V.W.
Call around. I read an article in Consumer Reports just this past year that specifically mentioned MRIs as one of the medical items that has a HUGE variability in costs. If I remember correctly from the article, the larger the institution the better chance of a lesser cost (although even amongst the larger hospitals/MRI facilities the cost varies), because the machines are extremely expensive and they have to be paid for. It's sort of a "duh" moment if you think about it. A larger, busier place will use it more, cutting down the "per use" expense to pay for the machine. A smaller, less busy place will need to charge more per use to cover the same cost of the machine.
Call around.