New Developments on Quantitative Imaging Using Ultrasonic Waves

Although ultrasound imaging is widely used for medical applications, conventional sonographic B-mode images are qualitative. As a consequence, medical diagnosis using sonograms is commonly subjective and depends on the expertise of the operator. The need to obtain quantitative information from tissues resulted in the development of alternative ways of processing the radiofrequency ultrasonic data. Two notable approaches are acoustic tomography and backscatter coefficient analysis. However, these techniques suffer from limitations that keep them from becoming widely used clinical tools. This dissertation presents several developments relevant to quantitative ultrasonic imaging using both acoustic tomography and backscatter coefficient analysis. First, a regularization method was developed to improve on the computational stability of acoustic tomography. The use of multiple frequency information to extend the region of convergence of acoustic tomography was validated experimentally. Second, the feasibility of obtaining quantitative density information (which is usually neglected in acoustic tomography) was explored. The practical limitations and convergence of existing density imaging approaches were studied, and improved algorithmic variations were developed and characterized. Third, two approaches for three-dimensional acoustic tomography were studied through simulations with emphasis on the effect of sensor topologies on the quality of the reconstructions. Finally, potential benefits of using an acoustic tomography scanner in conjunction with backscatter coefficient analysis were explored through simulations and experiments by performing full angular compounding and using acoustic tomograms for refraction correction.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Lavarello Montero, Roberto Janniel

Contributors dc:contributor

• Oelze, Michael L.

• Engineering, Electronics and Electrical

Language dc:language

eng

Identifier

(MiAaPQ)AAI3392112

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/81141