Chemical Brain Scan May Help Diagnose Recurrence

Brain tumor survivors live with the constant worry that their cancer might come back. And even if they have a brain scan every few months to check doctors often can't tell the difference between new cancer growth and tissue changes related to their treatment with radiation or chemotherapy.

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?

Now a research team led by Dr. Patrick Weybright of the University of Michigan shows that a relatively new kind of brain scan may give these patients the reassurance or early warning that they can't get from conventional scans. The radiologists-researchers presented the study results 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.

Weybright showed results from 29 patients ages four years to 54 years who were split almost evenly between those whose cancer had returned and those with no recurrence. In addition to the biopsy or surgery that verified their status nearly all of them had the 2D CSI type of scan also called a multi-voxel scan. One had a less sophisticated single-voxel chemical scan. All the patients also had conventional diagnostic imaging with MRI scans to show brain tissue and tumor structure.

The research team successfully showed that in the vast majority of cases they were able to tell the difference between recurring tumor normal tissue and tissue that's inflamed or dying because of successful treatment.

The U-M researchers are looking forward to the arrival of advanced three-Tesla MRI scanners that will increase their ability to look for more chemicals on the 2D CSI scans and allow them to do three-dimensional scans that will increase accuracy even more.

At the same time they hope their results will help physicians and insurance companies see the true clinical value of 2D CSI MRS which is still not universally covered by health plans in an amount sufficient to cover the time needed to read the scans.