Contrast-enhanced ultrasonography as an adjunctive method to ICG lymphography for functional lymphaticovenous anastomosis.

Abstract

Indocyanine green (ICG) lymphography is the reference standard for evaluating lymphedema stage and identifying lymphatic vessels. However, the penetration depth was limited to 1-2 cm from the skin surface. This prospective study compares clinical outcomes following lymphaticovenous anastomoses (LVA) in patients with upper and lower limb lymphedema using contrast-enhanced ultrasonography (CEUS) with ICG as a preoperative imaging modality. Under general anesthesia, Sonazoid® was injected subcutaneously to visualize functional lymphatic channels via CEUS. We analyzed the changes in limb circumference and inter-limb ratio (ILR) using bioimpedance to measure electrical resistance between the CEUS plus ICG group and the ICG-only group to see the effect of CEUS-assisted LVA. No significant demographic differences existed between the two groups (CEUS plus ICG group vs. ICG-only group). The ILR decrease of the Z1 value measured using bioimpedance was statistically significant (p = 0.042 for the upper limb, p = 0.002 for the lower limb)- CONCLUSIONS: CEUS allowed us to identify deep-lying, functional, and large lymphatic channels. In conclusion, the combination of CEUS and ICG for identifying lymphatic channels has the potential to lead to a more functional lymphovenous anastomosis.