Quantitative ultrasound assessment of thermal therapy in liver.

Abstract

High-intensity focused ultrasound (HIFU) is a promising modality for non-invasive therapy with application to cancer treatment. Non-invasive monitoring and assessment of HIFU remains a critical hurdle to widespread clinical acceptance of HIFU. Quantitative ultrasound (QUS) is a novel approach for characterizing tissue microstructure that shows promise for monitoring and assessment of HIFU therapy. The QUS parameters of effective scatterer diameter (ESD) and effective acoustic concentration (EAC) were examined differentially in rat liver specimens exposed to HIFU to form visible lesions. Increases in ESD of 15% and decreases in EAC of 3 dB were observed in post-exposure compared to pre-exposure scans, and statistical significance was observed in most cases (p < 0.05). These results were compared to rat liver samples heated in a water bath, in which the samples were heated to a therapeutic temperature (60 °C) for several minutes, and ultrasonic backscatter was measured at 37 °C. ESD was observed to decrease by an average of 15% in exposed compared to unexposed sample sections. [Work supported by NIH R01EB008992.]