What is MRI?

How can doctors monitor and assess a patient’s head injury to see what’s the best course of action to take? How can they know what problem is going on in a patient’s abdomen without having to use invasive forms of surgery? How can they better understand about a patient’s mind from a neuroscientific aspect? The answer to all of these questions, and many more, is because of MRI.

Magnetic resonance imaging is different to other forms of medical scans as they make use of strong magnetic fields and radio waves. This helps create detailed pictures of the inside of a patient’s body to find any problems. Many parts of the body can be examined such as the brain, spinal cord, bones and internal organs.

Image by toubibe from Pixabay. This is an example of a scan of a brain from an axial plane.

People with metal implants such as pacemakers and artificial joints cannot have an MRI scan because it uses highly magnetic fields which will affect the implants and cause injury. Metal also interferes with the MRI scanner, resulting in the machine being unable to produce a clear image. Therefore, people are also told to remove any items of clothing and jewellery containing metal such as earrings and belts to avoid these kind of problems.

The patient will lie on a bed and will be pushed into the MRI scanner which is controlled with a computer by a diagnostic radiographer (a healthcare professional who uses radiation to help diagnose medical problems). Only the patient undergoing the scan will usually stay in the room so that no-one else interferes with the magnetic field. The machine is very loud so patients will be given earplugs and noise-cancelling headphones to prevent damage to their ears. The time it takes to complete the scan depends on what part is being examined.

Photo by MART PRODUCTION from Pexels.

The science behind MRI is to do with your body being made up of around 60% water. The molecular structure of water molecules consist of oxygen and hydrogen atoms, the latter containing protons (subatomic particles that have a positive charge) that are very sensitive to magnetic fields. When the magnetic field is turned on, these protons in the body line up in the same direction as the field. Radio waves then are emitted in short bursts to certain parts of the body to knock the protons there out of their positions. When they are tuned off though, the protons go back to facing the same direction again. This action sends radio signals to a receiver, giving the exact locations of protons in the patient’s body, helping to find any problems in the patient.

Source: HowStuffWorks Here is a diagram that sums up this information.

MRI scans are very useful since they can be used across many applications and don’t use any radiation unlike X-rays, making them much more safer. All forms of medical scans, not only MRI, are incredibly important as they help diagnose a potentially life-threatening condition earlier, possibly saving a patient’s life.

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