Biomarkers in lymphedema assessment: integrating elastography and muti-frequency bioimpedance analysis

<b>Aim:</b> Multi-frequency bioimpedance analysis (MFBIA) is used to measure lymphedema, but it is a biomarker that is sensitive to stiffness. Lymphedema is a condition that can be accompanied by stiffness, but no studies have considered this, so we tried to use non-invasive elastography as a biomarker for stiffness.<b>Methods & results:</b> This retrospective study included 102 patients with lymphedema, divided into two groups according to the elastography strain ratio: stiff group (elastography strain ratio <0.7, n = 48) and non-stiff group (elastography strain ratio >0.7, n = 54). We estimated the volume of the affected arm based the extracellular water (ECW) volume calculated using MFBIA through a simple linear regression method. The adjusted R2 was 0.044 in the stiff group and 0.729 in the non-stiff group. Stepwise multivariate linear regression was used to investigate the significant factors for estimating the affected arm volume for each group. In the non-stiff group, the significantly associated factors were impedance at 50 kHz, weight, and height (adjusted R² = 0.724; <i>p</i> = 0.003). In the stiff group, significant associations were observed among impedance at 250 kHz, impedance at 1 kHz, weight, and height (adjusted R² = 0.705, <i>p</i> = 0.041).<b>Conclusion:</b> Considering the characteristics of lymphedema, using MFBIA concurrently with elastography can be useful biomarker for estimating lymphedema.