ABSTRACT
Objective: To establish porcine chronic ischemic myocardium model and to evaluate ultrasonic integrated backscatter(IBS) and Doppler tissue imaging(DTI) in detecting this model. Methods: An Ameroid constrictor was placed around the porcine proximal left circumflex artery. The calibrated average image intensity (%AⅡ), cyclic variation of IBS (CVIB), the subendo-epicardical gradient index (TGI) and the spectrum of left ventricular papillary muscle level short axis view (LVPM-SAM) and apical four chamber view (AP-4CV) were measured at normal state, 2 w, 4 w, 6 w and 8 w after Ameroid placement. Results: Normal %AⅡ, CVIB and TGI were 2.29?0.32,(9.69?2.22)dB and 0.22? 0.08 respectively. After Ameroid placement, the %AII increased gradually, the CVIB decreased gradually, and the decrease was higher in subepicardium than that in subendocardium. The most obvious decrease of TGI occurred from 2 w to 4 w after Ameroid placement and became zero at 8 w(P