| Part 1 Animal Study: Quantitative Evaluation of Acute Myocardial Infarction Model by Low Power Real-time Myocardial Contrast Echocardiography combined with Adenosine StressObjective To Quantitatively analyze the myocardial perfusion in acute myocardial infarction models by the low power real-time myocardial contrast echocardiography (RTMCE) with contrast pulse sequencing (CPS) and SonoVue?, and evaluate the parameters of the refilling curves and their changes under adenosine stress. Methods In 9 open-chest dogs, the low power real-time MCE was performed in 9 open-chest dogs immediately and 60 minutes after LAD ligation, with SonoVue administrated continuously using CPS imaging system. Adenosine stress was given 60minutes after the ligation. Perfusion of LAD and LCX territories was analyzed to obtain the refilling curves and the values of A(amplitude of enhancement of intensity ), P(rate of intensity rise) and A·β. Results At baseline, A was lower in LAD than LCX (P<0.05 ) , while β and A·β did not exhibit significant difference between the two areas. After LAD ligation, perfusion in LAD territory was reduced. Although both β and A·β decreased markedly in LAD territory immediately (P < 0.01) , β recovered in 60 minutes, with both parameters fluctuating little in LCX. The percent change caused by occlusion also proved significant perfusion defect in LAD territory. During the adenosine stress, β and A·β of LCX territory increased while LAD territory did not have much improvement. Accordingly, the perfusion-improving percentage ishigher in LCX. Conclusions β and A·β derived from quantitative low power RTMCE and adenosine stress can be used to quantitatively assess regional myocardial perfusion. A·β revealed better stability in delayed description of ischemia myocardium. Adenosine can exaggerate the difference between normal and ischemia myocardium because of the poor perfusion reserve of the ischemia.Part 2 Clinical Study: Quantitative Evaluation of Myocardial Perfusion with Low-dose Adenosine Stress Real-time Myocardial Contrast EchocardiographyObjective To test if the quantitative parameters of Low-dose Adenosine Stress Real-time Myocardial Contrast Echocardiography can accurately differentiate among the myocardium of normal perfusion, perfusion defect and successful reperfusion. Methods In 14 unselected patients who were going to have coronary angiography, the real-time MCE was performed under a half dose adenosine stress, with continuously infused Sonovue and CPS imaging system. Images were captured on four chamber and two chamber view before and after the adenosine stress. Segments of satisfied imaging was analyzed to obtain the refilling curves and the values of A(amplitude of enhancement of intensity ), β(rate of intensity rise) and A·β(myocardial blood flow volume). The segments was divided into 3 groups according to the angiography or CT angiography: group 1, without significant stenosis(<60%); group 2, successfully reperfued(TIMI 3 flow); group 3, significant stenosis(>80%); A, β and A·β of baseline and stress, and the improvement of each viable were compared among groups. Results Among a total 49 of segments, 20 were in group 1(41%), 12 were in group2(24%), 17 were in group 3(35%). Perfusion of group 3 did not decrease significantly at baseline, but was lower than group 1 and 2(p<0.05)after adenosine stress A·β; During adenosine stress, perfusion in group 1(A,β,A·β) and 2(A·β) were improved. The improvement of A·β and β were higher in group 1 than group 2 and 3. A·β under adenosine stress <1.74 dB/s for diagnosis of coronary stenosis and perfusion defect has a sensitivity and specificity of 71%; the sensitivity and specificity of A·β adenosine-improving percentage <81% for the diagnosis of low-reserved perfusion are both 79%, β improving percentage <54%, 86% vs 79%.Conclusions Low-dose Adenosine Stress Real-time Myocardial Contrast Echocardiography and provide good accuracy for the diangnosis, prognosisassessment of coronary heart disease. For the diagnosis of coronary stenosis, A·β has more stability, and A during stress and the adenosine-improving percentage of β also can be used.
|
PDF Full Text Request