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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

Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury

Khan, Z.Z., L.N. Cates, D.M. DeWees, A. Hannah, P. Mourad, M. Bruce, and C.P. Hofstetter, "Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury," J. Neurosurg. Spine, 29, 306-313, doi:10.3171/2018.1.SPINE171202, 2018.

More Info

1 Sep 2018

Traumatic spinal cord injury (tSCI) causes an almost complete loss of blood flow at the site of injury (primary injury) as well as significant hypoperfusion in the penumbra of the injury. Hypoperfusion in the penumbra progresses after injury to the spinal cord and is likely to be a major contributor to progressive cell death of spinal cord tissue that was initially viable (secondary injury). Neuroprotective treatment strategies seek to limit secondary injury. Clinical monitoring of the temporal and spatial patterns of blood flow within the contused spinal cord is currently not feasible. The purpose of the current study was to determine whether ultrafast contrast-enhanced ultrasound (CEUS) Doppler allows for detection of local hemodynamic changes within an injured rodent spinal cord in real time.

Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury

Khaing, Z.Z., L.N. Cates, D.M. DeWees, A. Hannah, P. Mourad, M. Bruce, and C.P. Hofstetter, "Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury," J. Neurosurg. Spine, 29, 235-350, doi:10.3171/2018.1.SPINE171202, 2018.

More Info

1 Sep 2018

Traumatic spinal cord injury (tSCI) causes an almost complete loss of blood flow at the site of injury (primary injury) as well as significant hypoperfusion in the penumbra of the injury. Hypoperfusion in the penumbra progresses after injury to the spinal cord and is likely to be a major contributor to progressive cell death of spinal cord tissue that was initially viable (secondary injury). Neuroprotective treatment strategies seek to limit secondary injury. Clinical monitoring of the temporal and spatial patterns of blood flow within the contused spinal cord is currently not feasible. The purpose of the current study was to determine whether ultrafast contrast-enhanced ultrasound (CEUS) Doppler allows for detection of local hemodynamic changes within an injured rodent spinal cord in real time.

The role of microbubble echo phase lag in multipulse contrast-enhanced ultrasound imaging

Tremblay-Darveau, C., P.S. Sheeran, C.K. Vu, R. Williams, Z. Zhang, M. Bruce, and P.N. Burns, "The role of microbubble echo phase lag in multipulse contrast-enhanced ultrasound imaging," IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 65, 1389-1401, doi:10.1109/TUFFC.2018.2841848, 2018.

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1 Aug 2018

In this paper, we assess the importance of microbubble shell composition for contrast-enhanced imaging sequences commonly used on clinical scanners. While the gas core dynamics are primarily responsible for the nonlinear harmonic response of microbubbles at diagnostic pressures, it is now understood that the shell rheology plays a dominant role in the nonlinear response of microbubbles subjected to low acoustic pressures. Of particular interest here, acoustic pressures of tens of kilopascal can cause a reversible phase transition of the phospholipid coatings from a stiff elastic organized state to a less stiff disorganized buckled state. Such a transition from elastic to buckled shell induces a steep variation of the shell elasticity, which alters the microbubble acoustic scattering properties. We demonstrate in this paper that this mechanism plays a dominant role in contrast pulse sequences that modulate the amplitude of the insonifying pulse pressure. The contrast-to-tissue ratio (CTR) for amplitude modulation (AM), pulse inversion (PI), and amplitude modulation pulse inversion (AMPI) is measured in vitro for Definity, Sonazoid, both lipid-encapsulted microbubbles, and the albumin-coated Optison. It is found that pulse sequences using AM significantly enhanced the nonlinear response of all studied microbubbles compared to PI (up to 15 dB more) when low insonation pressures under 200 kPa were used. Further investigation reveals that the origin of the hyperechoicity is a small phase lag occurring between the echoes from the full-and half-amplitude driving pulses, and that the effect could be attributed to the shell softening dynamics of lipid and albumin coatings. We assess that this additional phase in microbubble ultrasound scattering can have a dominant role in the CTR achieved in contrast sequences using AM. We also show that the pressure dependent phase lag is a specific marker for microbubbles with no equivalent in tissue, which can be used to segment microbubbles from the tissue harmonics and significantly increase the CTR.

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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