M.R. I. Okay? Adventures in a dark tunnel
I signed up a while ago to participate in a functional Magnetic Resonance Imaging (fMRI) study at UBC. The “functional” part means that the study looks at neural activity, on top of a regular MRI, which only looks at structure. The process for the patients is pretty similar whether MRI or fMRI, though the data generated is quite different. Anyhow, the study was to be conducted through the UBC MRI Research Centre. One of the neuroscience labs on campus (Dr. T Woodward’s) was seeking subjects to explore areas of the brain involved when making probability ratings of scenarios; there were also behavioural elements of the study and would eventually be comparison with reasoning tendencies in schizophrenic patients.
Though the consent form indicates no direct benefit to participants, I thought I would derive an experience worthwhile of a) sharing with patients under my care who will be sent for MRIs b) better understanding what a friend of mine goes through every year or two and c) sharing with the blogosphere.
The process of getting ready was fairly simple:
- One of the students running the experiment collected me from the hospital lobby and ushered me to the MRI
- I filled out a study consent form and the MRI checklist; there are many exclusion criteria but luckily nothing was a problem for me; things like pacemakers implanted, the possibility of metal foreign bodies in the eye, metallic prosthetic implants, etc. would be “no-gos.” Though it varies slightly from hospital to hospital, here is the MRI Safety Checklist that we went by
- They advised me that if I had a tattoo, it could become quite warm; this is interesting and was debunked on Mythbusters (sortof)… Anyway, there is lots of conflicting data about it so I’d like to write about it later
- We did a practice test on a laptop so that I would be familiar with the controls for the experiment and understand the scenarios I was to be responding to; basically I had to rank the likelihood that one object (either black or white) came from one pool vs. another pool filled with those black and white objects; the pools would have varying ratios of black:white objects. I also had to assess the proportion of one colour object in the pools (i.e. the total proportion that were black or white).
- I was instructed to change into hospital jammies, remove all jewelry or piercings, use the washroom, and sit in the waiting room
- They positioned me on the scanner bed, put a pillow under my legs and head, and put a blanket over my legs
- I was handed the controller; a sort of modified half-keyboard with only five buttons, to be controlled by my right hand
- They put earplugs in my ears, wrapped my head in a blanket, and put the guide around my head (to keep it still), and slowly advanced me head-first into the narrow tube
The scan itself was very noisy. It made awful screetching and clunking and whirring noises. I didn’t know when it was scanning and when it was doing other stuff. It was also very cosy; I could feel my arms touching the sides of the tubes. My head was so wrapped up and pretty well locked in place. I didn’t try moving it, but I doubt I could have if I had wanted to. Very tight.
- I had to stay still. About an hour with a few little ‘rest’ breaks of not moving. I was nervous about swallowing and blinking – unavoidable movements – but they weren’t a problem in the end
- It was a little chilly so I was glad to have the blanket on my toes. I recommend keeping your socks on!
- There was a panic button in case I freaked out, but I was more nervous about accidentally pressing it than actually needing to
- I did the trials (which I’m not going to describe in detail), by responding to questions on a screen that was displayed via an angled-mirror in front of my face; looking “outwards” made the experience less claustrophobic than it probably would have been had I not had anything to focus on
- It scanned me while I was doing the tasks; I wasn’t really that bothered by it, because I was focused on trying to answer the questions as best I could (even though I doubt my actual answers matter)
- The tech periodically asked me how I was doing. What to say other than “good!,” I don’t know
- When it was over, one of my feet was a little bit numb because it had been at a weird angle but otherwise I was pretty comfortable
They gave me my MRI images on DVD and I could not resist looking through them at home. There is fortunately an executable included on the disk that allows me to view the data. I’m not a radiologist, and the protocols used for the study are a bit different than would be used for a diagnostic study, but there were no obvious tumours, bleeds, plaques, or accelerated atrophy. Cool!