How Does Metal Affect MRI Scans?

If you're booked in for an MRI scan, then you'll have been given information about how to prepare for the procedure and what to expect during the scan. This information may include instructions about not having metal objects in the scanning chamber.

Why is it important not to have anything metal in the scan? What do you need to do to prepare for this?

How MRI Scans and Metals Interact

MRI scans use magnetic fields to create their pictures. If the machine's magnets come into contact with a metal, then this can cause a problem. The metal itself may affect the scan results. They may not be fully comprehensive or accurate.

Plus, the magnetic field may affect anything metal. It may damage things that contain metal or make them heat up. This is why your radiographer will want to make sure that no metal gets in the chamber.

How to Make Yourself Metal-Free Before a Scan

In general terms, you shouldn't take anything metal into the scan room. This includes anything you're wearing and, possibly, anything that contains metal that is inside your body.

Metals That You Wear

You'll typically be asked to leave watches, jewellery, phones and electronic devices outside of the scan room. If you have piercings, you'll need to remove them. Same goes for hearing aids and even removable dentures that have metal clasps. The facility should give you somewhere to store your stuff during the scan like a locker or a cubicle.

It's also important to make sure that you aren't wearing any cosmetics or even hairspray before the scan. Make-up and hairsprays may contain tiny traces of metal. These may disrupt the scan or even heat up during it, which will make you uncomfortable.

Internal Metals

In some cases, you may have some metal in your body that you can't remove. It's important to tell your radiographer about this so that they can assess if it might be a problem.

For example, if you have a pacemaker, IUD or a dental implant tooth, then your radiographer needs to work out if it is safe to go ahead with the scan. If the object is relatively new, it may well be OK in the scanner; however, older metal objects may not be as compatible.

If you aren't sure about something that might affect your scan, then contact the hospital or clinic department that provides the medical imaging services that you are using.