Regresar

Effect of spatial, temporal, and velocity resolution on doppler tissue image derived indices

Abstract:

Many indices derived from color Doppler Tissue Imaging (DTI) are computed mathematically from the velocity fields provided by the ultrasound scanner. We developed a procedure for assessing the uncertainty that temporal, spatial, and velocity resolution causes on cardiovascular parameters derived from myocardial velocity. A first-order Taylor's series for the functional relationship between velocity and the cardiac index under study is proposed, and analytically solved by using the chain rule. Performance on myocardial acceleration, strain, and strain rate, was tested both on a simulation model (symbolic calculations) and on a clinical image example. Velocity and temporal resolutions were the most determinant on DTI-derived parameters, and increasing color-Doppler bit-depth from 5 to 7 bits reduced to less than 10% the uncertainty of all the analyzed indices. Taylor-based error bounds are a useful tool to assess the effect of resolution on quantitative cardiovascular indices derived from tissue velocity measurements. © 2004 IEEE.