i. Age > 70 ii. Diabetes iii. Personal history of renal disease iv. Family history of renal disease (e.g., polycystic kidney disease) v. Known solitary kidney vi. Other medical conditions that may affect the kidney (e.g., Lupus, multiple myeloma) c. Subject has taken metformin (Glucophage) within 48 hours of procedure d. Subject has had a prior reaction to iodinated contrast e. Subject has multiple allergies and/ or severe asthma regularly treated with medication f. Subject has had an episode of serious allergic reaction (anaphylaxis) to any substance