Contrast echocardiography

The intravenous application of an ultrasound contrast agent induces enhance d display of blood in all its pathways. Within cardiology, this principle i s mainly utilized for signal enhancement of color Doppler and spectral Dopp ler in order to improve quantification of congenital and acquired valvular lesions and also for improved endocardial delineation during stress tests a nd in the evaluation of LV function. The new domaine of myocardial perfusion imaging by contrast echocardiograph y, however, needed profound technical developments before realization of th e clinical potential could even be conceived. These are based on the comple x reactions of microbubbbles in the acoustic field in order to allow the se nsitive and bubble specific display of intramyocardial contrast effects. Th e presently available acquisition techniques, second harmonic imaging and h armonic power Doppler, demonstrate significant improvements if compared to traditional fundamental 2-d echocardiography; however, they are still subje cted to important limitations. There are many anatomical, physiological, an d technical reasons for insufficient display of intramyocardial microbubble s, the most important one being attenuation. It is hoped that the most rece ntly developed imaging modality, pulse inversion technique, allows the nece ssary diagnostic accuracy and reproducibility in myocardial perfusion imagi ng.