How do MRI scans work on the brain

Question: How do MRI scans work on the brain
- Keywords:
  diagnosis,
  mri
Asked by anon-327560 on 29 Jun 2022.
- Algernon Bloom answered on 21 Jun 2022:
  
  An MRI works by using a magnet to align protons (specifical hydrogen molecules) in a patient in one direction. There is then a radiofrequency “pulse” applied that knocks some of the molecules out of alignment. As the molecules return to the magnetic alignment they release energy that is collected and an image is made of the energy collected
  
  You get the details in the image because the different tissues have different amounts of hydrogen in different states. For example, hydrogen molecules in fat (adipose tissue) are less restricted than those in muscle so with a certain pulse you will see fat light up brighter than muscle.
  This is why you will not see bones on an MRI scan.
  
  For the brain, it works the same way as everywhere else except you will normally be looking at the white matter, grey matter and cerebrospinal fluid (CSF).
  
  It gets more complicated but I don’t want to break out the quantum mechanics right here and this is already a long answer 🙂
  This is why the people that maintain and research MRI are mainly physicists.
- Karin Purshouse answered on 22 Jun 2022:
  
  I can’t beat the physics and detail on Algernon’s answer, but I always think of it as a massive magnet (which is what it is – you have to be certain you don’t have anything magnetic on or in you to be allowed in an MRI machine room!) and this is used to create tiny movements in the molecules of the body that can be read as an image.
  
  Algernon is right that it’s a better imaging modality than, say, a CT scan for looking at soft tissues like the brain, although you can still see the bones on an MRI scan. You can look at different phases of the scan which gives you different levels of detail and different information on different aspects of the brain – such as blood or fluid.
  
  In the hospital, we use MRI scans of the brain to get detailed information about where a brain cancer is, and any swelling it might be causing. It also shows if there are any bleeds or other problems.
  
  We use MRI scans of other parts of the body, such as the spine, to look at how the spinal cord, the fluid around the spinal cord and the bones of the back are looking. This is important in cancer because if someone has cancer in the bones of the back, and this causes squashing of the spinal cord, we need to treat that with surgery or radiotherapy.
- Sophie Richardson answered on 23 Jun 2022:
  
  Just wanted to say thanks to Algernon and Karin for their answers here. It’s helped me to learn something new today too!

Question: How do MRI scans work on the brain

Comments