Quantitative imaging of lymph function

Functional lymphatic imaging, was demonstrated in the abdomen and anterior hindlimb of anesthetized. intact Yorkshire swine by using near-infrared (NIR) fluorescence imaging following intradermal administration of 100-200 mu l of 32 mu M indocyanine green (ICG) and 64 mu M hyaluronan NIR imaging conjugate to target the lymph vacular endothelial receptor (LYVE)-1 on the lymph endothelium. NIR fluorescence imaging employed illumination of 780 nm excitation light (similar to 2 nW/cm(2)) and collection of 830 nm fluorescence generated from the ima imaging agents. Our results show the ability to image the immediate trafficking, of ICG from the plexus, through the vessels and lymph-angions, and to the superficial mammary. subiliac. and middle iliac lymph nodes. which were located as (Jeep as 3 cin beneath the tissue Surface. Packets of ICG-transited lymph vessels of 2-16 cin length propelled at frequencies of 0.5-3.3 pulses/min and velocities of 0.23-0.75 cm/s. Lymph propulsion Was independent of respiration rate. In the case of the hyaluronan imaging agent. lymph propulsion was absent as the dye progressed immediately through the plexus and stained the lymph vessels and nodes. Lymph imaging required 5.0 and 11.9 mu g of ICG and hyaluronan conjugate, respectively. Our results Suggest that mnicrogram quantities of NIR optical imaging agents and their conjugates have a potential to image lymph function in patients suffering from lymph-related disorders.