Imperial College London
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DrJamesChoi

Faculty of Engineering, Department of Bioengineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 1777j.choi Website

 
 
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Location

 

RSM 4.06Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Choi:2020:10.1109/TUFFC.2020.3011657,
author = {Choi, J and Pouliopoulos, A and Smith, C and Bezer, J and El, Ghamrawy A and Boulding, C and Morse, SV and Meng-Xing, T},
doi = {10.1109/TUFFC.2020.3011657},
journal = {IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control},
pages = {2692--2703},
title = {Doppler passive acoustic mapping},
url = {http://dx.doi.org/10.1109/TUFFC.2020.3011657},
volume = {67},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - In therapeutic ultrasound using microbubbles, it is essential to drive the microbubbles into the correct type of activity and the correct location to produce the desired biological response. Although passive acoustic mapping (PAM) is capable of locating where microbubble activities are generated, it is well known that microbubbles move rapidly within the ultrasound beam. We propose a technique that can image microbubble movement by estimating their velocities within the focal volume. Microbubbles embedded within a wall-less channel of a tissue-mimicking material were sonicated using 1-MHz focused ultrasound. The acoustic emissions generated by the microbubbles were captured with a linear array (L7-4). PAM with robust Capon beamforming was used to localize the microbubble acoustic emissions. We spectrally analyzed the time trace of each position and isolated the higher harmonics. Microbubble velocity maps were constructed from the position-dependent Doppler shifts at different time points during sonication. Microbubbles moved primarily away from the transducer at velocities on the order of 1 m/s due to primary acoustic radiation forces, producing a time-dependent velocity distribution. We detected microbubble motion both away and towards the receiving array, revealing the influence of acoustic radiation forces and fluid motion due to the ultrasound exposure. High-speed optical images confirmed the acoustically-measured microbubble velocities. Doppler PAM enables passive estimation of microbubble motion and may be useful in therapeutic applications, such as drug delivery across the blood-brain barrier, sonoporation, sonothrombolysis and drug release.
AU  - Choi,J
AU  - Pouliopoulos,A
AU  - Smith,C
AU  - Bezer,J
AU  - El,Ghamrawy A
AU  - Boulding,C
AU  - Morse,SV
AU  - Meng-Xing,T
DO  - 10.1109/TUFFC.2020.3011657
EP  - 2703
PY  - 2020///
SN  - 0885-3010
SP  - 2692
TI  - Doppler passive acoustic mapping
T2  - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
UR  - http://dx.doi.org/10.1109/TUFFC.2020.3011657
UR  - https://ieeexplore.ieee.org/document/9146913
UR  - http://hdl.handle.net/10044/1/81831
VL  - 67
ER  -
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