Visualization And Quantification Of Myocardium At Risk Using Three-Dimensional Contrast Echocardiography

Objective: To determine whether three-dimensional myocardial contrast echocardiography (3D MCE) could provide an accurate in vivo assessment of risk volumes, and to investigate ischemic preconditioning (IP) using 3D MCE. In addition to describe and quantify the difference of time intensity curves in myocardium and left ventricular cavity using MCE. Methods: Anesthetized open-chest dogs were classified into two groups: Ischemia-reperfusion group (IR) subjected to 4 hours left coronary artery occlusion 1 hour reperfusion followed by ischemic preconditioning group (IP) given 1 0mm ischemic and 1 0mm reperfusion for 3 times before 4 hours occlusion and 1 hour reperfi.ision. To display the non-perfused and perfused myocardium, a sonicated 5% human albumin was injected into the left atria before and after ligation of coronary artery in the 9 open-chest dogs. The scanning plane of the LV was obtained by the rotational scanning technique in 2-degree angular increments for three-dimensional reconstruction. The left ventricular was calculated using a Tomtec three-dimensional reconstruction computer. With the LV viewed in equidistant short-axis slices, the whole LV and the region of non-perfused LV were demarcated, and the risk myocardial mass was derived from this. With triphenyltetrazolium chloride (fTC) staining, anatomic infarct regions were delineated and dissected. Left heart images were recorded before and after injection of contrast. Using the PhotoShop software to quantity the gray-scale mean pixel intensity of LV and left cavity in different tim point Results: (1) Myocardial opacification was visible in all studies and retained in all three-dimensional datasets. (2)The anatomic infarct mass was (12.89±3.17) g; the niyocardial mass at risk estimated by 3D MCE was (14.33±3.67) g. The correlation between risk mass (x) and infarct mass (y) was y=0.97x-0.06, r=0.88 (p<0.01). A close linear relation was noted between the mass of myocardium of the whole LV mass estimated by 3D MCE and postmortem LV mass (49.04±1.72g Vs 47.18±1.75g. y 0.82x±7.62, r=0.90, p<0.01). (3) Both MCE and FX. show that the mass of infarct myocardium of IP group is less than the IR group, (12.06±2.62)g Vs (14.38 .01)g, p<0.Ol. (4) In repercussion stage, the mass of necrotic myocardium had no change in IP group (10.6±2.13) g Vs (9.7±1.72) g, p>0.05 while increased in IR group, (17.06±1 .87)g Vs (15.97±1.21)g, p