Accuracy of real-time single- and multi-beat 3-d speckle tracking echocardiography in vitro

With little data published on the accuracy of cardiac 3-D strain measurements, we investigated the agreement between 3-D echocardiography and sonomicrometry in an in vitro model with a polyvinyl alcohol phantom. A cardiac scanner with a 3-D probe was used to acquire recordings at 15 different stroke volumes at a heart rate of 60 beats/min, and eight different stroke volumes at a heart rate of 120 beats/min. Sonomicrometry was used as a reference, monitoring longitudinal, circumferential and radial lengths. Both single- and multi-beat acquisitions were recorded. Strain values were compared with sonomicrometer strain using linear correlation coefficients and Bland-Altman analysis. Multi-beat acquisition showed good agreement, whereas real-time images showed less agreement. The best correlation was obtained for a heart rate 60 of beats/min at a volume rate 36.6 volumes/s.