Modified Lymphoscintigraphy in Primary Lymphatic Insufficiency of the Lower Limb

Primary lymphedema of the foot and toes could be sometimes misdiagnosed by lymphoscintigraphy as a whole lower limb lymphatic insufficiency (LLLI). This is caused by using standard lymphoscintigraphic protocol based on one interstitial injection of radiotracer applied into the first interdigital space followed by image analysis of lower limb lymphatic vessels and lymph nodes. Here, we show that a modification of the lymphoscintigraphic protocol and introduction of a second dose of radiotracer right above the inner ankle to the clinically healthy tissue can more accurately describe morphological abnormalities of the superficial lymphatic system at the lower limb and thereby refine the diagnosis of the LLLI. Fourteen patients with swelling of the foot and toes (16 lower limbs) were examined using standard lymphoscintigraphic protocol. Subsequently, modified lymphoscintigraphy was performed. While standard lymphoscintigraphy showed severe lymphatic insufficiency of the superficial lymphatic system in all 14 patients (in 16 lower limbs), including significantly reduced number of inguinal nodes, modified lymphoscintigraphy revealed almost normal morphology of superficial lymphatic vessels in 11 patients (in 13 lower limbs) throughout the entire lower limb proximal to the application site. In conclusion, using the modified lymphoscintigraphy protocol in patients with foot and toes primary lymphedema can refine diagnosis and follow-up medical management.