Medical imaging's powers of detection are expanding

Washington -- Medical imaging has come a long way during the last 30 years, said National Institutes of Health Director Elias Zerhouni, MD. The field was considered a backwater of medicine when Dr. Zerhouni got his start in radiology, and now imaging techniques are rated among the most important recent medical advances.

In the next 25 years, imaging will continue to play a large role at NIH, Dr. Zerhouni said at a Jan. 31 educational briefing in Washington, D.C. For instance, advances in x-ray, ultrasound, magnetic resonance and radionuclide imaging likely will enable physicians to detect disease at its earliest stages, before it even becomes evident, he said.

The briefing was sponsored by the National Electrical Manufacturers Assn., a trade group responsible for setting industry standards; the Academy of Radiology Research, an advocacy group based in Washington, D.C.; and Research!America, a group based in Alexandria, Va., that promotes medical and health research.

Imaging has legions of fans. Its ability to detect smaller and smaller tumors has changed the standard of breast cancer treatment from radical to minimally invasive. Exploratory surgery has given way to powerful scans that enable physicians to evaluate disease progress without wielding a scalpel.

But there is still a way to go. While mammograms are advancing breast cancer treatment, there are as yet no comparable "manograms" to advance prostate cancer's diagnosis and treatment, notes a statement from the AdMeTech Foundation, a nonprofit Boston-based group of academicians and members of industry that promotes the uses of medical imaging.

The questionable value of current techniques to diagnose prostate cancer are all too apparent, said AdMeTech CEO Faina Shtern, MD, in a separate interview. The foundation is now trying to generate interest among the "best and the brightest" in academia and industry in applying advances in imaging techniques to prostate cancer, Dr. Shtern said.

There is some work currently under way at the National Cancer Institute in this area, said Roderic Pettigrew, MD, PhD, director of the National Institute of Biomedical Imaging and Bioengineering, speaking at the briefing. Peter Choyke, MD, director of NCI's molecular imaging program, is evaluating the use of high-resolution MRIs to guide prostate cancer treatment, Dr. Pettigrew said.

But imaging also is viewed by some as a potential troublemaker. For example, the recent increase in availability of full-body CT scans has resulted in many false alarms for patients when problem sites uncovered in the scans turned out to be harmless. The cost of the scans as well as the harm that could be caused by follow-up procedures sparked concern.

The response should be to continue to develop more sensitive scans that can determine accurately whether a problem is serious and worthy of further exploration or not, said Sanford Simon, PhD, professor and head of the laboratory of cellular biophysics at Rockefeller University in New York City. He spoke at the briefing.

Systems on the move

Medical imaging also is poised to unravel the complexities of unpredictable biological systems, Dr. Zerhouni said. On the molecular level, enzyme action can be studied; on the cellular level, cell traffic can be monitored; and in tissues, changes can be charted over time, he said.

Cell secretion of insulin or growth hormones also can be examined via imaging, Dr. Simon said. Researchers now can observe tumor cells as they metastasize in mice. "There are certain things you can't understand with static images," he said.

Physicians in the 21st century will be asked to intervene before disease symptoms appear, and they will be asked to do it noninvasively, Dr. Zerhouni predicted. The future will stand in sharp contrast to the 20th century, when physicians waited for disease to appear before acting, he said.

Imaging provides a noninvasive alternative to traditional biopsy as well as a method for monitoring patient response to treatments, noted James Thrall, MD, radiologist-in-chief at Massachusetts General Hospital. "When I was a student 36 years ago, there was always exploratory surgery." The advent of new energy sources, devices, software, contrast agents and molecular probes now provide a safer and more accurate alternative to surgery, he said.

The majority of Americans are in favor of continuing such advances, even if it hits them in the pocketbook, according to a national poll released at the briefing by Research!America. The telephone survey of 800 adults revealed that 77% think the United States should spend more for prevention and public health research than the current one cent out of every health dollar.

In addition, 58% believed that more should be spent on medical and health research than the current six cents of every health dollar. Sixty-three percent responded that they were willing to pay $1 more per week in taxes for additional medical research, and 57% were willing to pay $1 more for each prescription drug to support additional medical research.