High-Volume-Rate Ultrasound for Quantitative Assessments of Vascular Function
Abstract
Free flap surgery is a common reconstructive technique to repair tissue damage after trauma or cancer
removal. This complex procedure involves the transfer of tissue, along with its associated blood supply,
from one part of the body to another. While these surgeries have high overall success rates, the risk of
vascular complications remains a concern. Thus, rigorous post-operative vascular monitoring of free
flaps is required for the early detection and intervention of complications to prevent tissue necrosis or
complete flap failure. Despite the critical importance of vascular monitoring, clinicians do not currently
have an objective measurement tool that can quantify the volume of blood perfusing the flap. Instead,
they rely on tools which indicate the presence or absence of blood flow (e.g. Doppler pens) coupled
with visual inspection of the flap. As a result, vascular compromise can go unnoticed for several hours
which increases the risk of partial or total flap failure.
Ultrasound imaging is a potential solution to the vascular monitoring of free flaps given its ability to
accurately measure blood flow velocities at the bedside. However, the accurate quantification of blood
flow volumes requires the use of high-volume-rate 3D ultrasound imaging which generally lacks
bedside applicability due to the large size of the associated processing electronics. The goal of this
thesis is to investigate novel solutions which enable the acquisition of accurate 3D flow measurements
with portable ultrasound systems. Specifically, this work has two primary focal points: 1) the
investigation and validation of data reduction strategies for 3D ultrasound to facilitate the use of
portable processing systems, and 2) the enhancement of high-rate ultrasound flow estimation accuracy
to optimize the performance of volumetric blood flow measurements. At the end of this work, the first
in vivo volumetric blood flow measurement with a portable 3D ultrasound system is showcased.
Overall, this thesis presents several advances on the state-of-the-art of 3D ultrasound flow imaging
technology. The capabilities of small-scale 3D ultrasound technology are demonstrated indicating a
positive outlook for future clinical applications. Indeed, the core focus of this work on accurate blood
flow quantification is to ensure that clinicians have access to reliable, quantitative data enabling them
to make objective decisions on patient care. In the case of free flap vascular monitoring, 3D ultrasound
has the potential to significantly improve the early detection of vascular complications which could
mitigate the need for additional surgeries and reduce the rates of partial and total flap failures.
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Cite this version of the work
Rebekah Maffett
(2023).
High-Volume-Rate Ultrasound for Quantitative Assessments of Vascular Function. UWSpace.
http://hdl.handle.net/10012/20152
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