Edema Areas of Calves Measured with Magnetic Resonance Imaging as a Novel Indicator for Early Staging of Lower Extremity Lymphedema.

Abstract

Staging of lower extremity lymphedema (LEL) is difficult in clinical work. The excellent soft tissue contrast of magnetic resonance imaging (MRI) enables soft tissue changes to be feasibly and reproducibly characterized and distinguished. To determine whether cross-section areas of edema calves measured with MRI could be useful for staging of the LEL. We recruited 138 participants who were clinically diagnosed with LEL: 61 unilateral and 77 bilateral LEL. Two legs underwent different stages of LEL. Fourteen characters are diagnosed without LEL; we assumed them as stage 0; age-matched 54, 59, and 54 lower extremities had the LEL, which are classified as stages 1, 2, and 3, respectively. On fat-suppressed T2-weighted mid-axial images of calves, the total area of the soft tissue (TA), muscle area (MA), and the water area (WA) of subcutaneous tissue of the bilateral claves were measured and analyzed statistically for staging of LEL. The difference of TA (DTA) of the unilateral LEL was also analyzed. TA and DTA showed statistical differences among each stage (p < 0.0001), except that it was challenged in making off stages 0 and 1 (p > 0.05). No significant difference was found among four stages of LEL in MA. WA was able to display the perfect sensitivity to lymphedema appearance (p < 0.0001, sensitivity = 100%). The WA of the calves could be suggested as a specific indicator for diagnosis of LEL. TA and DTA are the secondary indicators for staging of LEL.