CONTRAST ECHOCARDIOGRAPHY FOR ASSESSMENT OF MYOCARDIAL PERFUSION

It has been suggested that the myocardial perfusion can be qualitative ly and quantitatively assessed by different ultrasound contrast techni ques. It has been reported that the intracoronary or intraaortic admin istration of the ultrasound contrast agents can be used to visualize p erfusion defects or to analyze the coronary flow reserve. The perfusio n analysis after intracoronary injection of ultrasound contrast agents seems to be established, but there are a lot of open questions. A top ographic (qualitative) perfusion analysis with visualization of perfus ion defects and perfusion areas or analysis of collaterals has been de monstrated. A quantitative analysis of myocardial blood flow has been described but the existing studies are inconsistent. It is not known w hich parameters of the contrast wash-out curves should be used for per fusion analysis and if the Stewart-Hamilton curve analysis can be tran sfered to all ultrasound contrast agents as a model for quantitative m yocardial blood flow assessment. The development of the transpulmonary contrast agents for echocardiographic evaluation of left ventricular cavity has the impact for myocardial perfusion imaging. The increase o f myocardial intensity does not mean that a qualitative or quantitativ e perfusion analysis can be clinically used. In this field we have to differentiate between the possibilities of qualitative discrimination of perfusion defects and quantitative perfusion (myocardial blood now) analysis. The different scanning conditions, the poor transthoracic u ltrasound window and insufficient enhancemant of the myocardial intens ity make it problematic to quantify the myocardial perfusion. At the m oment myocardial intensity will be increased after intravenous injecti on of transpulmonary contrast agents, but the value for perfusion anal ysis has not been shown. New ultrasound technologies such as second ha rmonic imaging, power-mode and raw data analysis have to show the clin ical importance of these techniques for perfusion analysis in daily cl inical routine. The open questions of the perfusion analysis by contra st echocardiography will be discussed in this review article.