On System-Dependent Sources of Uncertainty and Bias in Ultrasonic Quantitative Shear-Wave Imaging

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 63; no. 3; pp. 381 - 393
• Main Authors: Yufeng Deng, Rouze, Ned C., Palmeri, Mark L., Nightingale, Kathryn R.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.03.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Abdomen - diagnostic imaging; Acoustics; Algorithms; Analytical models; Bias; Frequency measurement; Humans; Image Processing, Computer-Assisted - methods; Imaging; Measurement uncertainty; Models, Biological; Phantoms, Imaging; Ultrasonic imaging; Ultrasonography - methods; Uncertainty; shear-wave speed estimation; ultrasound imaging; Beamforming; speckle bias; uncertainty and bias; phase aberration; shear-wave imaging
• ISSN: 0885-3010; 1525-8955; 1525-8955
• DOI: 10.1109/TUFFC.2016.2524260

Ultrasonic quantitative shear-wave imaging methods have been developed over the last decade to estimate tissue elasticity by measuring the speed of propagating shear waves following acoustic radiation force excitation. This work discusses eight sources of uncertainty and bias arising from ultrasound system-dependent parameters in ultrasound shear-wave speed (SWS) measurements. Each of the eight sources of error is discussed in the context of a linear, isotropic, elastic, homogeneous medium, combining previously reported analyses with Field II simulations, full-wave 2-D acoustic propagation simulations, and experimental studies. Errors arising from both spatial and temporal sources lead to errors in SWS measurements. Arrival time estimation noise, speckle bias, hardware fluctuations, and phase aberration cause uncertainties (variance) in SWS measurements, while pulse repetition frequency (PRF) and beamforming errors, as well as coupling medium sound speed mismatch, cause biases in SWS measurements (accuracy errors). Calibration of the sources of bias is an important step in the development of shear-wave imaging systems. In a well-calibrated system, where the sources of bias are minimized, and averaging over a region of interest (ROI) is employed to reduce the sources of uncertainty, an SWS error <; 3% can be expected.