Assessment of the uncertainty of shear wave speed measurements in ultrasound elastography

Accurate measurement of tissue mechanical properties is crucial for diagnosing and characterising various pathological conditions. Among these properties, shear wave speed (SWS) is an indicator of tissue stiffness and has been widely studied across multiple imaging modalities. Despite its advantages, the quantification of SWS is subject to various sources of uncertainty, which can impact its clinical and research applications. The uncertainty of SWS measurements based on acoustic radiation force impulse (ARFI) technology implemented using a research ultrasound system is investigated in this study. A linear array ultrasound transducer with 128 elements and a transmit frequency of 5.2 MHz was employed for both pushing and tracking. The contributions of different factors, including the effects of displacement estimator, speckle and temperature variation, to the overall measurement uncertainty were assessed using tissue-mimicking phantoms. The compiled uncertainty budget provided an expanded uncertainty of 8 % for the identified SWS, offering an in-depth understanding of the systematic effects influencing SWS and Young's modulus measurements in ultrasound elastography. The findings in this study aim to enhance the reliability of ultrasound elastography as a diagnostic tool and to provide a foundation for future studies.