During the MRI procedure, part or all of the body will be passed into a long, narrow tube scanner, which is open at both ends. The scanner has an intercom, which will allow you to speak to the doctors and staff during the procedure. The machine will produce a loud knocking noise. This is normal. You will be given earplugs to protect your ears. The MRI will also require a line to be inserted into one of your veins to inject the contrast agent. Healthy volunteers participating in this study will not have the contrast agent injected during the scan.