The accuracy of lymphatic ultrasound in measuring the lymphatic vessel size in lower limb lymphedema patients

Abstract

Lymphatic ultrasound is a newly developed method to observe the lymphatic vessels. In this study, we compared the diameter of lymphatic vessels observed on preoperative ultrasound with the actual lymphatic diameter (LD) of lymphatic vessels observed intraoperatively. The study included 32 lower limbs in 17 patients with lower limb lymphedema. Lymphatic ultrasound was performed using a commonly used ultrasound device, Noblus ultrasound system, with an 18MHz linear probe on preoperative day 1. We tracked the lymphatic vessels along the great saphenous vein, at the lateral calf, and at the lateral thigh, based on the lymphosome principle. We measured the cross-sectional height (CSH) and the cross-sectional width (CSW) of lymphatic vessels using ultrasound at the incision sites. Intraoperatively, we measured the diameter of the lymphatic vessel. Based on lymphatic degeneration, lymphatic vessels were categorized into four types using the normal-, ectasis-, contraction-, and sclerosis-type (NECST) classification. We evaluated 68 lymphatic vessels. The mean CSH, CSW, and LD were 0.65±0.35mm, 1.3±0.41mm, and 0.79±0.35mm, respectively. The correlation coefficient between the CSH and the LD was 0.36 and that between the CSW and LD was 0.24. A significant difference was observed in CSH between the ectasis and contraction types (p=0.0025). We can somehow predict the size of the lymphatic vessels with CSH in the lymphatic ultrasound, whereas CSW is not reliable.