Background: We previously invented a new technique to measure the cross-sectional area of soft tissue of a limb (ΔCSA) with lymphedema using ultrasonography. The measurement correlated strongly with both circumference and volumetry in normal subjects. The purpose of this study was to measure the reliability and accuracy of the method in patients with lymphedema. Methods and Results: Ultrasonography was performed on both arms of 69 female patients diagnosed with stage ≥1 lymphedema related to advanced breast cancer. At 10 cm above elbow (AE) and below elbow (BE), soft-tissue thicknesses at various locations were measured by two examiners. Subcutaneous tissue stiffness was also obtained by measuring thickness differences of soft tissue when applying minimal and maximal pressure to the skin (compliance) and its ratio to the initial thickness (compliance ratio). ΔCSA showed a strong positive correlation with circumference (r = 0.758 to 0.951), and a moderate negative correlation with Z at 5 Hz (r = -0.326 to -0.486). Intra- and interclass coefficients of all ultrasonography measurements were moderate to excellent (0.623-0.990). Compliance measured at 10 cm BE on the lesion side was significantly higher than on the normal side (p < 0.001), and compliance measured at 10 cm AE showed no difference between the two sides (p = 0.653). Conversely, compliance ratios measured at 10 cm AE and BE on the lesion side were significantly lower than on the normal side (p < 0.001). Conclusion: Thus, ΔCSA using ultrasonography could be a particularly viable option for determining status in lymphedema patients.
Keywords: cross-sectional area; lymphedema; ultrasonography.