Thickness of soft tissue of lower extremities measured with magnetic resonance imaging as a new indicator for staging unilateral secondary lower extremity lymphedema

BACKGROUND: Chronic progressive swelling of the lower extremity due to secondary lower extremity lymphedema (LEL) can affect a patient's quality of life, both physically and psychologically. A feasible and reproducible method for detecting and staging LEL will facilitate decision-making about appropriate management strategies. PURPOSE: To determine whether the thickness of the soft tissues of the lower extremities, measured with magnetic resonance imaging (MRI), could stage unilateral secondary LEL. MATERIAL AND METHODS: Seventy-two women with unilateral LEL and 22 participants without LEL underwent lower extremity MRI after treatment of uterine malignancies. LEL was classified clinically as stage 0, 1, 2, or 3. On fat-suppressed T2-weighted mid-axial images of calves and thighs, the total thickness of the soft tissue (TT), muscle thickness (MT), subcutaneous tissue thickness (STT), and the differences in TT (DTT), MT (DMT), and STT (DSTT) values and corresponding measurements in the contralateral lower extremity, were obtained and analyzed statistically for staging LEL. RESULTS: There was a trend for the TT and STT of the affected calf and thigh to increase with increasing LEL stage. These parameters were strongly and moderately correlated with LEL stage, respectively (P < 0.001). Both the DTT and DSTT of the calves or thighs were strongly correlated with LEL stage (P < 0.001). Among the parameters, the DSTT of the calves could best stage LEL, with an area under the receiver operating curve of more than 0.89. CONCLUSION: The DSTT of the calves could be recommended as an informative indicator for staging LEL.