Medical Clinic I
University RWTH Aachen
Pauwelsstraße 30
52074 Aachen
Germany
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Fax: +49 241 808 2414
E-mail address: RHoffmann{at}UKAACHEN.de
Clinic Johannes Gutenberg University Mainz
Mainz, Germany
Academic Hospital Dijkzigt Rotterdam
The Netherlands
University Charite
Berlin, Germany
Bieganski Hospital
Lodz, Poland
Deutsches Herzzentrum
Munich, Germany
Hopital du Haut Leveque
Pessac Cedex
France
University Charite
Berlin, Germany
University Bonn
Bonn, Germany
Bracco Diagnostics Inc.
Konstanz, Germany
John Radcliffe Hospital
Oxford, UK
Cliniques Universitaires Saint-Luc
Brussels
Belgium
In their editorial, Buck and Erbel1 raise the important question in which settings application of contrast agents to an echocardiographic examination is appropriate. There is no doubt that the beauty of echocardiography relates to its ease of use. We should acknowledge that highest accuracy in the determination of left ventricular function is not necessary in most patients referred for an echocardiographic evaluation. Thus, contrast echocardiography will not be a technique to be used in all patients for mere evaluation of left ventricular function as cardiac magnetic resonance imaging will not be used in routine clinical practice only for its known superb accuracy. However, there are patients with significantly impaired left ventricular function in whom important therapeutic decisions such as the implantation of cardioverter devices or biventricular pacing devices is based on an accurate assessment of left ventricular function. Serial follow-up studies in patients with known impairment of left ventricular function do frequently relate to the accurate analysis of possible changes in function. The limited reproducibility of left ventricular function measurements using unenhanced echocardiography has precluded the use of this technique in scientific studies in which accurate measurements are requested. Reliable stress echocardiographic studies also rely on an accurate analysis of regional left ventricular function as provided by contrast echocardiography.
Our study did not have the intention to evaluate the patient population to whom contrast echocardiography should be applied. The study results do not suggest that contrast injections should be used routinely as implied by Buck and Erbel1 and did not have this aim. Unfortunately, the editorial by Buck and Erbel1 although raising the matter of appropriate patient selection fails to give an advice in whom use of contrast echocardiography may be appropriate. We agree that in an ideal world we would like to perform all studies with 3D echocardiography and contrast to improve endocardial border definition. But we do not need to wait for everyday use of 3D/4D scanners as accurate tracing of borders is a prerequisite for quantitative LV function assessment regardless of imaging dimension, and to keep echocardiography simple, it is unlikely that contrast application will become routine practice in combination with realtime 4D echocardiography and multiparametric off-line analysis as proposed by Buck and Erbel1 In addition to previous studies which have shown the rewarding use of contrast echocardiography for accurate assessment of left ventricular function,2 our study demonstrates the advantages of contrast echocardiography in a multicentre setting and the multimodality comparison of imaging methods allowed a better assessment of the competitiveness of contrast echocardiography with other imaging modalities if accurate and reliable assessment of left ventricular function is required.3 The main finding of the study is that beyond the use of simple echocardiographic approaches for routine practice more sophisticated contrast techniques allows echocardiography to compete with other imaging modalities such as cMRI, if a reliable assessment of left ventricular function with low observer dependency is required. It will remain a matter of judgement in the future what accuracy we aim for in an echocardiographic study. In those patients in whom we need high accuracy in the assessment of ejection fraction and are not confident in conventional echocardiography, contrast echocardiography is the alternative to cMRI.
References
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