October 26th, 2011
06:01 PM ET
MRI machines allow doctors to see inside your body and diagnose what’s wrong with you, but if mistakes are made, they can hurt or even kill you.
“If administered properly, it’s one of the safest exams that have ever been invented,” says Tobias Gilk, an MRI safety advocate.
But accidents do happen.
“Most errors are a combination of human error and bad timing,” says Dr. Emanuel Kanal, a professor of radiology and neuroradiology at the University of Pittsburgh. Faulty training and lax rules about who can be around the machine also contribute.
There are four main ways MRI machines can pose dangers.
Gilk’s website, mrimetaldetector.com, shows photos of metal objects, including a bed, a floor polisher and a chair forced against the MRI machine.
If someone is being scanned when these devices fly into a machine, they could face serious injuries. A child in New York was killed in 2001 when the MRI machine sucked an oxygen canister into the machine where he was being scanned.
“Projectiles usually happen when there are breakdowns in policies and procedures and proper training wasn’t performed,” says Frank Shellock, an adjunct clinical professor of radiology and medicine at the University of Southern California. He points out that MRI magnets don’t just turn on when they are scanning. They are always energized and there is no visual cue the magnetic field is present. Newer MRI machines can be even more powerful.
“Generally it is supposed to be gentle, like a heat lamp,” says Gilk. “If there are electrical conductors like an EKG lead (on the body) it becomes an antenna and can pick up the RF and concentrate it.”
Touching the side walls of the MRI tunnel can also lead to burns, Shellock says. MRI operators should put material between the patient and the wall if there is a risk of the patient coming in contact with it. Some burns have been so severe patients have required skin grafts.
Gilk compares getting a scan to standing near a jet aircraft. He says patients and anyone else near the machine should be given adequate earplugs or protective earphones.
“Scanner technology is improving and machines are getting quieter,” Gilk says, but “anyone in the room could get hearing loss.”
Implants and medical devices:
“Most medical device manufacturer's products made in the last five years will be OK,” says Gilk. But, “if, for example, you had an aneurysm clip that is 15 years old, you should be particularly cautious.”
Shellock says he has studied 3,500 implant devices over about the last 25 years and the devices that are labeled as appropriate for use in an MRI should be fine.
In addition to the medical metal inside the human body, some patients require external devices to keep them alive or monitor their condition. Those devices need to be specifically designed to function around an MRI.
The federal government doesn’t regulate the use of MRIs and state regulations for the machines vary.
“Many states have more stringent requirements for hair colorists than who runs an MRI center,” Gilk says.
So what can patients do to make sure they are safe when they get an MRI?
1. Fill out MRI questionnaire: “Patients should fill out a screening form and ask the MRI technologist if they have questions,” Shellock says. It’s important that patients go over the questions with the technician to make sure they understand what is being asked.
Kanal says honest answers are essential. He gives the example that a patient might not want to reveal they have a wig, but it’s important for the operator to know.
Details about any metal that may be in the body, including bullets, medical devices like aneurysm clips, stents or pacemakers should also be shared with the operator.
2. Remove metal: Since magnetic metal poses such a risk in an MRI, it is essential patients and anyone near the MRI remove it.
3. Use hearing protection: Make sure you and anyone else in the room with you are given proper ear protection and make sure it fits.
4. Look for open doors: MRI facilities should be secure. Gilk says open doors could be a sign the facility isn’t as careful about access as it should be.
5. Look for wires: Make sure there are no unexpected wires or metallic objects like left over EKG sensors on your body. Some devices may be safe for an MRI, but others can be dangerous.
6. Don’t touch the side walls: Coming in contact with the inside of the MRI tube can lead to burns.
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