Differential phase analysis for high frame rate photoacoustic vector flow imaging

Blood flow can be a crucial diagnostic parameter for different pathologies. Photoacoustic imaging, unlike other imaging modalities, could play a role in enhancing blood flow measurements in smaller vessels without resorting to contrast agents. In this study, we show that differential phase analysis on photoacoustic signals acquired at a high frame rate (2 kHz) generated from flowing absorbers provides a good estimate of their velocities. Flow phantoms based on diluted Indian ink solutions with preset velocities ranging between 6 and 19 mm/s were imaged and profiled based on this method.