i am very claustrophobic so much so i could not complete a closed MRI, i was scheduled for an open one which took hours due to them scanning both head and spine. it was fine, i am unable to lay flat on my back so i was allowed to lat on my side, they packed sponge blocks around me so i stayed still and comfy, the machine makes some funny noises, stops and starts and every now and then the bed shakes a bit, but i took myself into my own thoughts and was surprised when they finished and i checked my watch to find how long i was in there, it was twice as long as it seemed!
the worst bit was the washed out feeling i had for a day or so afterwards, i think it was a slight reaction to the dye stuff they used.