Researchers and clinicians join forces to bring new imaging capabilities to cancer diagnosis and treatment
For several decades, magnetic resonance imaging (MRI) has given cancer researchers and physicians a sensitive tool to help track down tumors.
“Standard MRI provides great anatomic information about soft-tissue structure and distribution, which is critical in detecting brain and body cancers. You can see things you can’t with X-rays or CAT scans, like the difference between tumor and fatty tissue,” says Greg Metzger, Ph.D., a University of Minnesota imaging expert who specializes in using MR technology to study prostate cancer. MRI also produces images with harmless radiofrequency waves and powerful magnets rather than the radiation used by X-rays and CT scans, he says.
Still, University scientists believe there is room for improvement. Despite its benefits, MRI is an expensive test and hasn’t been practical for widespread application in certain areas of medicine—for instance, in cancer screening.
Now University physicians are working closely with research colleagues at the Center for Magnetic Resonance Research (CMRR) to push the capabilities of MRI and explore new ways it could be used in cancer detection, diagnosis, and therapy.
“The goal,” says Metzger, “is to bring those capabilities to patient management and treatment.”
Detecting breast cancer earlier
MRI is proving to be tremendously versatile. “We’re still learning everything it’s capable of,” says Michael Garwood, Ph.D., associate director of the CMRR.
By manipulating the pulse of radiofrequency waves and altering computer algorithms that process images, researchers can investigate several aspects of the same tissue—showing not only the location of a tumor, but also the chemical composition of malignant cells or blood vessels that have sprung up to help the tumor grow. Such information helps doctors characterize the mass, which in turn may allow them to catch cancers early and recommend treatment plans.
MRI turns out to be better than mammography, for example, at detecting breast tumors at an early stage while they are small, Garwood says. This makes the technique an excellent screening tool for women at the highest risk of developing breast cancer.
MRI also can help determine whether a suspicious mass is invasive cancer. With the help of an injection of contrast dye, MRI can reveal “leaky” blood vessels, characteristic of the type that feed malignancies.
“This technique can also give us information about the margins of a tumor, which may help guide a surgeon in removing it,” Garwood says.
MRI may soon be used to determine whether a woman is benefiting from chemotherapy as well.
Douglas Yee, M.D., director of the Masonic Cancer Center, and CMRR researcher Patrick Bolan, Ph.D., have studied the ability of MR technology to measure the chemical choline, a “fingerprint” of tumor cells. With a technique called spectroscopy, they can detect a drop in choline levels after a woman undergoes a single day of chemotherapy. They’re now determining whether the technique can be applied in medical centers to steer breast cancer treatment.
Guiding prostate cancer biopsies
When it comes to prostate cancer, MRI offers a unique view of difficult-to-access tissue. And now, as University professor Timothy Wilt, M.D., M.P.H., found in a recent study that surgery offered no better outcomes than active surveillance (otherwise known as “watchful waiting”) for men with nonaggressive prostate cancers, determining who benefits most from each approach is even more critical.
The CMRR’s Metzger is working with urologic surgeon Christopher Warlick, M.D., Ph.D., to study cancerous tissue from men who have undergone prostate surgery to identify the extent and aggressiveness of their tumors.
Warlick is optimistic about the latest application for MRI to help biopsy the prostate. After a standard MRI scan detects a suspicious area in the gland, an MRI-guided needle can take samples from specific locations.
“We now have the opportunity to home in on the very worst-appearing lesions, likely leading to more accurate grading of the disease and more informed treatment decisions,” Warlick says. “This may be very important for men considering active surveillance for their prostate cancer.”
Improving the patient experience
As science points to new benefits of MR technology, the latest CMRR developments may make the scanning process better for patients.
Garwood was playing with his computer at home when he had a physics epiphany: he realized it’s possible to condense a two-stage process (creating a radiofrequency wave and then capturing an image) into one step. The condensed MRI technique he developed, called SWIFT, was patented by the University of Minnesota and licensed exclusively by GE Healthcare last April.
SWIFT images are captured more quickly and make it possible to see more subtle contrasts in soft tissue, and, for the first time, hard tissue like bone and teeth.
The new SWIFT-based scanners, which could go into production in the next year or so, may cut down the time patients need to spend in the scanning machine, Garwood says. Better yet, SWIFT doesn’t make the loud banging noise of traditional MRI machines.
“Mike is really paying attention to the clinical issues,” says Yee.
And that’s an increasingly good thing, as these advanced technologies continue to become more useful in the clinic.
“I believe MRI will become even more indispensable in diagnosis and monitoring of patients as time goes by,” Garwood says.