²³Na-MRI Measures Tissue Sodium in Human Leg Lymphedema

Area of Science:

• Biomedical Imaging
• Physiology
• Medical Diagnostics

Background:

• Objective tools for quantifying lymphatic disease are limited.
• Tissue sodium (Na) is a potential physiological indicator of lymphatic dysfunction.
• Lack of in vivo imaging methods hinders characterization of sodium's role in lymphatic physiology.

Purpose of the Study:

• To apply 23Na-MRI for measuring tissue sodium content (TSC) in individuals with and without lower extremity lymphedema (LEL).
• To investigate the relationship between lymphatic dysfunction and TSC in LEL.
• To assess the potential of 23Na-MRI as an objective diagnostic tool for lymphedema.

Main Methods:

• A prospective, cross-sectional observational study enrolled participants with LEL and controls.
• 23Na-MRI was used to measure standardized TSC in the mid-calf.
• Lymphedema severity was assessed using clinical staging and 1H-magnetic resonance lymphangiography (MRL).

Main Results:

• TSC was nearly 50% higher in lymphedema legs compared to controls (p < 0.001).
• Elevated TSC was observed in skin (1.51-fold) and adipose tissue (1.47-fold) in lymphedema.
• TSC directly correlated with clinical stage and MRL-assessed lymphedema severity in skin and adipose tissue (p < 0.001).
• TSC accumulation patterns were identified in anterior subcutaneous adipose tissue, increasing with disease severity.

Conclusions:

• 23Na-MRI effectively demonstrates elevated TSC in lymphedema.
• Standardized TSC measurements are sensitive to lymphedema disease severity.
• 23Na-MRI shows promise as an objective imaging biomarker for lymphedema evaluation in clinical trials.