Four Big Advances in Imaging Technology
There have been many improvements to imaging technology
in recent years. Here are a few that experts singled out as especially
significant. While these are becoming more common, keep in mind that the newest
technology may not be available yet at your local hospital.
"CT
angiography is one of the greatest advances in imaging," says Lewin.
Just a
few years ago, an angiography -- an examination of the blood vessels -- could
only be done by inserting a catheter into an artery. In the procedure, contrast
material -- a substance that makes it easier to see tissue in an X-ray -- is
injected through the catheter. Then an X-ray is taken of the area to look for
blockages, internal bleeding, or
other problems. Catheter angiography can take up to several hours. It often
requires sedatives and sometimes a night in the hospital. It also has risks,
like a small chance of blood clots or
bleeding.
"The
newest CT scans allow a completely noninvasive way to get the same information
as an invasive catheter angiography," says Lewin.
In a CT
angiography, the doctor just injects the contrast material into the arm and
takes a CT scan. The arteries in the lungs, kidneys, brain and legs can then be examined.
The whole process takes just 10-25 minutes. It's safer, faster, and cheaper
than the traditional way.
CT
angiography hasn't completely replaced the old technique. For example,
traditional angiography is still commonly used to evaluate heart arteries for blockages.
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Imaging
Tests Instead of Exploratory Surgery
One of
the biggest changes in the use of imaging, says Hillman, is that it has largely
replaced exploratory surgery.
"In
the past, we had to do surgery just to see what was going on inside the
body," says Hillman. "But CT scans, MR scans, and ultrasound have
become so good that they have largely done away with the need for the surgical
approach."
PET (positron emission tomography)
scanning is not new. But it has become increasingly important in recent years,
particularly since it was combined with CT scanning in one device.
"PET
scanning has been around for a long time," says Hillman, who is also a
professor of radiology at the University of Virginia. "But for years no
one was sure just what to do with it."
PET
scans are a type of "nuclear medicine." The name is unnerving. But
"nuclear" refers to the small dose of radioactive material that you
are injected with before the test. The amount of radiation exposure is
similar to what you would get from a standard X-ray.
Unlike
many other imaging technologies, PET scans aren't designed to look at organs or
tissue. Instead, they can image biological functions, like blood flow or glucose metabolism. "PET is
able to pick up the metabolic changes associated with cancer much earlier
than you could see tumors or other physical changes in the organs," says
Lewin.
PET/CT
scans give a doctor a broader view of a person's condition.
"By
fusing PET and CT," says Lewin, "you get to see both the metabolic
information of PET and the anatomic detail of CT at once. It's a big
advance."
"Digital mammography for breast cancer screening is a
significant leap forward," says Lewin. "It gives us a much higher
level of detail than older technology."
Digital mammograms produce
similar results to traditional mammograms, which use X-rays and film. But the
digital approach has several advantages. Bruce J. Hillman, MD, chairman of the
American College of Radiology Imaging Network, notes that digital mammograms
are easier and faster to perform. And since they are digital, it's very easy
for a doctor to send the images instantly to other experts or medical centers.
Early
studies showed that digital mammography worked as well as traditional
mammography in detecting breast cancer. A 2005
study published in The New England Journal of Medicine found
digital mammography was actually more accurate for some women.
This includes women who were under 50, women with dense breast tissue,
premenopausal women, and women who were around the age of menopause.
