Imaging Way to Keep the Doctor Away

New diagnostic machines showcased at a global medical conference in Chicago are going to rewrite the future of medicine.


SOME IMAGING EQUIPMENT PRESENTED AT RSNA 2008: (From left) High-resolution MRI system; a 4-D imaging ultrasound system ; the 1000-slice CT scanner

If you ask any knowledgeable person to name an area of science or technology that is set to revolutionise medicine, you will probably get “genomics” as an answer. Not many would say that “medical imaging” is the future. But this seemingly mundane technology is rewriting medical diagnostics and treatment like never before.

In the public mind, medical imaging is synonymous with three technologies: x-ray, ultrasound and magnetic resonance imaging (MRI). While these three still remain the basis of most initial diagnostic investigations, medical imaging has gone far beyond these techniques.

Variations of these three basic technologies now provide images of unprecedented accuracy, while new methods like molecular imaging are taking imaging to uncharted territories. Imaging techniques can point out cancer cells early, map far-flung crevices of the brain and show blood vessels and the flow inside them.

“Genomics has got all the publicity, but imaging has really transformed medicine in the last decade or two,” stresses T.S. Sridhar, professor of molecular medicine at St John’s Hospital, Bangalore.

It is no accident that the largest medical conference in the world is in the field of imaging, and is organised by the Radiological Society of North America (RSNA). The conference in Chicago, held between November 30 and December 6, presented some cutting edge research and imaging equipment that provided a glimpse into the future. One could see, among other things, computed tomography (CT) scanners that could take up to 1000 images of a body part in no time, MRI machines that could compensate for movement of the heart and provide clear images, and molecular imaging equipment that map tumours and their activity with great accuracy.

More and more clinical investigations are going to depend on imaging to provide clues to health problems. Traditionally, an image of the body is taken when you investigate symptoms of some disorder, but this practice is going to change soon. “Molecular imaging can tell you about risks for many diseases well before symptoms appear,” says Jean Luc Vanderheyden, molecular imaging leader at GE Healthcare.

Imaging is a technology that is already transforming medicine every day, as evidenced by the research presented at the conference. Here are a few samples. Scientists presented a new technique called magnetoencephalography (MEG) that maps small magnetic fields associated with brain activity. Among other things, it was used by scientists at the Children’s Hospital in Philadelphia to study abnormalities in the brain of autistic children.

Scientists from the University of California in San Francisco showed how CT scans could probe two diseases at once: colorectal cancer and osteoporosis (brittle bone disease). A new variant of mammography, called positron emission mammography (PEM), can point out those cancers in the breast that neither conventional mammography nor MRI can identify.

Advances in imaging technology are now promising to rewrite healthcare in at least one major way: by detecting diseases early, at a stage when treatment is very effective. Traditionally, early detection of disease was not under the purview of medical imaging, and doctors advised an ultrasound or an MRI only when there was some symptom. There were two reasons for this practice. First, random screening of patients was expensive and impractical. And second, imaging technology had not advanced enough to detect diseases before symptoms appeared.

Now advances in fields such as genomics are providing us with clues about risk factors. We know about many genes that could increase the risk factor for diseases like cancer, Parkinson’s and Alzheimer’s. In developed countries, such high-risk people are already being screened regularly to check for the presence of the disease. And in recent years, imaging technology has advanced enough for radiologists to detect diseases in their early stages, sometimes well before other techniques can detect them. Which is why imaging companies like GE are campaigning to detect diseases early.

Take breast cancer. Regular screenings fail to detect all breast cancers, and sometimes there are false alarms. This is because the density of the breast needs to be high (with less fat than glandular and connective tissue) for MRIs. Hormonal changes that occur during a woman’s menstrual cycle also interfere with the technique. In addition to these gla-ring exceptions, mammogra phy routinely misses minute tumours.

PEM, on the other hand, can detect tumours even in less dense breasts and is also less dependent on hormonal cycles. Also, mammography is now advancing at such a rapid pace that it will soon be able to detect cancers that are barely visible to the naked eye. It seems medicine has finally mastered the art of detecting critical ailments early.

Sources: The Telegraph (Kolkata, India)

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