When you are getting an MRI purposely for one part of your body, why do they have to scan your whole body?

I am getting an MRI soon for my injured knee and I am just confused on why the process for an MRI has to be done with your entire body when it’s only one part of your body that is injured. I think they should have individual machines for each part of the body. Like one for the legs, one for the arms, head, ect. It just seems kinda weird an unnecessary for me to get my whole body scanned when it’s only my knee with an issue, Why go through all the extra trouble?

6 Answers

Relevance
  • Edna
    Lv 7
    3 weeks ago

    There is a individual machine that will look at just one part of your body. It's called a CT scan or a CAT scan. It's an X-ray image made using a form of tomography in which a computer controls the motion of the X-ray source and detectors, processes the data, and produces the image. It's similar to an MRI, except an MRI usually scans your entire body.

    There's no 'extra trouble', on your part. The MRI machine is doing all the work. You just lie there and let it do its job. 

    • Login to reply the answers
  • 3 weeks ago

    I had my leg scanned and it was just my leg, thats weird

    • Login to reply the answers
  • Roddy
    Lv 7
    3 weeks ago

    Each MRI machine costs thousands of pounds (dollars) and takes up a lot of space as well as requiring trained operators. Therefore it would be totally uneconomic to make machines that could only scan a particular part of the body.

    When you initially lie on the bed of the machine, your whole body is outside it with your head nearest to the active ring of the machine. In order to get it to scan your legs, the rest of your body above that area has to pass through the machine - but it's not being scanned at that time. Once the right part is just outside the 'ring' the machne is activated and starts to scan from there down until the readiographer stops the scan.

    • Edna
      Lv 7
      3 weeks agoReport

      Roddy, there IS a machine that will scan only a specific part of your body, and it's used in hospitals every day. It's called a CT scan or a CAT scan.

    • Login to reply the answers
  • Eva
    Lv 7
    3 weeks ago

    They don't scan your whole body, just the part they need to. You were in a closed MRI. They do have open ones that you just put in the body part they need to scan. Not every center has them, but they are becoming more common.

    • Login to reply the answers
  • How do you think about the answers? You can sign in to vote the answer.
  • Anonymous
    3 weeks ago

    The whole section of the body is in the machine horseshoe.

    But the machine is only "On" in the section required.

    The machines are so expensive, that in most areas only One Hospital is PERMITTED to have the machine.  The idea of smaller machines is out of the question. Money is involved here. It would be financially unprofitable to do that.

    It is only one of the Medical Monopolies permitted by law.

    • Edna
      Lv 7
      3 weeks agoReport

      Smaller machines that scan only a specific part of the body are in common use. in hospitals today. It's called a CT scan. 

    • Login to reply the answers
  • Pearl
    Lv 7
    3 weeks ago

    its probably just the way the machine works

    • Login to reply the answers
Still have questions? Get your answers by asking now.