Inclusion Criteria:  Age greater than or equal to 18 years For patients on maintenance hemodialysis: more than 3 months duration of therapy For patients with CKD: evidence of kidney disease persisting > 3 months and no indications to start dialysis For healthy controls: lack of kidney disease, cardiovascular disease, diabetes, liver cirrhosis and peripheral edema  Exclusion Criteria:  Pregnant, breastfeeding or intending pregnancy  Contraindication to MRI scan  Inability to tolerate MRI due to patient size and/or known history of claustrophobia. Mechanically implanted, electrically, or magnetically activated device or any metal in their body which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bioprosthesis, artificial limb, metallic fragment or foreign body, tattoos, shunt, surgical staples (including clips or metallic sutures and/or ear implants.)