Preoperative brain mapping alters tumor surgery

By pinpointing the motor and language areas of the brain with functional MRI, surgeons can target brain tumors more effectively, while reducing the risk of damaging important cognitive and motor processes, according to a study in the September issue of Radiology.

Half of the patients with brain tumors who were enrolled in an fMRI study at Duke University Medical Center had their treatment strategies altered after these critical brain regions were identified prior to surgery.

"In patients who underwent fMRI, neurosurgeons estimated that more tumor was removed at surgery, operations were shorter, and skull incisions were smaller compared with what they would have been if the fMRI data were not available," said Dr. Jeffrey R. Petrella, an associate professor of radiology in the neuroradiology division at Duke.

Petrella and colleagues evaluated with fMRI 39 patients diagnosed with potentially operable brain tumors. During the imaging exam, they performed sentence completion tasks to map areas of the brain involved in language function and hand-squeezing tasks to detect sensory motor areas. The entire procedure, including the time it took to train patients and acquire the images, took less than one hour.

The neurosurgeons who referred the patients for fMRI were given questionnaires to answer before and after fMRI to determine what effects, if any, the fMRI results had on their treatment plan. Surgeons also completed a postoperative questionnaire to confirm whether the post-fMRI plan was followed and to determine if fMRI findings affected surgical approach, amount of time spent in surgery, and surgical extent.

The researchers found that in 19 of 39 patients (49%), the surgeons significantly changed their treatment plans after receiving the fMRI findings. Eighteen of the 19 patients underwent more aggressive approaches than originally planned.

The fMRI findings also helped decrease surgical time by an estimated 15 to 60 minutes in 22 patients. In six patients who had surgery, the neurosurgeon specifically commented that knowledge of the fMRI results enabled a more complete resection than otherwise would have been achieved.

No neurological deficits were documented in any patients after undergoing surgical tumor removal.

Patients who may have previously been deemed ineligible for surgery based on tumor location may be able to undergo surgery safely, due to the valuable information available with fMRI, Petrella said.

"This is a pilot study," he said. "To establish whether fMRI can become a new standard of care, the next step is to assess whether patient outcomes are actually improved in a large multicenter trial with a control group."

The Centers for Medicare and Medicaid Services has recently approved reimbursement for fMRI services, effective Jan. 1, 2007.

For more information from the Diagnostic Imaging archives:

Scorpion venom eases sting of brain tumors

Functional MRI helps brain tumor treatment

Manipulating brain's protective barricade can help researchers

Focused ultrasound ablation goes after brain tumors