That leaves patients with a tricky choice. Do they wait and watch? Let doctors take a brain biopsy? Or, in some cases, endure another brutal round of treatment just in case the tumor has returned?
But a new University of Michigan study shows that a relatively new kind of brain scan may give these patients the reassurance -- or early warning -- that they can't get from the usual scans. U-M radiologists will present the evidence today at the annual meeting of the American Roentgen Ray Society, a major radiology organization.
The approach is called 2D CSI MRS, short for two-dimensional chemical shift imaging magnetic resonance spectroscopy. It allows doctors to non-invasively detect the levels of certain chemicals in brain tissue. Using the relative quantities of these chemicals, doctors can tell what's really going on near a tumor's original location.
The U-M Health System neuroradiology team will show that they have successfully developed a way to use the technique so that, in the vast majority of cases, they can tell the difference between recurring tumor, normal tissue, and tissue that's inflamed or dying because of successful treatment.
"Using 2D CSI is like making a chemical thumbprint of the tumor and the surrounding tissue, and we can use the unique readings from various areas to determine what's cancerous, and what's treatment-related change," says Patrick Weybright, M.D., the U-M radiology resident who will present the results. "This allows us to give the patient earlier and more accurate information on what's happening in their brain at a molecular level."