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

BACKGROUND AND OBJECTIVES: 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.

METHODS: 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.

RESULTS: 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.