Assessment of Renal Microcirculation With Rubidium Positron Emission Tomography

2\. Hypothesis 1. We hypothesize that RBF assessed with rubidium PET is on average lower in patients with CKD. To test our hypothesis, RBF of patients with CKD and coronary artery disease (CAD) risk factors, a population characterized by renal microvascular rarefaction, will be compared to RBF of healthy controls. 2. We hypothesize that RVR assessed with rubidium PET correlates with echographic measurements of renal resistance index (RI), the current non-invasive method of choice. 3. We hypothesize that RBF quantification with rubidium PET is technically reproducible, meaning that the variation on the measurements of RBF purely attributable to technical factors (camera, positioning, tracer injection, etc.) is relatively small. To test this hypothesis, two PET scans will be acquired within a short time period. 3\. Objectives and Endpoints 3.1. Primary Objective 1\) To compare RBF of patients with CKD and CAD risk factors to healthy controls 3.2. Secondary Objectives 1. To compare RVR of patients with CKD and CAD risk factors to healthy controls 2. To evaluate the correlation between RVR measured with PET to renal RI as measured with echography 3. To evaluate the repeatability and reproducibility of in vivo measurements of RBF and RVR