Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurement and simulation prediction

Abstract

Considering ultrasound propagation through complex composite media as an array of parallel sonic rays, a comparison of computer-simulated prediction with experimental data has previously been reported for transmission mode (where one transducer serves as transmitter, the other as receiver) in a series of 10 acrylic step-wedge samples, immersed in water, exhibiting varying degrees of transit time inhomogeneity. In this study, the same samples were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both 'primary' (internal sample interface) and 'secondary' (external sample interface) echoes. A transit time spectrum was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and amplitude of various echoes created, and compared with experimental data. Applying an amplitude-tolerance analysis, 91.7% ± 3.7% of the simulated data were within ±1 standard deviation of the experimentally measured amplitude-time data. Correlation of predicted and experimental transit time spectra provided coefficients of determination (R(2)%) ranging from 100.0% to 96.8% for the various samples tested. The results acquired from this study provide good evidence for the concept of parallel sonic rays. Furthermore, deconvolution of experimental input and output signals has been shown to provide an effective method to identify echoes otherwise lost due to phase cancellation. Potential applications of pulse-echo ultrasound transit time spectroscopy include improvement of ultrasound image fidelity by improving spatial resolution and reducing phase interference artefacts.

The dependence of broadband ultrasound attenuation on phase interference in thin plates of variable thickness and curvature: a comparison of experimental measurement and computer simulation

“…Future work could investigate the potential to predict the effect of the cortical shell on the measurement of BUA, potentially utilising the concept of pulse–echo ultrasound transit time spectroscopy (PE-UTTS) 15 to provide, for example, a histogram of thickness. Furthermore, this article considered only the effect of the cortical plates on BUA measurement.…”

“…of BUA, potentially utilising the concept of pulse-echo ultrasound transit time spectroscopy (PE-UTTS) 15 to provide, for example, a histogram of thickness.…”

“…12 This concept led to the development of ultrasound transit time spectroscopy (UTTS) that has been validated by several studies including estimation of solid volume fraction. [13][14][15][16][17] We hypothesised that the cortical end plate would significantly influence BUA measurement due to variation in cortex thickness, thereby creating significant phase interference due to TT inhomogeneity and not curvature of the cortex per se as previously suggested. 10 We studied three categories of 3D-printed replica cortex discs: (1) variable constant thickness (planar); (2) variable curvature, variable constant thickness (curved); and (3) variable thickness (step-wedge).…”

Ultrasound Transit Time Spectroscopy in Complex Media - Applications and Relationship with Phase Interference

“…The concept of ultrasound transit time spectroscopy (UTTS) has been initially validated utilising a transmission technique (Langton & Wille, 2013), comparing experimental measurement with computer simulation prediction in a range of acrylic step-wedge samples exhibiting varying transit time heterogeneity, reporting an agreement coefficient of determination ranging from 94.2% to 99%. This concept was further validated in pulse-echo mode, again comparing the experimental data to computer prediction in the step wedge models, with a total agreement between experimental and simulation signals of 91.7±3.7% at an amplitude threshold of ±1SD (M.-L. Wille et al, 2016).…”

“…A new approach to explain the propagation of ultrasound through cancellous bone has been proposed by Langton in 2011 (Langton, 2011) The parallel sonic ray concept has been initially validated in both transmission and pulse-echo modes (Langton & Wille, 2013;M.-L. Wille et al, 2016); by comparing experimental results with computer simulation prediction, confirming that the degree of phase interference is dependent upon lateral inhomogeneity of transit time.…”