Rapid Three-Dimensional Echocardiography

Abstract

Background-Clinical applicability of conventional ultrasonographic systems using mechanical adapters for 3D echocardiographic imaging has been limited by long acquisition and processing times. We developed a rapid (6-s) acquisition technique that collects apical tomograms using a continuously internally rotating transthoracic transducer. This study was performed to examine the clinical feasibility of rapid-acquisition 3D echocardiography to estimate left ventricular end-diastolic and end-systolic volumes using electron-beam computed tomography as the reference standard. Methods and Results-We collected a series of 6 to 11 apical echocardiographic tomograms, depending on heart rate, in 11 patients. There was good correlation, low variability, and low bias between rapid 3D echocardiography and electron-beam computed tomography for measuring left ventricular end-diastolic volume (rϭ0.96; standard error of the estimate, 21.34 mL; bias, Ϫ4.93 mL) and left ventricular end-systolic volume (rϭ0.96; standard error of the estimate, 14.78 mL; bias, Ϫ6.97 mL). Conclusions-The rapid-acquisition 3D echocardiography extends the use of a multiplane, internally rotating handheld transducer so that it becomes a precise and clinically feasible tool for assessing left ventricular volumes and function. A rapid-image acquisition time of 6 s would allow repeated image collection during the course of a clinical echocardiographic examination. Additional work must address rapid and automated data processing. hree-dimensional echocardiography has demonstrated superior accuracy and reproducibility over conventional 2D echocardiography for measuring left ventricular (LV) volume, because no geometric assumptions are necessary about LV shape. 1 Real-time volumetric 3D echocardiography 2 with a very fast, internally rotating crystal array for real-time 3D imaging, 3 various mechanical adapters for rotation or translation with conventional transthoracic echocardiography transducers, 4 or free-hand 3D image acquisition with magnetic 5 or spark-gap 6 spatial positioning systems were investigated in an effort to use the 3D approach in a clinical setting. However, the clinical application of these techniques is not widespread because of compromised image quality, challenging technical design, or slow acquisition times. The initial experience with a prototype handheld transducer with an internally rotating crystal array for multiplane image acquisition was reported recently. 7 The transthoracic echocardiography transducer is comparable in size to conventional probes and is stable during multitomographic data acquisition, because the rotating crystal array is not in direct contact with the body surface.Using the 180°continuous-rotation mode of the multiplane transducer, we developed a rapid 3D image-acquisition technique that addresses the issue of clinical practicality of 3D echocardiography.The purpose of this study was to assess the clinical feasibility and the precision and accuracy of the new rapid, 3D echocardiographic acquisition technique for...