I had another MRI scan recently and I thought it might be an idea to put some thoughts down about what it is and what the experience is like being inside one of these machines, but firstly, what is it:
What is an MRI scanner?
Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body. In many cases, MRI gives different information about structures in the body than can be seen with an X-ray, ultrasound, or computed tomography (CT) scan. MRI also may show problems that cannot be seen with other imaging methods. source
There are two types of MRI scanner, open and closed. I've never seen an open scanner, the scanner I've been in in our local neuro department is closed. Here is a picture I got from the web showing a typical MRI scanner:
So, what's it like as a patient?
Getting a limb scanned, I imagine, simply means being partially entered into this machine on the sliding bed that the operator controls and moves you in or out to the desired position, but in the case of any neurological condition, like MS, they insert you head first and put you in the machine to the full extent. In the case of a head or neck scan it's very important that the patient doesn't move at all, so your head is placed inside a smaller tube (something like a motorcyclist's helmet, but more open) and some foam pads are inserted at either side of your head to make you fit. Of course, this is after they've given you earplugs to wear (as the scanner is quite noisy) and sometimes it gets quite hard to hear what the staff are saying to you. This is easily remedied by saying something like, "Speak up! I can't hear you!"
The scanning room and preparation
The actual scanning room is kept quite warm to make it comfortable and because you've probably had to leave your regular clothes in a locker in a nearby changing room and put on one of those dreadful hospital gowns - don't worry, everyone looks terrible in them. This is so that no metal is accidentally brought into the room as anything with iron (Fe) in it will heat up in the presence of a strong magnetic field. The staff will also ask you to remove jewellery or metal hair clips and ask you if you have any metal pins or clips within your body, following surgery. Metal fillings are OK, but you would be asked to remove any metal dentures as a precaution. I use a metal walking stick and even that was replaced with a wooden one for the duration of my visit to the scanning room.
Someone will go over your medical history with you and ask you to sign a consent form.
Getting the scan
The scanner itself is a long and fairly narrow metal tube. Some people find this very claustrophobic and simply can't do it, although I have heard of patients being offered sedation to help calm there nerves. I have never found this a problem, although when getting my most recent scan after about 45 minutes I was getting uncomfortable and simply wanted to move a bit, so I got to the point that I was keen to get out, but I've never been panicky as I can imagine some people might find it. You are given a button or squeezy ball to press in the event of you really needing to get out in a hurry, so there is a 'get out clause' if you really can't go through with it.
One thing I quite like is a mirror is fitted at an angle above your eyes so that you can see out the open end of the scanner and watch the person doing your scan through the glass of the control room. I either watch him/her or simply lie with my eyes shut. There is a speaker in the scanner so that the operator can speak to you, but this is woefully quiet in my experience - not surprising with a head surrounded by foam and ears stuffed with earplugs! I've asked a couple of times that they turn the volume up, but it's never sounded very good. When I have heard what is being said, it's things like, "Just setting up for another scan, now...", "This scan takes six minutes...", "You're doing really well!" So, if you can't hear them it's not as if you're missing anything important, such as, "Do you want a cup of coffee?"
I've heard that in some scanning rooms they play music, but I've never been treated to that, or maybe I haven't heard it because of all the foam around my ears.
The scanner is very noisy, so any thoughts (certainly, in my case) of falling asleep are forgotten, however, I personally try to relax as much as possible and drift of into my own thoughts to pass the time. The sounds are intermittent, but regular. They remind me of an old type of school fire alarm than gave a horrible metallic sound. The MRI scanner's sound starts and stops and the ear plugs do help. The sounds only occur when they're actually doing a scan, you get a rest in between scans.
Every time I've had a scan, they've also used a contrast medium. This is a chemical that produces a different appearance on the scan and hopefully allows the medical team to see things they wouldn't ordinarily see without it. If you are to get this, you are brought back out of the scanner and get an injection into a vein in your arm. Some people feel the cold running up their arm as it goes in, but I've never felt this. Then it's back in for another scan - and by this time you're becoming quite an expert.
When it's over
When the scan is finished, you are brought out of the scanner on the electric bed that you are still lying on and foam, then earplugs are removed. The staff, in my experience, sit you up and insist you take a minute to get your balance back and then it's all over. Last time I was in for a scan I suggested that patients should be given a cup of tea and a chocolate biscuit as a reward, like the Blood Transfusion Service do, but although I managed to get a few chuckles from the staff I was unsuccessful.
Getting the results
The results are not generally available immediately. The scans are sent to your consultant who updates you at your next appointment. If it's urgent that the results are known more quickly, then you'd no doubt know a short time later.
The scan isn't painful in anyway, it just takes a bit of time. If you have a problem with small spaces it could be difficult for you, or not possible at all. The staff, in my experience, are excellent and do their best to put you at ease and guide you through the procedure. My only bugbear is they speak too quietly through the MRI speaker, despite knowing you've got earplugs in!