An MRI magnet is an incredibly powerful thing. Here’s some perspective on that statement: The magnetic field of current MRI magnets ranges from 0.3-3.0 tesla. The magnetic field of the Earth (yes, the ENTIRE planet) is approximately 0.5 gauss. If you’re not up on your units of magnetic measurement, this means the magnetic fields of our MRIs are anywhere from 1,660 to 60,000 times stronger than that of the world on which they sit.
Still, every Goliath has his David. As powerful as MRI magnets are, some relatively small things can interfere with their capacity to produce diagnostic images. Overhead electrical lines, air conditioning units, or proximity to elevators, other imaging systems, and broadcast infrastructure can all cause interference, distorting or producing artifacts in MRI images.
Ultimately, the best way to beat MRI interference is to avoid it altogether by properly shielding your magnet’s field from its sources. Before you sign a deal on an MRI, before you remove doors or cut holes in walls, before you plumb a chiller, make sure you’ve done the following:
Contact a shielding vendor:
There’s a good chance the vendor you buy your MRI machine from won’t be the same vendor that will provide your MRI shielding. Our recommendation is that you contact this vendor before you go too far in the purchasing process to confirm that your site is in a location suitable for an MRI to be installed. The following tests will all fall under that vendor’s purview. The information they give you will be vital.
Test for AC/DC interference:
This test measures the potential effects of electrical currents in the vicinity of the intended MRI site. Those high tension towers across the street might become a hassle in the near future.
Test for RF interference:
This test measures the potential effects of RF-producing equipment within or around the building. If your site is only a block or two from the local radio station, chances are this test will come back with some interesting results for you.
Test for vibration:
This test measures…you guessed it: vibrations! If your system is shaking (even imperceptibly) as it’s scanning, your images are going to suffer. Hopefully, your building sits many miles from the nearest fault line or L train.
The vendor and tests detailed above will ultimately determine what kind and how much shielding your MRI needs. Not only will these steps validate your ability to use MRI in your location, but they will also reveal an important aspect of your overall MRI project budget.