Renal Blood Flow Measurement With Positron Emission Tomography (PET)

Arm 1. Inclusion Criteria: * males and females, age 18-40 years * willingness to provide written informed consent Exclusion Criteria: * history of coronary artery disease (CAD) * history of renal disease * risk factors for cardiac disease, renal disease, or atherosclerosis, including diabetes mellitus, hypertension, tobacco abuse, hyperlipidemia, family history of CAD or chronic renal failure * history of liver disease or other significant disease * pregnant females Arm 2. Inclusion Criteria: * males and females, age \> 18 years * active hemodialysis or peritoneal dialysis for at least six months * any etiology of chronic renal failure except active glomerular nephritis * presence of two kidneys * willingness to provide written informed consent Exclusion Criteria: * decompensated heart failure (subjects must be on stable medical therapy for one month) * any previous renal transplant (subjects may be on renal transplant waiting list) * history of liver disease * pregnant females Arm 3. Inclusion Criteria: * males and females, age \> 18 years * documented evidence of renal artery stenosis equivalent to a 75% stenosis by one of the following clinical tests: MRA, Doppler, Renal Angiogram, Abnormal captopril renal scan * evidence of renal insufficiency with serum creatinine \>= 1.3 mg/dL * presence of two kidneys * willingness to provide written informed consent Exclusion Criteria: * revascularization of stenotic renal artery * decompensated heart failure (subjects must be on stable medical therapy for one month) * any previous renal transplant (subjects may be on renal transplant waiting list) * history of liver disease * pregnant females