ELASTIC IMAGE REGISTRATION TO QUANTIFY 3-D REGIONAL MYOCARDIAL DEFORMATION FROM VOLUMETRIC ULTRASOUND: EXPERIMENTAL VALIDATION IN AN ANIMAL MODEL

Although real-time 3-D echocardiography has the potential to allow more accurate assessment of global and regional ventricular dynamics compared with more traditional 2-D ultrasound examinations, it still requires rigorous testing and validation should it break through as a standard examination in routine clinical practice. However, only a limited number of studies have validated 3-D strain algorithms in an in vivo experimental setting. The aim of the present study, therefore, was to validate a registration-based strain estimation methodology in an animal model. Volumetric images were acquired in 14 open-chest sheep instrumented with ultrasonic microcrystals. Radial strain (epsilon(RR)), longitudinal strain (epsilon(LL)) and circumferential strain (epsilon(CC)) were estimated during different stages: at rest, during reduced and increased cardiac inotropy induced by esmolol and dobutamine infusion, respectively, and during acute ischemia. Agreement between image-based and microcrystal-based strain estimates was evaluated by their linear correlation, indicating that all strain components could be estimated with acceptable accuracy (r = 50.69 for epsilon(RR), r = 50.64 for epsilon(LL) and r = 50.62 for epsilon(CC)). These findings are comparable to the performance of the current state-of-the-art commercial 3-D speckle tracking methods. Furthermore, shape of the strain curves, timing of peak values and location of dysfunctional regions were identified well. Whether 3-D elastic registration performs better than 3-D block matching-based methodologies still remains to be proven. (E-mail: brecht.heyde@med.kuleuven.be) (C) 2013 World Federation for Ultrasound in Medicine & Biology.