Kachenoura N, Mor-Avi V, Frouin F, Delouche A, Polonsky TS, D'Amore S, Diebold B, Lang RM. Diagnostic value of parametric imaging of left ventricular wall motion from contrast-enhanced echocardiograms in patients with poor acoustic windows. J Am Soc Echocardiogr. 2009 Mar; 22(3):276-83.