Effect of Echocardiographic Contrast on Velocity Vector Imaging Myocardial Tracking

Background: Two-dimensional speckle tracking is an evolving ultrasound technology that allows objective evaluation of left ventricular function. The effect of echocardiographic contrast with 2-dimensional speckle tracking image processing is poorly defined. Methods: A total of 11 patients undergoing clinically indicated transthoracic echocardiography who also required echocardiographic contrast for left ventricular endocardial border enhancement were prospectively studied. Offline velocity vector imaging analysis was performed to calculate global and regional longitudinal strain from the apical 4-chamber view while corresponding circumferential strain was obtained from the parasternal short-axis view at the papillary muscle level. Images were isochronally normalized and the systolic phase was studied precontrast and postcontrast opacification. Results: Intraclass correlation coefficients were high for global circumferential strain in the short-axis view (0.77) and global longitudinal strain in the apical 4-chamber view (0.87) precontrast and postcontrast. Significant regional variability was present, more pronounced in the apical 4-chamber view (intraclass correlation coefficient 0.24-0.64) versus short-axis view (intraclass correlation coefficient 0.64-0.68). Conclusions: Velocity vector imaging is able to quantify global and regional strain with and without contrast. There is, however, wide interindividual variability in regional strain quantification with and without contrast, potentially limiting the clinical applicability.