Characterization of digital waveforms using thermodynamic analogs: detection of contrast-targeted tissue in vivo.

We describe characterization of backscatter from tumor tissue targeted with a nanoparticle-based ultrasound contrast agent in vivo using analogs of thermodynamic quantities. We apply these waveform characteristics to detection of tumor neovasculature in tumors implanted in athymic nude mice, which were imaged using a research ultrasound scanner over a 2-hour period after injection of alpha upsilon beta3-targeted perfluorocarbon nanoparticles. Images were constructed from backscattered ultrasound using two different approaches: fundamental B-mode imaging and a signal receiver based on a thermodynamic analog (H(C)). The study shows that the thermodynamic analog is capable of detecting differences in backscattered signals that are not apparent with the B-mode approach.