Document Type

Thesis

Publication Date

Spring 2019

Disciplines

Biological and Chemical Physics | Fluid Dynamics | Translational Medical Research

Advisor

Philip Chu, Biology

Abstract

The aim of this experiment was to investigate the effect of manipulating ultrasound scanner settings on time-intensity curve parameters in a tube perfusion phantom system using contrast-enhanced ultrasound imaging. Imaging was performed using a Philips LOGIQ E9 ultrasound scanner equipped with a C1-6VN transducer and utilized two different microbubble contrast agents: Definity and Lumason. The ultrasound scanner settings manipulated included: gain, dynamic range, and frequency. Additionally, relative microbubble concentration, microbubble type, and perfusion flow rate were manipulated. Four time-intensity curve parameters (time to peak, area under curve, gradient, peak intensity) were measured from linearized pixel data. Time to peak was the least impacted time-intensity curve parameter by manipulation of ultrasound scanner settings or the tube perfusion phantom system. Dynamic range and perfusion flow rate manipulation resulted in moderate variation in area under curve, gradient, and peak intensity. Gain, frequency, and relative microbubble concentration manipulation resulted in a high degree of variation in area under curve, gradient, and peak intensity. Both microbubble contrast agents demonstrated similar effects when manipulated. The tube perfusion phantom system contained a small degree of built-in variation, which was incorporated into all variation measurements. Contrast-enhanced ultrasound offers a novel way to quantify microvasculature perfusion. However, variability caused by manipulation of ultrasound scanner settings is still a challenge that hinders the clinical application of contrast-enhanced ultrasound quantification. Standardization practices can be used to limit some of the observed variation. Further research is warranted to investigate how variability in contrast-enhanced ultrasound affects the clinical assessment of microvasculature perfusion.

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