I frequently receive emails from therapists questioning protocols they were taught in view of treatments being promoted that use fluorescent mapping of superficial pathways to guide treatment. I recently posted an explanation on the imaging technique and also reported on a studying which had used it to measure the rate of lymph flow, finding a doubling in the speed under MLD. View the previous post.
The earliest paper using ICG to image superficial lymph vessels during MLD was in 2011 (1). Tan and colleagues showed that ICG can quantify the rate of lymph flow and the contractile function of the lymph collector vessels in the superficial system. Their findings showed that that average apparent lymph velocity increased in both the symptomatic (+23%) and asymptomatic (+25%) limbs of subjects with LE and control limbs (+28%) of healthy subjects. The average lymphatic propulsion period decreased in symptomatic (-9%) and asymptomatic (-20%) limbs of subjects with LE, as well as in control limbs (-23%). This reduction in the propulsion period essentially means the contraction were faster. Although this video is from a different research team it does show how the lymph vessels respond to MLD (2).
What ICG fluoroscopy can't tell us, is what is happening in the deep system, nor the systemic effects of MLD which were shown by Heutzschenreuter, so it can't measure all our treatment outcomes. It will certainly help us to diagnose lymphatic disorders better as is demonstrated in the case study reported by Rasmussen et al (3) on diagnosis of lymphatic dysfunction in lower limb oedema.
Currently, ICG imaging for lymphoedema can only happen in research settings in Australia as it is an off label use of the ICG dye.