Question: What's the worst thing about MRIs?

Rebecca Dewey answered on 18 Jun 2015:

I wouldn’t say it was “worst” particularly, but there are a few limitations of MRIs:
(1) The big one. You can’t have one if you have any metal in your body that you can’t remove. So I work with deaf people and some of them use hearing aids or cochlear implants – this is a no no. You can’t have an MRI if you have a pacemaker or any other kind of medical device that can’t be removed. Some metal implants that are used to hold bones together (like if you’ve had your broken wrist pinned) are ok but you need to make sure that it’s safe and sometimes only the surgeon will know. A lot of women who use a particular kind of contraceptive device in the uterus can’t have an MRI. You need to take off any jewellery and body piercings. This is so very important because it can be very unsafe if you don’t follow this rule.

(2) It’s quite noisy. Yes, this isn’t nearly as big a problem as the metal thing. You put earplugs in, wear headphones, it’s fine! It makes some research into how the brain processes sounds quite difficult because you can hear the sound of the MRI still.

(3) It’s quite slow. If you want a really good picture of the brain to see every little detail it takes about 5 minutes. For the whole body it probably takes baout 1 hour. That’s not too bad. If you want to see how the brain responds to a picture, you need to take a very quick picture of the brain and take lots of them in very close succession. Taking one quick (not very good quality) picture of the brain takes at least 1.5 to 2 seconds. So if you want to see how the brain reacts to the picture, you only have one shot at it, or you have to show the picture for ages, which isn’t as helpful an experiment, or you have to show lots of pictures over and over, and record the brain each time. Basically this can get complicated. But because you can measure quite small differences, and you can fairly accurately tell where the places are that start responding to the picture, we put up with it being slow and find ways to work around it.

(4) It’s a bit tight. This is getting a lot better now as we have MRI scanners that have wide openings so you can see out easily and very big people can fit in them (and also animals – sometimes zoo animals or race horses need to have an MRI to see what is wrong with their knee etc). Some people find it uncomfortable being in a tight space. It doesn’t bother me!