Quantitative lymphoscintigraphy of the lower limbs for the diagnosis of phlebolymphoedema

Phlebolymphoedema is caused by the interaction of the venous and lymphatic systems in a state of chronic venous insufficiency in which increased microvascular filtration causes an increased rate of lymph production. Lymphatic drainage rate increases in response, but this is unsustainable and can cause lymphatic failure and oedema. We hypothesise that in phlebolymphoedema we could measure unusually high lymphatic drainage while the lymph system is still fully functional.

Patients referred for lymphoscintigraphic investigation of swollen legs between April 2021 and December 2022 were reviewed. Quantitative lymphoscintigraphy was performed following the technique of Keramida et al . (2017) and ilio-inguinal nodal uptake (IIQ%) was calculated. The presence of scintigraphic features of increased lymph production was noted for each limb.

A total of 39 patients were reviewed (78 limbs, 29F, 10M). Seven limbs were identified with supranormal lymphatic function (IIQ > 30%) plus three borderline. Of these 10 limbs, all had at least two scintigraphic features of increased lymph production.

Quantitative lymphoscintigraphy, although developed for diagnosing abnormally low lymphatic function, may also have utility at the upper end of the spectrum for identifying chronic venous insufficiency. An IIQ% upper normal limit of 30% could be used to diagnose venous insufficiency as the cause for limb swelling. This is of note for patients of large body habitus in whom venous ultrasound is difficult.