A systematic approach to Interictal FDG PET done in the Evaluation for Epilepsy

Introduction: Around one third of patients with epilepsy are unresponsive to treatment with antiepileptic drugs and may be candidates for surgical treatment. More recently, there have been studies indicating early surgical treatment may be more beneficial in selected patients without drug resistance. However, only appropriately selected patients can be considered for this intervention, which is why clinicians should be capable of performing a thorough evaluation of each patient for appropriate counseling and decision making. Recent medical advances have made multiple methods available as presurgical steps including MRI, fMRI, SPECT, FDG PET and intracranial electroencephalograph to evaluate each case and improve evaluation of surgical efficacy and potential risks. Interictal FDG PET is a crucial method for decision making and medical management, which becomes even more important in patients with normal or equivocal MRI. Currently, there is limited literature guidance on how to approach the interpretation of FDG brain PET done in the evaluation of seizure in an accessible, and digestible format. Therefore, our purpose with this exhibit is to provide imaging interpreters with a case-based, systematic approach to the interpretation of interictal FDG PET done in the evaluation for intractable focal epilepsy syndrome.

Methods: This educational presentation will provide a literature-guided checklist to use before image acquisition and during imaging processing and review. We include interpretation pearls provided by several of the authors who are dual fellowship trained in nuclear imaging and neuroradiology with a combined experience of 28 years interpreting these types of exams. This presentation will pair this checklist with salient statistical information taken from relevant research to improve interpretations based on pretest probabilities. In the conclusion of the presentation, the reader will be provided with important post imaging considerations that may further help the interpreting physician and the clinical team to decide on next steps.

Results: This exhibit will provide a case-based systematic approach for interpretation of interictal FDG PET that includes pre-imaging checkpoints and imaging setup recommendations to ensure better image quality; review of age-based normal imaging appearance; imaging interpretation checklist with anatomic and clinical guidance as well as post-imaging considerations for problem-solving when needed.

Conclusions: By combining a better data driven understanding of lesion incidence and creating consistency in a search pattern, we can allow a more comprehensive approach to each case, improve lesion identification, and deliver valuable information that could affect medical management.