Near infrared CCD imaging of hemodynamics

This paper presents preliminary results of near infrared CCD imaging of hemodynamics with inexpensive system components. The motivation behind this is the requirement of a low-cost and easy to use system capable of aiding the physician in daily assessment of venous disorders such as chronic vein insufficiency (CVI) and deep vein thrombosis (DVT). Photoplethysmographic (PPG) systems with optical sensors are in wide use for these tests today. They essentially measure the blood volume in the top skin layers. Another method that has been described for imaging of veins is near infrared photography. The presented method combines the two. A monochrome CCD camera equipped with a >700 nm filter is mounted on a tripod. A constant indirect illumination is applied, then an exercise is performed by the patient. The camera takes a sequence of pictures of the perfusion area of interest, i.e. the lower leg. Digital filtering and sequence evaluation results in image-mapped data about venous reflow time, venous pump power and other relevant parameters. From this, conclusions can be taken as to the reason and location of disorders.