Monitoring aspects of an ultrasonic esophageal transducer. Initial experience

A method of semi-automatic contour detection is described using a commercial (Kontron) image analysis instrument. Input data consists of high-quality transesophageal echocardiograms of short-axis left ventricular cross-sections. The purpose of the study is to evaluate the feasibility of such a method for the quantitative monitoring of the dynamic behaviour of the left ventricle during high risk surgery. From the first experience it is authors' impression that the automatically derived contour depends strongly on the selected algorithm parameters. Therefore derivation of absolute measurements from these contours seems problematic. Automatic contour detection seems much better fit for monitoring situations, where the patient acts as his own reference and there is no need to change the algorithm parameters.