Staging System of Three-Dimensional Non-Contrast Magnetic Resonance Lymphography in Secondary Lower Extremity Lymphedema.

Non-contrast magnetic resonance lymphography (NMRL) has been reported to be efficient for the evaluation of lymphedema. However, its characteristic findings and grading system are yet fully clarified. We retrospectively examined 48 patients with secondary lower extremity lymphedema (LEL) who underwent NMRL and indocyanine green lymphography (ICG-L). The lower extremity was divided into 5 areas for NMRL evaluation, and the prevalence of characteristic NMRL findings (Mist, Spray, and Inky) and the 3D NMRL stage that we proposed were compared according to the ICG-L stage. All characteristic NMRL findings increased in prevalence with the progression of the ICG-L stage (Mist, Spray, and Inky: P < 0.001, < 0.001, and < 0.001, respectively) Pre-dominant findings in each segment changed significantly from Mist in the ICG-L stage 0-Ⅱ, to the Spray in ICG-L stage Ⅲ-Ⅳ, to the Inky in ICG-L stage Ⅴ (P < 0.001). 3D NMRL stage significantly advanced with the progression of the ICG-L stage (rs = 0.72; P < 0.001). We believe this severity grading system is useful for efficient evaluation of fluid accumulation in LEL patients.