyzed 2-dimensional transthoracic echocardiographic imag es in 18 patients at different time points after infarction using the wavelet transform method. Regional wall motion of infarcted segments w as analyzed on a follow-up echocardiographic study obtained 6 months a fter infarction, To verify the accuracy of the proposed texture measur e and energy difference cutoff value, we prospectively evaluated anoth er group of 19 patients. In addition, histopathologic changes in 9 dog s with experimental infarction were correlated with the texture measur es. Sensitivity, specificity, and accuracy of the wavelet method for d etection of reperfusion in the study group were 73%, 86%, and 78%, res pectively, on day 2; 91%, 86%, and 89%, at 1 week; and 100%, 100%, and 100% at 3 weeks. Among 9 patients with improvement in regional wall m otion on a follow-up study, 7 on day 2, 8 at 1 week, and 9 at 3 weeks were classified into the reperfused group by the wavelet method. Histo pathologic features associated with the classification of reperfusion by the wavelet method were infarct transmurality (P=0.024) and degree of necrosis (P=0.028). Conclusions-Our clinical and experimental data suggest that the wavelet method can be used to differentiate between v iable myocardium with recovery potential and definite myocardial necro sis in the early postinfarction period.