An open environment for quantitative analysis of left ventricular function using ultrasound images.

We have developed an open environment for quantitative analysis of left ventricular function using ultrasound images. The system is primarily intended for experimental purposes, i.e. clinical research and the evaluation of quantification algorithms. The modular design allows easy expansion with new analysis methods. The core of our system is the user-interface and image presentation. Image analysis methods are included as a set of tools available to the operator. Using this approach, the expensive, expert knowledge of the cardiologist is used more efficiently than in most delineation systems. During delineation, images of a complete heart cycle can be simultaneously displayed dynamically ('cine mode') in a separate window. This feature improves visual edge perception and enables accurate determination of the endocardium even in cases of very poor echogenicity. The resulting contour can be corrected locally by interactive modification using 'rubber banding'. After delineation of the images from different echocardiographic views, volume, ejection fraction, and regional wall motion are determined. Studies using contrast-enhanced echocardiography can be quantified by image intensity analysis in a region of interest in order to determine myocardial perfusion. We evaluated our method by quantifying echocardiographic studies from 12 healthy volunteers. We compared the results with magnetic resonance imaging and concluded that there was no significant difference in volume and ejection fraction calculated from both modalities. Moreover, the image display features and contour correction methods were greatly appreciated by the cardiologists who used the system.

Determination of left ventricular volume by two-dimensional echocardiography: comparison with magnetic resonance imaging.

Left ventricular volume was determined in 12 healthy volunteers using a newly developed two-dimensional echocardiographic delineation method. The results were compared with those of magnetic resonance imaging, which served as the method of reference. Left ventricular end-diastolic volume was 123 +/- 12 ml, echocardiographically defined, and 121 +/- 12 ml calculated with magnetic resonance imaging. End-systolic volume was 41 +/- 7 ml on echocardiography and 37 +/- 6 ml on magnetic resonance imaging. Left ventricular ejection fraction was 67 +/- 4%, echocardiographically defined, and 70 +/- 5%, calculated with magnetic resonance imaging. There was no statistical difference for any of the measured parameters. Interstudy and inter-observer variability was minimal. In conclusion, in healthy volunteers left ventricular volume was accurately defined, using this newly developed two-dimensional echocardiographic delineation method. During endocardial delineation a dynamic display is continuously available on a second window, allowing precise visual edge-detection. Moreover, corrections can be made easily and quickly. These two advantages enhance the accuracy of the method, even in cases of poor echogenicity.