Ultrasonic RF time series for early assessment of the tumor response to chemotherapy

// Qingguang Lin 1, * , Jianwei Wang 1, * , Qing Li 1, * , Chunyi Lin 2 , Zhixing Guo 1 , Wei Zheng 1 , Cuiju Yan 1 , Anhua Li 1 and Jianhua Zhou 1 1 Department of Ultrasound, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, P.R. China 2 School of Electronic and Information Engineering, South China University of Technology, Guangzhou, 510640, P.R. China * These authors have contributed equally to this work Correspondence to: Jianhua Zhou, email: zhoujh@sysucc.org.cn Keywords: chemotherapy; cancer; ultrasonic radio-frequency time series; microstructure Received: March 21, 2017 Accepted: December 15, 2017 Published: December 23, 2017 ABSTRACT Ultrasound radio-frequency (RF) time series have been shown to carry tissue typing information. To evaluate the potential of RF time series for early prediction of tumor response to chemotherapy, 50MCF-7 breast cancer-bearing nude mice were randomized to receive cisplatin and paclitaxel (treatment group; n = 26) or sterile saline (control group; n = 24). Sequential ultrasound imaging was performed on days 0, 3, 6, and 8 of treatment to simultaneously collect B-mode images and RF data. Six RF time series features, slope, intercept, S1, S2, S3 , and S4 , were extracted during RF data analysis and contrasted with microstructural tumor changes on histopathology. Chemotherapy administration reduced tumor growth relative to control on days 6 and 8. Compared with day 0, intercept, S1 , and S2 were increased while slope was decreased on days 3, 6, and 8 in the treatment group. Compared with the control group, intercept, S1, S2, S3 , and S4 were increased, and slope was decreased, on days 3, 6, and 8 in the treatment group. Tumor cell density decreased significantly in the latter on day 3. We conclude that ultrasonic RF time series analysis provides a simple way to noninvasively assess the early tumor response to chemotherapy.