Diagnostic Imaging: Beam Me Up Dr. McCoy
We're not quite at the Star Trek level yet with imaging technology, but recent advances are fine-tuning your medical care.
Easier, Faster Imaging Exams Yield Better Information
It's not just the quality and detail of the images that has improved. Some
advances have made the actual experience of having an imaging exam
For one thing, they are a lot faster. "When I was doing my training 20
years ago, a CT exam might take half an hour," says Lewin. "We can now
literally get the same amount of information in less than two seconds."
The full length of an exam varies depending on the person and the type of
imaging. But Hillman estimates that an MRI (magnetic resonance imaging) takes
between 20 to 40 minutes. However, the imaging itself only takes up a few
seconds or minutes of that time. (The rest is taken up by the technicians
preparing the exam.) Because the exams are quicker, fewer people need sedation
or pain medicine to lie still, says Lewin.
Open MRIs Ease Claustrophobia
Other modifications are helping too. For many people, MRIs have
traditionally been an unpleasant experience. In standard MRI exams, a person
slides into a narrow tube and has to stay there for the length of the exam.
People with claustrophobia can find it unbearable.
"It can feel like being in a coffin," says Lewin.
There have been "open MR" imagers for years. They are not enclosed
on the sides and are less restrictive. But experts also say they may be less
"In the past, there were trade-offs between the openness of an MRI and
the image quality," says Hillman. "But we're seeing the gaps being
New MRI machines are available that are just as accurate as traditional
ones, but much shorter, so that they never fully enclose the person.
Another problem with some older imaging devices is that they couldn't
accommodate heavy people. That has been at least partially resolved.
"With new machines, we can give exams to people who are 350-400
pounds," says Hillman. But he says that because of image degradation,
imaging tests for the obese are often less accurate in general than for people
of average weight.
Using Imaging for Routine Screening -- the Pros and Cons
A topic that's spurred interest -- and debate -- is screening apparently
healthy people for cancer, heart disease, and other problems. Sophisticated
imaging tests can sometimes detect disease in very early stages, long before a
person shows any other symptoms.
So given the obvious benefits, why isn't everyone in America being screened?
It turns out that there are some real drawbacks to routine screening.
First of all, imaging has risks. Many tests involve exposure to small
amounts of radiation or radioactive material. While the odds that this could
cause harm are low, they still exist, says Eversman.
The other problem is that screening can detect abnormalities that don't
actually need any treatment. But once the doctor sees them, further tests must
be ordered to make sure that these abnormalities are harmless. So people may
need a number of tests or even surgery -- and suffer a lot of anxiety - only to
discover that they didn't need treatment!