Indocyanine Green Lymphography Findings in Primary Leg Lymphedema

Abstract

Indocyanine green (ICG) lymphography has been reported to be useful for the evaluation of secondary lymphedema, but no study has reported characteristic findings of ICG lymphography in primary lymphedema. This study aimed to classify characteristic ICG lymphography patterns in primary lymphedema. The study was a retrospective observational study. Thirty one primary lower extremity lymphedema (LEL) patients with a total of 62 legs were studied. ICG lymphography patterns were categorized according to the visibility of lymphatics and dermal backflow (DB) extension. Clinical demographics were compared with categorized ICG lymphography patterns. All symptomatic legs showed abnormal patterns, and all asymptomatic legs showed normal patterns on ICG lymphography. Abnormal lymphographic patterns could be classified into proximal DB (PDB), distal DB (DDB), less enhancement (LE), and no enhancement (NE) patterns. There were significant differences between PDB (16 patients), DDB (6 patients), LE (4 patients), and NE patterns (5 patients) in age (37.3 ± 18.3 vs. 61.8 ± 19.2 vs. 50.8 ± 27.7 vs. 29.2 ± 18.0 years, p = .035), onset of edema (23.9 ± 19.4 vs. 46.8 ± 27.0 vs. 43.0 ± 31.3 vs. 6.6 ± 14.2 years, p = .020), laterality (bilateral; 18.8% vs. 66.7% vs. 75.0% vs. 0%, p ¼ .016), cellulitis history(56.3% vs. 100% vs. 25.0% vs. 0%, p ¼ .007), and LEL index (292.2 ± 32.8 vs. 254.2 ± 28.6 vs. 243.3 ± 9.4 vs. 295.2 ± 44.8, p = .016). ICG lymphography findings in primary lymphedema could be classified into four patterns withdifferent patient characteristics.