Skin Layer Thickness and Shear Wave Elastography Changes Induced by Intensive Decongestive Treatment of Lower Limb Lymphedema

Background: A detailed quantitative evaluation would be beneficial for management of patients with limb lymphedema. Methods and Results: In 47 patients with lower limb lymphedema at International Society of Lymphology clinical stage 2A (18 limbs), 2B (41 limbs), and 3 (13 limbs), we measured the limb circumference and thickness of epidermis, dermis, and subcutis layers with B-mode ultrasonography and subcutis elastic modulus with ultrafast shear wave velocity (ultrasound elastography) at 5 anatomical levels (M1 to M5) before and after a 3- to 5-day intensive decongestive therapy (IDT) session. Limb circumference and thickness of the epidermis, dermis, and subcutis were greater in the 72 limbs with lymphedema than in the 22 unaffected limbs before and after IDT. The affected limb volume was 10,980 [8458–13,960] mL before and 9607 [7720–11,830] mL after IDT (p < 0.0001). The IDT-induced change in subcutis thickness was −9 [−25 to 13]% (NS), −11 [−26 to 3]% (p = 0.001), −18 [−40 to −1]% (p < 0.0001), −15 [−35 to 3]% (p = 0.0003), and −25 [−45 to −4]% (p < 0.0001) and significantly correlated with the change in elastic modulus, which was 13 [−21 to 90]% (p = 0.004), 33 [−27 to 115]% (p = 0.0002), 40[−13 to 169]% (p < 0.0001), 9 [−36 to 157]% (p = 0.024), and −13 [−40 to 97]% (NS), respectively, at the M1, M2, M3, M4, and M5 levels. Intraobserver reproducibility was satisfactory for skin thickness and fairly good for elastography, but interobserver reproducibility was poor or unacceptable. Conclusions: IDT reduced the circumference and subcutis thickness of lower limbs with lymphedema and increased their elastic modulus, implying greater tissue stiffness probably due to fluid evacuation. Although subcutis thickness measurement proved to be reliable, technological and methodological improvements are required before ultrasonographic elastography can be used in clinical practice.