Nearly automated left ventricular long axis tracking on real time three-dimensional echocardiographic data

The measurement of left ventricular (LV) long axis length (LAL) is an integral part of echocardiographic evaluation of LV volume, the most important determinant of LV systolic function. LAL measurements from 2D echocardiography (2DE) are highly dependent on the ability to obtain non-foreshortened LV images. Real-time 3D echocardiography (RT3DE) could potentially overcome the effects of long-axis foreshortening, but LAL measurements on RT3DE data are currently based on manual analysis and are time-consuming. We developed and tested a nearly automated method based on optical flow techniques for the measurement of the LV LAL throughout the cardiac cycle from RT3DE data. Results of comparisons on 10 patients with manual tracing on RT3DE data showed good agreement and no significant bias (r=.99, bias=-1.8 mm). The proposed method allowed fast and accurate quantification of the LAL throughout the cardiac cycle with minimal user interaction and short computational time