When Your Child Needs a Diagnostic Scan
● By Sandy Kauten
OK, your doctor has just ordered an MRI. What does that mean?
MRI stands for “Magnetic Resonance Imaging.” A radiologist – that's a doctor trained in medical imaging – uses a machine that has huge magnets in it to look into some part of your body and record detailed three-dimensional pictures of what's going on inside.
MRI is different from the other big diagnostic tool of recent years, the CT or “cat” scan. The two procedures use completely different methods to look inside your body. The CT scan is a very high-tech version of an old-fashioned x-ray.
The MRI doesn't use radiation. Instead, it uses powerful magnetic fields to form the image. As a result, if all else is equal, most doctors prefer to use the MRI.
How does it work?
The MRI turns a strong magnetic field rapidly on and off. That causes hydrogen atoms in water – remember, out bodies are mostly made of water – to send out weak radio signals. The MRI machine records those signals, conducts some highly technical computations and – ta-da! – creates a picture of, say, the inside of your elbow.
Does it hurt?
Not at all. The machine doesn't even touch you. Turning those big magnets on and off, though, makes really loud noises. It can sound a bit like you're lying inside a steel drum while someone is banging on the outside with a hammer. Don't worry, earplugs are standard equipment, and we encourage you to bring your favorite music to play through our headphones. It’s a great distraction.
Are there any dangers?
Not really. You can't have an MRI, though, if you have any metal containing iron in your body. The big no-no here is cochlear implants and pacemakers. You don't want those moving around on account of a giant magnet nearby.
Don't you have to lie very still in a small tunnel during the procedure?
Yes and no. Getting a conventional MRI, on account of the noise and the confined space, can be a little unnerving for small children or for adults with claustrophobia. As a result, “open” MRIs have been developed that don't put you in a tunnel. OIC has an open MRI machine for just this reason.
Are all MRI machines created equal?
No. More recent MRI machines, such as the new 3T machine used by Oregon Imaging, are much more powerful. That means getting a more detailed image, more quickly. The 3T MRI also has a larger tunnel, making it easier for people who might feel confined in a conventional machine. Your radiologist will recommend which one to use. (Be sure your scan is being read by a specialized radiologist, as well, as the image is just part of the equation.)
Does my insurance cover the bill?
Most likely it does. Check with your health plan to be certain. You do need a physician referral for an MRI.
-- Dr. Stephan Thiede and Dr. David Tsai are radiologists at Oregon Imaging Centers, which provides a full range of imaging services, including MRIs, low-dose CT, PET/CT, Ultrasound, Digital X-ray and Fluoroscopy and Digital Mammography. They join 14 specialized radiologists in providing services from locations at University District and RiverBend Pavilion.