Magnetic resonance imaging has long been studied as a noninvasive tool for detecting breast tumors, and in fact, has nearly 100 percent sensitivity for detecting breast cancer. But the technology, which offers telling views of a tumor’s morphology, margins, and associated blood vessels, still can’t always discern whether the lump is benign or malignant.
A decade ago, some groups began looking at lumps using magnetic resonance spectroscopy, which can detect choline, a chemical that increases in the presence of a cancerous tumor. Then, in 1999, oncologist Douglas Yee, M.D., director of the Masonic Cancer Center, University of Minnesota, and Center for Magnetic Resonance Research (CMRR) associate director Michael Garwood, Ph.D., became curious about using MR spectroscopy from another angle: Could it be used to quantify the presence of choline and could the amount it revealed determine whether a therapy was working?
What the researchers found using a 4 Tesla research magnet was that spectroscopy could pinpoint the choline levels, says Patrick Bolan, Ph.D., who joined the project as a graduate student a decade ago and continues to advance this line of research as a CMRR faculty member today. Even further, their experiments determined, a tumor that was responding to an effective drug would show a drop in choline within a single day, and the technology was sensitive enough to detect the decrease.
That pilot study, published in 2004 in the journal Radiology, has led to a multicenter trial now under way using MR spectroscopy to get a glimpse of how tumors are responding to chemotherapy one day after it’s given. One long-term challenge will be whether the highly technical spectroscopy can be implemented with standard magnets for easy, widespread use in a clinical setting, but the potential benefits of the technology seem clear.
“If you can actually determine whether a drug works after a day, you can switch drugs or try new ones without exposing a patient to a long-term course [of chemotherapy]. There are no other tools like this one in oncology right now,” Bolan says. “It could have a very big impact.”