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Magnetic Resonance Imaging (MRI)

Written by Chris Heywood - MSc BSc (Hons) MCSP HCPC reg
Physiotherapist

The Acronym MRI stands for 'Magnetic Resonance Imaging'. This technique was first used in 1977 in America to visualise the structures of the body but wasn’t more widely available until the mid to late 80’s. 

What is an MRI Scanner?

An MRI (Magnetic Resonance Imaging) scanner is a sophisticated medical imaging device that uses powerful magnets and radio waves to create detailed images of the inside of your body. Unlike X-rays or CT scans, MRI does not use ionizing radiation, making it a safer option for many patients.

How Does an MRI Work?

  • Magnetic Fields: The MRI scanner uses a strong magnetic field to align the hydrogen atoms in your body.

  • Radio Waves: It then sends radio waves through your body, causing these atoms to produce signals.

  • Image Creation: These signals are detected by the scanner and sent to a computer, which processes them to create detailed cross-sectional images of your body.

A picture of an MRI scanner

What To Expect During An MRI

Although the size and shape of scanners are now much more varied that they used to be, they are most synonymous with being a long tunnel in to which the patient is placed on a padded bed. If you are very claustrophobic there are now open and upright scanners which help to alleviate the feeling of being enclosed, but they are less widespread, often have a longer waiting list on the NHS, and privately carry a significant fee up-charge. 

Duration: The scan can take anywhere from 15 minutes to 90 minutes, depending on the area being examined. This will be explained to you as part of your booking process. 

 

Comfort: The clinicians who take you through the MRI process and look after you are called Radiographers and they may also have a radiology assistant with them. They are very used to people being nervous and will ensure you are fully informed about the process, helping you on and off scanner bed and positioning you so that the best possible image can be captured. You might feel comfortably warm during the scan. This is simply due to the heat given off my the large magnets charging and releasing during the scanning process.

 

Noise: The machine makes a series of loud banging noises during the scan. Again, this is due to the charging and energy release of the large magnets that are part of the scanning process. It is nothing to worry about. Ear protection will be provided, and some facilities offer music to help you relax.

 

Safety: MRI is a very safe procedure. However, it is not suitable for patients with metal implants or devices. This will be checked before your scan.

Extra 'Nerd' Level Info About How MRI Works?

The unique way MRI scanners work makes this specific type of imagery possible. Here’s a simplified explanation.

 

The Basics

 

Your body is made up of billions of small particles that spin in different directions around their central axis. The composition of these particles (protons and neutrons) affects their electrical charge and how they spin. The MRI scanner emits Radio Frequency (RF) energy that specifically targets the positively charged hydrogen ions in your body.

 

The Magnetic Field

 

A large, powerful electromagnet runs along the length of the MRI tube in which you lie. These magnets are incredibly strong, between 10,000 to 40,000 times more powerful than Earth's magnetic pull. This powerful magnet aligns a small proportion of your hydrogen ions with the magnetic field, energizing them. Additional smaller magnets rapidly switch on and off (the Resonance part of MRI) to concentrate the energy on the area being scanned.

A cartoon picture depicting a metal robot being pulled in to a MRI machine.

There is a good reason why we ask you to remove any metal jewellery, or implants, prior to scanning, ...... and why we don't MRI robots! If it does not pull you in to the machine, it will still heat the metal up so make sure you don't forget any hidden piercings.

Signal Detection

 

When the magnets are turned off, the hydrogen atoms return to their normal spin pattern, releasing energy as they do so. This energy is detected by the scanner as mathematical data. The process is extremely quick and is repeated hundreds of times, which causes the loud banging noises associated with MRI scans. The computer analyzes this data to create detailed images of the body's internal structures.

 

Image Types

 

The mathematical data is processed to produce different types of images, commonly referred to as T1 and T2 scans:-

 

T1 Images: These scans provide detailed images of anatomical structures without highlighting fluid.

 

T2 Images: These scans highlight areas of fluid, such as intervertebral disc fluid, spinal cord fluid, or inflammation, showing them as bright areas.

 

This differentiation allows radiologists and surgeons to examine various anatomical details more closely. For example, degenerated discs appear darker on T2 images due to their lower fluid content. There are many more types however there is little to be gained here by delving any deeper.

 

Diagnostic Power​

 

MRI is an invaluable tool for diagnosing and managing spinal pain. The detailed images it provides enable healthcare professionals to make accurate diagnoses and develop effective treatment plans.If you have any questions about your MRI scan, your healthcare provider is there to help ensure you have a safe and comfortable experience.

Understanding The Results

There are some professionals who discourage the use of MRI scans in spinal pain except for potential fusion clients (and Red Flags) due to the possible negative psychological impact of the results. Here's why:

 

MRI scans often reveal various 'changes' in your body, which are often detailed in complex medical terms on the radiology report. This can make even minor issues sound alarming. Some argue that this can cause certain individuals to become overly concerned about their condition (known as 'yellow flags'), potentially leading to more anxiety and negative feelings than necessary.

 

Our Perspective

 

While there might be some truth to this concern for a small number of patients, we believe that when medically justified, an MRI scan can be extremely beneficial. When the results are explained in a clear, informative manner, the benefits far outweigh the risks. We do however worry now that patients are often able to get hold of their scan reports from their GP NHS access points prior to any professional input. While this may save time and reassure those whom have completely normal scan results, for those that do not, however innocent, Dr Google has an amazing ability to scare the Sh** out of you! Just bear this in mind even if there is a wait to see you practitioner.

 

Remember Imperfections are Normal

 

Contrary to popular belief, nobody has a perfectly healthy body, and it's normal for everyone to experience some wear and tear over time. Not all findings on an MRI report are bad news. In fact, most of the changes are likely unrelated to your pain and may never cause any issues. It's the expertise of your surgeon to determine which findings, if any, are relevant to your condition.

 

If you have any concerns or questions about your MRI scan, feel free to discuss them with your healthcare provider. They are here to help you understand the process and ensure you have a positive experience.

If you feel our information is helpful, please feel free to share it with others but do not take ownership in anyway

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