Myocardial contrast echocardiography: influence of ischaemia and hyperaemia in an animal model.

Abstract

To evaluate changes in myocardial contrast echocardiography during ischaemia and hyperaemia, contrast studies were performed in 16 open chest dogs. Time-intensity curves were generated using videodensitometry after contrast injections to demonstrate ischaemic and non-ischaemic areas of interest during a wide range of coronary blood flow levels. For each time-intensity curve, the peak contrast intensity (PCI), washout halftime (T1/2) and area under the curve (AUC) were calculated. PCI and AUC decreased significantly only with severe ischaemia (90% or more reduction in flow), and increased significantly with hyperaemia of more than 2.5 times baseline flow. Both ischaemia and hyperaemia were found to prolong the T1/2. There was only a moderate linear correlation between the magnitude of hyperaemia and myocardial contrast echocardiographic parameters. There was significantly less increase in myocardial contrast echocardiographic parameters during hyperaemia in segments supplied by a stenosed coronary artery.