fMRI Reduces Epilepsy Testing

Santiago Medina, M.D., M.P.H., co-director of neuroradiology, director of the Health Outcomes, Policy and Economics Center at Miami Children's Hospital (FL, USA), and lead author of the study. "This imaging technology is a powerful tool that improves surgical decision making in patients being considered for seizure surgery.”

The study assessed the effect of fMRI on the diagnostic screening and treatment planning of 60 consecutive seizure disorder patients, including 27 female and 33 male patients. The results of this study helped five patients avoid further surgical procedures and changed the extent of surgery on four other patients. The study was published in the July 2005 issue of the journal Radiology.

A seizure is a noticeable symptom of a defect in the brain's electrical activity. Seizures that happen more than once without special cause are called seizure disorder or epilepsy. According to the Epilepsy Foundation of America, 2.5 million Americans have been diagnosed with epilepsy. Brain surgery has been shown to be a successful treatment for patients with seizure disorders who do not respond to medication. The surgical treatment involves resecting brain tissue that contains a seizure focus--the area in the brain where the seizures begin. Before resection surgery is done, the treatment team utilizes diagnostic tests to help determine the proximity of a seizure focus to crucial areas of brain function and to provide a map of the region.

The Wada test and electrical cortical mapping--both invasive, expensive tests that require large medical teams--were until recently the only methods for detecting these critical areas. fMRI is capable of identifying the location of critical brain functions that could be affected by the region of the seizure focus. Based on these fMRI findings, five patients in this study avoided a two-stage surgery with extraoperative direct electrical stimulation mapping and instead received a one-stage resection surgical procedure. The degree of surgical resection was changed in another four patients, because fMR images located vital areas of the brain close to the seizure focus.

Based on fMRI results, the team changed patient and family counseling in 58% of patients, intraoperative mapping was altered in 52% of patients, overall surgical plans were changed in 42% of patients, and 63% of patients were able to avoid additional studies, including the Wada test. "When the medical team reviewed functional MR images of the brain, they significantly changed the patient's diagnostic and treatment plans,” said neurologist Byron Bernal, M.D., co-author of the study. "With fMRI, the physician, patient, and family have more information about important critical areas of brain function, helping them make more informed decisions.”

Out of the study's 60 patients, 32 were not candidates for surgery or did not want surgical treatment. Of the 28 patients who proceeded with surgery, 17 were seizure-free following the resection, and eight had a 50-90% reduction in seizures. Three of the surgical patients experienced less than a 50% reduction in seizures at six-month follow-up.




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