Lee, M. D.; Osborne, C.; Stevenson, R.; MacDonald, A.; Ebner, G.; Jeffrey, D. A.; MacDonald, M. A.; Zhang, X.; Buckley, C.; Dabertrand, F.; Machin, D. R.; Au, J.; Harraz, O. F.; Tykocki, N.; McCarron, J. G.; Wilson, C.

VasoTracker 2 is an open-source platform for studying blood vessel dynamics, featuring versatile diameter-tracking software and complementary low-cost hardware components. This system surpasses existing tools through accessible, high-resolution analysis across multiple imaging modalities, enabling comprehensive assessment of vascular dynamics in both real-time and pre-recorded experiments. Advanced algorithms enable multi-point diameter tracking in branched vessels, automated pressure-response protocols, and reliable edge detection. The software can assess vessels imaged by brightfield microscopy, fluorescence imaging, and in ultrasound recordings, supporting diverse applications from isolated vessel studies to in vivo assessment. For ex vivo applications, VasoTracker 2 includes modular open-source hardware components that can be used to create a low-cost pressure myograph system: a confocal-compatible vessel chamber and a programmable pressure controller, VasoMoto. By combining powerful analytical capabilities with an open-access approach, VasoTracker 2 provides free software and low-cost hardware alternatives to commercial systems, democratizing access to advanced vascular research tools for scientists worldwide.