This study will be divided into two stages. In the first stage the investigators will assess the transplant kidney with ultrasound after contrast injection (Sonazoid) to determine if contrast in the kidney is detectable by ultrasound and to determine if the amount of perfusion can be quantified directly or qualitatively. The investigators aim to have one to two subjects in this stage. If perfusion of the kidney can be assessed, then the investigators will move to stage two of the study.