901-51 Three Dimensional Reconstruction Using a New Dual Axis Multiplane Transesophageal Echo Probe: Calculation of Left Ventricular Volume

Abstract

The purpose of this study is to validate LV volume measurements using a newtransesophageal echo (TEE) probe for 3 dimensional (3D) imaging which allows multiple intersecting “fan-like” scans of the heart to be obtained from a single scanning position. The transducer can be tilted (±30°), and rotated (0°–104°), without moving the probe's tip. A locator system, with a magnetic sensor in the probe's tip, tracks movement in three x, y, and z axes. A customized computer system directly digitizes echo images, and endocardial borders are manually traced and applied to a surface reconstruction algorithm. Scans of 6 excised canine left ventricles have been initially performed. Volumes computed from the 3D reconstructions compared to true volumes are shown below. The regression equation was 3d volume = 0.82 true volume +0.6, r 2 = 0.95, p = 0.01. LV no. 1 2 3 4 5 6 True vol (ml) 30.3 23.0 24.0 27.5 60.5 28.8 3D vol (ml) 30.3 18.3 19.2 23.7 49.5 21.2 The underestimation of LV volumes with these preliminary results may be due to inaccuracies related to the probe, the reconstruction algorithm, and ultrasound beam width. An example of intersecting LV endocardial borders and a wireframe reconstruction are shown: Dual axis multiplane transesophageal scanning enables: acquisition of multiple intersecting scans from a single probe position, 3D reconstruction of the LV, and calculation of the volume.