Ultrafast Myocardial Principal Strain Ultrasound Elastography during Stress Tests: in vitro Validation and in vivo Feasibility

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2022-12, Vol.69 (12), p.1-1
• Main Authors: Wang, Diya, Chayer, Boris, Destrempes, Francois, Poree, Jonathan, Cardinal, Marie-Helene Roy, Tournoux, Francois, Cloutier, Guy
• Format: Article
• Language: English
• Subjects: Acoustics; Echocardiography; Echocardiography - methods; Echocardiography, Stress - methods; Elasticity Imaging Techniques - methods; Feasibility Studies; Heart rate; Humans; Imaging; In vivo methods and tests; Medical imaging; myocardial elastography; Myocardium; optical flow; Optical flow (image analysis); principal strain; Strain; Stress; stress test; tissue Doppler; Tracking; Ultrafast ultrasound imaging
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2022.3216447

Objective myocardial contractility assessment during stress tests aims to improve the diagnosis of myocardial ischemia. Tissue Doppler imaging (TDI) or optical flow (OF) speckle tracking echocardiography has been used to quantify myocardial contractility at rest. However, this is more challenging during stress tests due to image decorrelation at high heart rates. Moreover, stress tests imply a high frame rate which leads to a limited lateral field-of-view. Therefore, a large lateral field-of-view robust ultrafast myocardial regularized lateral field-of-view robust ultrafast myocardial regularized OF-TDI principal strain estimator has been developed for high-frame-rate echocardiography of coherently compounded transmitted diverging waves. Feasibility and accuracy of the proposed estimator were validated with in vitro (using sonomicrometry as gold standard) and in vivo stress experiments. Compared with OF strain imaging, the proposed estimator improved the accuracy of principal major and minor strains during stress tests, with an average contrast-to-noise ratio improvement of 4.4 ± 2.7 dB ( p -value < 0.01). Moreover, there was a significant correlation and a very close agreement between the proposed estimator and sonomicrometry for tested heart rates between 60 and 180 beats per minute. The averages ± STD of R 2 and biases ± STD between them were 0.96 ± 0.04 ( p -value < 0.01) and 0.01 ± 0.03 % in the axial direction, respectively; and 0.94 ± 0.02 ( p -value < 0.01) and 0.04 ± 0.06 % in the lateral direction, respectively. These results suggest that the proposed estimator could be useful clinically to provide an accurate and quantitative 2D large lateral field-of-view myocardial strain assessment at high heart rates during stress echocardiography.