Validation of 3-Dimensional Speckle Tracking Imaging to Quantify Regional Myocardial Deformation

Abstract

Three-dimensional speckle tracking imaging (3D-STI) has been introduced to assess regional left ventricular (LV) myocardial function. This study was designed to validate LV strain measurements by 3D-STI against data obtained by sonomicrometry. In each of 10 anesthetized sheep, sonomicrometry crystals were implanted on the endocardium and epicardium at the LV basal, mid, and apical anterior and lateral walls. LV 3D-STI data sets were obtained from the apical approach at a frame rate of approximately 30 frames/s. Segmental longitudinal (LS), radial (RS), and circumferential strain (CS) measurements by 3D-STI were compared with those by sonomicrometry at baseline and during pharmacological stress tests (dobutamine and propranolol infusion) and acute myocardial ischemia induced by coronary artery occlusion. Data were available from 136 LS, 108 CS, and 175 RS measurements. Good correlations were observed between strain measurements by 3D-STI and those by sonomicrometry (LS: r=0.89, P<0.001; RS: r=0.84, P<0.001; CS: r=0.90, P<0.001). In each segmental study, significant correlations of the 3 strain components were observed (LS: r=0.65 to 0.68, P<0.001; RS: r=0.59 to 0.70, P<0.001; CS: r=0.71 to 0.78, P<0.001). The newly developed 3D-STI technique can estimate LV regional circumferential, longitudinal, and radial strain components with reasonable correlation to sonomicrometry data. This methodology could be applied clinically to assess alteration of myocardial function by accurately measuring strain in basal, mid, and apical LV segments, even during pharmacological and ischemic interventions. Therefore, 3D-STI appears to be a reliable tool to assess LV regional wall function.