 Sodium Na hemostasis is abnormal in CKD patients, and this element can be deposited in the skin, muscle and skeleton - to cope with long term sodium loading. It is known that sodium stored in this non-osmotically active way, is profoundly inflammatory. Furthermore, inflammation has been associated with a number of uremic symptoms. The investigators will use novel Na MRI imaging to examine the Na deposition in skin, muscle and skeleton of three groups of patients: 1 chronic 3-times-a-week in-center hemodialysis patients, 2 peritoneal dialysis patients, and 3 patients with CKD stage 4-5; and compare these results to age and sex matched healthy controls. Additionally, they will investigate the association between sodium deposition in these tissues with uremic symptomatology and biochemical markers of metabolism. 