Study Procedure: Each subject will undergo a single MRI scanning session. Caffeine will be stopped 12 hours prior to the procedure. One IV will be started and subjects positioned in the scanner. Resting perfusion with Multihance Gd-BOPTA contrast agent will be performed first. The perfusion acquisition acquires 3-6 short axis slices each heartbeat and lasts for one minute. Then a standard regadenoson injection of 400ug/5cc will be given and MR imaging performed with a Gd-BOPTA contrast agent bolus 60-100 seconds later [9] [10].