The objective of this collaborative research proposal is to develop a contrast aided sonographic diagnosis of thyroid cancer using subharmonic contrast imaging (imaging at half the excitation frequency). Although thyroid nodules are found in 30-70% of the adult population, only 5-7% of them are malignant that needs surgical intervention. Accurate differentiation of a nodule into a benign or malignant category can decrease unnecessary surgery and the morbidity and mortality associated with this procedure.
In contrast enhanced ultrasound imaging (CEUS), micron-size gas bubbles are injected in patients to improve the image contrast. In conventional CEUS, imaging frequency is the same as the exciting frequency. Here the nonlinear signal from contrast microbubbles – specifically subharmonic signals at half the exciting frequency with superior contrast-to-tissue ratio – will be interrogated for its ability to detect changes in vascular environment associated with malignancy. We will use in vitro experiments with several contrast agents, mathematical analysis and clinical investigation of thyroid patents. This study will result in the in vitro optimization of the proposed subharmonic contrast enhanced ultrasound based characterization of thyroid nodules. Upon completion of this project, we will seek NIH funding for appropriate animal model study for thyroid cancer diagnosis using ultrasound.