922-60 How Positionally Stable is a Transesophageal Echo Probe During 3 Dimensional Imaging? Implications for 3 Dimensional Reconstruction

Abstract

Three dimensional (3D) reconstruction from a single esophageal scanning position requires a stable relationship between the probe and the heart. The purpose of this study was to examine the movement of a transesophageal echo (TEE) probe during 3D image acquisition. A new dual axis multiplane probe was used which includes a miniature (6 × 6 × 9 mm) 6D sensor in the tip. The sensor identifies the probe's 3D position and orientation in space with respect to the location of a magnetic field generator placed beneath the subject. In vivo 3D scans were performed in 5 anesthetized, ventilated dogs. Positional determinations were acquired every 66 ms. The sensor axes were: x-mediolateral. y-superoinferior, z-anteroposterior, and r-radial distance = √(x 2 + y 2 + z 2 ). The movement was estimated by computing standard deviations of the x, y, and z positions during each 3D scan and each cardiac cycle. From 2337 determinations, the mean standard deviation for 10 3D scans and 264 cardiac cycles and histograms of the radial movement were calculated and are shown. x(mm) y(mm) z(mm) r(mm) Total 3D scans 0.63 ± 0.63 0.56 ± 0.64 0.65 ± 0.45 0.57 ± 0.43 Cardiac cycle 0.28 ± 0.36 0.21 ± 0.28 0.25 ± 0.35 0.24 ± 0.35 Probe movement during 3D imaging is measurable and in these anesthetized subjects was within acceptable limits. This capability will be useful in awake patients where greater movement is expected, and will optimize the 3D data set by discarding scans where significant probe movement has occurred.