Investigation of the changes in breast tumor vascular morphometrics and hemodynamics during chemotherapy by using optical imaging systems

Abstract

Development of a biomarker for predicting tumor-treatment efficacy is a matter of great concern, to reduce time and medical expense and thus to enhance life quality in oncology therapy. This thesis focuses on the development and translation of OCT angiography (OCTA) and laser speckle flowmetry (LSF) into preclinical study for tumor growth assessment. By using OCTA, first, several blood flow parameters – vessel skeleton density (VSD), vessel diameter index (VDI), fractal dimension (FD), lacunarity, and blood flow rate (BFR) indices – are presented to have positive or negative correlations with the tumor volume during tumor growth and its regression due to chemotherapy. Especially, the changes in the VSD and FD by OCTA responded one day earlier than the tumor shrinkage during chemotherapy in a dorsal skin-fold window chamber (DWC) model. Likewise, second, the changes in the BFR based on LSF occurred one day earlier than the tumor regression. Conversely, the variation in the hypercapnia-induced BFR lagged tumor shrinkage by one day. As a supplementary work in LSF, site-dependent blood flow variations were exhibited between tumor-bearing dorsal skin-fold layers vs. normal cerebral cortex during hypercapnia. These findings may provide a more understanding of tumor heterogeneity and its metabolism, which may contribute to predicting the treatment outcome and thus to designing anticancer strategies.