Inclusion Criteria:  Age 18-80 years Recipient of living donor kidney transplantation 4 or 7 years earlier Competent and able to provide written informed consent; Ability to comply with protocol  Exclusion Criteria:  Patients have clinically significant medical conditions within the prior 6 months before: e.g. myocardial infarction, congestive heart failure, stroke, that would, in the opinion of the investigators, compromise the safety of the patient. Severe chronic liver, heart or lung disease Undergoing acute rejection Contra-indication to biopsy; bleeding disorders Chronic infection Any active malignancy and undergoing therapy Kidney or ureteric stone Unable to give valid informed consent Known pregnancy or intent to conceive during the study period Pacemaker, implantable defibrillator, magnetically active metal fragments, claustrophobia or other contraindication to MRI Federal medical center inmates. Latex allergy