Center to Advance Imaging Technology
MADISON – The Wisconsin researcher who created the “gold standard” for medical imaging of blood vessels will lead a new center to tackle the next generation of imaging: taking sharper, cleaner, four-dimensional pictures hundreds of times faster than is possible now.
Charles Mistretta, the John Cameron Professor of Medical Physics at the UW School of Medicine and Public Health,
will direct the International Center for Accelerated Medical Imaging to advance and disseminate the groundbreaking medical imaging technology he and his colleagues have developed over the past several years.
Based on concepts that are radically different from the ones that have governed medical imaging for the past several decades, the technology is yielding greatly improved views of the heart, brain, blood vessels, breast and joints.
The new center will bring together researchers from around the world to expand the new technology. Some 70 UW medical physicists will form the center of the effort.
Focused originally on magnetic resonance (MR) imaging, the technology appears to be applicable to all other imaging techniques as well - including X-ray, CT, PET and ultrasound.
“When we recognized how generalized this technology could be, we wanted to get the best minds in the world together to share ideas about it and move the science forward,” Mistretta says.
In addition to continuing their own studies, center scientists will make the technology available to all qualified research groups and will participate in training interested individuals through visits, symposia and a Web site.
No stranger to scientific breakthroughs, Mistretta was responsible for digital subtraction angiography (DSA), a computerized imaging technique that today is used in almost every radiology department in the country for cardiac and blood vessel imaging. The DSA patent is among the top three earners of all patents issued by the Wisconsin Alumni Research Foundation, or WARF.
To make the best diagnoses, physicians rely on medical images that reveal as much information as possible in as short a time as possible. The new technology, which combines two developments stemming from Mistretta’s labs, produces superior, four-dimensional images much faster than in the past.
The first development entails collecting information in a new way with a technique called “vastly under-sampled isotropic projection reconstruction” (VIPR). With VIPR, three-dimensional anatomical data is acquired in a series of radial lines that all pass through a central targeted spot in a theoretical place physicists call K-space.
Conventional MR scanners, on the other hand, acquire two-dimensional data in parallel lines on a rectangular grid, often missing the center of K-space. The conventional method also takes much more time than VIPR.
The second development involves a technique called “highly constrained back projection” (HYPR), which, according to Mistretta, reconstructs the acquired data into diagnostically relevant renderings of organs, bone, vessels and disease in a novel way.
Essentially, HYPR exploits the correlations in a series of medical images to produce a new series that is remarkably clean and clear.
The UW researchers are finding additional advantages in the technology at every turn. They’ve discovered that they don’t need to inject a contrast medium when they combine VIPR with a process called phase contrast, which measures blood velocity. And when used in dynamic CT scanning, the VIPR-HYPR combination reduces patients’ radiation exposure five- to 10-fold.
Recently, the scientists also reported in the journal Radiology that, when used in an animal model, the noninvasive dual techniques can accurately measure the degree of stenosis, or artery blockage, caused by atherosclerosis. An accompanying editorial in the journal said the technology has the potential to be a “major advance in the diagnosis and management of vascular diseases…”
Concludes Mistretta, “I think there’s going to be a real revolution in medical imaging.”
The center will be housed in the first tower of the Interdisciplinary Research Complex, scheduled for completion next spring.
Date Published: 12/28/2007