Report from ISMRM: Zerhouni defines terms for future of medical imaging

As the first radiologist to serve as director of the National Institutes of Health, Dr. Elias Zerhouni envisions a central role for medical imaging in 21st century medical research and practice.

Past is prologue to imaging's role as a research instrument, Zerhouni said Monday in his Mansfield Lecture at the 2006 International Society for Magnetic Resonance in Medicine meeting in Seattle. Imaging innovation has always begun with discovery of a basic physical process such as x-rays, ultrasound, or magnetic resonance. That fundamental process is first used to display anatomy and structure.

Biological knowledge is then used to apply the discovery in new ways. Use of a contrast media and development of angiography or diffusion tensor imaging are examples of this next step. The methods applied to the study of function ultimately lead to advanced applications: the study of cardiac mechanics, renal perfusion, brain activation patterns, or cellular metabolism.

Zerhouni emphasized that breakthroughs that have transformed medicine use discoveries made at the juncture of scientific disciplines. The application of computers to imaging revolutionized the discipline. Real-time cine allowed cardiac imaging to progress, and television adopted for x-ray technology led to interventional radiology, he said.

"It is important to understand this cycle," Zerhouni said. "Today, biology is again driving new research, be it genomics or proteomics or targeted agents."

He defined imaging as the science of extracting spatially and temporally resolved information.

"Imaging is no longer simply a method for creating images. Imaging in this general sense is a method of extracting information for all physical scales from single molecules to the full organ," he said.

To a large extent, imaging science is currently inspired by discoveries in genomics and cellular biology, while helping propel such research in practical directions. Zerhouni looks to imaging to winnow out thousands of potential biomarkers for disease and find those targets with the greatest relevance for risk assessment, diagnosis, and therapy monitoring.

With healthcare costs now consuming nearly 18% of gross domestic product, this knowledge must be used to short-circuit diseases, especially increasingly prevalent chronic conditions such as dementia and diabetes, before their symptoms produce substantial morbidity and cost, according to Zerhouni.

"In this century, we will have to intervene before the damage is done. We need to preserve normal function, and our ability to detect patients at risk is increasing remarkably," he said.

Future medicine will be more predictive, more personalized, and preemptive because physicians will be able to identify the molecular signatures of diseases and the individuals who are genetically predisposed to them. Recent studies have found that 16 genes are most relevant to the recurrence of Her-2 breast cancer, for example. The findings promise to eliminate the need for chemotherapy for the majority of patients whose genetic makeup indicates recurrence is unlikely.

Zerhouni predicted growth for image-guided therapies and the use of quantitation in medical imaging, which will become more targeted and precise and less destructive.

He sees a huge role for imaging in genotype/phenotype correlations and in defining biomarkers. Image processing and computer-assisted technologies will help radiologists make sense out of complex biochemical interactions. In vivo molecular imaging represents radiology's clinical frontier, he said.

Zerhouni recalled that radiology was not a popular field when he became a radiologist in 1973. During his career, he has seen radiology move to the forefront of medicine, a trend he expects to continue.

"Imaging will be central to the transformation of biology and medicine in the 21st century," he said.

For more information from the Diagnostic Imaging archives:

National Press Club briefing plots future of diagnostic imaging

Radiology plays prominent role in NIH road map

Residency reforms foster radiology science careers

NIH chief foresees critical need for MSK radiologists