Tissue sodium content is elevated in the skin and subcutaneous adipose tissue in women with lipedema

Objective To test the hypothesis that tissue sodium and adipose content are elevated in patients with lipedema; if confirmed, this could establish precedence for tissue sodium and adipose content representing a discriminatory biomarker for lipedema. Methods Participants with lipedema (n=10) and control (n=11) volunteers matched for biological sex, age, body-mass-index, and calf circumference were scanned noninvasively with 3.0T sodium and conventional proton MRI. Standardized tissue sodium content was quantified in skin, subcutaneous adipose tissue (SAT), and calf muscle. Dixon MRI was employed to quantify tissue fat and water volumes of the calf. Nonparametric statistical tests were applied to compare regional sodium content and fat-to-water volume ratio between groups (significance: two-sided p≤0.05). Results Skin (p=0.01) and SAT (p=0.04) sodium content were elevated in lipedema (skin: 14.9±2.9 mmol/L; SAT: 11.9±3.1 mmol/L) relative to control (skin: 11.9±2.0 mmol/L; SAT: 9.4±1.6 mmol/L) participants. Relative fat volume in the calf was elevated in lipedema (1.2±0.48 ratio) relative to control (0.63±0.26 ratio, p