LE is a progressive condition, characterised by an accumulation of protein rich lymph in the interstitial space. It is caused by failure of the lymphatic system to conduct lymph back to the blood circulation, which leads to chronic inflammation [1]

LE is rarely fatal, but it is a disabling disorder that affects the patients' quality of life and causes significant morbidity.

It's management is very difficult: traditionally, LE has been commonly treated with a conservative approach, such as physiotherapy, lymphatic massage, wrapping and controlled compression [2]

In recent times, the implementation of new surgical techniques have changed the therapeutic approach of this disorder [3, 4]:

• free lymph nodes autologus transplantation that is recommended for patients affected by aplastic or hypoplastic LE

   

• lymphatico-venular anastomoses, thatis considered the treatment of choice for hyperplastic LE

Therefore, the is a need to perform proper imaging to assess lymphedema characteristics to establish correct selection of treatment and optimal management.

Different imaging techniques can be used for LE evaluation:

Lymphography that has been the only available technique to study LE for a long time. It involves the injection of lipiodol ultra-fluid into a previously surgical exposed and cannulated lymphatic vessel. This is an invasive technique and required long acquisition times and was often complicated by allergic reactions and complications like pneumonia, and it was therefore abandoned 

Lymphoscintigraphy is performed by injecting intradermal Technetium 99m sulfur colloid; the progression and the distribution of the radio-labeled particles is evaluated by a gamma camera, but subdermal lymphatics cannot be assessed

Indocyanine green (ICG) lymphography is performed by injecting ICG into the interdigital web spaces. After 4 hours, fluorescence images of lymphatic vessels can be obtained with a near-infrared camera device; the fluorescence images are digitalised for real-time display. The main limits are: the long time after the injection needed to mark the lymphatic vessels and difficulty to clearly identify lymphatic vessels in late-stage lymphedema