Can bioimpedance spectroscopy (BIS) tell us about the form of lymphoedema?

Abstract

Bioimpedance spectroscopy (BIS) has proved useful for the rapid accurate and quantification of lymphoedema. The underlying principle is that the impedance of a limb to an applied low frequency alternating electric current is inversely proportional to the quantity of extracellular fluid, including lymph. While many studies have shown a high degree of concordance between impedance and limb volume measurements, the question has often been asked: “How is this influenced by the form of lymphoedema?” Lymphoedema may present in various forms, e.g. primarily fluid, fibrotic etc. Broadly, these may be envisaged to represent a continuum from “purely” fluid through gel-like to a pseudo-membraneous tissue-like structure. BIS allows estima-tion of tissue capacitance which for biological structures is a characteristic of the cell membrane and tissue inter-faces. This study tested the hypothesis that membrane capacitance (Cm) would differentiate limbs with lym-phoedema from normal. Cm was measured (SFB3, Im-pediMed Ltd, Brisbane) for both arms of 116 women with no history of lymphoedema and 41 women with clinically affirmed unilateral post-mastectomy lymphoe-dema.