LAUSR

Subcutaneously implanted experimental tumors in mice are commonly used in cancer research. Despite their superficial location, they remain a challenge to image non-invasively at sufficient spatial resolution for microvascular studies. Here we evaluate the capabilities of optical coherence tomography (OCT) angiography for imaging such tumors directly through the murine skin in-vivo. Data sets were collected from mouse tumors derived from fibrosarcoma cells genetically engineered to express only single splice variant isoforms of vascular endothelial growth factor A (VEGF); either VEGF120 or VEGF188 (fs120 and fs188 tumors respectively). Measured vessel diameter was found to be significantly (p<0.001) higher for fs120 tumors (60.7 ± 4.9μm) compared to fs188 tumors (45.0 ± 4.0μm). The fs120 tumors also displayed significantly higher vessel tortuosity, fractal dimension and density. The ability to differentiate between tumor types with OCT suggests that the visible abnormal vasculature is representative of the tumor microcirculation, providing a robust, non-invasive method for observing the longitudinal dynamics of the subcutaneous tumor microcirculation.