New MRI reduces stress of test
Machine designed to give same detail as full-body scan, with only extremities inside
Hadiya Jackson of Hanover Park is prepared for an MRI by technologist Erica Sanza at Loyola University Health System in Burr Ridge, IL. (Scott Strazzante, Chicago Tribune)
Jackson slides her left leg into a circular tube in a new MRI machine that's smaller than a refrigerator and leans back in a padded reclining chair. It's a far cry from the MRI she had in 2008 after injuring her wrist in a car crash. For that, she had to lie down and stay still for almost an hour as she was inserted into a conventional full-body MRI.
"I liked it," Jackson, 15, said after undergoing the recent MRI, which stands for magnetic resonance imaging, at the Loyola Center for Health at Burr Ridge. "It was much easier, much more comfortable."
Last year, Loyola's new outpatient health center in Burr Ridge became the first medical facility in the Chicago area to offer a powerful new MRI machine designed specifically for the arms and legs that produces images with the same level of detail and precision as full-body MRIs.
MRI machines use a powerful magnet to attract and align tiny positively charged particles within the body known as protons. Pulses of radio waves then spin the protons, producing a faint signal that the MRI scanner detects and uses to create a detailed image of a "slice" of the body. They're used to look for structural abnormalities such as brain tumors, aortic aneurysms, spinal disk herniations and torn knee ligaments.
The new extremity MRI offered at Loyola marks the next step in the natural evolution of MRIs, said Dr. Jeffrey Weinreb, professor of diagnostic radiology at the Yale School of Medicine, and chief of MRI and director of medical imaging at Yale-New Haven Hospital.
Though extremity MRI machines have been around for about 20 years — as have so-called open MRIs, which do not entirely enclose a patient in a tube — there is considerable variability in the quality of the images they produce and the skill level of the operators using them, Weinreb said. The type of MRI machine at Loyola is the first to use the same magnetic field strength, 1.5 Tesla, as full-body MRI machines, and thus will home in on finer, subtler details to help radiologists make diagnoses and guide surgeons in operations.
"The higher-field strengths are more likely to produce diagnostic-quality images and find what's wrong," Weinreb said.
Many radiologists without access to a high-power extremity MRI machine use the conventional machines — in which patients lie motionless as they are inserted into a 6-foot-long tube surrounded by a giant circular magnet — even if the MRI is just to look at an injured wrist, said Dr. Albert Song, an assistant professor for diagnostic radiology at Loyola's Stritch School of Medicine.
This can present problems for patients who are claustrophobic or have conditions such as back pain or chronic obstructive pulmonary disease that make it difficult to lie flat on their backs.
Even for healthy patients, it can be a strain to hold still for that long in sometimes awkward positions. For instance, for her previous wrist MRI, Jackson had to lie down and extend her one arm forward above her head in what radiologists call the "Superman position." With the new MRI machine, patients are seated and less likely to fidget, Song said.
"Any movement can blur over images," Song said. "The more comfortable the patient is, the better it is for our images."
Some children also find it impossible to lie still for so long and have to be sedated to conduct an MRI. With new machines like the one in Burr Ridge, they can sit next to their parents as they comfort them or even read them a book.
The 1.5 Tesla MRI machine was first approved by the U.S. Food and Drug Administration in 2009. There are 33 in use throughout the United States, said Rebecca Hayne, a spokeswoman for GE Healthcare, which produces the new machines. She said that there is just one in the Chicago area, though there are some extremity MRI machines in use in the region with lower magnetic strength.
The new machine also is less expensive and much smaller than the traditional MRI machine, so it uses up less space in a medical facility and consumes less energy.
"We're very happy to have it," Song said. "I love it, personally."