Authors' objectives:

This report is a systematic review of literature on positron emission tomography (PET) imaging using the radionuclide 2-[18F]fluoro-2-deoxy-D-glucose (FDG) for the indication of epilepsy.

Authors' results and conclusions: Safety: PET is a noninvasive and safe diagnostic procedure. Safety issues are primarily discussed in terms of the safety of the positron-emitting radiopharmaceutical, rather than the safety of the procedure as a whole. In a large study of 22 FDG PET centres in the United States, no adverse reactions to positron-emitting radiopharmaceuticals were reported retrospectively for 33,925 doses of positron-emitting radiopharmaceuticals from before 1994 and for 47,876 prospective doses from 1994 to 1997. The United States Pharmacopoeia drug information for FDG also indicates that there are no known adverse effects associated with the use of FDG. In addition, radiotracers are generally used in microgram quantities, and as such the incidence of adverse reactions to very small amounts of labelled molecules is likely to continue to be low. Patients undergoing a PET scan will be exposed to a certain amount of ionisin radiation. It has been estimated that the radiation dose in a patient undergoing a FDG-PET scan is on par with that received during a diagnostic CT scan. Effectiveness: There is no evidence from controlled trials about the effectiveness of PET in patients for whom EEG and MRI results are insufficient to proceed to surgery. Evidence from case series suggests that PET provides localisation information in some patients (median 70%, range 39-100%), and that some patients (median 67%, range 29-100%) have good postsurgical outcomes after having a PET scan in their presurgical workup (Level IV evidence). The accuracy of PET in this patient group cannot be estimated due to problems in defining a reference standard. A single study (Level IV) investigating the impact of PET on clinical management suggests that PET is promising in this regard. Any conclusions made by linking the evidence of extra localisation data provided by PET to improved surgical outcomes assume firstly that the efficacy of surgery is equivalent in patients with structural and functional foci, and secondly that PET results in altered management. If, based on current clinical expertise, these assumptions are judged to be reasonable, then it may be concluded that PET provides extra localisation information in some patients with medically refractory epilepsy, in whom MRI and EEG had not been able to localise a seizure focus, and that some of these patients will have good postsurgical seizure control outcomes. There is insufficient evidence to determine the size of this effect.

Authors' recommendations: In relation to positron emission tomography prior to surgery in patients with refractory epilepsy, where there is no focus with concordant results on usual structural imaging and electroencephalogram, this assessment finds the technology: - is safe; - provides additional localising information in some patients, for whom a proportion will have good post-surgical outcomes as a consequence; and - is likely to be cost-effective in the long term. MSAC recommends that public funding should be supported.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.msac.gov.au/pdfs/reports/msacref26.pdf

Year Published: 2004

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Australia

Organisation Name: Medical Services Advisory Committee

Contact Address: MSAC (MDP 107), GPO Box 9848, Canberra, ACT 2601, Australia. Tel: +61 2 6289 6811; Fax: +61 2 6289 8799.

Contact Name: msac.secretariat@health.gov.au

Contact Email: msac.secretariat@health.gov.au

Copyright: Medical Services Advisory Committee (MSAC)