Multi-nuclear 1H and 23Na MRI investigation of fibroadipose tissue sodium in patients with secondary lymphedema

Advanced-stage lymphedema is a disease of chronic fluid accumulation and tissue inflammation that results in fibrosis and subcutaneous fat expansion in affected limbs. Assessment of fat and fibrosis currently relies on biopsies or non-specific bedside measures. Noninvasive MRI could be important for understanding pathophysiology and evaluating emerging therapies. We cross-sectionally evaluated multi-nuclear proton and sodium MRI in patients with lower-extremity secondary lymphedema. Results reveal subcutaneous adipose tissue expansion throughout the affected calf, locoregional fibrosis, and elevated sodium content in fibroadipose tissues particularly in the anterior calf, thereby highlighting the relevance of these technologies for interrogating tissue health in lymphedema.