The major cause of mortality and morbidity in these patients is the deterioration of pulmonary function by chronic chylous effusions and progressive interstitial lung disease. Unfortunately, little is known about biomarkers, risk stratification or the pathophysiology of this progression. The understanding of changes in patients' lymphatic anatomy with LA is hindered by the difficulty of imaging the lymphatic system. Dynamic Contrast Enhanced MR Lymphangiogram (DCMRL) is a technique that has recently been developed, allowing dynamic MR imaging of the lymphatic system by injecting gadolinium contrast agent in the groin lymph nodes.