The limited information identified does not appear to support the use of PET alone in the evaluation of epilepsy before surgery and did not indicate a significant association of PET with favorable outcomes after surgery. One HTA in 2006 concluded that effectiveness of PET in the preoperative evaluation of epilepsy surgery is inconclusive due to limitations of the included studies. Another HTA of the same year stated that PET may provide extra localization information in patients whose MRI or EEG results failed to localize a seizure focus. The identified systematic review also found that PET did not add any additional value in patients with their seizure focus localized by MRI or EEG. Results from the identified observational studies suggest that the combination use of PET and other imaging modalities such as MRI or SPECT during preoperative evaluation increases the likelihood of localization and yields favorable outcomes after surgery, especially when MRI or EEG results are normal. The American College of Radiology guidelines have rated their recommendations for the use of PET in the preoperational evaluation of different variants of epilepsy in both adult and pediatric patients. The Australian guidelines recommended that PET for the indication of epilepsy should be supported by public funding, based on level IV evidence. One study showed that FDG-PET had an impact on changing clinical management in patients considered for epilepsy surgery.