My experience... First they start an IV. Then you just lay there in the machine. If your gallbladder is difficult to see they may give you morphine which somehow makes it easier to visualize. You must have a driver with you if this is necessary. I didn't need it. I think I laid there about 45 minutes (?) then they come for the dreaded CCK injection. This will make you gallbladder contract and it may replicate your symptoms. Peope's response to this will be different. For me, it was the worse nausea and pain I ever experienced. I almost couldn't stand it. It (the slow injection of CCK) lasted about 7 minutes. I felt for sure I was going to vomit but I never did. After I was done I felt quite nauseous for a couple days but those seven minutes really sucked. The study showed my gallbladder functioned at 23%. I was told because I reacted so strongly to the CCK I was a good candidate for gallbladder removal. I had it out and five months later I am worse off then before but that is another story. Not trying to scare you, except for the CCK it was very easy and maybe you won't react to that at all. Good luck.