Estimation of Arm Adipose Tissue Quotient Using Segmental Bioimpedance Spectroscopy.

Background: Breast cancer-related lymphedema (BCRL) is a chronic condition characterized by accumulation of lymph fluid that may subsequently become fibrotic with infiltration of adipose tissue. Bioimpedance spectroscopy (BIS) is the preferred method for early detection of lymphedema as it can estimate extracellular lymph fluid. This study developed a modified impedance technique that concurrently estimates both lymph accumulation and increases in adipose tissue. Methods and Results: BIS was used to estimate the adipose tissue volume in a cohort of healthy women (n=171), which was found to be highly correlated (r>0.87) with measurements of adipose tissue obtained using the reference method of dual-energy X-ray absorptiometry (DXA). In a separate cohort of women with BCRL (n=16), adipose volumes measured by BIS and reference method, respectively, were 2452.9933.3mL and 2109.1 +/- 824 6mL for affected arms; 1770.9 +/- 747.8mL and 1801.4 +/- 775.7mL for unaffected arms; and comparable values for a group of age-matched controls were 1862.5 +/- 661.6mL and 1657.0 +/- 641.1mL for age-matched control arms. The increase in adipose tissue in affected arms was significant irrespective of the method of measurement, p<0.02 and p<0.001 for BIS and DXA, respectively. Conclusions: An impedance method is described that can estimate increase both in lymph accumulation and adipose tissue in breast cancer-related lymphedema.