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It’s always a bit daunting to be told that you need to have a head MRI – especially if you’ve never had one before. If the procedure is completely alien to you, you may be wondering exactly what happens in an MRI. Specifically, what happens in an MRI of the brain?
It’s always best to go in prepared, so read on to find out exactly what to expect before, during and after a head MRI.
What exactly is a head MRI?
MRI stands for Magnetic Resonance Imaging. It uses magnetic fields and radio waves to create images of the inside of your body. In the case of head MRIs, very detailed images of your brain are produced. Radiologists can then examine these images to see the inside of your brain in very fine detail. An MRI is a non-invasive procedure, which means it doesn’t involve opening you up or putting anything inside your body.
The MRI scan machine (which looks like a big tube) contains very powerful magnets. These magnets are so strong that they actually affect the protons inside the atoms which make up your body! When you lie inside the MRI scanner, the magnetic field makes all of your protons line up in the same direction. It’s a bit like how the Earth’s magnetic field makes the needle on a compass point due north. Once the protons are all aligned, the scanner sends out radio waves, which knock them out of alignment again. After the radio waves stop, your protons shift back to their normal position. As they do this, the protons actually send out tiny radio signals of their own. These minute signals are picked up by the receivers in the scanning machine.
The radio signals produced by the protons in your body allow the machine to detect exactly where they are. The different kinds of tissue in your body – soft tissue, bone, etc – all produce slightly different signals. So when all the signals are put together, they create a very detailed picture of the inside of your head.
Why might I need a head MRI?
Head MRIs can be used to detect all sorts of different brain conditions. If a doctor suspects that you might have a medical condition affecting your brain, a head MRI may be used to see what’s going on, without the need to open you up and look inside.
There are certain telltale symptoms which usually suggest that there is a problem in the brain. These include dizziness, blurred vision, seizures, headaches, and changes in behavior or personality. However, these symptoms usually aren’t enough to go by on their own, as many brain conditions can have similar symptoms to each other. A persistent headache, for example, could be simply a headache, or it could be a symptom of one of many potential underlying problems.
As head MRIs give a detailed picture of the brain, they can be used to detect (amongst other things): brain tumors, haemorrhages, cysts, aneurysms, hydrocephalus, and even problems with the brain’s structure (such as Chiari malformations). It goes without saying, but being able to see the brain and therefore see exactly what’s wrong is invaluable. The earlier a brain condition is identified and diagnosed, the easier it tends to be to control or treat it.
There are also other reasons why you might need a head MRI. For example, if you’ve suffered a stroke or a head injury, a radiologist may use an MRI to see the extent of the problem. They can use the scan to see where exactly the brain has been damaged, and how bad the damage is.
What actually happens in an MRI of the brain?
So, now that we know exactly what an MRI is and why you might need one, let’s find out exactly what happens in an MRI. You’ll be pleased to hear that the procedure itself isn’t painful or uncomfortable, and MRIs are extremely safe. If you are having an MRI with contrast, you will need to have an injection, but it shouldn’t hurt too much and it will be over with quickly.
The first thing you’ll need to do is remove any clothing or accessories that contain metal, like zippers, watches, jewellery or belts. Because the MRI scanner uses magnets, any metal in the machine can interfere with the scanner. You won’t be able to get an MRI if you have a pacemaker or any kind of metal in your body. You should also tell the medical staff if you’re pregnant, as the scan may affect the unborn baby.
When you’re ready to start, you’ll be asked to lie down on a table which slides into the MRI machine. You might need to wear a plastic coil around your head. The inside of an MRI scanner is quite a small space, so if you suffer from claustrophobia, you may be offered a sedative to make the experience more tolerable. While you’re in the scanner, you’ll need to keep very still so that the images come out clear. The MRI scanner will make loud banging noises during the procedure, so you might be offered earplugs for comfort. Depending on what kind of scan you’re having, the whole scan should take between 30 to 60 minutes. You’ll be able to talk to staff through a microphone in the machine through the entire process.
What happens afterwards?
Once the scan is finished, you’ll be able to get dressed and go home straight away! If the MRI has made you feel uncomfortable or unwell due to claustrophobia, don’t be afraid to ask to sit down for a while or have a drink before you leave. If you were sedated, the staff will move you to a recovery area until you’re fully awake and ready to go.Once the radiologist has analysed the images of your brain, they’ll send your doctor the results, who will then contact you to tell you the next steps.
Well, there you have it – now you know exactly what happens in an MRI of the brain! And if there’s anything you’re still not sure about, why not give us a call? We look forward to hearing from you.