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Matthew Bruce

Principal Scientist/Engineer

Email

mbruce@apl.washington.edu

Phone

206-685-2283

Education

B.S. Electrical and Computer Engineering, Michigan Technological University, 1991

M.S. Electrical and Computer Engineering, Virginia Polytechnic University, 1993

Ph.D. Bioengineering, University of Washington, 2004

Matthew Bruce's Website

http://staff.washington.edu/mbruce

Publications

2000-present and while at APL-UW

Histotripsy treatment of abscesses

Matula, T.J., Y.-N. Wang, T. Khokhlova, D.F. Leotta, J. Kucewicz, A.A. Brayman, M. Bruce, A.D. Maxwell, B.E. MacConaghy, G. Thomas, K. Richmond, K. Chan, and W. Monsky, "Histotripsy treatment of abscesses," in Proc., IEEE International Ultrasonics Symposium, 7-11 September, Las Vegas, NV, doi:10.1109/IUS46767.2020.9251683 (IEEE, 2020).

More Info

7 Sep 2020

Abscesses are walled-off collections of infected fluids containing pus and bacteria. They are often treated with percutaneous drainage in which a drainage catheter may be sutured in place for up to several weeks. Complications such as clogged drains or secondary infections require rehospitalization and wound management. Bacteria are susceptible to mechanical damage, and thus we hypothesize that histotripsy may be a potential new paradigm for treating abscesses noninvasively, without the need for long term catheterization and antibiotics. We developed a porcine animal model that recapitulates some of the features of human abscesses (including size and loculations). Boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses in this porcine model. Ultrasound imaging was used to evaluate abscess maturity, for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

Ultrasound imaging of abscesses before and during histotripsy treatment

Bruce, M., D.F. Leotta, Y.-N. Wang, T. Khokhlova, J. Kucewicz, A.D. Maxwell, K. Chan, W. Monsky, and T.J. Matula, "Ultrasound imaging of abscesses before and during histotripsy treatment," in Proc., IEEE International Ultrasonics Symposium, 7-11 September, Las Vegas, NV, doi:10.1109/IUS46767.2020.9251386 (IEEE, 2020).

More Info

7 Sep 2020

Abscesses are walled-off collections of infected fluids most often treated with percutaneous drains placed under CT guidance. Complications such as clogged drains or secondary infections require rehospitalization and wound management. Histotripsy treatment has the potential to eliminate the need for long term catheterization and antibiotics. The progression of abscess development has yet to be fully described. The objective of this study was to use the latest advances in non-contrast ultrasound technologies to characterize abscess development in a porcine animal model. Intramuscular or subcutaneous injections of bacteria plus dextran particles as an irritant led to identifiable abscesses over a 2- to 3-week period. Ultrasound imaging was performed at least weekly, in some cases with a 3D tracking device that provided quantifiable size and shape measurements. Abscess progression was also measured with a plane-wave Doppler mode providing increased sensitivity to low-velocity flows, while abscess stiffness was quantified using shear wave elastography. Most of the mature abscesses were characterized by a rounded core of varying echogenicity surrounded by a hypoechoic capsule that was highly vascularized on Doppler imaging. A treatable abscess was defined by its hypervascular rim and avascular core. Stiffness varied within the abscess but generally decreased over time. Abscess echogenicity, shape, stiffness and vascularity potentially provide features to identify lesions suitable for treatment.

High-frequency nonlinear Doppler contrast-enhanced ultrasound imaging of blood flow

Bruce, M., A. Hannah, R. Hammond, Z.Z. Khaing, C. Tremblay-Darveau, P.N. Burns, and C.P. Hofstetter, "High-frequency nonlinear Doppler contrast-enhanced ultrasound imaging of blood flow," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 67, 1778-1784, doi:10.1109/TUFFC.2020.2986486, 2020.

More Info

1 Sep 2020

Current methods for in vivo microvascular imaging (<1 mm) are limited by the tradeoffs between the depth of penetration, resolution, and acquisition time. Ultrasound Doppler approaches combined at elevated frequencies (<7.5 MHz) are able to visualize smaller vasculature and, however, are still limited in the segmentation of lower velocity blood flow from moving tissue. Contrast-enhanced ultrasound (CEUS) has been successful in visualizing changes in microvascular flow at conventional diagnostic ultrasound imaging frequencies (<7.5 MHz). However, conventional CEUS approaches at elevated frequencies have met with limited success, due, in part, to the diminishing microbubble response with frequency. We apply a plane-wave acquisition combined with the non-linear Doppler processing of ultrasound contrast agents at 15 MHz to improve the resolution of microvascular blood flow while compensating for reduced microbubble response. This plane-wave Doppler approach of imaging ultrasound contrast agents also enables simultaneous detection and separation of blood flow in the microcirculation and higher velocity flow in the larger vasculature. We apply singular value decomposition filtering on the nonlinear Doppler signal to orthogonally separate the more stationary lower velocity flow in the microcirculation and higher velocity flow in the larger vasculature. This orthogonal separation was also utilized to improve time-intensity curve analysis of the microcirculation, by removing higher velocity flow corrupting bolus kinetics. We demonstrate the utility of this imaging approach in a rat spinal cord injury model, requiring submillimeter resolution.

More Publications

Inventions

Improved Detection of Kidney Stones with Ultrasound

Record of Invention Number: 47629

Matthew Bruce

Disclosure

19 Feb 2016

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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