Speckle Tracking Ultrasound Is Independent of Insonation Angle and Gain: An In Vitro Investigation of Agreement with Sonomicrometry

Objective: It has been shown that speckle tracking ultrasound (STU) is capable of measuring peak strain accurately in vitro over a range of compression rates and amplitudes. The aim of this study was to investigate the influence of different angles of insonation with a range of scanner settings. Methods: A tissue-mimicking phantom was cyclically deformed to imitate the beating heart. With different combinations of scanner settings, strain was measured by STU using sonomicrometry as reference. Results: Over a majority of parameter combinations, speckle tracking measured strain accurately. However, a combination of large echocardiographic image displacements, low frame rates, and small sector depths resulted in increased difference between STU and sonomicrometry. The angle of insonation and gain setting did not affect STU. Conclusion: Despite the limitations exhibited by image displacement, frame rate, and sector depth, STU remains a promising technique for angle-independent assessment of strain. (J Am Soc Echocardiogr 2009; 22: 852-858.)