Recent advances in imaging technology – like CT scans, MRIs, PET scans, and other techniques — have had a huge impact on the diagnosis and treatment of disease.
Advances in imaging over the last five years have revolutionized almost every aspect of medicine.
More detailed imaging is allowing doctors to see things in new ways. Imaging can provide early and more accurate diagnoses. In some cases, it might even lead to better and more successful treatment.
Just about every field of medicine is using imaging more than they used to. I’m not saying that the physical exam is a dying art. But doctors are coming to see just how valuable and accurate these tests can be
Four Big Advances in Imaging
There have been many improvements to imaging technology in recent years. Here are a few that experts singled out as especially significant.
Computed Tomography (CT) Angiography:
It is one of the greatest advances in imaging
Just a few years ago, an angiography could only be done by inserting a
catheter into an artery. In the procedure, contrast material is injected through
the catheter. 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
In a CT angiography, the doctor just injects the contrast material into the arm
and takes a CT scan. 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.
Imaging Tests Instead of Exploratory Surgery
One of the biggest changes in the use of imaging 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. 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/CT Scans for Cancer
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. But for years no one was
sure just what to do with it
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.
PET/CT scans give a doctor a broader view of a person’s condition.
By fusing PET and CT, 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
Digital mammography for breast cancer screening is a significant leap
forward. 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.
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.
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 easier.
For one thing, they are a lot faster.
The full length of an exam varies depending on the person and the type of imaging. But MRI 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.
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.
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 accurate.
In the past, there were trade-offs between the openness of an MRI and the image quality. But we’re seeing the gaps being narrowed.
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. But 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
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!
There are a lot of nonspecific abnormalities. For instance, an enormous number of people have nodules in their chests. But only a fraction of them actually turn out to be cancer. Universal screening could lead to a lot of unnecessary and risky tests and procedures.
Even in apparently healthy people who really do have a disease, screening may not always help. Catching the disease early and stopping it would be great. But lots of times, that doesn’t happen. You find the disease earlier, you treat it earlier, but the outcome is the same and the person dies anyway. Early detection helps many people, of course. But it doesn’t always make a difference. For those who aren’t helped, it leads to tests, treatments, and intense distress much earlier than someone who wasn’t screened.
Smarter Use of Imaging for Screening
As for now, no one recommends routine high-tech screening for everyone. The American College of Radiology does not endorse whole body screening of healthy people. It probably shouldn’t be done, since there’s no proof that it saves lives or even improves them.
I think it’s fair to say that at this point, the only cancer screening that we know to work in reducing the death rate is mammography. Everything else is undergoing testing or completely unproven.
But experts are trying to figure out how to use screening as a tool for people at higher risk of certain diseases. As imaging exams become safer and more accurate, the pros of screening may outweigh the cons. As MR screening continues to improve, and as we lower the dose of radiation with CT, routine screening will make sense for a bigger and bigger proportion of people.
Imaging Moved Into the Operating Room
Soon, imaging tests may not only be used to diagnose disease. They may also become a key part of some medical procedures. During minimally invasive surgery, imaging will allow surgeons to see inside the body better, to improve treatment and minimize complications.
Minimally invasive surgery and new imaging technologies are developing hand in hand. MRI in particular but also other technologies, like ultrasound — may have the ability to monitor a surgery in real time. They could potentially detect when all of a tumor was removed, or when a surgeon was accidentally beginning to harm normal tissue.
Using MRI during brain surgery is already helping. The studies are still being done. But I’ve seen that combining the surgeon’s eyes with MR improves the operation. Because the human eye, even with a microscope, just can’t see what an MR can see.
CT scans are starting to be used to create computer-generated models of the heart for use during surgery. During the operation, the 3D model is shown on a screen, and it moves and rotates to show where the surgeon currently is in the heart. It’s a great innovation. Experts say that imaging will become even more detailed and focused in the future.
In the next 20 years, imaging technology is going to focus on the molecular and cellular levels. Instead of only seeing the gross anatomy like we do now, we’re going to be looking at metabolism and physiology. PET scanning is the first step in this direction.
In general, imaging technology is certain to become faster and more accurate. More combination devices like the CT/PET scan are inevitable.
There are some prototype PET/MR scanners now and people are talking about CT/MR scanners.
Fusing different imaging techniques will allow doctors to get a much fuller understanding of a person’s condition.
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