What Factors Affect Interpretation of Tissue Dielectric Constant Values?

Objective.To investigate factors possibly impacting tissue dielectric constant (TDC) values. Background.TDC measurements are increasingly used as quantitative adjunctive tools to detect and assess lymphedema but factors affecting TDC values have not been fully studied. Methods.The factors of interest in this study were; 1) anterior vs. medial arm measurements, 2) total body water percentage (TBW) and arm fat percentages (AF), 3) TDC measurement depth and 4) skin firmness. In 40 healthy women (24.5±2.5 years) TDC was measured bilaterally on anterior forearm to 0.5, 1.5, 2.5, and 5.0 mm depths using a multi-probe device and on anterior and medial aspects using a compact device. TBW and AF were measured at 50 KHz and skin firmness measured by skin indentation force (FORCE) required to indent skin 1.3 mm. Results. Resultsshowed: 1) No statistically significant difference in TDC values between anterior and medial arm, 2) A moderate direct correlation between TDC and TBW (r=0.512, p=0.001), 3) an inverse correlation between TDC and AF (r=-0.494, p Conclusions.The findings provide a framework to help interpret TDC values among many divergent conditions in both research and clinical applications