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We’re all familiar with the acronym, but what’s is a MRI? And what is it, anyway?

What’s the deal?

In short, MRI means “magnetic resonance imaging”. It is a widely used imaging technique that combines magnetic fields and radio waves to make a pristine picture of a person’s innards and alike. Otherwise known as one of the world’s most sophisticated diagnostic tools around, these massive machines assist medical professionals when divvying out difficult diagnoses.

The backstory

The first-ever full-body MRI scanner was invented in 1977, by Prof. Raymond Damadian. Back then, a single scan took around five hours to produce (yikes!), giving the machine the nickname “the Indomitable”. Medical history buffs can get a closer peek at the early model at the Smithsonian Institute, where the machine now lives.

The science inside

Most MRI machines resemble human-shaped tubes. When a patient lies within one (upright machines also exist), a magnetic field quickly realigns their body’s hydrogen atoms, while radio waves cause those atoms to emit faint signals. These signals are then collected to create cross-sectional MRI images (3D images can also be employed).

The scanning process

Before entering a machine, the patient is sometimes injected with intravenous contrast liquid to improve the visibility of certain tissues. Typically, the liquid is gadolinium, which is less likely to cause allergic reactions than the contract material used for CT scans. From there, the patient will be assisted with entering the machine. Often earplugs or headphones are provided, to decrease any anxiety around the machine’s loud noises.

A technologist will monitor the scan from another room, and enable communication with the patient via an imbedded intercom system. For those who suffer from claustrophobia, necessary medication/sedation techniques may be utilized. It is vital that patients hold still during the MRI scan to avoid blurring any images.

During a functional MRI, a patient may be asked to perform occasional small tasks (i.e. taping thumbs against fingers, rubbing a block of sandpaper, or answering basic questions) to better pinpoint portions of the brain that control specific actions. The entire process usually takes between 15-60 minutes, depending on what part of the body is being scanned. For a quick, visual rundown of the process, check out this video:

The picture worth 1,000 words

By scanning specific areas of a patient’s body, MRIs can bring to light—literally—anything around brain ailments, spinal conditions, pelvic and/or prostate issues, gastrointestinal tract conditions, as well as soft tissue and bone pathology conditions. Additionally, a functional MRI (fMRI) offers an even more specified look into brain activity, by using MRI technology to measure and monitor blood flow to the brain.

Who’s not allowed

While MRI scans are generally as accessible as they are easy to employ, some patients cannot have an MRI.  Why?  Any metal implanted in the body (pacemakers, cochlear implants, shrapnel) will be pulled toward the magnet.  Those who have had surgery within eight weeks, might be directed towards alternative imaging. While there’s no evidence to suggest MRI scans pose a risk during pregnancy, as a precaution, MRI scans aren’t usually recommended during pregnancy, particularly in the first three months. Additionally, patients who are breastfeeding, should consult their doctor before scheduling any scans.

All in all, a MRI is a pretty impressive technology improving the lives of patients every day. While they can appear daunting at first, they’re essentially the working proof of science, research and technology combined.


For more information, check out the following posts.

All about MRIs
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