论文部分内容阅读
Objective: To construct an animal model of chronic ischemic myocardium, and evaluate it by ultrasonic integrated backscatter (IBS) and Doppler tissue imaging (DTI). Methods: An Ameroid constrictor was placed around the porcine left circumflex coronary artery (LCX). The calibrated average image intensity ( % AII), cyclic variation of IBS(CVIB), transmural gradient index (TGI) of CVIB in lateral- posterior wall (LPW), and DTI spectrum of LPW in left ventricular papillary muscle level short axis view (LVPM-SAM) and apical four chamber view (AP-4CV) at normal state, 2, 4,6 and 8 weeks postoperatively were measured. Results: Normal %AII, CVIB and TGI were 2.29 ± 0.32, 9.69 ± 2.22dB and 0.22 ± 0.08, respectively. The % AII increased gradually postoperatively. The CVIB decreased also gradually, and the decrease was higher in subepicardium than in subendocardium. Most of TGI decrease occurred from 2 to 4 weeks postoperatively and became zero at 8 weeks (P ＜ O. 01 ); Normal Vs (peak systolic velocity) of AP-4CV was higher than that of LVPM-SAM ( P ＜ 0.01 ). VE (peak early diastolic velocity) of AP-4CV was lower than that of LVPM-SAM ( P ＜ 0.05). Vs and VE were all decreased after operation ( P ＜ 0.01 ). The decrease of Vs in AP-4CV was greater than that in LVPM-SAM.Conclusion: The pathological changes of the myocardium in human ischemic heart disease (IHD) are similar to that of Ameriod model. IBS and DTI can detect echo changes and ventricular wall motion in chronic ischemic myocardium, and provide more information for clinical investigation and treatment of IHD.