Photoacoustic imaging of valves in superficial veins

Background and Objectives: In intravenous access to veins there is a risk of puncturing venous valves or blocking of the catheter by the valves. Therefore, we have investigated whether and how photoacoustic imaging (PAI), which visualizes the lumen of blood vessels, can be used to detect these valves. Study Design/Materials and Methods: Venous valves in superficial veins on the dorsal side of the hand of human volunteers were located by palpation and visual inspection. Next, this location was imaged using PAI. Results: In 16 of 21 human volunteers venous valves that were found by palpation could be observed by PAI as local discontinuities in the imaged vessel. From these images, four characteristic features by which venous valves can be recognized in photoacoustic images were identified. Conclusions: PAI has the potential to be applied in the detection of venous valves.