White Plains, N.Y. — When workers dismantled an MRI machine recently at the University of Texas, they discovered dozens of pens, paper clips, keys and other metal objects clustered inside.
Each had sailed through the air from a pocket or a folder, drawn to the huge magnet that powers the MRI's scanner. Much less common is the kind of accident that killed 6-year-old Michael Colombini on Friday.
Experts believe it was the first death caused by an outside object in an MRI room, although a recent study suggests that similar accidents may be on the rise. MRIs are used across the country for more than 1 million scans each year.
An oxygen tank the size of a fire extinguisher became a magnet-seeking missile, killing Michael in the MRI machine at Westchester Medical Center in Valhalla.
Deaths have been reported before when an MRI machine's magnetic power disrupted metal aneurysm clips or cardiac pacemakers inside patients' bodies. At least once, a patient was blinded when a piece of metal, long embedded in his eye, moved in response to the machine.
Regulations to prevent accidents are strict. Operators insist that magnetic objects be kept out of the MRI room. Pockets are emptied; watches, earrings and eyeglasses are removed; patients are stripped and quizzed about implants, shrapnel and bullets in their bodies. Some patients are deemed ineligible for MRI.
There are MRI-compatible gurneys, wheelchairs and oxygen tanks, made of aluminum.
Still, accidents may be occurring more often than ever. Dr. Gregory Chaljub of the University of Texas medical branch in Galveston studied records covering 15 years and nearly 138,000 MRI scans for an article published last month in the American Journal of Roentgenology.
He found five cases in which tanks were mistakenly brought into MRI rooms and immediately headed toward the magnet. They all occurred in 1997 or later, leading him to suggest such incidents are on the increase.