I did have an MRI that I shivered so much, they had to stop the MRI and get me heated blankets. I was simply frozen! it was the middle of winter, and they used the portable truck, cause the inside machine was on the fritz. It was 4 below outside, and felt the same inside.

Its important to get the pillow wedge under your knees, get two if its not high enough, and a warm blankie. You can always pull the blankie off, but its a pain to have to stop the test to go find one. Make sure you toilet first, and do some relaxation exercises.

its a difficult mental jump for me. Takes alot of focus, and relaxation to keep me in the tube.