A system for evaluating patency includes a light sensor (128) positionable relative to a blood vessel to receive light from the blood vessel and convert the light into an image signal. Aphoto-plethysmography (PPG) interpretation module (115) is configured to receive the image signal and output pixel values in an image representing PPG information. An image generation module(148) is coupled to the PPG interpretation module to receive the pixel values and generate a PPG map to be output to a display for analysis.
