ASSESSING LOCAL TISSUE EDEMA IN POSTMASTECTOMY LYMPHEDEMA

Abstract

Overall limb lymphedema can be assessedby several methods but none are suitable todetermine local edema. Quantifying localedema could provide important informationnot previously available. Our goal was todetermine the suitability of using the tissuedielectric constant (TDC) as and index oflocal tissue water to detect and quantify edemain postmastectomy patients with unilateralarm lymphedema. Segmental arm volume andTDC were measured in both arms of 18women with unilateral lymphedema, and in15 premenopausal and 15 postmenopausalcontrols. TDC was measured at a frequencyof 300 MHz using open-ended coaxial probeswith effective measuring depths of 0.5, 1.5,2.5 and 5.0 mm. For patients and controls,absolute TDC depended on measurementdepth but for any depth the TDC of lymphedematoussegments was significantly greaterthan for non-affected contralateral arms(p<0.001). At a depth of 2.5 mm, the TDCratio between arms for patients was 1.64±0.30vs.1.04±0.04 for both control groups (p<0.001).No patient’s TDC ratio was as low as 1.2and no control subject’s TDC ratio was asgreat as 1.2. Results suggest that this methodis a good quantitative discriminator of thepresence of lymphedema in patients withunilateral limb lymphedema.