The Complete Guide to MRI Safety

First: What can actually go wrong?

Three things:

• Thermal burns – Metal heats up in a magnet. Think "microwave fork" energy.
• Artifacts – Even MRI-safe metal can mess with image quality. Your scan may miss something important.
• Projectile risk – A strong magnet + loose ferromagnetic metal = "MRI cannon." Not great.

These are rare. But not rare enough to ignore.

Absolute No-Gos (a.k.a. hard stops)

There are three implants that we never scan at TrueScan – not because they're always unsafe, but because they require highly specific protocols that we don't run:

• Pacemakers
• Defibrillators
• Neurostimulators or spinal cord stimulators

Some of these are labeled MRI-conditional, meaning they can be scanned under special circumstances (hospital setting, device-specific programming, manufacturer clearance).

But our scans are not one-size-fits-all. We don't want to risk your safety or compromise your results.

Got one of these? You might still be eligible for an MRI – just not with us.

Metal in the eye? Stop right there.

This one's sneaky.

If you've ever worked with metal – welding, machining, grinding – and didn't wear eye protection, you might have tiny metal fragments in or near your eye.

They don't always hurt. But in an MRI, they move.

That's why we screen for it, and why we might require an orbital X-ray before scanning you.

Even a microscopic sliver could shift and cause damage to your eye. Not worth the risk.

The MRI-Conditional Zone (a.k.a. "maybe safe, but prove it")

Here's a list of things that might be safe – if you have documentation.

We'll need to review your implant card or medical records for these:

• Aneurysm clips
• Cochlear implants
• Retinal or ocular implants
• Heart monitors (loop recorders, etc.)
• Medication pumps
• Brain shunts or valves
• Stents, coils, or vascular filters
• Smart orthopedic implants (like Zimmer knees)
• Any device labeled "MRI-conditional" by its manufacturer

The rule here: Don't guess.

If you're unsure, we'll help you figure it out. But no card = no scan.

What about pregnancy?

This one's tricky.

A big study out of Ontario (JAMA, 2016) showed that first-trimester MRI exposure did not increase fetal or early childhood risk.

But we still don't scan pregnant patients at TrueScan. Not because it's dangerous – but because it's untested.

No one wants to be the test case.

Shrapnel and other war stories

If you've ever had shrapnel, bullets, or pellets lodged in your body, we'll take it on a case-by-case basis.

Most are non-ferromagnetic (meaning they won't move), and if they're embedded in scar tissue, they're unlikely to budge.

Unless it's near your eye.

Then it's a no. (See "metal in the eye" above.)

What's usually safe?

Here's the good news. Most of the common stuff? Totally fine.

These are typically MRI-safe and don't require an implant card:

• Orthopedic hardware (screws, rods, pins – except Harrington rods)
• Dental implants or fillings (unless they're magnetic)
• Hip and knee replacements
• Breast implants (even silicone ones – but let us know)

Still let us know about them. But we probably won't cancel your scan over them.

Before your scan: stuff to take off

Metal isn't just inside you.

It's also hiding in your mascara, lotion, and that cute hairpin.

Before your scan, we'll ask you to remove anything that might contain metal particles:

• Makeup (especially mascara or shimmer)
• Hair products, accessories, wigs, extensions, magnetic lashes
• Jewelry or body piercings
• Skin patches (like nicotine or birth control)

Pro tip: If you're unsure, leave it at home. Safety > style when you're inside a giant magnet.

Wait – even "MRI-safe" metal can mess things up?

Yep.

Even if it doesn't move or heat up, metal can cause artifacts – giant black shadows on your scan that block out anatomy.

Radiologists hate them. So do we.

These shadows can hide early-stage tumors, aneurysms, or other subtle findings.

So even "safe" metal is something we'd prefer to work around – or remove, if possible.

How we screen for MRI safety at TrueScan

We don't wing it.

When you book your scan, you'll get an email with medical intake forms – including a detailed MRI safety questionnaire.

Our medical team reviews your responses before you arrive. If anything needs clarification, we'll contact you.

That way, we can ensure your scan is both safe and as accurate as possible.

Want to dive deeper? If you're curious (or just love a good rabbit hole), check out MRIsafety.com – a brilliant resource maintained by Dr. Frank Shellock and colleagues.

And remember: the best source for whether your device is MRI-safe is almost always the manufacturer.

TL;DR

MRI safety is about more than just magnets – it's about keeping you safe and your scan clear.

• Pacemakers, defibrillators, and neurostimulators = no go.
• Implants? Email your card to hello@truescanmri.com.
• Metal in or near the eye? Get an orbital X-ray.
• Shiny makeup and cute clips? Leave them at home.

MRI is one of the most powerful diagnostic tools in medicine – but only if we keep it safe.