Thumping along at peak levels of 113 dB (just a couple ticks below a rock concert), MRI gradients are often unnerving and sometimes frightening. If you've ever wondered what it is inside an MRI scanner that makes the loud noise they are known for- gradients are the culprit.
Gradients are actually smaller magnets inside the main MRI magnet. Their job is to modify the magnetic field in the area being scanned so the system can “listen” for the resonance and create an image. It's difficult work to modify a magnetic field strong enough to lift a car (really), so the coils in these smaller magnets move and stress, literally vibrating. These vibrations are the source of the sound.
In spite of being noisy, they drive MRI value on the secondary market and they come in many varieties. That being said, let's dig a bit deeper so you can:
- Be better informed when you are selling your used MRI on the secondary market
- Compare gradients across manufacturers when buying a 1.5T MRI