Dual-imaging Technique Useful Before And During Brain Surgery

Neuroradiologist James Leach, MD, and his UC colleagues are among the first in the United States to combine functional magnetic resonance imaging (MRI) and "diffusion tensor tractography" data to outline important areas of brain function and their connections prior to surgery--and then transfer that data to the operating room to track those areas during actual surgery.

This approach, Leach says, has already been used in 20 cases at Cincinnati's University Hospital.

"Combining tractography and functional MRI intraoperatively has been in use clinically for only a few years," says Leach, associate professor of radiology at UC and a neuroradiologist with University Hospital, "but our preliminary data is very promising because it allows us to optimize surgical approaches to treating brain tumors to ultimately improve patient outcomes."

He says that combining standard visual, sound, and voice-based tests, whose results are measured by MRI, performed on a high-field-strength (3 Tesla) scanner, with a precise intraoperative guidance system will improve patients' post-operative speech, movement and memory, and also optimize quality of life for those with brain tumors and other neurological conditions.

To combine both functional MRI and diffusion tensor tractography images in the operating room, Leach and his colleagues use a high-tech surgical navigation system known as BrainLAB. The BrainLAB technology incorporates functional MRI data to identify brain areas linked to speech, movement and vision, and diffusion tensor imaging data to map critical "white-matter tracts"--the electrical connections between different parts of the brain that should be avoided during surgery.

Leach says the detailed, easy-to-understand images produced from functional MRI data also help patients understand what is happening in their head and how the surgery will be conducted.

"We can essentially show patients a color-coded picture of their brain and explain to them where their tumor is in relation to areas that control critical functions like expressive speech, movement and vision," says Leach. "This can help alleviate the patient's apprehension and help explain what will happen during surgery."

Although researchers expect this dual-imaging technique to become standard practice across the United States in the next five years, there are still limitations. For example, explains Leach, patients with limited vision may not demonstrate as much activity in the brain in areas linked to vision during functional MRI testing.

"That doesn't necessarily mean that there's no function there--it may just be that functional MRI is not sensitive enough to detect it," says Leach.

Collaborators in this study include UC and Neuroscience Institute colleagues Christopher McPherson, MD, Ronald Warnick, MD, Raj Narayan, MD, and John Tew, MD.

Leach will present this preliminary research in a special scientific exhibit at the American Society of Neuroradiology's annual meeting, June 9--13 in Chicago.