Characterizing tumour heterogeneous response to chemotherapy using low-frequency ultrasonic spectroscopy

Abstract

Textural analysis techniques in conjunction with low-frequency ultrasonic spectroscopy have been proposed for characterization of heterogeneous responses developed within tumours undergoing chemotherapy. Such characterization can be beneficial for early appraisal of tumour responses to the cancer therapy. Breast xenograft tumour-bearing animals were treated with chemotherapy. Animals were assessed with low-frequency ultrasound data acquired at different times after chemotherapy exposure. Following imaging, tumours underwent standard histological analysis for detecting cell-death effects. Several average and texture-based parameters were derived from normalized ultrasonic spectral parametric maps. Statistically significant differences were revealed between parameters extracted from treated and untreated tumours 12-24 hours after exposure. Regression analyses were also performed in order to assess levels of correlation between non-invasive ultrasonic surrogates of therapy response and standard histological findings, where strong correlations were obtained with a maximum r2 value of 0.98. Obtained results demonstrate that ultrasound-based textural properties of tissue can be used for characterizing the micro-structure alterations and heterogeneous responses within tumours early on during treatment. This is an important observation which can be applied clinically for treatment response monitoring and predicting patient responses to therapy early after therapy initiation. © 2013 Acoustical Society of America.