Experimental Study To Evaluate The Perfusion Of Normal And Ischemic Myocardium By Intravenous Myocardial Contrast Echocardiography And Relevant Techniques

Objective: First, to study intravenous myocardial contrast echocardiography(MCE) in dogs by Intermittent second harmonic imaging (ISHI) and Intermittent power Doppler harmonic imaging(IPDHI), then to quantificationally analyse the blood perfusion of normal and ischemic myocardium by acoustic densitometry(AD).Methods: The perfluorocarbon-albumin ultrasound contrast agent (UCA) was made with Albumin enwrapping perfluorocarbon gas. The model of acute anterior myocardial ischemia was established by ligating the left anterior descending coronary arteries. MCE was performed in 11 normal dogs and 10 dogs with acute myocardial ischemia by ISHI and IPDHI after bolus injection or Continuous infusion of the self-made UCA, the contrast effects were assessed by AD and visual score(VS).Results: We succeed in making the perfluorocarbon-albumin UCA(mean microbubble size 4.2~7.8μm, concentration 1.6×109 microbubbles/ml,PH6.5). Both normal myocardial VS and AD produced by ISHI were significantly increased (P<0.01), but there were no significant difference in ischemic myocardial VS and AD(P>0.05), and perfusion defect was found in anterior myocardium. MCE with IPDHI showed normal myocardium as yellow, and VS obviously changed compared with before contrast(P<0.01), but the above didn't appear in ischemic myocardium(P>0.05), perfusion defect was found inanterior myocardium, too. The area of perfusion defect detected by ISHI or IPDHI correlated well with that by pathologic staining(r1=0.82, r2=0.86,P<0.01).Conclusion: Our self-made perfluorocarbon UCA is safe and effective in MCE, with which we can easily evaluate normal and ischemic myocardial perfusion in animal experiment. The perfusion defected by ISHI and IPDHI significantly correlate with that by pathologic staining. AD is an excellent half-quantified method to evaluate myocardial perfusion. IPDHI is a good qualitative method in MCE, by which normal and ischemic myocardium appear brightly colorific contrast.