Session S21.1

Quantitative Evaluation of Regional Left Ventricular Function Using Three-Dimensional Speckle Tracking Echocardiography

F Maffessanti*, HJ Nesser, L Weinert, R Steringer-Mascherbauer,
J Niel, W Gorissen, EG Caiani, RM Lang, V Mor-Avi

University of Chicago
Chicago, IL, USA

A variety of quantitative techniques for the evaluation of global and regional left ventricular (LV) function have been used in an attempt to overcome the subjective nature of visual interpretation of LV dynamics from echocardiographic images. Although 2D speckle tracking echocardiography (STE) has been recently shown useful for the assessment of regional LV function, it is limited by the assumption that ultrasound speckles can be tracked frame-to-frame within the imaging plane, despite the fact that cardiac motion is three-dimensional (3D). The inability to quantify one of the three components of the local displacement vector interferes with the evaluation of the true magnitude of the displacement vector and affects the accuracy of the derived indices of local dynamics. Our goal was to evaluate the newly developed 3D-STE software by: (1) comparing regional wall motion (RWM) measurements against 2D-STE, and (2) testing its ability to identify RWM abnormalities. Methods. 2D images and real-time 3D datasets (Toshiba Artida 4D) obtained in 32 subjects with a wide range of LV function were analyzed to measure radial and longitudinal displacements and rotation, as well as radial, longitudinal and circumferential strains in 16 standard 3D LV segments. Inter-technique comparisons included linear regression and Bland-Altman analyses. Additionally, cardiac magnetic resonance images (Siemens 1.5T scanner) acquired on the same day were reviewed by an expert who classified segments as normal or abnormal. Values of each 3D-STE index were compared between normal and abnormal segments. Results. Color-coded 2D-STE images showed considerable variability in the color patterns, hampering the ability to easily visualize hypokinetic areas. In contrast, 3D-STE datasets obtained in normal subjects showed considerably more uniform color patterns, consistent with normal LV wall motion, and depicted the known gradual decrease in displacement towards the LV apex. 3D-STE datasets obtained in patients with wall motion abnormalities showed less uniform color patterns with reduced motion in areas of hypokinesis. Quantitative analysis showed that 3D-STE and 2D-STE indices of wall motion did not correlate well (r: 0.16-0.76) and showed wide limits of inter-technique agreement (2SD: 5-6 mm for displacements, 14° rotation, 17-52% strains) despite only minimal biases, indicating that these two techniques are not interchangeable. In normal segments, 3D-STE showed: (1) higher displacements, reflecting the out-of-plane motion component; (2) smaller SDs, indicating tighter normal ranges; (3) gradual decrease in radial and longitudinal displacement and reversal in rotation from base to apex. In abnormal segments, all 3D-STE indices were reduced, reaching significance for 5/6 indices. Conclusion. This is the first study to evaluate the new 3D-STE technique for measurements of RWM indices and demonstrate its superiority over 2D-STE.

(Abstract Control Number: 190)