Non-invasive monitoring of 4T1 murine mammary carcinoma blood vessels after electroporation-based therapy using combined hyperspectral imaging and laser speckle contrast imaging

Tumor vasculature plays an essential role in tumor growth and is a potential target for cancer treatment. Monitoring the vasculature during tumor growth, disease progression, and after treatment (e.g., radiotherapy and gene electrotransfer (GET)) could provide valuable diagnostic information and improve knowledge of tumors and their microenvironment. Moreover, it could provide predictive information for tumor treatment and improve therapeutic outcomes. This study combined hyperspectral imaging (HSI) with laser speckle contrast imaging (LSCI) to monitor 4T1 murine mammary carcinomas grown subcutaneously in dorsal skinfold window chambers (DSWCs) over 14 days. Specifically, we utilized a custom-built HSI system with a spectral range of 400-1000 nm and an LSCI system with a 650 nm laser. Using LSCI, we monitored the blood flow in blood vessels and tissue perfusion, while HSI enabled us to detect tumor margins and track oxygenation changes during tumor growth and after electroporation-based therapy. Our findings indicate an immediate >70% reduction in blood flow within tumor vessels after the GET procedure, which could be attributed to vasoconstriction induced by the electrical pulses. Additionally, the overall tumor perfusion decreased by at least 30% post-treatment and gradually increased in the following days. In contrast, a control tumor that received no treatment exhibited a substantial increase in blood flow, possibly linked to an elevated need for oxygen and nutrients due to tumor progression. Our study demonstrates that the combined HSI and LSCI optical imaging techniques effectively monitor blood flow, tumor perfusion, and oxygenation alterations within tumor vessels following electroporation-based therapy.