Open MRI vs. Closed MRI

A friend of mine who had an MRI a few years ago described it as being inside a garbage can while someone pounded the outside with a rubber mallet. The noise, he said, was the worst part.

Most people you ask find the closeness to be a problem. My grandmother — who has been ordered several times to have an MRI by various doctors — refuses because she is afraid to be enclosed in the machine.

An open MRI is sometimes an option for people who are too large to fit in a closed MRI, or too claustrophobic to undergo the procedure. But the two tests aren’t identical.

Let’s start with how an MRI works. I’m not a doctor, so I’m going to make this as simple as possible, knowing that I’m leaving out a lot of details. Bear with me!

MRI stands for magnetic resonance imaging — a very powerful magnet manipulates the very atoms of a certain area of the body. Radio frequency pulses send protons spinning in a certain direction. Normal and abnormal tissue react differently to the magnetic fields, giving signals that are translated into images. An MRI can give a very specific look at a part of the body, as if the body were divided into slices like a loaf of bread. The scans can be used to generate a 2D or a 3D image of a part of the body.

The magnetic field strength often determines how clear the resulting images are. Open MRI scanners often have a lower magnetic field strength than closed or traditional MRI scanners — so you tend to get a better picture with the closed version.

So why offer an open MRI at all? As mentioned above, the open MRI gives larger or extremely claustrophobic patients an opportunity to have advanced imaging. The only other way to produce such a clear image is to perform surgery and physically look inside the body. An MRI is much less invasive! An open MRI is better than no MRI at all.

A friend of mine has been journaling his experiences with cancer, and recently underwent a traditional MRI at his doctor’s orders. I was more than a little uncomfortable just reading about the process — I can’t even imagine actually going into the tube!