Multi-segment bioimpedance can assess patients with bilateral lymphedema

Bioimpedance spectroscopy (BIS) is used to assess lymphedema by measuring limb fluid content as an electric current passes through cell membranes and tissues. There are two primary device modalities, through which BIS is used clinically: single-segment bioimpedance (SSB) and multi-segment bioimpedance (MSB), which differ in their mechanisms of gathering measurements. In this cross-sectional study, we study the difference between SSB and MSB in evaluating lymphedema by referencing the results with indocyanine Green (ICG) lymphography. Patients with unilateral and bilateral lymphedema, presented to our department, were assessed with both SSB and MSB as part of a pre-lymphatic surgery evaluation between May 1, 2017, and November 31, 2017. Patients were imaged with ICG lymphography to confirm lymphedema presence. Standardized device measurement outputs from SSB and MSB were recorded and statistically analyzed. SSB was more sensitive (0.9) than MSB (0.75) for unilateral lymphedema. However, MSB had the added ability to assess patients with bilateral lymphedema with a sensitivity of 0.56 and specificity of 0.60. Furthermore, MSB had a stronger correlation with relative disease severity compared to SSB and quantified the differential extents of edema. In comparison, SSB provided a manipulated number, which was derived from a comparison of the abnormal to the normal limb. Medical staff reported MSB being easier to perform, and all patients reported the MSB measurement experience being more favorable. While both SSB and MSB provide diagnostic information on lymphedema, MSB is notably easier to perform, can detect bilateral disease states, and objectively quantifies limb fluid volume, allowing for disease tracking and assessment of surgical and rehabilitative treatment efficacy. On the basis of this study, our department has switched to universal MSB measurement.