Magnetic resonance imaging (MRI) is a radiology technique used to visualise in detail internal structures of the body. MRI scanners produce strong magnetic fields and radio waves that interact with atoms that make up certain substances, making them detectable by the scanner. This type of scan is especially used for soft tissue imaging, being quite effective to diagnose health conditions that affect organs, muscle tissues, bones and joints.
So far, I had three MRI scans in order to check the condition of my TMJs. The first one was back in 2005, requested by my first oral-maxillofacial surgeon in Portugal. The other TMJ MRIs were done in November 2010 and November 2011, both at Cardiff University Hospital under Mr. C.'s care.
Fortunately, I didn't have to pay of any of these. The health insurance I had in Portugal covered the first MRI expenses. The last two were done free of charge, thanks to the welsh public health system. The waiting time can considerably long through the NHS (National Health Service). However, depending on the severity of the health condition in question, it might be preferable to wait a few months than to pay the full cost of the scan. MRIs are really expensive, generally priced above £200 (UK).
Although a MRI is a safe and harmless procedure, it may be quite uncomfortable, and it is certainly painful for people affected by TMJ disorders. Therefore, it is best to be prepared and to know what to expect beforehand.
Because of the strong magnetic field generated by the scanner, there is a list of things to be checked before the scan. People with certain medical devices implanted in the body may not be able to have a MRI, as the scanner may interfere with these. Tattoos present some concern, as old types of ink contain traces of metal, which can be also affected. However, tattoos done recently are safe since inks used nowadays are metal-free. Since I have several tattoos, the radiologist had to confirm that it was safe for me to be scanned. For the same reason, all jewellery and clothes that have metallic parts must be removed prior to the scan.
The TMJ MRIs I have done were twenty to thirty minutes long. I was always given soft earplugs to wear during the scan, as the scanner produces really loud sounds while working. Because these were TMJ scans, only the top half of my body was lying inside the scanning tube, so it wasn't as claustrophobic as some people may think.
The scan is done in two parts, with both TMJs visualised for comparison. During the first stage the mouth remains closed, making this the easiest part of the scan. In the second stage, the mouth is locked open with a syringe between the teeth. Needless to say, this is the painful and most uncomfortable part. It is necessary to remain completely still throughout the scan. But with the mouth locked open, a lot of saliva accumulates in the back of the throat, and one has the need to be constantly swallowing it. Also, after the first few minutes the facial muscles begin to contract and twitch, but there is nothing one can do alleviate this. Just take deep breaths and do the best to ignore the pain till the end of the scan.
The hardest MRI I've done was the last one, because of my limited mouth opening. I was given the smallest syringe they had, but even so, it could barely fit between my teeth. By the end of the scan, I couldn't control the tears due to the pain. I was completely knackered for the rest of the day.
The two stages of the scan are done in order to compare the relative position of the condyle and the disc during mouth opening and closing. Bone structure is also analysed in detail, to check any alterations there might be. The images below are examples of TMJ MRI scans showing a normal joint (left) and an unhealthy joint (right), in open (bottom) and closed (top) mouth positions.
TMJ MRI scan images
A findings report is usually ready a week after the scan. However, I never had access to my scans done at Cardiff University Hospital, and their results were only made known to me on the consultation following each scan. Even so, I was not given the original reports, as these are part of my file at the oral-maxillofacial surgery.
Thanks for posting this! I'm having a TMJ MRI soon and have found a lack of information on the test so far. Thank you.
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