What is an MRI and how does it work?


You have probably heard about MRI scans or even had to undergo one. If you have ever wondered what is an MRI and how this can help to detect any abnormalities in the body, here are some answers.

An MRI scan or Magnetic resonance imaging is a technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues within your body.
Most MRI machines are large, tube-shaped magnets. When you lie inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in your body. Radio waves cause these aligned atoms to produce very faint signals, which are used to create cross-sectional MRI images — like slices in a loaf of bread. The MRI machine can also be used to produce 3-D images that may be viewed from many different angles.

For an MRI test, the area of the body being studied is placed inside a special machine that contains a strong magnet. Pictures from an MRI scan are digital images that can be saved and stored on a computer for more study. The images also can be reviewed remotely, such as in a clinic or an operating room. In some cases, contrast material may be used during the MRI scan to show certain structures more clearly.

Magnetic resonance imaging (MRI) is done for many reasons. An MRI scan can create clear pictures of most parts of the body. So, it is useful for all sorts of reasons where other tests (such as X-rays) do not give enough information required. It is commonly used to get detailed pictures of the brain and spinal cord, to detect abnormalities and tumours. Even torn ligaments around joints can be detected by an MRI scan. So, it is being used more and more following sports injuries.

Here are the basic things you should know about the MRI scanning:
(1) MRI scanning uses magnetism, radio waves, and a computer to produce images of body structures

(2) MRI scanning is painless and does not involve x-ray radiation

(3) Patients with heart pacemakers, metal implants, or metal chips or clips in or around the eyes cannot be scanned with MRI because of the effect of the magnet

(4) Claustrophobic sensation can occur with MRI scanning

According to Patient.co.uk, MRI scans are painless and thought to be safe. MRI scans do not use X-rays so the possible concerns associated with X-ray pictures and CT scans (which use X-rays) are not associated with MRI scans. However:

(1) Rarely, some people have reactions to the contrast dye which is sometimes used.

(2) Pregnant women are usually advised not to have an MRI scan unless it is urgent. Although the scan is thought to be safe, the long-term effects of strong magnetic fields on a developing baby are not yet known.
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