Medical Physics Seminar – Monday, December 9, 2013
Advanced spectral analysis methods for quantification of coherent ultrasound scattering: applications in the breast
Ivan Rosada-Mendez (student of Dr. James Zagzebski)
Research Assistant, Department of Medical Physics, UW-School of Medicine & Public Health, Madison, WI - USA -
Parametric images depicting the spatial variability of acoustic properties of tissue aim at increasing the specificity and objectivity of ultrasound as a technique for detecting and diagnosing diseases. Estimation methods for most of these properties are based on the assumption that echo signals are stationary and that underlying scattering sources have no spatial organization, conditions that are consistent with incoherent scattering. However, this is not always the rule in biological tissue because of the presence of large scale interfaces and/or subresolution scatterers that present some level of organization.
This work aims at creating parametric images quantifying the coherence that originates in these scenarios. A Generalized Spectrum approach to measure coherence is optimized for this purpose. A reference-phantom approach is developed to evaluate statistical significance of the detected coherence and to define the nature of its source. Results of a preliminary in vivo application of these procedures to classify breast tumors are presented.