Bone health assessment using synthetic aperture ultrasound reflectometry

Stress fracture is a common condition in athletes and military personnel yet objective methods for detection and tracking of stress fractures (e.g., MR and scintigraphy) remain complex and expensive. Methods involving ultrasound are in common use; however, they are thus far subjective (relying on patient report of pain). The goal of this work is to develop quantitative and sensitive ultrasonic evaluation methods that could be deployed broadly in smaller clinical setting for use by a wide range of medical professionals. Such methods would complement beam-formed images of the bone surface by adding information about even sub-wavelength features. We have demonstrated that small imperfections on the bone surface significantly alter the characteristics of the reflectivity as made evident in the relative magnitude of the specular vs. diffuse scatter. In this paper we will present our work toward developing methods for acquiring, enhancing, visualizing, and evaluating such effects. We will present results from measurements with ex vivo bone samples and phantoms, and discuss the ultimate applicability of our methods to in vivo diagnosis.